Universe Today

In the summer of ’69, Apollo 11 delivered humans to the surface of the Moon for the first time. Neil Armstrong and Buzz Aldrin spent just over two hours exploring the area near their landing site on foot. Only during Apollo 15, 16, and 17 did astronauts have a vehicle to move around in.

Artemis astronauts on the Moon will have access to a vehicle right away, and NASA is starting to test a prototype.

Momentum is building behind NASA’s Artemis program despite some setbacks. Artemis astronauts will explore the Moon far more thoroughly than the Apollo astronauts did, and technology is behind the improvement. Surface mobility is a key piece of Artemis. In April of 2024, NASA selected three vendors as part of their Lunar Terrain Vehicle Services contract.

NASA engineers at the Johnson Space Center are designing an unpressurized rover prototype known as the Ground Test Unit. It’s a human-rated, unpressurized LTV (Lunar Terrain Vehicle). The unit is being designed and built as a platform to evaluate rover designs being developed by three private companies: Intuitive Machines, Lunar Outpost, and Venturi Astrolab.

Intuitive Machines is known for its IM-1 mission with its Nova-C Lander. They were the first private company to land a spacecraft on the Moon.

Intuitive Machines’ Nova-C lunar lander was the first private spacecraft to land on the Moon. Image Credit: By NASA Marshall Space Flight Center / Intuitive Machines Photo ID: IM_00309., Public Domain, https://commons.wikimedia.org/w/index.php?curid=145130774

Lunar Outpost is known for its Mobile Autonomous Prospecting Platform (MAPP) rover (MAPP) rover. MAPP will be used on Intuitive Machines’ IM-2 and IM-3 missions and will demonstrate aspects of In-Situ Resource Utilization.

Venturi Astrolab is known for developing hyper-deformable wheels and batteries for lunar rovers. They’re also developing their FLEX rover, a larger vehicle designed to be modular to meet different objectives.

The LTV will be used to test the technologies these three companies develop. It’ll be used to evaluate crew compartment design, rover maintenance, science payload, and many other aspects of their rovers.

“The Ground Test Unit will help NASA teams on the ground, test and understand all aspects of rover operations on the lunar surface ahead of Artemis missions,” said Jeff Somers, engineering lead for the Ground Test Unit. “The GTU allows NASA to be a smart buyer, so we are able to test and evaluate rover operations while we work with the LTVS contractors and their hardware.”

Two engineers in suits sit on the prototype during testing at the Johnson Space Center. Image Credit: NASA/Bill Stafford

NASA has some requirements that the three selected companies need to meet. The rover must support two crew members and be able to be operated remotely. It can use multiple control concepts, such as supervised autonomy, different drive modes, and self-levelling.

NASA used its ‘Moon Buggy’ or Lunar Roving Vehicle (LRV) on Apollo 15, 16, and 17 in 1971 and 1972. It could carry 440 kg, including two astronauts, and had a top speed of 18 km/h. Though it provided range and mobility, it never travelled further than walking distance from the landers in case of breakdown. Image Credit: By NASA/Dave Scott; Public Domain, https://commons.wikimedia.org/w/index.php?curid=6057491

By supplying the Ground Test Unit, NASA is making it easier to test the designs from the three companies. It also helps build private sector capacity by enabling testing and iterative design without the separate companies needing to spend money on a GTU. Ground testing also allows for a safer testing environment.

An artist’s illustration of astronauts at the lunar south pole. Image Credit: NASA

When Apollo 11 reached the Moon, it was a civilization-defining moment. There was no reason to explore beyond the landing site since it was as unexplored as the rest of the Moon. But things are much different now.

Thanks to other missions and satellites that orbit the Moon, we have an almost encyclopedic knowledge of our natural satellite compared to the Apollo days. We know what questions we want answered, where we can do the best science, and where useful resources like water ice is. The idea behind Artemis is to go to the Moon and create an infrastructure that will allow us to maintain a presence there.

The Artemis lunar missions will rely on mobility to meet their goals. The LTV will be critical to Artemis’ success by allowing each mission to explore and develop a larger area. NASA intends to use the new rovers starting in Artemis V, which will launch no sooner than 2030.

The post Artemis V Astronauts Will be Driving on the Moon appeared first on Universe Today.

In June 2018, Japan’s Hayabusa 2 mission reached asteroid 162173 Ryugu. It studied the asteroid for about 15 months, deploying small rovers and a lander, before gathering a sample and returning it to Earth in December 2020.

The Ryugu sample contains some of the Solar System’s most ancient, primitive, and unaltered material, opening a window into its earliest days about 4.6 billion years ago.

The Ryugu sample is small, only about 5.4 grams (0.19 oz). However, scientific instruments that examine the sample’s chemical characteristics don’t need a large sample.

In new research, scientists examined tiny fragments of Ryugu using the Argonne National Laboratory’s Advanced Photon Source (APS). The APS is a particle accelerator that accelerates photons to nearly the speed of light. These photons release X-rays that are used in a wide variety of scientific endeavours. (The APS was even involved in developing COVID-19 vaccines.) In this research, the APS X-rays were used in a special technique called Mössbauer spectroscopy that can determine the oxidation rate of iron in the Ryugu sample.

The research is titled “Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples.” It’s published in the journal Science, and the lead author is Tetsuya Nakamura from Tohoku University in Sendai, Japan.

Ryugu is a rare type of asteroid. As a Cb spectral type, it has characteristics of both C-type carbonaceous asteroids, the most common type by far, and B-type asteroids, a more uncommon type of carbonaceous asteroid.

5.4 grams is not a large sample, but it’s large enough to reveal the nature and history of asteroid Ryugu. Image Credit: Yada et al./Nature Astronomy 2021

JAXA, the Japan Aerospace Exploration Agency, chose Ryugu for their sampling mission for several reasons. As a Near-Earth Asteroid (NEA), Ryugu was easier to reach. It’s also classified as a primitive, carbon-rich asteroid, so they hoped it would contain organic chemicals that hold clues about the early Solar System. Ryugu is also relatively small (900 metres) and rotates slowly, making sampling easier. The asteroid’s orbit also brings it close to Earth, making it easier to return the sample.

