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Astronomers saw the Same Supernova Three Times Thanks to Gravitational Lensing. And in Twenty Years They Think They’ll see it one More Time

4 hours 5 min ago

It is hard for humans to wrap their heads around the fact that there are galaxies so far away that the light coming from them can be warped in a way that they actually experience a type of time delay.  But that is exactly what is happening with extreme forms of gravitational lensing, such as those that give us the beautiful images of Einstein rings.  In fact, the time dilation around some of these galaxies can be so extreme that the light from a single event, such as a supernova, can actually show up on Earth at dramatically different times.  That is exactly what a team led by Dr. Steven Rodney at the University of South Carolina and Dr. Gabriel Brammer of the University of Copenhagen has found. Except three copies of this supernova have already appeared – and the team thinks it will show up again one more time, 20 years from now.

Finding such a supernova is important not just for its mind bending qualities – it also helps to settle an important debate in the cosmological community.  The rate of expansion of the universe has outpaced the rate expected when calculated from the cosmic microwave background radiation. Most commonly, this cosmological conundrum is solved by invoking “dark energy” – a shadowy force that is supposedly responsible for increasing the acceleration rate.  But scientists don’t actually know what dark energy is, and to figure it out they need a better model of the physics of the early universe.

UT video describing the cosmic microwave background radiation, which is used to partially calculate the expansion rate of the universe.

One way to get that better model is to find an event that is actively being distorted through a gravitational lens.  Importantly – the same event must show up at two separate, distinct times in order to provide input to a calculation about the ratio of the distance between the galaxy doing the lensing and the background galaxy that was the source of the event.

That ratio is an important component in calculating some of the variables associated with dark energy.  And the supernova candidate Drs. Rodney and Brammer found is one of the best defined to date.  It is only the third such example of a multiply lensed supernova.  Quasars have also been caught with their own time delays, but the variable nature of quasars themselves make them less than ideal for the kind of angular distance calculations needed by cosmologists.  

UT Video describing gravitational lensing.

The new supernova, known as AT2016jka, was mined from Hubble data collected back in 2016.  Located in “the most spectacular galaxy targeted by REQUIEM [the observational program at Hubble that captured the data]”, it is in the galaxy known as MRG-M0138.

MRG-M0138 is “quadruply lensed” meaning that four copies of the galaxy can be seen dispersed around a galaxy cluster closer to our own galaxy, known as MAC J0138.02155.  So when the team was surveying data in the region in July 2019, they noted the three point sources of light that were present in data from July 2016 were no longer there.  Most likely the data in July 2016 captured a supernova lensed 3 different ways.

UT video on the topology of the universe, showing how matter clumps together and can impact time.

However, the expected fourth lensing did not show up in the Hubble data.  Using their lensing model for the system, the team determined that the fourth image should show up sometime around 2037, plus or minus a few years. With such a long baseline time between appearances of the same event, this supernova would provide valuable data to the debate over time dilation in gravitational lensing events.

Unfortunately, that also means that scientists have to wait almost 20 years to get their hands on that data.  It also means that they have to keep a watchful eye on that part of the sky in the 2 year window the calculations predict the fourth image of the supernova would appear in.  It probably wouldn’t be a bad idea to keep half an eye there the rest of the time as well just in case it appears sooner than expected.

UT video on dark energy and how we know it exists.

If all goes well, that final piece of data as to the exact date of peak brightness of the supernova will be well monitored by a new fleet of cosmological instruments.  Telescopes like the Vera Rubin and Nancy Grace promise to observe hundreds of these lensed supernovae that can provide even more data to further constrain dark energy.  Hopefully they’ll be able to catch the final gasp of the supernova in MRG-M0138 as well, to cap off some great detective work and prove how incredible gravitational time dilation truly is.

Learn More:
arXiv – A Gravitationally Lensed Supernova with an Observable Two-Decade Time Delay
Sci-News – Astronomers Discover Twelve New Quadruply-Imaged Quasars
Forbes – Eight New Quadruple Lenses Aren’t Just Gorgeous, They Reveal Dark Matter’s Temperature

Lead Image:
Image of the MAC J0138.02155 cluster and gravitationally lensed MRG-M0138 galaxy showing the locations of the three observed instances of the supernova (SN1-3) and the expected location of the fourth instance (SN4), estimated to appear around 2037.
Credit – Rodney, Brammer et al.

The post Astronomers saw the Same Supernova Three Times Thanks to Gravitational Lensing. And in Twenty Years They Think They’ll see it one More Time appeared first on Universe Today.

Categories: Astronomy

Astronomers Find a Blinking Star Near the Center of the Milky Way

Sat, 06/19/2021 - 11:28pm

In this week’s edition of new unexplained astronomical phenomena, a team of astronomers led by Dr. Leigh Smith from Cambridge found a star 100 times larger than our sun that nearly disappears from the sky every few decades.  They also have no idea why it does so.

The star, called VVV-WIT-08, is located 25,000 light years away, and decreases in brightness by a factor of 30 rather than disappearing altogether.  It’s not the first star to be discovered with this changing brightness pattern, but evidence is beginning to mount that this might just be another example of a new class of stars.

UT Video discussing one potential reason for the dimming – transiting

VVV-WIT-08’s name itself is calling out for an explanation.  The “WIT” in the middle actually stands for “what is this”, which is what astronomers call stars that are difficult to classify into any particular established category. 

The team, which included members from the University of Edinburgh, University of Hertfordshire, University of Warsaw, and Universidad Andres Bellow in Chile, found this new variable star by using the VISTA Variables in the Via Lactea survey (VVV), which utilizes the VISTA telescope in Chile.  Its dimming pattern was then confirmed using the Optical Gravitational Lensing Experiment (OGLE), which showed the star dimming in both infrared and visible light.

The VISTA telescope in its dome at sunset. Its primary mirror is 4.1 meters wide.
Credit – G. Hüdepohl/ESO.

Astronomers think the most likely cause of this dimming process are opaque disks of dust and gas, or potentially a binary companion or planet transiting in front of the star.  But more novel explanations cannot yet be ruled out.  With more stars steadily being added to this new category of “blinking giants”, it’s only a matter of time before more theories abound on what could be causing the dimming.  And there’s still so many more phenomena to find and explanations to explore.

Learn More:
Cambridge – Astronomers spot a ‘blinking giant’ near the centre of the Galaxy
Royal Astronomical Society – VVV-WIT-08: the giant star that blinked
Sci-News – Giant ‘Blinking’ Star Spotted in Milky Way’s Central Region

Lead Image:
Artist’s impression VVV-WIT-08
Credit: Amanda Smith

The post Astronomers Find a Blinking Star Near the Center of the Milky Way appeared first on Universe Today.

Categories: Astronomy

Apollo 17 Astronauts Brought Home Samples From the Oldest Impact Crater on the Moon

Sat, 06/19/2021 - 11:08pm

Internal geological processes on the moon are almost non-existent.  However, when it gets smacked by a space rock, its surface can change dramatically.  Debris from that impact can also travel over large distances, transplanting material from one impact site hundreds of kilometers away, where it can remain untouched in its inert environment for billions of years.  

So when Apollo 17 astronauts took regolith samples at their landing site near Serenitatis Basin, they collected not only rocks from the basin itself, but from other impacts that had happened billions of years ago.  Differentiating material that actually formed part of the Basin from material that landed their after an impact has proven difficult.

Apollo 17 astronaut Harrison Schmitt collecting a soil sample in Serenitatis basin, his spacesuit coated with dust.
Credit: NASA

One nearby impact in particular caused problems – material from the impact that created the Imbrium basin made up the majority of samples taken by the Apollo 17 astronauts.  Located slightly to the northwest of Serenitatis, this basin was caused by a much larger impact, which also happened much more recently than the one that created Serenitatis.  

Despite that age difference, it is hard to differentiate rocks from one basin or another just by looking at them.  A particular rock did stand out though – known as the Station 8 boulder after the geological station it was found next to, it did form as part of the Serenitatis basin rather than its younger neighbor.  It also surprised scientists with its age.

Image of the Station 8 Boulder from the Apollo 17 archives. It’s sample turns out to be the oldest of all those collected by Apollo 17 astronauts.
Credit – NASA

Previous estimates of the age of the basin put it at 3.8-3.9 billion years.  However, analysis of the phosphate materials in the sample returned from the Station 8 boulder show its age to be closer to 4.2 billion years.  That would make it one of the oldest craters on the moon, having formed only approximately 300 million years after the moon itself.

With plenty of manned moon missions on the horizon, this certainly won’t be the last time samples will be gathered from the basin.  And the techniques the scientists, led by a team at the Open University, used are applicable to other missions such as the sample return mission currently on its way back from Bennu.  Maybe in the future a crater will be found that’s even older than Serenitatis – but for now, it looks like we already have a sample of some of the oldest rocks possible from the moon.

Learn More:
The Open University – Lunar samples record impact 4.2 billion years ago that may have formed one of the oldest craters on the Moon
NASA – NASA Opens Previously Unopened Apollo Sample Ahead of Artemis Missions
UT – NASA Has a New Challenge to Bring Frozen Samples of the Moon Back to Earth

Lead Image:
Image of the moon highlighted with the two basins mentioned in the article. Serenitatis is shown with the Apollo 17 landing site demarcated.
Credit: Wikipedia

The post Apollo 17 Astronauts Brought Home Samples From the Oldest Impact Crater on the Moon appeared first on Universe Today.

Categories: Astronomy

A New Technique for “Seeing” Exoplanet Surfaces Based on the Content of their Atmospheres

Fri, 06/18/2021 - 7:57pm

In November of 2021, the James Webb Space Telescope (JWST) will make its long-awaited journey to space. This next-generation observatory will observe the cosmos using its advanced infrared suite and reveal many never-before-seen things. By 2024, it will be joined the Nancy Grace Roman Space Telescope (RST), the successor to the Hubble mission that will have 100 times Hubble’s field of view and faster observing time.

These instruments will make huge contributions to many fields of research, not the least of which is the discovery and characterization of extrasolar planets. But even with their advanced optics and capabilities, these missions will not be able to examine the surfaces of exoplanets in any detail. However, a team of the UC Santa Cruz (UCSC) and the Space Science Institute (SSI) have developed the next best thing: a tool for detecting an exoplanet surface without directly seeing it.

The paper that describes their research, titled “How to Identify Exoplanet Surfaces Using Atmospheric Trace Species in Hydrogen-dominated Atmospheres,” recently appeared in The Astrophysical Journal. As they indicated, the team sought to develop ways to study the surfaces of exoplanets based on their atmospheric composition. This is necessary since none of the upcoming space telescopes have the capacity to study surface features of an exoplanet indirectly.

However, these same telescopes will be excellent tools for determining the composition of exoplanet atmospheres. Beyond the James Webb and Roman Space Telescopes, a number of next-generation ground-based observatories will become operational in the coming years that will have similar capabilities. These include the Extremely Large Telescope (ELT), the Giant Magellan Telescope (GMT), and the Thirty Meter Telescope (TMT).

With their combination of high-sensitivity, coronographs, and adaptive optics, these observatories will be able to conduct Direct Imaging studies of exoplanets, where light reflected directly from an exoplanet’s atmosphere will be studied to determine atmospheric composition. This will help astronomers and astrobiologists place tighter constraints on which exoplanets are “potentially habitable” and which are not.

However, the conditions we consider prerequisites for life also include geological processes like volcanic activity and plate tectonics, which are discernible from their associated surface features. While we may not be able to discern these in the near future, Xinting Yu (an Earth and Planetary Sciences Postdoctoral Fellow at UCSC) and her colleagues have proposed a novel way to determine surface features based on the abundances of atmospheric gases.

As Dr. Yu explained to Universe Today via email, the inspiration for this method came from two bodies in our Solar System – Jupiter and Titan (Saturn’s largest moon). Both bodies have dense gaseous atmospheres with two chemical species – ammonia (NH3) and methane (CH4) – that play a major part in atmospheric processes. Said Yu:

“Titan has a cold and shallow surface with almost no (or not supposed to be any) ammonia and methane, while Jupiter’s atmosphere has lots of ammonia and methane. Why is this happening? In the upper atmosphere of both Jupiter and Titan, ammonia and methane are destroyed by UV photons constantly, forming nitrogen (for ammonia) and more complex hydrocarbons (for methane). On Titan, the photochemistry-formed nitrogen and complex hydrocarbons keep forming and piling up.”

Cassini image of Saturn’s largest moon Titan. Credit: NASA/JPL-Caltech/Space Science Institute

In short, methane and ammonia are destroyed in Titan’s atmosphere and then consumed to form nitrogen and hydrocarbons. This is what led to nitrogen becoming the dominant gas in Titan’s atmosphere (98% by volume) and the large deposition of hydrocarbons on its surface, leading to the formation of an organic-rich environment. Due to the extreme cold of Titan’s surface, this conversion process is irreversible.

Jupiter, on the other hand, also has ammonia and methane in its dense atmosphere but has no surface to speak of. As Yu explained, this results in a rather different process where the chemical species involved:

“Because there is no surface on Jupiter, the atmosphere just extends all the way to thousands of Earth surface pressures and thousands of kelvins. The photochemistry-formed nitrogen and complex hydrocarbons in the upper atmosphere can transport to this deep, hot part of the atmosphere. There, they could combine hydrogen to reform methane and ammonia. The reformed methane and ammonia are then “recycled” back into the upper atmosphere. This cycle continues to replenish the destroyed methane and ammonia.”

Another key point addressed by Yu and her team has to do with the current exoplanet census. To date, the majority of exoplanets discovered have been mini-Neptunes – i.e., planets that are less massive than Neptune but have a thick atmosphere dominated by hydrogen and helium. In fact, of the 4,401 confirmed exoplanets to date, 1,488 have been identified as “Neptune-like,” with masses ranging from 9 times that of Earth to slightly less than Jupiter.

Jupiter’s atmosphere, as imaged by the Juno mission (colorized by Kevin M. Gill). Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill

Because of their gaseous envelopes and the distances involved, it is impossible to determine if these planets have surfaced and where they are located. Because of their statistical significance, Yu and her team decided to use one in particular to test their novel approach. This was K2-18b, a mini-Neptune with about 8 times the mass of Earth that orbits within the habitable zone (HZ) of a red dwarf star (K2-18) located 124 light-years from Earth.

Originally detected by the Kepler Space Telescope in 2015, K2-18b is the first HZ exoplanet found to have significant amounts of water vapor in its atmosphere. Using a photochemical model, Yu and her team simulated how the presence of a surface on this exoplanet would affect the atmospheric evolution of K2-18b. They also accounted for different atmospheric pressure and temperature levels, factors that are linked to surface elevation.

“We are wondering if we can use the abundance of species like ammonia and methane to tell if an exoplanet has a surface or not,” said Yu. “A cold and shallow surface would cut all the “recycling” reactions that require high temperatures and pressures in deep planetary atmospheres to reform methane and ammonia. Thus, we expect to see little methane and ammonia on an exoplanet with a cold and shallow surface, and lots of methane and ammonia on an exoplanet with no surface or a deep and hot surface.”

What they found was that ammonia and methane, as predicted, were both sensitive to both the presence and elevation of a surface. This is consistent with what has been observed with exoplanets that have cold and shallow surfaces, where chemical species like water, hydrogen cyanide, and heavier hydrocarbons are broken down by UV exposure. Meanwhile, species like carbon monoxide and carbon dioxide (which are less prone to UV destruction) are retained.

Artist’s impression of a Super-Earth planet orbiting a Sun-like star. Credit: ESO/M. Kornmesser

What was unexpected, however, was the way that different chemicals are sensitive in different ways to different levels of elevation. According to Yu, this is due to the fact that carbon and nitrogen species have a “sweet spot” where they can be fully recycled. Whereas ammonia and hydrogen cyanide (HCN) are sensitive to atmospheres with densities of 100 bar at the surface (100 times that of Earth, similar to Venus), methane, carbon monoxide, and carbon dioxide are sensitive to pressures below 10 bar at the surface (ten times that of Earth).

These findings present multiple implications for the study of exoplanets, foremost of which are the fact that planetary surfaces matter. Said Yu:

“Previously, scientists were predicting the atmospheric compositions of exoplanets using thermochemical equilibrium models. The atmospheric compositions are solely determined by the pressure and temperature of the atmosphere. But our study shows, even if pressure and temperature are the same, adding a surface can drastically change the atmospheric composition of an exoplanet!”

Another implication of this study is that it is possible for astronomers to learn about exoplanet surfaces based on their atmospheric composition. “For example, when the observers see depleted amounts of ammonia and HCN, we can tell this exoplanet has a surface of less than 100 bar,” added Yu. “Then if we also see depleted quantities of methane, hydrocarbons, and an increased amount of carbon monoxide, that indicates a surface less than 10 bar. That is pretty promising for identifying habitable exoplanets!”

Beyond the characterization of mini-Neptunes, this research also has implications for all other types of exoplanets – including rocky, “Earth-like” ones. In fact, as long as the planet in question has an atmosphere and is subject to UV radiation in its upper atmosphere, the size of the exoplanet is irrelevant. In all cases, astronomers will see the same differences in chemical abundances depending on whether or not there is a surface.

Artist’s impression of the Earth-sized, rocky exoplanet GJ 1132 b, located 41 light-years away around a red dwarf star. Credit: NASA, ESA, and R. Hurt (IPAC/Caltech)

According to Yu, it is the smaller colder exoplanets that are more promising testing targets for this method since they are more likely to have shallow and cold surfaces. However, smaller planets are also more likely to have interior or surface processes that will affect the abundance of certain chemicals in their atmospheres – such as volcanic activity and plate tectonics. The smaller they are, the more significant these processes could be.

These and other concerns are things that Yu and her team look forward to studying in greater detail in the future to determine the robustness of their results and how it might be affected by different perturbations from the surface/interior of the exoplanets. Their efforts, and those of astrobiologists in general, will benefit greatly from the launch of the JWST, which is currently scheduled to take place sometime in November of 2021. Said Yu:

“Our study points out an exciting science angle for JWST. It is fine to have solely atmospheric characterization data. Without direct surface observations, we can still tell if an exoplanet has a surface, and even roughly where the surface is located. Knowing whether an exoplanet has a surface is also undoubtedly important for astrobiology. A liquid or a solid surface is likely necessary for sustaining complex lifeforms. Thus, the existence of a surface would be an essential thing to look for when assessing an exoplanet’s habitability.”

The ability to study exoplanets directly, combined with the ability to constrain their surface conditions, will advance the study of astrobiology considerably. The field will also benefit from innovative methods that could allow scientists to search for life (aka. biosignatures) based on different levels of entropy in an environment or different levels of complexity with organic particles. Little by little, we are narrowing the focus and tightening the constraints!

If there is life out there to be found, we find it sooner or later!

Further Reading: The Astrophysical Journal

The post A New Technique for “Seeing” Exoplanet Surfaces Based on the Content of their Atmospheres appeared first on Universe Today.

Categories: Astronomy

The Lunar Lantern Could be a Beacon for Humanity on the Moon

Thu, 06/17/2021 - 5:10pm

In October of 2024, NASA’s Artemis Program will return astronauts to the surface of the Moon for the first time since the Apollo Era. In the years and decades that follow, multiple space agencies and commercial partners plan to build the infrastructure that will allow for a long-term human presence on the Moon. An important part of these efforts involves building habitats that can ensure the astronauts’ health, safety, and comfort in the extreme lunar environment.

This challenge has inspired architects and designers from all over the world to create innovative and novel ideas for lunar living. One of these is the Lunar Lantern, a base concept developed by ICON (an advanced construction company based in Austin, Texas) as part of a NASA-supported project to build a sustainable outpost on the Moon. This proposal is currently being showcased as part of the 17th International Architecture Exhibition at the La Biennale di Venezia museum in Venice, Italy.

The Lunar Lantern emerged from Project Olympus, a research and development program made possible thanks to a Small Business Innovation Research (SBIR) contract and funding from NASA’s Marshall Space Flight Center (MSFC). Consistent with ICON’s commitment to developing advanced construction technologies, the purpose of Olympus was to create a space-based construction system that will support NASA and other future exploration efforts on the Moon.

To realize this vision, ICON partnered with two architectural firms: the Bjarke Ingels Group (BIG), and Space Exploration Architecture (SEArch+). Whereas BIG is renowned for its iconic architecture and its work on multiple Lunar and Martian concepts in the past several years, SEArch+ is recognized for its “human-centered” designs for space exploration and its long-standing relationship with NASA’s Johnson Space Center (JSC) and Langley Research Center (LRC).

In fact, SEArch+ past involvement with NASA includes their work as part of the Human Habitability Division at NASA JSC and the Moon to Mars Planetary Autonomous Construction Technologies (MMPACT) team. They have also participated in multiple Phases of the NASA 3D-Printed Habitat Challenge (2015-2019) which included the Mars Ice House and Mars X-House V2 (the winning entries of Phase 1 and Phase 3, respectively).

The result of their collaboration is the Lunar Lantern, a comprehensive lunar outpost that can be constructed on the Moon using automated robotic 3D printers. Consistent with the philosophy of these companies and NASA’s Artemis Program, the construction of this outpost leverages a number of burgeoning technologies as well as In-Situ-Resource Utilization (ISRU) to minimize dependence on Earth.

For the sake of their presentation at the Architectural Exhibition, SEArch+ prepared an updated video of their base concept (shown below) that illustrates how the Lunar Lantern concept will enable a sustained human presence on the Moon. To address the various hazards of the lunar environment, the main habitat employs three structural components: a Base Isolator, Tension Cables, and a Whipple Shield.

Base isolators are essentially seismic dampeners, which are deployed at the foundation to absorb the shocks and stresses caused by regular “moonquakes” – which are either “shallow” or “deep.” Shallow quakes occurr at depths of 50-220 km (31-137 mi and are attributed to changes in surface temperature and meteorite impacts. Deep quakes are more rare and powerful, originating at depths of ~700 km (435 mi), and are caused by tidal interactions with Earth.

Then there are the externally mounted tension cables, which apply compressive stress to the habitats 3D printed walls. The outermost component, the Whipple Shield, is a double shell made up of an interior lattice and external shield panels. This provides protection against ballistic impact from micrometeorites and ejecta (caused by impacts nearby) while also shielding the interior structure from the extreme heat caused by direct exposure to the Sun.

In addition to protecting against the extremes in temperature, radiation, and seismic activity, one of the chief concerns is the hazard posed by all the jagged and statically charged lunar regolith (aka. “moon dust”). As they illustrate, the Lunar Lander base is equipped to contain (and benefit from) this problem:

“The Lunar Lantern outpost consists of habitats, sheds, landing pads, blast walls, and roadways. Landing pads, thought to be one of the first lunar structures, will need to contain and control the supersonic and subsonic dust ejecta created during launch and landing. SEArch+’s design offers multiple strategies for dust mitigation and dust collection in printability, form, and function.”