Ryugu could answer certain questions, all related to the history of the Solar System. Ryugu’s structure and composition, including the presence of water and organic matter, can reveal details about how planets and asteroids formed and how these essential materials for life may have been delivered to Earth. Scientists also hoped to classify Ryugu in more detail and understand its internal structure and how it might have evolved. Researchers also wondered about the asteroid’s resource potential.

Scientists working with the samples have already learned a lot. They’ve found that the asteroid is rich in organic matter, which supports the idea that asteroids could have delivered these materials to Earth. Ryugu contains water-bearing minerals, which is evidence that it held more water or water ice in the past. Scientists have also detected the effects of space weathering on the asteroid’s surface and solar wind particles trapped within its grains.

Artist’s impression of the Hayabusa2 taking samples from the surface of the asteroid Ryugu. Credit: Akihiro Ikeshita/JAXA

This new research added to the bounty of knowledge provided by the tiny 5.4-gram sample. The researchers analyzed 17 Ryugu particles, ranging in size from 1 to ~8 mm. They were mostly interested in uncovering a more detailed understanding of the asteroid’s history. They wanted to find answers to several specific questions:

1. When and where did Ryugu’s parent body form?
2. What is the original mineralogy, elemental abundances as a whole, and chemical compositions of the accreted materials, including their ice content?
3. How did these materials evolve through chemical reactions?
4. How was Ryugu ejected from its parent?

The APS and its Mossbauer Spectroscopy revealed more detail about Ryugu, and the researchers used impact simulators and other tools to piece together the history of the asteroid and its parent.

The researchers found carbon dioxide-bearing water inclusions in a certain type of crystal. This is evidence that Ryugu’s parent body formed in the outer Solar System, where cold temperatures allowed water ice to be incorporated. APS also identified a large concentration of pyrrhotite in the sample. Pyrrhotite is an iron sulphide found nowhere in meteorite fragments that resemble Ryugu. This helps limit the location and temperature of the parent body when it formed. The research team says that the parent body formed about 1.8 million to 2.9 million years after the beginning of Solar System formation.

In the outer Solar System, materials that form at low temperatures are dominant, and Ryugu’s parent was largely made of ice. The parent body formed beyond the H2O and CO2 snow lines and possibly beyond Jupiter.

The samples are porous and fine-grained, indicating that the parent contained ice that melted over a long period of time. The researchers say that radioactive heating in the parent body’s interior melted the water ice about three million years ago. Over time, reactions between the water and rock slowly changed the asteroid’s initial anhydrous mineralogy to a largely hydrous mineralogy.

The material was initially less altered at shallow depths and more hydrous at deeper depths. After about five million years, all of the material in the parent body reached its maximum temperature, and aqueous alteration continued.

The catastrophic head-on collision that blasted Ryugu’s parent happened about one billion years ago. The parent was about 50km in diameter, and the impactor was about 6 km. Ryugu isn’t a single chunk of its parent. Instead, it’s a rubble pile asteroid, a collection of debris dislodged from its parent body by the impact. Ryugu’s material originated at different depths on the opposite side of its parent from the impact and then coagulated into Ryugu.

This research helps paint a timeline of Ryugu’s parent and Ryugu itself on its long journey through the Solar System.

Ryugu itself began its journey as part of a larger body only about two million years after the birth of the Solar System. After billions of years as part of its parent body, it was created in the aftermath of a collision. After a long time, it made its way into its near-Earth orbit, and in the last blink of an eye, humanity arose and built a technological civilization. We’ve reached out and sampled this messenger from the past, and it’s taught us a lot about our Solar System’s history.

Hayabusa 2 is now on an extended mission to visit two other asteroids. In 2026, it will perform a high-speed fly-by of the S-type asteroid 98943 Torifune. In 2031, it will rendezvous with 1998 KY26, a small 30m asteroid that is a fast rotator.

Hayabusa 2 won’t sample either of these asteroids, but its observations will add to its already impressive contribution.

The post Tiny Fragments of a 4-Billion Year Old Asteroid Reveal Its History appeared first on Universe Today.

Neutron stars are as dense as the nucleus of an atom. They contain a star’s worth of matter in a sphere only a dozen kilometers wide. And they are light-years away. So how can we possibly understand their interior structure? One way would be to simply spin it. Just spin it faster and faster until it reaches a maximum limit. That limit can tell us about how neutron stars hold together and even how they might form. Obviously, we can’t actually spin up a neutron star, but it can happen naturally, which is one of the reasons astronomers are interested in these maximally spinning stars. And recently a team has discovered a new one.

All neutron stars rotate on their axes. They form from the collapse of a massive star’s core, and just as an ice skater spins faster as they pull in their arms, a neutron star spins up as it forms. Young neutron stars can rotate hundreds of times a second, though they generally slow down as they age. Interactions between their magnetic fields and interstellar space cause their rate of rotation to decay. This is why, for example, we can observe pulsars gradually slow down over time.

But many neutron stars have a binary companion. If their companion happens to be a closely orbiting regular star, the neutron star can pull off some of the companion’s outer layer and capture it. The slow exchange of matter can cause the neutron star to speed up as it essentially steals some of the orbital angular momentum of the companion. They are known as millisecond pulsars because they emit a radio pulse every few milliseconds. They are the fastest-rotating stars in the cosmos.

So, just how fast can these neutron stars spin? The record for the fastest spinning pulsar is held by PSR J1748–2446ad. Observations in 2004 and 2005 confirmed it rotates 716 times per second. That’s a bit faster than number two, which rotates at 707 times a second. This new study has found another neutron star rotating at 716 times a second, and it’s interesting because it isn’t a pulsar.