Artist’s impression of the interior of the Lunar Lantern habitat. Credit: ICON/BIG

As the animation demonstrates, the configuration of the landing pads allows for the dust to be collected, preventing it from dispersing across the surface and interfering with operations. The collected dust can then be used as feedstock for the construction robots, which rely on regolith to fashion 3D printed structures. This way, the design not only prevents ejecta from becoming a serious hazard but also provides a steady supply of material that can be used to effect repairs to the structure.

As for the name, this was inspired by another important design feature, one which ensures human comfort. In short, the Lantern admits light from the lunar surface and then turns it into interior lighting that is adjusted (based on the section of the habitat) and turned off entirely to simulate nighttime. Or as they explain in the video:

“In order to replicate the Earth’s daily circadian rhythms and seasonal cycles, the Lunar Lantern utilizes a fiber optic system which captures the nearly perpetual light at the Moon’s south pole and modulates it in both brightness and color temperature. The interior of the habitat is organized vertically, with three designated levels – for work and exercise, dining and social, sleeping and private spaces.”

There are also a few “Easter Eggs” in the video, which commercial space and space exploration aficionados will not fail to notice! In both videos posted above (particularly the one produced by SEArch+), some familiar vehicles can be seen on the landing pads. This includes the SpaceX Starship, which Musk has promised will be ready to transport cargo and crews to the Moon in a few years, and Blue Origin’s Blue Moon lander – possibly the Human Landing System (HLS) variant specifically designed for NASA’s Artemis Program.

Artist’s impressions of the Lunar Lantern’s interior. Credit: ICON/SEArch+

There is no shortage of ideas for how humans could live on the Moon and Mars someday. While the design elements differ from one concept to the next, they all share the same commitment to leveraging 3D printing, sustainability, and the ability to provide for water, power, and food using local resources. Each also emphasizes how planning to live sustainably in a hostile environment can shape how we live on Earth.

The Lunar Lantern is not the only space architecture exhibition featured at the 17th International Architecture Exhibition (which will run until Nov. 21st). The European Space Agency (ESA) – in partnership with the international architecture firm Skidmore, Owings & Merrill (SOM) – are also showcasing their proposal for a fully operational semi-inflatable lunar habitat, known as the “Lunar Village.”

These two proposals beautifully illustrate how proposals for living beyond Earth are becoming a part of mainstream architecture. As this decade comes to a close, this trend is likely to continue, eventually becoming an entirely new form of architectural, industrial, and interior design. If and when humans begin to settle on the Moon and Mars, we can expect the real estate industry will follow suite!

Further Reading: ICON, Search+, Biennale Architettura 2021

The post The Lunar Lantern Could be a Beacon for Humanity on the Moon appeared first on Universe Today.

Categories: Astronomy

The Largest Rotating Objects in the Universe: Galactic Filaments Hundreds of Millions of Light-Years Long

Thu, 06/17/2021 - 3:41pm

We’ve known for a while about the large-scale structure of the Universe. Galaxies reside in filaments hundreds of millions of light-years long, on a backbone of dark matter. And, where those filaments meet, there are galaxy clusters. Between them are massive voids, where galaxies are sparse. Now a team of astronomers in Germany and their colleagues in China and Estonia have made an intriguing discovery.

These massive filaments are rotating, and this kind of rotation on such a massive scale has never been seen before.

Obviously, there’s no way to take an actual picture of the Universe’s large-scale structure. But there are some almost-famous images that come from the Millennium Simulation Program. The Millennium Simulation was a super-computer simulation of a cubic portion of the Universe over 2 billion light-years on each side. The image contains about 20 million individual galaxies organized in filaments and clumps, and it was our first real glimpse of the Universe’s LSS.

It’s remarkable to look at that image now and imagine those filaments rotating.

Image of the large-scale structure of the Universe, showing filaments and voids within the cosmic structure. Credit: Millennium Simulation Project

The team of astronomers behind this discovery worked with data from the Sloan Digital Sky Survey (SDSS.) The SDSS created a very detailed 3D map of the Universe, so SDSS data was critical to the team’s discovery.

“By mapping the motion of galaxies in these huge cosmic superhighways using the Sloan Digital Sky survey – a survey of hundreds of thousands of galaxies – we found a remarkable property of these filaments: they spin.” says Peng Wang, first author of the now published study and astronomer at the AIP (Institute for Astrophysics Potsdam).

Each of the galaxies in the filaments amounts to no more than a speck of dust on the grand scale, and they’re not only rotating but moving along the tendrils as if they’re pipelines.

“They move on helixes or corkscrew like orbits, circling around the middle of the filament while travelling along it.”

Noam Libeskind, Study Co-Author, AIP.

“Despite being thin cylinders – similar in dimension to pencils – hundreds of millions of light years long, but just a few million light years in diameter, these fantastic tendrils of matter rotate,” added Noam Libeskind, initiator of the project at the AIP. “On these scales the galaxies within them are themselves just specs of dust. They move on helixes or corkscrew like orbits, circling around the middle of the filament while travelling along it. Such a spin has never been seen before on such enormous scales, and the implication is that there must be an as yet unknown physical mechanism responsible for torquing these objects.”

The fact that these filaments spin is difficult to visualize, and fascinating once you succeed. But the discovery is about more than our own fascination. These are the largest objects we’ve ever seen spinning, and that means that angular momentum can take place on a massive scale. One of the mysteries in cosmology is how that angular momentum is generated on such a massive scale since there was no primordial rotation in the early Universe.

The discovery rests on observations of individual galaxies in the filaments and their Doppler shift. In this study, red-shift is a proxy for rotation, Red-shifted galaxies are receding, and blue-shifted galaxies are approaching.

This figure from the paper shows the filament rotation speed as a function of the distance between galaxies and the filament spine. The distance of galaxies from the filament spine in the receding region is displayed in red and ascribed positive values, while the distance of galaxies in the approaching region is marked in blue and ascribed negative values. Error bars represent the standard deviation about the mean. Image Credit: Wang et al 2021.

In the current working model of the Universe’s structural formation, overdensities grow via gravitational instability. Material from underdense regions flows into regions of overdensity. But that flow of material has no rotation or curl to it. That’s why cosmologists say that there was no rotation in the early Universe. And here’s where this discovery gets more interesting.

The rotation evident in these filaments of galaxies must be generated as the structures form. And these filaments and the rest of the cosmic web are connected to the formation and evolution of galaxies themselves. They also have a powerful effect on the spin of individual galaxies and can regulate how a galaxy and its dark matter halo rotate. There’s an unknown piece in all of this: scientists don’t yet know how our current understanding can predict that the filaments themselves spin.

“Such a spin has never been seen before on such enormous scales, and the implication is that there must be an as yet unknown physical mechanism responsible for torquing these objects.”

Noam Libeskind, Study Co-Author, AIP.

Before this study, other scientists have theorized that these filaments spin. For example, Dr. Mark Neyrinck, a Fellow at the Department of Theoretical Physics at the University of the Basque Country, Spain, is known for theorizing on this. He’s also known for developing the “origami” description of cosmic structure formation. In a 2016 article in The Paper he said, “…if galaxies rotate (and they do), so must filaments sticking out of them. Furthermore, galaxies joined by a filament should rotate mostly together, like objects attached to the ends of a rod. In fact, this is consistent with astronomical observations; nearby galaxies tend to be spinning in the same direction.”

Dr. Neyrinck’s work was an important starting point for the team behind this paper.

“Motivated by the suggestion from the theorist Dr. Mark Neyrinck that filaments may spin, we examined the observed galaxy distribution, looking for filament rotation,” says co-author Noam Libeskind. “It’s fantastic to see this confirmation that intergalactic filaments rotate in the real Universe, as well as in computer simulation.”

The team used a sophisticated mapping method that divided the observed galaxy distribution into segments. Then each of the filaments was approximated by a cylinder. The galaxies in the filament were then divided into two regions on either side of the filament’s spine. Then they carefully measured the mean redshift difference between the two regions. “The mean redshift difference is a proxy for the velocity difference (the Doppler shift) between galaxies on the receding and approaching side of the filament tube,” the authors write. That’s how they measured the filaments’ rotation.

In their paper, the team writes that what they found cannot be random. “What is measured and presented here is the redshift difference between two regions on either side of a hypothesized spin axis that is coincident with the filament spine. The full distribution of this quantity is inconsistent with random regardless of the viewing angle formed with the line of sight…”

However, the researchers caution, their results don’t imply that every filament in the Universe is rotating. That would be an over-reach. “This work does not predict that every single filament in the Universe is rotating,” they write, “rather that there are subsamples—intimately connected to the viewing angle end point mass—that show a clear signal consistent with rotation. This is the main finding of this work.”

“Taken together,” the team writes in their conclusion, “the current study and <references> demonstrate that angular momentum can be generated on unprecedented scales, opening the door to a new understanding of cosmic spin.”

Lead author of this work is Peng Wang, an astronomer at the Institute for Astrophysics Potsdam (AIP). The title of the paper is “Possible observational evidence for cosmic filament spin.” It’s published in Nature Astronomy.

More:

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Categories: Astronomy

Catch New Galactic Nova Herculis 2021 in Hercules the Hero

Wed, 06/16/2021 - 1:35pm

Now’s the time to catch Nova Herculis 2021, before it fades from view.

…And then, there were two. Fresh off of the eruption of Nova Cassiopeiae 2021 early this year, another galactic nova made itself known earlier this past weekend, as a ‘new star’ or nova flirted with naked eye visibility in the constellation Hercules the Hero on its border with Aquila the Eagle.

The Discovery: The nova was discovered at +8th magnitude ‘with a bullet’ on the night of June 12th by astronomer Seiji Ueda from Hokkaido, Japan. The nova initially gained the telephone number-like monikers TCP J18573095+1653396 (denoting its position in the sky), and ZTF (Zwicky Transient Facility) 19aasfsjq (another alphabet soup designation), before getting the much more straightforward designation of Nova Herculis 2021, or simply N Her 2021. Just a few days ago, the American Association of Variable Star Observers (AAVSO) released the formal Alert Notice 745, notifying observers that a new bright northern hemisphere nova was indeed afoot.

The story thus far: This one came up fast, as Nova Her 2021 topped out at magnitude +5.5 on Sunday, June 13th, just a day after discovery. As of writing this, the nova has faded a bit but is still sitting at a respectable magnitude +9, worth hunting for with binoculars or a small telescope. Keep in mind, if history sets any precedent, Nova Her 2021 could well brighten again… and soon. Just look at how it flared and faded in this amazing sequence:

As imagens mostram a “nova” recém-descoberta e agora já oficialmente batizada como V1674 Herculis (V1674 Her). As imagens feitas em torno de 0H BRT nos dias 13, 14 e 15 mostram a nítida variação do brilho. Vem saber mais:#ObservatorioNacional #Nova #Constelação #estrelas@mcti pic.twitter.com/IsUD7tTTaD

— Observatório Nacional (@Obs_Nacional) June 15, 2021

Nova Her 2021’s position in the sky: First, the good part: the region hosting Nova Her 2021 is currently rising to the east for northern hemisphere observers at sunset in mid-June. With the Moon waxing towards Full on June 24th, the time to catch Nova Her 2021 is tonight.

The nova’s position in the sky is:

Right Ascension 18 hours 57’ 31”

Declination +16 degrees north, 53’ 40”

The general field of view for Nova Her 2021 (centered on the Telrad finder). Credit: Stellarium/Dave Dickinson.

…and here’s a narrow, two degree wide finder chart:

N Her 2021 finder. Note that FF Aquilae is the brightest star in the field, just north of center. Credit: AAVSO.

The nova is very near (less than one degree away from) the +5.3 magnitude variable star FF Aquilae. Note that the famous ‘Coat-Hanger’ asterism is in the same general field of view:

Nova Herculis (marked) in the center of the field of view. Credit: Filipp Romanov

The nova’s position in the galaxy: Like extra-galactic supernovae seen in other galaxies, galactic novae tend to flare in a predicable fashion, making them good standard candles to roughly gauge distance. Based on this, Nova Her 2021 seems to be about 18 to 20 kilo light-years (kly) distant, in the Sagittarius Arm of the galaxy, offset from the direction from the core of the Milky Way and about five degrees north of the galactic plane.

Possible location (based on direction and brightness) for Nova Herculis 2021 in the Milky Way Galaxy. Credit: NASA

What exactly is Nova Herculis 2021? Galactic novae occur when a white dwarf star accretes material from a large nearby main sequence star. This material builds up, compresses, and ultimately gives way to a violent runaway fusion process, igniting in a brilliant flash over a period of several weeks. U Scorpii and T Pyxidis are members of a rare sub-category of variable stars known as recurrent novae.

An eVscope capture of Nova Herculis 2021. Credit: Mario Billiani

How common are novae seen in our galaxy? On average, a dozen or so novae are cataloged in our galaxy every year; once every decade or so, we get a good naked eye nova, which may top out as bright as magnitude +1, rivaling all but the very brightest stars, briefly changing the outline of the host constellation. The last such example was Nova Delphini 2013 in the tiny constellation of Delphinus the Dolphin.

Be sure to check out Nova Herculis 2021 while you can!

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Categories: Astronomy

Black Holes don't Just Destroy, They Also Help With Star Formation

Wed, 06/16/2021 - 11:55am

Black holes are the most powerful destructive forces in the universe. They can rip apart a star and scatter its ashes out of the galaxy at nearly the speed of light. But these engines of destruction can also pave the way for new stars to form, as a new study in Nature shows.

The study looks at the question of why some galaxies actively create stars, while others do not. For example, in the Milky Way galaxy, new stars form at an average rate of 1 – 2 per year. Other galaxies, known as starburst galaxies, have extremely active star-producing regions. But in some galaxies, there is almost no star production. These “quenched” galaxies are often smaller satellite galaxies to larger galaxies.

It’s generally thought that satellite galaxies are often quenched because they are more susceptible to intergalactic wind. This diffuse intergalactic gas can flow through these small galaxies, clearing them of gas and dust, thus removing the material needed to produce new stars.

Our galaxy has bubbles of gas seen in gamma ray light. Credit: NASA Goddard

Since these small galaxies often orbit larger ones, they would also be affected by the flow of gas from active supermassive black holes within the main galaxy. The team figured that satellite galaxies passing through the flow region of the black hole would be more quenched than those outside the flow since the flow of a black hole should be more effective at clearing matter from the satellite galaxy. But when they looked at the star production of these galaxies, they found it was slightly higher for regions in the flow. It turns out that supermassive black holes actually help increase star production in satellite galaxies.

Based on computer simulations, the team thinks they know why. An active supermassive black hole can clear gas and dust from a region, and this creates low-density regions, or bubbles, near its galaxy. These bubble regions have an even lower density than the surrounding intergalactic regions. So if a satellite galaxy is within this bubble, less of its gas and dust is stripped away, and it can produce stars more easily.

This study is a great example of the complexity of galactic dynamics, and how the behavior of one galaxy can affect the creation of stars in another. It’s also a good example of testing your hypotheses, even when you think the answer is obvious. Sometimes the answer is completely unexpected, and that’s when we can learn the most.

Reference: Martín-Navarro, Ignacio, et al. “Anisotropic satellite galaxy quenching modulated by black hole activity.” Nature 594.7862 (2021): 187-190.

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Categories: Astronomy

CHIME Detected Over 500 Fast Radio Burst in its First Year, Providing new Clues to What’s Causing Them

Tue, 06/15/2021 - 7:17pm

Much like Dark Matter and Dark Energy, Fast Radio Burst (FRBs) are one of those crazy cosmic phenomena that continue to mystify astronomers. These incredibly bright flashes register only in the radio band of the electromagnetic spectrum, occur suddenly, and last only a few milliseconds before vanishing without a trace. As a result, observing them with a radio telescope is rather challenging and requires extremely precise timing.

Hence why the Dominion Radio Astrophysical Observatory (DRAO) in British Columbia launched the Canadian Hydrogen Intensity Mapping Experiment (CHIME) in 2017. Along with their partners at the National Radio Astronomy Observatory (NRAO), the Massachusetts Institute of Technology (MIT), the Perimeter Institute, and multiple universities, CHIME detected more than 500 FRBs in its first year of operation (and more than 1000 since it commenced operations)!

To recap, astronomers have only been studying FRBs since 2007 when the first event was reported. Prior to mid-2017 when CHIME became operational, only about two dozen had ever been observed and their origin remains unknown. However, it has since been learned that as cosmological phenomena go, they are ubiquitous, with thousands of events arriving at Earth every day from every corner of the sky.

CHIME’s Mission

Originally conceived to map the distribution of hydrogen over much of the observable universe, the novel design of CHIME also makes it highly effective for the study of FRBs. In addition to being stationary with no moving parts, it is optimized for high “mapping speed,” thanks to its large instantaneous field of view (~200 square degrees) and broad frequency coverage – 400 to 800 megahertz (MHz).

While most radio astronomy is performed using large dish antennas that focus light from different parts of the sky, CHIME is motionless and focuses incoming signals onto its four massive cylindrical radio antennas. The telescope also relies on a powerful digital signaling processor (aka. correlator) that is capable of sorting through data at a rate of about 7 terabits per second – a small percent of the world’s internet traffic.

Since it became operational, CHIME has nearly quadrupled the total number of FRBs that have been detected. In its first year of operation (between 2018 and 2019), it detected 535 new FRBs. After mapping the timing and locations, scientists found that the bursts were evenly distributed in space and occur at a rate of about 800 per day, which is the most precise estimate of the overall rate of FRBs to date.

As Kiyoshi Masui, a member of MIT’s Kavli Institute for Astrophysics and Space Research, explained in an MIT press release:

“That’s kind of the beautiful thing about this field — FRBs are really hard to see, but they’re not uncommon. If your eyes could see radio flashes the way you can see camera flashes, you would see them all the time if you just looked up.”

Artist’s impression of CSIRO’s Australian SKA Pathfinder (ASKAP) radio telescope finding a fast radio burst and determining its precise location. The KECK, VLT and Gemini South optical telescopes joined ASKAP with follow-up observations to image the host galaxy. Credit: CSIRO/Dr Andrew Howells New Events and Insights

These were assembled in the telescope’s first FRB catalog, which was presented last week at the 238th American Astronomical Society Meeting (AAS), a virtual event that ran from June 7th to 9th. The new catalog expands the current library of known FRBs and is already leading to new insights about their properties and possible causes. In particular, the catalog is informing astronomers about the difference between the two distinct classes of FRBs.

These include FRBs that repeat and those that are a one-off occurrence. Whereas one-off bursts are believed to be entirely natural in occurrence, repeating FRBs defy conventional explanation. There are even some that think that repeating bursts could be a possible technosignature – i.e., an indication of extraterrestrial intelligence. To date, only 18 FRBs have been reported that burst repeatedly, whereas the rest appear to be singular in nature.

The repeating FRBs also differ in that they last slightly longer than non-repeating ones, and emit more focused radiofrequency bursts. What this suggests is that those FRBs that repeat and those that don’t have different mechanisms and astrophysical sources. This is an important step in resolving what causes these enigmatic bursts and something astronomers hope to build upon soon.

As Kaitlyn Shin, a graduate student in MIT’s Department of Physics and a member of the CHIME Collaboration, said in a recent MIT press release:

“Before CHIME, there were less than 100 total discovered FRBs; now, after one year of observation, we’ve discovered hundreds more. With all these sources, we can really start getting a picture of what FRBs look like as a whole, what astrophysics might be driving these events, and how they can be used to study the universe going forward.”

This artist’s impression represents the path of the fast radio burst FRB 181112 traveling from a distant host galaxy to reach the Earth. Credit: ESO Mapping the Cosmos

Another benefit to all these recorded events is the way they will allow astronomers and cosmologists to gain a better understanding of the structure and distribution of matter in the Universe. The reason is that as radio waves travel across space, they pass through the dust and gas that permeate interstellar and intergalactic space. This can distort or disperse the properties and trajectory of radio waves, the degree of which can

The degree to which a radio wave is dispersed can give clues to how much gas it passed through, and possibly how much distance it has traveled from its source. From each of the 535 FRBs that CHIME detected, Masui and his colleagues measured the dispersion and found that most bursts likely originated in distant galaxies. The fact that they were bright enough to be detected by CHIME suggests that they must have been produced by very energetic sources.

As CHIME and other radio observatories detect more FRBs, scientists hope to pin down exactly what kind of exotic and powerful phenomenon causes them. They also hope to use them to create more detailed maps of the cosmos. As Shin summarized:

“Each FRB gives us some information of how far they’ve propagated and how much gas they’ve propagated through. With large numbers of FRBs, we can hopefully figure out how gas and matter are distributed on very large scales in the universe. So, alongside the mystery of what FRBs are themselves, there’s also the exciting potential for FRBs as powerful cosmological probes in the future.”

This research was supported provided by the Canada Foundation for Innovation (CFI), the Dunlap Institute for Astronomy and Astrophysics, the Canadian Institute for Advanced Research (CIFAR), the McGill Space Institute (MSI), the Trottier Family Foundation, and the University of British Columbia (UBC).

Further Reading: MIT News

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Categories: Astronomy

NASA has Approved a Space Telescope That Will Scan the Skies for Dangerous Near-Earth Asteroids

Tue, 06/15/2021 - 5:17pm

A lot of the threats humanity faces come from ourselves. If we were listing them, we’d include tribalism, greed, and the fact that we’re evolved primates, and our brains have a lot in common with animal brains. Our animalistic brains subject us to many of the same destructive emotions and impulses that animals are subject to. We wage war and become embroiled in intergenerational conflicts. There are genocides, pogroms, doomed boatloads of migrants, and horrible mashups of all three.

Isn’t humanity fun?

But not all of the threats we face are as intractable as our internal ones. Some threats are external, and we can leverage our technologies and our knowledge of nature in the struggle against them. Case in point: asteroids.

NASA can’t do much about our own destructive impulses, but they are definitely in a position to help protect us from asteroids and comets that pose a threat. Those objects are called Near-Earth Objects, or NEOs. In 2005, the US Congress passed the NASA Authorization Act of 2005.

Among its requirements, it obligates NASA to raise its game when it comes to detecting NEOs. It states in part that NASA should “…detect, track, catalogue, and characterize the physical characteristics of near-Earth objects equal to or greater than 140 meters…” It also directs NASA to undertake a survey program that will “…achieve 90 percent completion of its near-Earth object catalogue (based on statistically predicted populations of near-Earth objects) within 15 years after the date of enactment of this Act.”

NASA’s made progress in this area, and so far has found about 40% of objects equal to or greater than 40 meters. And they’re about to get a new tool to help complete their survey. It’s called the NEO Surveyor and it’s an infrared space telescope designed to find, track, and characterize NEOs. The University of Arizona will lead this new mission, with Amy Mainzer in charge. Mainzer is an expert in infrared astronomy and a professor in the University of Arizona’s Lunar and Planetary Laboratory.

“Even asteroids as dark as a chunk of coal won’t be able to hide from our infrared eyes.”

Professor Amy Mainzer, University of Arizona.

NASA has approved only the preliminary design phase at this stage, so many details could change between now and when the spacecraft is scheduled to be deployed sometime in 2026. But here’s what we know so far.