X-ray burst showing the 716 Hz oscillation. Credit: Jaisawal, et al

Known as 4U 1820-30, it is part of a binary X-ray system. As the neutron star captures material from its companion, part of its surface will heat up to such a degree that it emits X-rays. As the neutron star rotates, the hot-spot swings in and out of view, and we observe a periodic pulsation of X-rays. Using NASA’s NICER X-ray telescope, the team observed the binary from 2017 to 2021 and captured data on 15 powerful X-ray bursts. One of these bursts had a clear periodicity of 716 Hz. This strongly suggests the neutron star rotates at that rate.

While it could just be a statistical fluke, the fact that we now have two 716 Hz neutron stars found in two different ways suggests they may be near the maximal rotation limit for a neutron star.

Reference: Jaisawal, Gaurava K., et al. “A Comprehensive Study of Thermonuclear X-Ray Bursts from 4U 1820–30 with NICER: Accretion Disk Interactions and a Candidate Burst Oscillation.” The Astrophysical Journal 975.1 (2024): 67.

The post Astronomers Have Found the Fastest Spinning Neutron Star appeared first on Universe Today.

Carbon is the building block for all life on Earth and accounts for approximately 45–50% of all dry biomass. When bonded with elements like hydrogen, it produces the organic molecules known as hydrocarbons. When bonded with hydrogen, oxygen, nitrogen, and phosphorus, it produces pyrimidines and purines, the very basis for DNA. The carbon cycle, where carbon atoms continually travel from the atmosphere to the Earth and back again, is also integral to maintaining life on Earth over time.

As a result, scientists believe that carbon should be easy to find in space, but this is not always the case. While it has been observed in many places, astronomers have not found it in the volumes they would expect to. However, a new study by an international team of researchers from the Massachusetts Institute of Technology (MIT) and the Harvard-Smithsonian Center for Astrophysics (CfA) has revealed a new type of complex molecule in interstellar space. Known as 1-cyanoprene, this discovery could reveal where the building blocks of life can be found and how they evolve.

The research was led by Gabi Wenzel, a postdoctoral researcher from the Department of Chemistry at MIT. She was joined by researchers from the CfA, the University of British Columbia, the University of Michigan, the University of Worchester, the University of Virginia, the Virginia Military Institute (VMI), the National Science Foundation (NSF), the National Radio Astronomy Observatory (NRAO), and the Astrochemistry Laboratory at NASA’s Goddard Space Flight Center (GSFC). The paper that describes their findings recently appeared in the journal Science.

Artist’s impression of complex organic molecules in space. Credit: NSF/NSF NRAO/AUI/S. Dagnello

For their study, the team relied on the NSF Green Bank Telescope (GBT), the most accurate, versatile, and largest fully-steerable radio telescope in the world, located at the Green Bank Observatory in West Virginia. This sophisticated instrument allowed the team to detect the presence of 1-cyanopyrene based on its unique rotational spectrum. 1-cyanoprene is a complex molecule composed of multiple fused benzene rings and belongs to the polycyclic aromatic hydrocarbon (PAHs) class of molecules. On Earth, they are created by burning fossil fuels or other organic materials, like charred meat or burnt bread.

By studying PHAs, astronomers hope to learn more about their lifecycles and how they interact with the ISM and nearby celestial bodies. As co-author Harshal Gupta, the NSF Program Director for the GBO and a Research Associate at the CfA, explained in a recent CfA press release:

“Identifying the unique rotational spectrum of 1-cyanopyrene required the work of an interdisciplinary scientific team. This discovery is a great illustration of synthetic chemists, spectroscopists, astronomers, and modelers working closely and harmoniously.”

This was an impressive feat due to the difficulty (or even impossibility) of detecting these molecules due to their large size and lack of a permanent dipole moment. “These are the largest molecules we’ve found in TMC-1 to date. This discovery pushes the boundaries of our understanding of the complexity of molecules that can exist in interstellar space,” added co-author MIT professor Brett McGuire, who is also an adjunct astronomer at the NSF and the NRAO.

Previously, these molecules were believed to form only in high-temperature environments, like the region surrounding older stars. This concurs with what astronomers have known for a long time about certain carbon-rich stars, which produce massive amounts of small molecular sheets of carbon that they then distribute into the interstellar medium (ISM). In addition, previous research has suggested that the infrared fluorescence of PAHs – caused by the absorption of ultraviolet radiation from nearby stars – could be responsible for infrared bands observed in many celestial objects.

Artist’s impression of Green Bank Telescope conducting radio astronomy with the help of AI algorithms. Credit: Breakthrough Listen/Danielle Futselaar.

The intensity of these bands has led some astronomers to theorize that PAHs could account for a significant fraction of carbon in the ISM. Other astronomers have maintained that these carbon-rich molecules could not survive the harsh conditions of interstellar space because temperates in the ISM are far too low – averaging about 10 K (-263 °C; -442 °F). However, the 1-cyanopyrene molecules Wenzel and her colleagues observed were located in the nearest star-forming region to Earth, the cold interstellar cloud known as Taurus Molecular Cloud-1 (TMC-1).

Since this Nebula has not yet started forming stars, its temperature is the same as that of the ISM. “TMC-1 is a natural laboratory for studying these molecules that go on to form the building blocks of stars and planets,” said Wenzel. These observations suggest that PHAs like 1-cyanopyrene may have a different formation mechanism entirely and/or can survive the harsh environment of space. In the meantime, detecting cyanopyrene can provide indirect evidence of even larger and more complex molecules in future observations. 

This research was supported by measurements and analysis conducted by the molecular spectroscopy laboratory of Dr. Michael McCarthy at the CfA. As he indicated:

“The microwave spectrometers developed at the CfA are unique, world-class instruments specifically designed to measure the precise radio fingerprints of complex molecules like 1-cyanopyrene. Predictions from even the most advanced quantum chemical theories are still thousands of times less accurate than what is needed to identify these molecules in space with radio telescopes, so experiments in laboratories like ours are indispensable to these ground-breaking astronomical discoveries.”

Further Reading: CfA

The post Astronomers Discover Potential New Building Block of Organic Matter in Interstellar Space appeared first on Universe Today.

The Solar System’s hundreds of moons are like puzzle pieces. Together, they make a picture of all the forces that can create and modify them and the forces that shape our Solar System. One of them is Miranda, one of 28 known moons that orbit the ice giant Uranus. Miranda is its smallest major moon, at 471 km in diameter.

New research shows that this relatively small, distant moon may be hiding something: a subsurface ocean.

Miranda stands out from the other moons for one reason: its surface is a bizarre patchwork of jumbled terrain. There are cratered areas, rough scarps, and grooved regions. It may have the tallest cliff in the Solar System, a 20 km drop named Verona Rupes. Many researchers think its surface is deformed by tidal heating from gravitational interactions with some of the Uranus’ other moons.

New research in The Planetary Journal set out to explain Miranda’s jumbled geology. It’s titled “Constraining Ocean and Ice Shell Thickness on Miranda from Surface Geological Structures and Stress Modeling.” The lead author is Caleb Strom, a graduate student at the University of North Dakota.

“To find evidence of an ocean inside a small object like Miranda is incredibly surprising,”

Tom Nordheim, co-author and planetary scientist at the Johns Hopkins Applied Physics Laboratory

Scientists don’t have much to go on when it comes to Miranda. The only spacecraft to image it was Voyager 2 in 1986. Even then, the flyby was brief, and the spacecraft only imaged the moon’s southern hemisphere. But that was enough to reveal the moon’s bizarre and complex geological surface features. Miranda’s strange surface coronae attracted a lot of attention.

This figure from the study shows some of Miranda’s surface features. The moon is known for its coronae features, two of which are labelled here. Image Credit: Strom et al. 2024.

When the images were first received, scientists were baffled by Miranda’s complexity. Some called it a “patchwork planet,” and there was much healthy speculation about what created it. Attempts to understand the moon are still limited by the amount of data that Voyager 2 provided. However, modern scientists have access to a more powerful tool than scientists did in the 80s: computer models and simulations.

Strom and his co-researchers used a computer model to work backward from Miranda’s current surface. They started by mapping Miranda’s surface features, including its cracks, ridges, and unique trapezoidal coronae, and then reverse-engineered it. They tested different models of the moon’s interior to see what could account for the varied surface.

This simple schematic shows the four-layer model Strom and his co-researchers worked with. Image Credit: Strom et al. 2024.

The model that best matched the surface was one where Miranda had a vast ocean under its surface some 100-500 million years ago. The icy crust is probably 30 km thick or less, and the ocean could be up to 100 km thick.

“Our results show that a thin crust (?30 km) is most likely to result in sufficient stress magnitude to cause brittle failure of ice on Miranda’s surface,” the authors explain in their research. “Our results also suggest the plausible existence of a ?100 km thick ocean on Miranda within the last 100–500 million yr.”

“To find evidence of an ocean inside a small object like Miranda is incredibly surprising,” said Tom Nordheim, a planetary scientist at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, a study co-author, and the principal investigator on the project that funded the study. “It helps build on the story that some of these moons at Uranus may be really interesting — that there may be several ocean worlds around one of the most distant planets in our solar system, which is both exciting and bizarre.”

Tidal heating is responsible for this, and it came from gravitational relationships between Miranda and Uranus’ other moons. Moons tug on each other, and when they’re in an orbital resonance with one another, where each moon’s period around a planet is an exact integer of the others’ periods, those tugs are amplified. These forces can periodically deform the moons, and as they’re squeezed, they heat up, keeping subsurface oceans warm and liquid.

Miranda and other moons of Uranus were likely in resonance in the past, which could’ve created surface fractures and related terrain.

A digital elevation model (DEM) of Miranda’s Inverness Coronae. The relative elevation ranges from 0 km (purple) to 4 km (red). Image Credit: Beddingfield et al. 2022.

However, resonances don’t last forever, and the researchers think that some time ago, Miranda left orbital resonance, and its interior began to cool. They don’t think it’s completely cooled yet because if the ocean had completely frozen, it would’ve expanded and displayed telltale surface cracks. So, the interior ocean likely still exists but is probably much thinner than in the past. “But the suggestion of an ocean inside one of the most distant moons in the solar system is remarkable,” Strom said.

Nobody predicted that Miranda would have an ocean. As far as scientists could tell, it was a frozen ball. But they’ve been wrong about moons before.

Researchers used to think that Saturn’s moon, Enceladus, the most reflective object in the Solar System, was just a ball of ice. After all, its surface is smooth and clearly frozen solid. However, the Cassini mission showed us that it may not be totally frozen. There’s a bevy of evidence that Enceladus has a warm ocean under a layer of ice.

This false-colour image of the plumes erupting from Enceladus is easily recognizable to many. Enceladus and Miranda are similar in important ways. Could Miranda also be geologically active? Image Credit: NASA/ESA

“Few scientists expected Enceladus to be geologically active,” said co-author Alex Patthoff. “However, it’s shooting water vapour and ice out of its southern hemisphere as we speak.”

Since both Enceladus and Miranda are roughly the same size and may have similar ice shells, it increases the chances that Miranda also has an ocean. Other moons, like Saturn’s Europa, may also be icy ocean moons. Now, scientists think these moons and their warm oceans are the best targets in the search for life in our Solar System.

Other recent research suggests that Miranda could be more like Enceladus than thought. One 2023 study showed that the moon may be releasing material into space like Enceladus does. The ESA and NASA are both sending probes to Jupiter to study Europa and other potential ocean moons. Should we expand that search to distant Uranus and its small moon Miranda?