The spacecraft will perform its survey in infrared. Earth-based telescopes have found most of the NEOs that have been catalogued so far, but finding the remaining ones in visible light is extremely difficult. It would take decades to do so, according to a press release. Searching for them in the infrared will be much more efficient, but that can’t be done from Earth. It takes a spacecraft to do it.

Infrared observation is critical to the mission because of what happens to NEOs when they approach the inner Solar System. They’re warmed by the Sun, and that heat is what the NEO Surveyor will detect. Even the blackest, most non-reflective of asteroids will be visible in infrared. In a press release Mainzer said, “Earth-approaching asteroids and comets are warmed by the sun, and they give off heat that the NEO Surveyor mission will be able to pick up. Even asteroids as dark as a chunk of coal won’t be able to hide from our infrared eyes.”

An artist’s illustration of the NEO Surveyor, a space telescope designed to detect and catalogue NEOs. Image Credit: NASA/JPL

The artist’s illustration above gives us an idea of how NEOs will appear to the NEO Surveyor. Their faint heat signatures will appear as a streak of dots which are shown in red in this image, for our convenience. Thus, they’ll appear distinct from background stars, which are coded blue in this image. Hunting NEOs in infrared will also allow scientists to determine not only the position and trajectory of the objects but also their sizes. And it’s their sizes that determine how devastating they could be if they strike Earth.

“Impact energy depends heavily on how big an individual asteroid is, so the infrared observations delivered by NEO Surveyor will greatly expand our ability to predict the behavior of some of Earth’s neighbors that could be on a trajectory to pay us a surprise visit,” Mainzer said.

The NEO Surveyor will build on the success of the Near-Earth Object Wide-Field Infrared Sensor (NEOWISE.) NEOWISE was a predecessor to the NEO Surveyor. It was a four-month mission extension to the WISE mission, undertaken once the mission ran out of coolant. Professor Mainzer is NEOWISE’s lead scientist.

This graphic shows asteroids and comets observed by NASA’s Near-Earth Object Wide-field Survey Explorer (NEOWISE) mission. Credit: NASA/JPL-Caltech/UCLA/JHU

The University of Arizona will provide overall mission management, including designing and building the infrared detectors themselves. The University will also monitor the mission and manage the investigation and the overall operations of the team. The U of A has a successful track record in this regard, including their participation in the OSIRIS-REx mission and their management of the HiRISE (High-Resolution Imaging Science Experiment) camera on the Mars Reconnaissance Orbiter (MRO.)

“The university’s leading roles in infrared astronomy and asteroid science make it uniquely suited to leading this next-generation infrared sky survey,” said Elizabeth “Betsy” Cantwell, senior vice president for research and innovation at the University of Arizona.  

Professor Mainzer and her team will provide eight infrared detectors for the spacecraft’s camera. Each of the eight will provide 4 megapixels of resolution. That’s enough resolving power to let the NEO Surveyor spot the tiny spots of infrared light coming from NEOs. As part of their role, they’ll test various infrared detector assemblies and select the best eight for the telescope.

Like its big brother, the James Webb Space Telescope (JWST), which is also an infrared ‘scope, the NEO Surveyor will use a heat shield to shelter it from the heat of the Sun. For infrared detectors to function well, they must operate at a frigid temperature. The shield will deal with the Sun’s heat as the 6-meter (20 ft.) spacecraft follows an orbit that takes it outside the Moon’s orbit. The observatory will continuously scan the sky. In particular, it’ll carefully observe areas near the Sun, where asteroids on potential Earth-bound trajectories tend to originate.

Of course, merely finding them isn’t good enough. One of the primary ideas behind the NEO Surveyor is advance warning. “With NEO Surveyor, we want to spot potentially hazardous NEOs when they’re years to decades away from possible impact,” Mainzer said. “The whole idea is to provide as much time as possible to develop mitigation efforts that enable us to push them out of the way.” NASA’s already working on potential mitigation efforts for dangerous asteroids, especially with its Double Asteroid Redirection Mission, or DART mission. DART will test a kinetic impactor as a way to redirect dangerous asteroids away from Earth.

NASA can’t save us from ourselves. But they may be able to help protect us from nature. Who knows? Maybe their efforts will give humanity the time we need to sort ourselves out down here on Earth. As Steven Pinker makes clear in his book “The Better Angels of Our Nature: Why Violence Has Declined,” humanity is waging fewer and fewer wars, and the ones we do wage are becoming smaller and more contained.

It would be a shame if an asteroid ended humanity, and even life on Earth, while we were still struggling to become reliably peaceful. If NASA can play its part, maybe we’ll make it.

More:

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Categories: Astronomy

Rare Triple Galaxy Merger With at Least Two Supermassive Black Holes

Tue, 06/15/2021 - 3:18pm

One of the best things about that universe is that there is so much to it.  If you look hard enough, you can most likely find any combination of astronomical events happening.  Not long ago we reported on research that found 7 separate instances of three galaxies colliding with one another.  Now, a team led by Jonathan Williams of the University of Maryland has found another triple galaxy merging cluster, but this one might potentially have two active supermassive black holes, allowing astronomers to peer into the system dynamics of two of the universe’s most extreme objects running into one another.

To find this unique system, Mr. Williams looked at data from a wide variety of sources, including the Very Large Array, European Southern Observatory, W. M. Keck Observatory, Chandra X-ray Observatory, and the Atacama Large Millimeter / Submillimeter Array.  Sifting through all of that data, he found the system in an extremely bright patch of the sky about 800 million light-years away.

UT video on black holes orbiting each other.

The three galaxies differ from one another in a variety of ways.  One galaxy is known as a Seyfert type – large swirling discs which are known to have supermassive black holes at the center.  Another of the galaxies is known as a “low-ionization nuclear emission-line region”, or LINER galaxy, which some scientists speculate also contain supermassive black holes at their center, but this has yet to be incontrovertibly proven.

Not to be outdone by its larger neighbors, the third galaxy – a dwarf galaxy with no active supermassive black hole – is leaving a trail of dust behind it and seems to be traveling perpendicularly to the Earth.  This combination of factors allows data about the physical characteristics of the merger that would otherwise be undetectable.

UT video discussing black hole mergers.

Even with this wealth of data, there are still some confusing outcomes from it – both the Seyfert and LINER galaxies don’t act purely in line with expectations of those two types of galaxies.  Getting a better understanding of what the galaxies actually are and the physics around the merging process itself will require even more data.  As such, Mr. Williams plans to collect additional data using Hubble to shed some more light on this already extraordinarily bright, and extraordinarily interesting, region of the sky.

Learn More:
UMD – Triple Galaxy Merger Sends Mixed Signals
AAS – 2MASS 1631 : A Merging Galaxy Triple Hosting a Potential Dual AGN
UT – What Happens to Their Supermassive Black Holes When Galaxies Collide?

Lead Image:
Image of the three merging galaxies with potentially two active black holes.
Credit: VLT / MSU R-V-B- composite image

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Categories: Astronomy

Iridescent Clouds on Mars Seen by Curiosity

Tue, 06/15/2021 - 2:53pm

Laying on a grassy field staring at the cloud formations in the sky and coming up with harebrained ideas about their shapes is a common feature in childhood summers – at least as they’re portrayed in media.  Someday that image might translate to a child laying on a sandy or rocky outcropping, looking up at the sky seeing iridescent, shimmering clouds in the sky.  The biggest differences would be that the child would be looking through a visor, and those clouds would be on Mars.  And Curiosity recently released some stunning images of what they might look like.

Curiosity’s project scientists were caught a little bit off guard one Martian year ago when clouds started to form earlier in the year than they expected.  This year they were ready with the rover’s Mastcam and black-and-white navigational cameras, and not only did they capture some breathtaking images, they collected some interesting scientific data as well.

Clouds moving over Curiostiy on March 19th, 2021.
Credit – NASA / JPL-Caltech / MSSS

Some of the data collect was on cloud height – the clouds the cameras saw formed much higher up than they originally expected.. Usually, Martian clouds form around a height of 60km, but these appeared much higher than that.  It can be hard to calculate altitude without a second reference point to triangulate from, but the clouds were visible at sunset, so the scientists were able to track how long they were illuminated once the sun had receded behind the Martian surface and thereby calculate their height.  

Clouds at that height most likely aren’t formed of the water ice crystals that are so common in Earth-bound clouds.  Frigid temperatures in the Martian atmosphere meant that the clouds were more likely formed by CO2, or dry ice crystals.  There is other data that will need collecting before that hypothesis is confirmed, but most likely Curiosity saw clouds of both water and carbon dioxide.  

More clouds captured by Curiosity – these ones over a rock outcropping.
Credit – NASA / JPL-Caltech / MSSS

While the clouds were relatively easy to see in the black-and-white images from the navigational cameras, the truly spectacular pictures came from the Mastcam.  The color images show two types of clouds that were particularly stunning.

In a beautiful turn of naming, the first type of clouds are known as “noctilucent”, or “night shining” in Latin.  They burst with brightness as the atmosphere cools around sunset, causing more crystals to from in the cloud, and then fade from view after the sun dips below the horizon.  

UT Video discussing the Martian atmosphere, or lack thereof.

Even more striking are the “mother of pearl” clouds that are wispy but iridescent clouds that are one of the only splashes of certain color in the Martian landscape.  Wisps of red, yellow, and blue can be seen in the Curiosity images, and scientists predict that a person would have been able to see the colorful display unaided if they happened to be standing next to the rover.

These displays are surely not the last time a Martian rover will encounter clouds, nor will it be anytime soon before a person can be there to observe them first hand.  In the meantime, maybe some kids sitting on a grassy hill in the summertime back on Earth can imagine what the scene in the sky would look like on a different planet.

Learn More:
JPL – NASA’s Curiosity Rover Captures Shining Clouds on Mars
UT – There’s One Cloud on Mars That’s Over 1800 km Long
UT – High Altitude Clouds on Mars
UT – Martian Clouds Might Start with Meteor Trails Through the Atmosphere

Lead Image:
Mother of pearl clouds captured by Curiosity’s Mastcam on March 5 2021.
Credit: NASA / JPL-Caltech / MSSS

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Categories: Astronomy

Blue Origin Auction Ends With a Closing Bid of $28 million

Tue, 06/15/2021 - 1:28pm

On July 20th,, Blue Origin will conduct the first crewed launch of their New Shepard rocket, the reusable launch vehicle that will send small payloads and customers to space. In addition to Jeff Bezos and his brother Mark, the company announced that one of the seats was being left open for auction. On Saturday, June 12th, the company announced that the auction had closed with a winning bid of $28 million USD.

The auction kicked off on May 5th, coinciding with the 60th anniversary of the first crewed space flight by an American astronaut. This was none other than Alan Shepard, the man for whom the New Shepard launch vehicle is named, who flew to space on May 5th, 1961 aboard the Freedom 7 capsule as part of the Project Mercury. The auction consisted of three phases, with sealed online bidding until May 19th, followed by unsealed online bidding until June 12th.

All told, nearly 7,600 people registered from 159 countries to bid on the seat aboard the maiden flight (dubbed RSS First Step Crew Capsule). Things then culminated in a live auction that was broadcast online (see video below), where people bid in person (and things intensified!) Prior to the live auction, the highest bid had been $4.8 million, but the offers escalated to over five times that much ($28 million) in the space of about five minutes.

As noted in a previous article, the winning bid amount will be donated to Blue Origin’s foundation, Club for the Future. Founded by Jeff Bezos in 2019, the purpose of this foundation is to inspire future generations to pursue careers in STEM and advance space exploration. Three seats aboard the four-seat crew capsule are now spoken for, with the fourth passenger still waiting to be revealed.

“The name of the auction winner will be released in the weeks following the auction’s conclusion,” the company said in an official press release. “Then, the fourth and final crew member will be announced—stay tuned.”

This historic flight will take place on Tuesday, July 20th, and will see the New Shepard take off from the company’s launch facility (Launch Site One) located near the town of Van Horn in West Texas. Once the launcher reaches an altitude of 6.7 km (22,000 feet), the RSS First Step Crew Capsule will separate from the first-stage booster and the crew will experience a few minutes of weightlessness.

This mission, and Bezos’ recent announcement that he and his brother would be passengers aboard it, has certainly shaken up the commercial space sector. If all goes as planned, Bezos will be the first billionaire to go to space using a launch vehicle built by his own company. This not only demonstrates a degree of confidence in his launch vehicles (not to mention inviting his brother along), it also puts Bezos ahead of the competition in one major respect.

So far, SpaceX founder Elon Musk has not indicated when he plans to go to space using the Starship and Super Heavy, which he hopes to use to conduct regular missions to the Moon and Mars very soon. But Virgin Galactic founder and CEO Richard Branson appears to be thinking of accelerating his own plans to go to space aboard one of his spaceplanes in response to Bezos’ announcement.

In the past, Branson said that he would be among the first passengers to fly aboard the SpaceShipTwo VSS Unity when it starts making crewed flights. Prior to Bezo’s announcement, the company indicated that it planned to mount three crewed test flights starting later this year (the second involving Branson). But according to industry insider’s, Virgin Galactic is hoping to move Branson’s flight up to July 4th and beat Bezos to space by a little over two weeks.

With this inaugural flight under their belt, Blue Origin will be one huge step closer to offering regular suborbital flights using the New Shepard. There’s no indication how much a single seat will cost, but it’s definitely not going to run into the double-digit millions! Currently, Virgin Galactic chargest $250,000 per seat for future flights aboard the SpaceShipTwo fleet, and Musk has quoted a pricetag of $200,000 to $500,000 for a one-way trip to Mars.

Not exactly affordable, yet. But as flights to space become a regular occurrence, we will see prices drop to the point where more and more can afford them. One thing is clear though: in the current age of space exploration, the commercial sector is no longer following the lead of federal space agencies. Between SpaceX, Blue Origin, Virgin Galactic, and thousands of smaller companies, the goal of making space more accessible rests with private companies.

Further Reading: Blue Origin

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Categories: Astronomy

Astronomers Have Found the Perfect Exoplanet to Study Another World’s Atmosphere

Mon, 06/14/2021 - 6:09pm

TESS (Transiting Exoplanet Survey Satellite) has found a new planet, and the discovery of this sub-Neptune exoplanet has scientists excited about atmospheres. The combination of the planet’s size, its thick atmosphere, and its orbit around a small M-class star close to Earth provides researchers with an opportunity to learn more about exoplanet atmospheres. We’re getting better and better at finding exoplanets, and studying their atmospheres is the next step in understanding them as a whole.

All of our exoplanet-detection strategies have an observation bias. It seems impossible to avoid. Even TESS (Transiting Exoplanet Survey Satellite), probably our most adept planet-finder, has an observation bias. Its predecessor Kepler was biased towards larger planets, and TESS doesn’t share that bias. But TESS still has a sort of blind spot due to how it operates.

No telescope can look everywhere at once, and TESS is no exception. It observes the sky mostly in 28-day chunks. So for one of those chunks, it focuses on one area for 28 days. To be confirmed as an exoplanet, an object must pass in front of its star twice in that 28 days. The end result of all this is that most of the planets TESS finds have orbital periods of less than 14 days.

Most of TESS’s observing is done in 28 day chunk, as the image shows. Image Credit: NASA/JPL

But this new planet, named TOI-1231 b, has a 24-day orbital period. This makes it a great target for the study of exoplanet atmospheres because it’s in front of its star longer and can be more easily studied. Universe Today readers know that studying light as it interacts with things is how we gain most of our knowledge about space. TESS itself won’t study the planet. Other missions like the James Webb Space Telescope (JWST) will take care of that by watching the starlight as it passes through the planet’s atmosphere.

“This new planet we’ve discovered is still weird – but it’s one step closer to being somewhat like our neighborhood planets.”

Jennifer Burt, Paper Lead Author, NASA-JPL.

Since TOI-1231 b spends so much time in front of its star relative to other TESS planets, missions like the JWST will get a much better look at it.

But it’s not only the planet’s orbital period that makes it an ideal target. Its size relative to its star also helps. Since the star is so small, the planet blocks out more of its light than if the planet and star were more similar to Earth and the Sun. “In a sense, this creates a larger shadow on the surface of the star, making planets around M dwarfs more easily detectable and easier to study,” the press release says.

The paper outlining TOI 1321-b’s discovery is titled “TOI-1231 b: A Temperate, Neptune-Sized Planet Transiting the Nearby M3 Dwarf NLTT 24399.” The lead author is NASA JPL scientist Jennifer Burt. The paper will be published in The Astrophysical Journal but is up now on the pre-press site arxiv.org.

“Working with a group of excellent astronomers spread across the globe, we were able to assemble the data necessary to characterize the host star and measure both the radius and mass of the planet,” said Burt in a press release. “Those values in turn allowed us to calculate the planet’s bulk density and hypothesize about what the planet is made out of. TOI-1231 b is pretty similar in size and density to Neptune, so we think it has a similarly large, gaseous atmosphere.”

The team that found TOI-1321 b says the planet is similar to Neptune and likely has a similar gaseous atmosphere. Image Credit: NASA/JPL

The new planet has a radius of about 3.65 times that of Earth. It has an orbital period of 24.26 days and mass of about 15.5 Earth masses. The star it orbits is an M-dwarf star about 90 light years away in the constellation Vela.

The planet is a lot closer to its star than the Earth is to the Sun. But 1321 b is about the same temperature because its star is so much cooler than the Sun. That lower temperature also makes it a desirable object for further study with the JWST and other telescopes. Its equilibrium temperature is only about 330 Kelvin, making it one of the coolest small planets available for atmospheric study. For comparison, Earth’s mean temperature is about 288 Kelvin, and an ultra-Hot Jupiter can have a dayside temperature of up to 2700 K, hotter than many stars.

“TOI-1231 b is one of the only other planets we know of in a similar size and temperature range, so future observations of this new planet will let us determine just how common (or rare) it is for water clouds to form around these temperate worlds,” said Burt.

This image from the study shows the transmission spectroscopy metric (TSM) values for some small exoplanets with temperature less than 1000 Kelvin. The four filled-in planets with black circles and labels have undergone follow-up study with the Hubble. TOI-1231 b is next, and gives scientists another opportunity to study the atmospher of small, cooler planets. The horizontal axis shows the J magnitude of the stars the planets orbit. Image Credit: Burt et al 2021.

Adding to its desirability as a target, it has a high systemic radial velocity. Astronomers are especially excited about that because it may permit the observation of low-velocity hydrogen atoms escaping from the atmosphere. TOI-1231 b’s characteristics and relationship with its star are similar to another star named GJ-436 and its planet GJ-436 b. GJ-436 b is well-known for its atmospheric escape, so astronomers think that the newly-discovered exoplanet will also experience atmospheric escape, though at a much lower rate than GJ-436 b. Hydrogen is the most likely escape culprit, but it’s hard to see because of the presence of interstellar gas. But TOI-1232 b is travelling away from Earth very quickly, making the hydrogen more visible.

Diana Dragomir is one of the co-authors of the paper. In the same press release she said, “The low density of TOI-1231 b indicates that it is surrounded by a substantial atmosphere rather than being a rocky planet. But the composition and extent of this atmosphere are unknown!” said Dragomir. “TOI-1231 b could have a large hydrogen or hydrogen-helium atmosphere, or a denser water vapor atmosphere. Each of these would point to a different origin, allowing astronomers to understand whether and how planets form differently around M dwarfs when compared to the planets around our Sun, for example. Our upcoming HST observations will begin to answer these questions, and JWST promises an even more thorough look into the planet’s atmosphere.”

It’ll be a while before the JWST can train its sensors on the newly-discovered exoplanet, even though the space telescope is launching soon (). But the Hubble is ready to go. In fact, one of the paper’s numerous authors is planning to observe TOI-1231 b later this month.

The James Webb Space Telescope in June 2020. We’ve been told it’ll launch soon. Image Credit: NASA/JPL

All of these exoplanet discoveries are showing us the wide variety present in other solar systems. There are some downright weird planets out there, at least compared to Earth. But this one is more similar to Earth than all the Hot Jupiters we’ve found, and while it’s still different, it at least might teach us something about our own Solar System and the planets that reside there.

One of the most intriguing results of the last two decades of exoplanet science is that, thus far, none of the new planetary systems we’ve discovered look anything like our own solar system,” said Burt. “They’re full of planets between the size of Earth and Neptune on orbits much shorter than Mercury’s, so we don’t have any local examples to compare them to. This new planet we’ve discovered is still weird – but it’s one step closer to being somewhat like our neighborhood planets. Compared to most transiting planets detected thus far, which often have scorching temperatures in the many hundreds or thousands of degrees, TOI-1231 b is positively frigid.”

More:

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Categories: Astronomy

Asteroid 16 Psyche Might Not be a Solid Chunk of Metal After All, but Another Rubble Pile

Sun, 06/13/2021 - 2:49pm

Asteroid 16 Psyche, often sensationally dubbed the 10,000 quadrillion dollar asteroid due to its composition of valuable metals, may not be entirely what it seems.  A new paper out of the University of Arizona suggests that the asteroid is possibly more porous, and less metallic, than previous studies indicated. It still certainly has a mostly metallic structure, but its composition is more complex – and that’s good news. Given the impracticality of space mining (in the near future anyway) 16 Psyche’s real value is scientific: planetary scientists think it is probably the exposed core of a protoplanet from the early days of the Solar System. Studying such an object up close would be enormously useful for understanding planet formation, and this paper is the latest attempt to understand its structure.

The researchers based their work on previous observational data that showed the asteroid was mainly a mix of three ingredients: metal, low-iron pyroxene, and carbonaceous chondrite. In the laboratory, they then tried to recreate the visible and near-infrared spectra seen by the telescopic observations, using various mixtures of the three ingredients. This allowed them to determine with a higher degree of accuracy the percentages of each ingredient that make up 16 Psyche’s surface. The result was 82.5% metal (previously estimated at a staggering 94%), 7% low-iron pyroxene, and 10.5% carbonaceous chondrite. They were also able to determine that the asteroid’s density must be quite low, with a porosity around 35%.

Artist’s depiction of 16 Psyche. Image Credit: NASA/JPL-Caltech/ASU

As lead Author David Cantillo explains, “That drop in metallic content and bulk density is interesting because it shows that 16 Psyche is more modified than previously thought…Having a lower metallic content than once thought means that the asteroid could have been exposed to collisions with asteroids containing the more common carbonaceous chondrites, which deposited a surface layer that we are observing.”

Low density is common in smaller asteroids. NASA’s OSIRIS-REx mission to asteroid Bennu discovered that the building-sized object was more like a rubble pile than a single chunk of rock, with a porosity higher than 50%. But for larger objects like Psyche (which is the sixteenth-largest asteroid in the Solar System by diameter and the ninth-largest by mass – about the size of Massachusetts), such a low density was a surprise. If 16 Psyche really is an ancient planetary core, it doesn’t appear like we expect it should.