An artist’s impression of Uranus and its five largest moons (innermost to outermost): Miranda, Ariel, Umbriel, Titania and Oberon. A 2023 paper showed that Ariel and/or Miranda could be releasing material into space. Image Credit: NASA/Johns Hopkins APL/Mike Yakovlev

“We won’t know for sure that it even has an ocean until we go back and collect more data,” said study co-author Nordheim. “We’re squeezing the last bit of science we can from Voyager 2’s images. For now, we’re excited by the possibilities and eager to return to study Uranus and its potential ocean moons in depth.”

For now, all we have is decades-old Voyager 2 data. However, the data and the computer models the team employed shed new light on Miranda.

“We interpret the tidal stress model results to indicate that at some point in Miranda’s geologic past, it experienced an intense heating event that resulted in a thin crust (?30 km). Such a thin crust would also have resulted in a ?100 km thick ocean to account for the molten part of the hydrosphere. This thin ice crust and thick ocean could have allowed for intense tidal stress leading to significant geologic deformation in the form of brittle deformation at Miranda’s surface,” the authors explain.

“In conclusion, our results suggest that Miranda could have had a subsurface ocean in the geologically recent past from an intense heat pulse, consistent with dynamical modelling results of previous studies,” they conclude.

The post There’s Another Ocean Moon Candidate: Uranus’ Tiny Moon Miranda appeared first on Universe Today.

Saturn’s moon, Titan, is an anomaly among moons. No other moons have surface liquids, and aside from Earth, it’s the only other Solar System object with liquids on its surface. However, since Titan is so cold, the liquids are hydrocarbons, not water. Titan’s water is all frozen into a surface layer of ice.

New research suggests that under the surface, Titan is hiding another anomaly: a thick crust of methane.

The evidence for the methane comes mostly from craters. Observations have found few confirmed impact craters on the frigid moon, and the ones that have been observed are hundreds of meters shallower than the same-sized craters on other moons. If Titan’s crust was rock, the craters should be much deeper.

The new research, published in The Planetary Science Journal, is titled “Rapid Impact Crater Relaxation Caused by an Insulating Methane Clathrate Crust on Titan.” Lauren Schurmeier, from the Hawai’i Institute of Geophysics and Planetology at the University of Hawai’i at Manoa, is the lead author.

Titan stands apart from other moons for multiple reasons. Unlike any other natural satellites in the Solar System, it has a thick atmosphere. Its atmosphere is about 50% more dense than Earth’s and extends about 600 km into space. A haze made of complex organic molecules called tholins gives the atmosphere its characteristic orange colour. The atmosphere is so thick that it blocks optical light, making Titan’s surface features nearly inscrutable.

The Cassini spacecraft has given us our best looks at Titan. It used radar and infrared instruments to see the moon’s surface. The small Huygens probe that went to Saturn with Cassini was released into Titan in 2005 to study the atmosphere and surface. It’s thanks to Huygens that we have our best images of Titan’s surface.

The new research suggests a link between Titan’s unusual atmosphere, its shallow surface craters, and a layer of methane in the moon’s crust. The methane keeps the underlying layer of ice convective by insulating it and helps impact craters rebound quickly and remain shallow.

There’s no consensus on how many craters Titan has because its surface is veiled behind its thick atmosphere, but there is some data on the craters.

This graph shows crater candidate counts binned by latitude regions and certainty level. Craters of certainty level 1 have more lines of evidence pointing toward an impact crater origin; certainty level 4 is the least certain. Image Credit: Schurmeier et al. 2024.

The research centres on the fact that Titan displays few craters and that the ones we do see are shallow. This sets it apart from other moons.

These are Cassini SAR (synthetic aperture radar) images of Titan’s impact craters. Arrows indicate potential forms of crater modification processes, including dunes and sands (purple), channels (blue), and significant crater rim erosion (pink). Afekan crater is one of Titan’s largest impact craters at 115 km. Jupiter’s moon, Ganymede, which is about the same size as Titan, has way more craters, including 20 that are larger than Afekan. Image Credit: NASA/ Cassini

“This was very surprising because, based on other moons, we expect to see many more impact craters on the surface and craters that are much deeper than what we observe on Titan,” said lead author Schurmeier. “We realized something unique to Titan must be making them become shallower and disappear relatively quickly.”

A handful of processes have been proposed to explain Titan’s diminishing craters. Liquid hydrocarbon rainfall, aeolian sand infill, and topographic relaxation induced by insulating sand infill have all been discussed. “Here, we propose an additional mechanism: topographic relaxation due to an insulating methane clathrate crustal layer in Titan’s upper ice shell,” the authors write.

This simple schematic of Titan’s interior (not to scale) shows a methane clathrate crust over a convecting ice shell. The methane clathrate can insulate the ice below and keep it convective. That convection could explain why Titan’s craters are so few and so shallow. Image Credit: Schurmeier et al. 2024.
 

There’s very little new information coming from Titan, so researchers have to work with what they have. To try to understand its shallow craters, the researchers built a computer model. They used it to try to understand how Titan’s topography might respond to impacts if a layer of methane clathrate was trapped under the surface. A clathrate is a substance where one type of molecule is trapped within a structure of molecules of another type. In this case, methane is trapped in water ice.

Methane’s insulating properties are key.

“Methane clathrate is stronger and more insulating than regular water ice,” said Schurmeier. “A clathrate crust insulates Titan’s interior, makes the water ice shell very warm and ductile, and implies that Titan’s ice shell is or was slowly connecting.”

With their model, they tested clathrate crusts that were 5, 10, 15, or 20 km thick. They used craters that were 40, 85, 100, and 120 km in diameter, each with two initial depths based on Ganymede’s crater diameters and depths. The result?