Rendering of the Psyche spacecraft, due to arrive at the asteroid by 2026. NASA/JPL-Caltech/Arizona State Univ./Space Systems Loral/Peter Rubin

There’s only one way to find out what’s going on there, of course, and that’s to go visit it. NASA has been planning a robotic orbiter to visit 16 Psyche for years now, and the launch date is getting closer. Originally planned to arrive at the asteroid in 2030, the schedule was moved up to take advantage of a more direct orbital trajectory, and the spacecraft will now launch in 2022 and arrive in 2026. What it finds when it gets there is anyone’s guess, but Cantillo’s research has given us a better estimate of what to expect, and fuels excitement for more surprises to come.

Learn More:

Mikayla Mace Kelley, “Asteroid 16 Psyche Might Not Be What Scientists Expected.” University of Arizona.

David C. Cantillo et al., “Constraining the Regolith Composition of Asteroid (16) Psyche via Laboratory Visible Near-infrared Spectroscopy.The Planetary Science Journal

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Categories: Astronomy

It’s Time for Perseverance to get to Work

Sun, 06/13/2021 - 10:35am

Given all of the news surrounding the landing and first few months of operation of the Perseverance rover on Mars, it might be surprising that its actual science mission hasn’t even started yet.  That changed on June 1st when the rover officially kicked off its first science mission by leaving its landing site.

UT has reported on a variety of firsts coming from the rover, including the first sound recordings on Mars, when it first zapped a rock with its laser, first use of its MOXIE experiment, and lately the trials and tribulations of the Ingenuity helicopter.  But when all is said and done, there is still more science to do.

Video showing Perseverance’s current location and some of the area it will be traveling to as part of its first science mission.
Credit: NASA / JPL-Caltech / ASU / MSSS

One big to-do on Perseverance’s task list is to collect samples that will eventually be returned to Earth on the first ever Martian sample return mission later in the decade.  The rover is carrying 43 sample tubes that can be filled with interesting rocks or regolith that scientists want to take a closer look at.  

Where those rocks and regolith come from is one of the most important considerations of the mission as a whole, and Perseverance’s first science mission will focus on two major areas of interest.  The first stop will be the “Crater Floor Fractured Rough”, which hopefully will be blessed with a more whimsical name, if for no other reason than to make it easier on us science writers when talking about it in the future.  For now, this stop can be thought of as the floor of the Jezero crater, where Perseverance landed. Almost 4 billion years ago it was covered with at least 100m of liquid water, and the geology of the region should reflect that much wetter past.

Astronomy Cast Episode discussing the first 100 days of Perseverance.

The more whimsically named second area of the trip is the Séítah unit.  Meaning “admist the sand” in Navajo.   Filled with rocks, ridges, and sand dunes, the area could potentially offer up a more recent geological history than the the samples found on the crater floor.

Navigating around these two areas of interest is no mean feat for a rover being controlled from millions of miles away, so mission scientists have drawn up an old school road map to help illustrate the path the rover intends to take.  The overall route is expected to be between 2.5km and 5 km, and will end with a return to the “Octavia E. Butler” landing site, having left behind some samples for the return mission to pick up.  From there the rover will transition into a second phase of science experiments, which will see it travel north and west to a delta region of the crater, where a river once flowed into the lake that used to occupy the area.

Planned map of Perseverance’s first (south) and second (north) science missions in Jezero crater.
Credit : NASA / JPL-Caltech / University of Arizona

All of these areas could provide vital evidence for one of the big mission objectives of the rover – signs of life.  It’s exactly these types of environments that evidence for any ancient life forms that might have lived on the wetter, warmer Mars, might still show up.  Carbonates, which are common in the delta region, are known to have preserved fossils on Earth.  

At this point, any such evidence is still wishful thinking, and even the collection of the samples that might eventually contain that evidence is still months away.  But Perseverance is finally ready to take that first step – or wheel rotation – on the journey to collect even more data from the bottom of an ancient Martian lakebed.

Learn More:
JPL – Perseverance’s First Road Trip
JPL – NASA’s Perseverance Rover Begins Its First Science Campaign on Mars
UT – NASA’s Perseverance Rover: The Most Ambitious Space Mission Ever?

Lead Image:
Image of the Séítah unit from one of Ingenuity’s flights about 30m off the surface.
Credit: NASA / JPL-Caltech

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Categories: Astronomy

What’s the Connection Between the Chemistry of a Star and the Formation of its Planets?

Sun, 06/13/2021 - 9:57am

Scientists seem to have come up with a new parlor game – how many ways can we potentially detect exoplanets?  The two most common methods, the transit method and the Doppler method, each have their own problems.  Alternative methods are starting to sprout up, and a new one was recently proposed by Jacob Nibauer, an undergraduate student in the University of Pennsylvania’s Department of Physics and Astronomy.  His suggestion: look at a star’s chemical composition. And his findings after analyzing data on some 1,500 stars hold some surprises.

Spectroscopy allows scientists to directly collect data on the chemical composition of stars.  Mr. Nibauer’s method took into account that stars and planets form from the same nebular material.  Given that the chemical compositions of that material can be estimated before a star is formed, if the star itself happens to be lacking some of the material that would be used to make rocky planets, it’s a pretty strong indicator that there are in fact rocky planets orbiting that star.

UT Video discussing some possibilities for types of rocky exoplanets.

To prove this theory, Mr. Nibauer used data from APOGEE-2, part of the Sloan Digital Sky Survey, and focused on 5 different elements prevalent in rocky planets whose chemical composition was in the APOGEE-2 data.  He then applied a statistical tool called Bayesian analysis to separate types of stars in the data set into either a regular category, where the star still has the expected amount of “refractory” (i.e. rock forming) elements that would be expected from the nebular cloud, or a “depleted” category where the concentrations are less than expected.  

Interestingly, the data showed that most stars in the survey were actually Sun-like in their chemical composition, falling into the “depleted” category from their lack of refractory materials.  Previous studies of stars’ chemical compositions showed the Sun as an outlier, but may have been biased in that they used some characteristic of the Sun itself as a sorting mechanism.  But the methodology of categorizing the two groups before analyzing the Sun, and then slotting our nearest star into the appropriately categorized group, is a much more unbiased approach.

Data from the study showing stars from the study (orange) and the ratios of iron to hydrogen and for each of the five elements in the study.
Credit: Jacob Nibauer

Even with the elimination of that bias, there are still plenty of unanswered questions in this research.  So far, there hasn’t been any clear evidence that links “depleted” stars to rocky planets more than non-depleted ones.  Additionally, even 1500 stars is a relatively small sample size given the total number of stars in the galaxy.  As more data is collected on both exoplanets themselves and of the chemical signature of stars, it will build a clearer picture of what, if any, relationship there is between the presence of these rock forming minerals and that of any rocky planets in these extrasolar systems.

Learn More:
UPenn – Connecting a star’s chemical composition and planet formation
The Astrophysical Journal – Statistics of the Chemical Composition of Solar Analog Stars and Links to Planet Formation
UT – What are Stars Made Of?

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Categories: Astronomy

How To Search the Chemical Makeup of Exoplanet Atmospheres for Hints at Their History

Sun, 06/13/2021 - 9:37am

Author’s note – this article was written with Dr. Vincent Kofman, a scientist at NASA’s Goddard Space Flight Center (GSFC), working in the Sellers Exoplanet Environments Collaboration (SEEC), and the lead author on the research it discusses.

Thousands of exoplanets have been discovered in the recent decades. Planet hunters like TESS and Kepler, as well as numerous ground-based efforts, have pushed the field and we are starting to get a total number of planets that will allow us to perform effective statistical analysis on some of them.

Not only do the detected number of planets show us how common they are; it exposes our lack of understanding about how planets form, what conditions are present, and when planets may be habitable. The transit detection of an exoplanet primarily yields the orbital period, or the length of a year on the planet, and the relative size of the planet with respect to the star. The next steps are to characterize the planet. This usually requires follow up studies, using different observational strategies and more powerful telescopes.

UT Video on how to search for exoplanets.

Next to studying the occurrence, sizes, orbital periods, and the amount of light they receive, the composition of the atmospheres can provide much insight into our understanding of these new worlds. The composition of the atmospheres of exoplanets can be revealed by observing these using space-based telescopes, such as the Hubble Space Telescope, or from the ground using observatories like the Very Large Telescope or Keck.

These remote observations rely on interaction of the molecules in the atmosphere with light, and are highly specific to the conditions in the atmosphere, serving as a strong diagnostic for both the planet’s composition and its temperature. However, not all molecules are equally visible and the light from exoplanets very faint. Therefore, currently we are only able to see the brightest molecules, such as water, methane, carbon monoxide, sodium, as well as a number of metal-oxides. For the rest of the atmosphere, the planets in our solar system provide a first start to what may be present, but scientists strongly rely on chemical and physical models to assess what may be hidden from their spectroscopic studies.

Fortunately, the detectable molecules can teach us many things about the conditions in the atmosphere. For instance, the carbon to oxygen (C/O) ratio, inferred from the abundance of (amongst others) carbon monoxide, carbon dioxide, methane, and water, essentially indicates whether the chemistry in the atmosphere is oxygen or carbon dominated. These are different chemical end members, and lead to very different environments. Titan’s atmosphere for instance is carbon dominated, leading to a hazy world with hydrocarbon lakes. Mars’ atmosphere is an example of a C/O ratio of less than 1. As the C/O ratio can also be determined in protoplanetary disks, this is a valuable ratio that may link the birthplace of planets to their current state.

Another stochiometric ratio that has proven to be very insightful in the solar system, is that of hydrogen (H), the most common element in the universe, to its slightly heavier isotope, deuterium (D).  Known as the D/H ratio, it can provide a glimpse into the history and planet and its atmosphere, and is the focus of a new paper from scientists at NASA’s Goddard Space Flight Center (GSFC), led by Dr. Vincent Kofman.

UT video on water worlds.

The D/H ratio was originally set as part of the Big Bang at about 1 / 8700 – or 8700 atoms of hydrogen for every one of deuterium.  There are not many natural processes that have changed that ratio over time, with the exception of some active processes in stars.  That 1/8700 ratio is then passed on to planets as they begin to form, yet the initial endowment value can differ across the formation region in the nebula, where stars and planets form. This is because of the different temperatures at which hydrogen and deuterium containing molecules freeze out. Particularly for the extremely cold regions, the amount of deuterium is substantially higher. Planets can therefore have very different primordial D/H values depending on when and how they form.  Our solar system is a good example where that original ratio was in place during the planetary formation process.

The higher deuterium content of primordial ices is which is why the ice giant Uranus and Neptune have a higher D/H ratio than Jupiter and Saturn. After the planets were formed, though, the ratio on some planets changed. For the rocky planets, it is believed that they received their water from asteroids and comets, which formed at very different locations in the nebula as those planets, resulting in higher deuterium content in the atmospheres of Earth, Venus, and Mars.

Planets in the solar system with their deuterium / hydrogen levels compared to original nebula values.
Credit: NASA / Kofman

Subsequently, that ratio was increased even more by significant water loss. This effect, which can be most starkly seen on Mars and Venus, can be understood as following. As much of the hydrogen and deuterium in planetary atmospheres is tied up in water, which is easily destroyed by sunlight, resulting in elemental oxygen and hydrogen.

That hydrogen, floating high in the atmosphere, is then susceptible to being accelerated into space by the solar wind, then flying fast enough to escape the gravity of the terrestrial planets.  With that loss of hydrogen, the water molecule cannot reform, and the planet is left with a lower total quantity of water.  Over the course of billions of years, this process, if it continues, can cause a significant drop in the water content of a planet’s atmosphere.