“We find that all clathrate crustal thicknesses result in rapid topographic relaxation despite Titan’s cold surface temperature,” the researchers write. “The 5 km thick clathrate crust can reproduce nearly all of the observed shallow depths, many in under 1000 yrs.”

They also found that a 10 km clathrate crust can reproduce Titan’s observed crater depths over geologic timescales. “If relaxation is the primary cause of the shallow craters, then the clathrate thickness is likely 5–10 km thick,” they write.

Across all simulations, most of the crater relaxation occurred in 1,000 years. “This finding suggests that thin clathrate crusts cause crater shallowing in a geological instant, similar to a fast-flowing terrestrial glacier,” the authors explain. It could certainly explain why none of Titan’s craters are deep.

The researchers point out a couple of caveats, though. They assumed that Titan’s initial craters had depths similar to Ganymede’s. They could’ve formed at different depths and shapes. Their model also didn’t include heat generated by the impact itself or account for an impact-triggered discontinuity in the methane clathrate layer. “These thermal and dynamic changes might alter the morphological evolution of the crater,” they write.

Juno captured this image of Ganymede in July 2022. The moon’s impact craters are easily visible, including the crater Tros, which is prominent below the center at left. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill

This research adds to Titan’s mystery and our fascination with the unusual moon. It also adds another element to comparisons with Earth. Earth and Titan both have surface liquid and are the only two objects in the Solar System that do. Earth also has methane clathrates in its polar regions.

“Titan is a natural laboratory to study how the greenhouse gas methane warms and cycles through the atmosphere,” said Schurmeier. “Earth’s methane clathrate hydrates, found in the permafrost of Siberia and below the arctic seafloor, are currently destabilizing and releasing methane. So, lessons from Titan can provide important insights into processes happening on Earth.”

In the end, their results are clear: “We conclude that if crater relaxation is the primary cause of Titan’s unexpectedly shallow craters, then the clathrate crust is 5–10 km thick,” the authors write.

The post Titan May Have a Methane Crust 10 Km Thick appeared first on Universe Today.

Sungrazer C/2024 S1 ATLAS broke apart at perihelion.

Alas, a ‘Great Halloween Comet’ was not to be. The Universe teased us just a bit this month, with the potential promise of a second naked eye comet in October: C/2024 S1 ATLAS. Discovered on the night of September 27th by the Asteroid Terrestrial Last-alert impact System (ATLAS) all-sky survey, this inbound comet was surprisingly bright and active for its relative distance from the Sun at the time of discovery. This gave the comet the potential to do what few sungrazers have done: survive a blisteringly close perihelion passage near the Sun.

S1 ATLAS on final solar approach. NASA/ESA/SOHO Perishing at Perihelion

But as perihelion day approached yesterday on October 28th, things started to look grim. S1 ATLAS began to resemble a garden variety Kreutz sungrazer more and more. Little more than an icy rumble pile on final approach, the comet went in the inner field of view of the Solar Heliospheric Observatory’s (SOHO) LASCO C2 imager and behind the central occulting disk yesterday morning… and failed to exit.

Comet S1 ATLAS ends its days, as seen via SOHO’s LASCO C2 imager. NASA/SOHO

Perihelion distance (and time of expiry) for the comet was 330,600 miles/532,000 kilometers from the surface of the Sun yesterday, at around 7:30 AM EDT/11:30 Universal Time. Curiously, the final estimates for the comet put its orbital period at 953 years, suggesting that this may not have been its first passage through the inner solar system.

The finale for Comet S1 ATLAS, just hours prior to perihelion. ESA/NASA/SOHO/NRL

The comet gave us a few tell-tale signs that it was under-performing leading up to perihelion. After a brief outburst around its discovery 1.094 Astronomical Units (AU) from the Sun, the comet then faded considerably in early October. The lackluster performance was confirmed as it entered the field of view of SOHO’s LASCO C3 viewer this weekend. Still, its final solar dive put on a good show.

As I’m sure you’re aware, little comet ATLAS didn’t make it. ? It was clearly already a pile of rubble by the time it reached the LASCO field of view, and solar radiation took care of the clean-up for us. ???? pic.twitter.com/s8HrchtWnF

— Karl Battams (@SungrazerComets) October 28, 2024

A Brief History of Sungrazers

The demise of Comet S1 ATLAS yesterday brought to mind memories from early on in my Universe Today writing career of another great comet that wasn’t: C/2012 S1 ISON. That particular comet met its end on U.S. Thanksgiving Day 2013. The last great surprise for sungrazers was Comet W3 Lovejoy in 2011-2012, which survived a perihelion just 87,000 miles/140,000 kilometers from the surface of the Sun (!), and went on to become a great comet. Another example showing us what is possible was Comet Ikeya-Seki, which survived perihelion 280,000 miles/450,000 miles from the Sun in 1965 and became one of the great comets of the 20th century.

Light curve magnitude comparisons of comets Ikeya-Seki, W3 Lovejoy and S1 ATLAS in the lead up to their respective perihelia. Credit: Jakub Cerný

Astronomer Heinrich Kreutz discovered the existence on the Kreutz family of sungrazing comets in the 1890s. The earliest documented report of a sungrazer was from Greece by Aristotle and contemporary historian Ephorus in 371 BC. Prior to 1979, only nine confirmed sungrazers were known of… the launch of the joint NASA European Space Agency’s SOHO mission in 1995 changed the game considerably. Now, SOHO’s sungrazer tally after over a quarter of a century in space is 5,065 comets and counting. It turns out, we were still missing lots of what was passing through the inner solar system, all this time.

More in Store?

Last week, the NOAA revealed the successor for SOHO’s coronagraph aboard its GOES-19 satellite. The CCOR-1 (Compact Coronagraph) should start releasing public images in early 2025.

This comes as the ‘other’ October comet, C/2023 A3 Tsuchinshan-ATLAS fades from view. A3 T-ATLAS is now outbound at +6th magnitude in the constellation Ophiuchus. The comet had a decent evening apparition post perihelion a few weeks ago. The spiky ‘anti-tail’ provided an amazing view.

Are there any great comets on tap for 2025? Well, as of writing this, there’s only one comet with real potential to reach naked eye visibility in 2025: Comet C/2024 G3 ATLAS. This comet reaches perihelion 0.094 AU from the Sun on January 13th. G3 ATLAS and ‘may’ top -1st magnitude or brighter.

S1 ATLAS may have joined the ranks of comets that failed to live up to expectations… but you just never know. Its fast-paced story from discovery to demise shows us just how quickly the next bright comet could make itself known. Keep watching the skies: its only a matter of time.

The post Death of a Comet: S1 Didn’t Survive its Sungrazing Plummet appeared first on Universe Today.

In May 2023, the ESA’s Exomars Trace Gas Orbiter (TGO), currently in orbit around Mars, sent a signal to Earth to simulate a possible extraterrestrial transmission. As part of the multidisciplinary art project “A Sign in Space,” the purpose was to engage citizen scientists in helping to decode it. The campaign was inspired by Cosmicomics by Italian writer/journalist Italo Calvino, a series of short stories exploring various scientific principles. The project is partnered with the SETI Institute, the Green Bank Observatory, the European Space Agency (ESA), and the Istituto Nazionale di Astrofisica (INAF).

After three radio astronomy observatories on Earth intercepted the message, the challenge was to extract the message from the raw data of the radio signal and then decode it. After ten days, more than 5000 citizen scientists worldwide gathered online and used their combined resources to extract the signal. After a year of attempts, two U.S. citizens – the father-daughter team of Ken and Keli Chaffin – managed to crack the code after days of simulations. They discovered that the message consisted of five clusters of white dots and lattices against a black background, suggesting cellular formation and life!

The project was founded by Daniela de Paulis, a media artist and licensed radio operator currently serving as the Artist in Residence at the SETI Institute and the Green Bank Observatory. Daniela and a small group of astronomers and computer scientists crafted the message with support from the ESA, the SETI Institute, and the Green Bank Observatory. On June 7th, 2024, she received the decoded image, which depicted five amino acids—the very building blocks of life—in a retro-like format.

Ken Chaffin included the following message with the solution he and his daughter submitted:

“My decoded message is a simple image with 5 amino acids displayed in a universal (hopefully) organic molecular diagram notation and a few single pixel points that appear between the clusters and molecular diagrams. I used a Margolus reversible 2×2 block cellular automata (BCA) with the simplest reversible rule, which is called ‘single point (CCW) rotation,’ acting only on 2×2 cells that contain only a single point or pixel per the header instructions, conserving pixel or point count, 625 pixels in and 625 out. The starmap image appears to have the molecular forms encoded in a 3D local degree of freedom set of basis vectors (also shown in the header).

“The CA effectively transforms and projects this 3D info onto a 2D plane. I can run my Unity game engine based simulator forwards (CCW rotation) and backwards (CW rotation) in time and transform the starmap representation to the amino acid diagrams in 6625 generations and reverse the rotation process to transform the amino acid diagrams back to the starmap image in 6625 generations. I say starmap but I really read from the binary message file each run. The decoded image is only visible for 1 frame lasting about 1/10th of a second, but I can pause and manually step as well as reverse my CA engine…Here is a screen capture of my decoded image [see below].

“The ‘blocks’ have 1, 6, 7, or 8 ‘pixels’ representing the atomic number of hydrogen, carbon, nitrogen, and oxygen. Single and double bonds are designated as single and double lines. C-H bond angle is indicated with a caret ^ sign. These signs were produced by the CA. I have not edited the image in any way. It’s absolutely obvious to me what this is, as well as to my chemist friend I ran this by. It is amazing to watch all of the CA gliders or spaceships carry the binary bits of the message all over the ‘galaxy’ and then suddenly come together in coherence and meaning…”

The image shows the Chaffis solution. Credit: A Sign in Space

Now that the tasks of extracting and decoding the message are complete, Daniela and her colleagues are taking a step back to observe how citizen scientists are shaping the challenge. The next step is to interpret the message and determine what it was meant to convey, a task that currently remains open. According to the project team, there are several ways for the public to engage, which include using the description and solution provided by the Chaffins to conduct independent analysis and post the results on the project’s Discord channel.

Participants must include a description of the method they used so that their approach can be replicated and verified. The possibilities are endless, ranging from an attempt at communication, cultural exchange, or a threat of invasion. Ultimately, this exercise aims to determine whether or not humanity is ready to make first contact with an alien civilization.

Further Reading: ESA

The post Remember that “Alien Signal” Sent by the ExoMars Orbiter Last Year? It’s Just Been Decoded appeared first on Universe Today.

Though there are no firm plans for a crewed mission to Mars, we all know one’s coming. Astronauts routinely spend months at a time on the ISS, and we’ve learned a lot about the hazards astronauts face on long missions. However, Mars missions can take years, which presents a whole host of problems, including astronaut nutrition.

Nutrition can help astronauts manage spaceflight risks in the ISS, but long-duration missions to Mars are different. There can be no resupply.

In physiological terms, low gravity and radiation exposure are the two chronic hazards astronauts face on the ISS. Low gravity can lead to muscle loss and bone density loss, and radiation exposure increases the risk of developing cancer and other degenerative diseases. When astronauts make the trip to Mars, each leg of the journey can take 6 or 7 months, and they may stay on Mars for 500 days.

This dwarfs the eight days that the Apollo 11 astronauts spent in space. These long trips will tax astronauts’ health and NASA is working to understand what role nutrition can play in helping astronauts stay healthy and manage the risks.

Their current work on astronaut nutrition is a freely available PDF book titled “Human Adaptation to Spaceflight: The Role of Food and Nutrition—2nd Edition.” Its four authors are all researchers working in nutrition, biochemistry, biomedical research, space food systems, and preventative health.