UT video on water vapor in exoplanet atmospheres

However, there is one confounding factor in this story of lost water – deuterium, which is approximately twice as heavy as elemental hydrogen, is much less likely to be blown into space.  Therefore, any “heavy” water molecule that is split in the atmosphere is much less likely to lose its deuterium atom than a normal water molecule is to lose its regular hydrogen atom.  Over billions of years, this increases the D/H ratio in those atmospheres. 

To be able to investigate the D/H ratio on exoplanets the GSFC researchers had to pull information from huge spectroscopic databases.  In order to lessen the burden, they built a tool that allowed them to do so orders of magnitudes more quickly than existing systems. The databases have been incorporated into a tool they built called the Planetary Spectrum Generator (PSG). PSG is an online tool that allows the simulation spectra of (exo)planets, taking into consideration all elements of the calculations (the Solar/stellar spectrum, the planets’ surface and atmosphere, as well as absorption by the Earth’s atmosphere and the specifics of the telescope used).

Diagram of how we can use absorption spectral reading to determine the atmosphere of an exoplanet.
Image Credit: A. Feild, STScl, NASA

Using the Planetary Spectrum Generator to simulate the interaction of the exoplanet Trappist 1b with the light of its star while passing in front of it, the researchers have investigated the possibility of detecting the D/H ratio using the soon-to-be-launched James Webb Space Telescope. They demonstrated that for atmospheres rich in water, the D/H ratio could be constrained by observing a few transits of the planet in front of its host star.

With a better understanding of the D / H ratio, exoplanet hunters should be able to determine some of the atmospheric and hydrological history of these new planets. This will improve our understanding of the chemistry taking place on exoplanets and refine atmospheric models. Ultimately, it may enable a better grip on what it takes for a planet to be habitable.

Learn More:
Journal of Quantitative Spectroscopy and Radiative Transfer – Absorption in exoplanet atmospheres: Combining experimental and theoretical databases to facilitate calculations of the molecular opacities of water
Planetary Spectrum Generator
Philosophical Transactions of the Royal Society – D/H ratios of the inner Solar System
UT – The Color of Habitable Worlds
UT – New Technique to Search for Life, Whether or not it’s Similar to Earth Life

Lead Image
Artist’s conception of the Trappist system.
Credit – NASA / JPL-Cal Tech

Dr. Vincent Kofman, (NASA Goddard Space Flight Center, Greenbelt, MD, and Department of Physics, American University, Washington, DC)

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Categories: Astronomy

Relativity Space Gets a Huge Investment to Take on SpaceX With Reusable Rockets

Sat, 06/12/2021 - 5:28pm

They say imitation is the sincerest form of flattery, and that competition is a great way to foster progress and innovation. If these truisms are to be believed, then the NewSpace industry is destined to benefit from the presence of Relativity Space, a commercial space company based in Los Angeles. At the same time, SpaceX founder Elon Musk should be flattered that Tim Ellis and Jordan Noone (founders of Relativity Space) are following his example.

Roughly six years ago, Ellis and Noone founded Relativity for the purpose of using new technologies to disrupt the aerospace industry. Earlier this week (Tuesday, June 8th), the company announced that it had raised an additional $650 million in private capital. This money will go towards the development of rockets that are entirely 3D-printed and fully reusable, as well as the creation of a new class of heavy launch vehicles known as the “Terran-R.”

Years back, Ellis indicated that he and co-founder Noone were both inspired by Elon Musk and SpaceX’s achievements in space. At the time, Musk had proven that his company could retrieve and reuse their Falcon 9‘s first stage boosters and that the commercial space industry could handle everything from launching payloads to orbit to sending resupply missions to the International Space Station (ISS).

Innovation & Disruption

However, Ellis and Noone were concerned that when it came to his long-term ambitions (i.e., building a self-sustaining city on Mars), there was a certain lack of planning. Similarly, they felt that the space industry was still reliant on labor-intensive practices that were rapidly growing obsolete with the introduction of additive manufacturing (3D printing). As Ellis explained recently to Ars Technica:

“In every SpaceX animation, we saw a fade into black right when people walked out of the rocket on Mars. So what was clear [is] that there needed to be some other company building humanity’s industrial base on Mars. Replicating the infrastructure for a million people that live on Mars is a massive undertaking, and I think a lot of people need to work on it.”

As aerospace engineers, Ellis and Noone were both intimately acquainted with the NewSpace industry. The two even worked for Blue Origin and SpaceX before founding Relativity Space, and much of their concerns arose from the practices they witnessed firsthand. Essentially, it came down to the inefficient way in which rockets were being produced, which was inconsistent with the companies’ vision of reducing costs and making space more accessible.

This led to their decision to launch their own commercial space company that would fuse 3D printing, sensor and analytics-driven machine learning, and autonomous robots to create the structure and engines of their rockets. This, they hoped, would lead to a tenfold increase in production speed, a hundredfold decrease in the number of parts needed, a simplified and optimized supply chain, and a more rapid design and iteration process.

Optimized Production

At the center of their production efforts is their Factory of the Future, which relies on the Stargate – the world’s largest metal 3D printing system – to build all of their hardware. This includes the Aeon 1 rocket engine, which relies on a combination of liquid natural gas (LNG) and liquid oxygen (LOX) and can generate 69,000 Newtons (N, or 15,500 pounds-force) at sea level and 113,000 N (25,400 pounds-force) in the vacuum of space.

The same method is used to create their rocket fleet, which includes the two-stage Terran 1, the world’s first 3D printed rocket. This first stage relies on nine Aeon 1 engines, the second relies on a single Aeon VAC, and the entire launch system is capable of sending a maximum payload of 1,250 kg (2,760 lbs) to Low Earth Orbit (LEO), and 700 to 900 kg (1,500 – 2,000 lbs) to Sun-Synchronous Orbit (SSO).

Then there’s the Terran R, the world’s first 3D printed rocket that is fully reusable – engines, first stage, second stage, and payload fairing – which relies on seven Aeon R (LNG/LOX) engines for its first stage and one Aeon VAC for its second. This rocket is designed to compete with the Falcon 9 and will be capable of launching over 20,000 kg (44,000 lbs) to LEO, with a maiden launch from Cape Canaveral targeted for 2024.

These rockets and engines are printed from a propriety alloy using a process known as selective laser sintering and can build an entire rocket in just 60 days (and using less than 100 parts). This stands in contrast to the time-honored method of using traditional tooling to manufacture the various components, then relying on a hands-on process to assemble the thousands of parts together.

View inside Relativity’s Los Angeles facility. Credit: Relativity Space Seek What They Sought

The Terran R also has the distinction of being one of just two fully reusable launch systems in the world, the other being the SpaceX Starship. As Ellis indicated, the vehicle will also execute similar mission profiles to the Starship, such as transferring payloads through space, to the Moon, and perhaps even Mars. One can’t help but notice some similarities between the configuration of the Terran R and the Starship as well.

This includes the grid fins on the first stage (which assist in recovery) and the shape of the second stage/payload launcher – which looks like the Starship’s second stage. Once fully developed, the Terran R would be the Falcon 9‘s chief rival for lucrative government and commercial launch contracts. But the ultimate goal here, according to Ellis, is not to just compete with SpaceX, but augment its overall efforts.

“We’re trying to ice skate to where the puck is going,” he said. “What we keep hearing from customers is that they don’t want just a single launch company that is, frankly, the only quickly moving, disruptive provider.” I am reminded of the words of Matsuo Basho, “Do not seek to follow in the footsteps of the wise. Seek what they sought.”

With this latest round of funding, Relativity Space plans to accelerate the development of the Terran-R launch vehicle. In the meantime, the company is getting closer to the inaugural launch of its Terran 1 rocket. According to Ellis, the first and second stage are 85% finished and the second stage is expected to be shipped to NASA’s Stennis Space Center in Mississippi for hot-fire tests later this summer.

Whether it’s the commercial aerospace sector or national space agencies, one of the defining characteristics of the modern age of space exploration is the way more contenders are joining the fray. Whereas the “Space Race” was a constant struggle of one-upmanship between two superpowers, today, there are five major space agencies and any number of commercial providers working (in competition and cooperation) to ensure humanity’s future in space.

With their focus on optimized production, rapid iteration, and analytics that are driven by data and machine learning, Relativity Space is likely to give SpaceX, Blue Origin, and Virgin Galactic a run for their money in the coming years!

Further Reading: Ars Technica, Relativity Space

The post Relativity Space Gets a Huge Investment to Take on SpaceX With Reusable Rockets appeared first on Universe Today.

Categories: Astronomy

ESA is Joining NASA With Their own Mission to Venus

Sat, 06/12/2021 - 4:34pm

It’s an exciting time to be a Venus watcher.  Our sister planet, which has been the target of only one mission since the 1980s, is now the focus of not one, not two, but three missions from NASA and ESA.  Combined, they promise to give the closest look ever at the Morning Star, and some of the processes that might have made such a similar world so different from our own.

The first two missions were officially selected by NASA on June 2nd as part of the agency’s Discovery program.  Both missions have had a pedigree going back years, but with official program support now they are much better supported by the space exploration community, and much more likely to get off the ground.

YouTube video describing the DAVINCI+ mission announced last week.
Credit: NASA

DAVINCI+ and VERITAS, the two NASA missions have both been covered in detail in previous UT articles.  DAVINCI+, which evolved from the previously proposed Deep Atmosphere Venus Investigation of Noble gases Chemistry and Imaging probe, is focused on understanding the atmosphere and surface of Venus.  It will mark the first time the Venusian atmosphere will be directly sampled since 1985 when it launches a spherical probe into the atmosphere. It will also provide high resolution pictures of some features of the planet’s surface.

With that second objective, it overlaps with VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy), whose primary mission is to map the planet’s surface.  Using a combination of synthetic aperture radar and infrared imaging it will try to draw an accurate picture of both the contours of the surface as well as its makeup.

Trailer for NASA’s two new Venus missions.
Credit: NASA

Both missions will also serve a platform for technology demonstrators.  VERITAS will carry the Deep Space Atomic Clock-2, meant to keep accurate time to help with spacecraft maneuvering, while DAVINCI+ will sport the Compact Ultraviolet to Visible Imaging Spectrometer (CUVIS), a new type of imaging sensor for particular use in the ultraviolet range of the spectrum.

But they are not the only missions hosting NASA technology – on June 10th, ESA announced its own mission to Venus.  Known as the EnVision, the mission will serve as part of ESA’s Cosmic Vision plan of exploration.  One key component to EnVision is another synthetic aperture radar known as VenSAR.  Like the one hosted on VERITAS, this instrument will help EnVision study three different layers of the Venus system – the atmosphere, the surface, and even underground.  Using radio signals the probe will attempt to map the internal structure of the planet, allowing researchers to better map deposits of certain materials or unstable structures.  

Video showing some details of how EnVIsion will operate.
Credit European Space Agency / Paris Observatory / VR2Planets

Since these missions are all now officially accepted into formal development programs, their coordination can continue up to launch.  Though they are still years away from launching, let alone arriving at our sister planet, these missions will give Venus enthusiasts a whole slew of new things to look forward to.

Artist conception of the EnVision probe recently announce by ESA.
Credit: European Space Agency/Paris Observatory/VR2Planets

Learn More:
NASA – Then There Were 3: NASA to Collaborate on ESA’s New Venus Mission
ESA – ESA selects revolutionary Venus mission EnVision
NASA – NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus

Lead Image:
Image showing the similarity between Earth and Venus, with a concept of the EnVision spacecraft in the foreground.
Credit: European Space Agency / Paris Observatory / VR2Planets

The post ESA is Joining NASA With Their own Mission to Venus appeared first on Universe Today.

Categories: Astronomy