“The importance of nutrition in exploration has been documented repeatedly throughout history, on voyages across oceans, on expeditions across polar ice, and on treks across unexplored continents,” the authors write.

Scientists have learned a lot about nutrition since the age of sailing and exploration, but the authors write that “a key difference between past journeys and space exploration is that astronauts are not likely to find food along the way.” This means that understanding astronaut nutritional requirements and food system requirements on long journeys is “as critical to crew safety and mission success as any of the mechanical systems of the spacecraft itself.”

The book examines the unique challenges astronauts face and presents data from multiple studies that are analogous to those challenges. For example, nutrition research from Antarctica duplicates the isolation and lack of sunlight astronauts can face on long missions, and head-down tilt-bed rest duplicates the musculoskeletal disuse they must endure.

This figure shows how HDT bed rest is used as an analogue for astronauts during long-duration microgravity spaceflight. Image Credit: Hargens AR et al. 2016.

Astronauts face a long list of health risks on long-duration spaceflights. Radiation exposure and its cancer risk and microgravity and its effect on muscle and bone are the most well-known risks. But there are other lesser-known risks, too.

Astronauts can suffer from neuro-ocular syndrome, their immune systems can be weakened, and their gut biota can change. All of these conditions are linked with nutrition. While scientists don’t have a complete understanding of how everything works, it’s clear that nutrition plays a role. The book outlines the types of research being done and what the current understanding is. But the authors are clear about one thing: the system of providing astronauts with proper nutrition needs work.

ISS astronauts, except for Russians, get part of their food in Crew Specific Menu (CSM) containers that each astronaut orders. They provide between 10% and 20% of their food. They also receive a small supply of fresh foods and limited shelf-life foods on each re-supply mission. This has increased the variety of foods for astronauts and helped with nutrition, but astronauts still say they’d like more CSM and fresh foods.

Here in the developed world on Earth, it’s fairly straightforward to meet nutritional needs. Most of us have access to supermarkets and/or farmer’s markets where we can buy fresh produce and other healthy foods. That same variety simply isn’t available in space. ISS astronauts have done some experimental “farming” and have successfully grown a few food plants like lettuce, kale, and cabbage. However, that’s a long way away from growing enough food to help with nutrition, especially on a Mars mission, where presumable space and payload will be at a premium.

Crops successfully grown in Veggie include lettuce, Swiss chard, radishes, Chinese cabbage and peas. Image Credit: NASA

One obvious question about astronaut nutrition is whether supplements can replace nutritious food. The authors present evidence that discredits that idea. “Many previous studies have shown that the complex synergistic benefits provided by whole foods cannot be replicated by supplements,” they write. In fact, in some instances, supplements can be dangerous. “Recent studies have also found that supplementation with certain antioxidants such as vitamin E and vitamin A can increase risks of cancer and all-cause mortality,” the authors explain.

The need for a space food system goes beyond nutrition. There are social and well-being benefits, too. Knowing that you have access to a variety of healthy foods keeps morale up. The ability to share or trade high-value food items with your fellow astronauts can create goodwill and a desire to cooperate. Think of sharing a meal with friends or family and all the social connection it provides.

According to the authors, there’s currently no solution to the nutrition roadblock for Mars missions. In fact, there’s currently no system designed to supply astronauts with the needed nutrition for any long-duration spaceflight. “Currently, no food system exists to meet the nutrition, acceptability, safety, and resource challenges of extended exploration missions, such as a mission to Mars,” the authors write.

However, the researchers say it’s critical that we develop one. Without it, long-duration missions and the astronauts who crew them will suffer and possibly face catastrophic failure.

“A space food system, developed and provisioned to deliver all the defined nutritional requirements, should be available on every human mission as an essential countermeasure to health and performance decrements,” the authors write.

The post Add Astronaut Nutrition to the List of Barriers to Long-Duration Spaceflight appeared first on Universe Today.

In 1181, Japanese and Chinese astronomers saw a bright light appear in the constellation Cassiopeia. It shone for six months, and those ancient observers couldn’t have known it was an exploding star. To them, it looked like some type of temporary star that shone for 185 days.

In the modern astronomical age, we’ve learned a lot more about the object. It was a supernova called SN 1181 AD, and we know that it left behind a remnant “zombie” star. New research examines the supernova’s aftermath and the strange filaments of gas it left behind.

Though it was seen almost 850 years ago, only modern astronomers have been able to explain SN 1181. For a long time, it was an orphan. While astronomers were able to identify the modern remnants of many other historical supernovae, SN 1181 was stubborn. Finally, in 2013, amateur astronomer Dana Patchick discovered a nebula with a central star and named it Pa 30. Research in 2021 showed that Pa 30 is the remnant of SN 1181. The SN exploded when two white dwarfs merged and created a Type 1ax supernova.

SN 1181 is unusual. When supernovae explode, there’s usually only a black hole or a neutron star left as a remnant. But SN 1181 left part of a white dwarf behind, an intriguing object astronomers like to call a zombie star. Strange filaments resembling dandelion petals extend from this strange star, adding to the object’s mystery.

Researchers have gotten a new, close-up look at Pa 30 and published their results in The Astrophysical Journal Letters. The research is titled “Expansion Properties of the Young Supernova Type Iax Remnant Pa 30 Revealed.” The lead author is Tim Cunningham, a NASA Hubble Fellow at the Center for Astrophysics, Harvard & Smithsonian.

“The recently discovered Pa 30 nebula, the putative type Iax supernova remnant associated with the historical supernova of 1181 AD, shows puzzling characteristics that make it unique among known supernova remnants,” the authors write. Pa 30 has a complex morphology, including a “unique radial and filamentary structure.”

The hot stellar remnant at Pa 30’s center is also unique. Its presence, as well as the lack of hydrogen and helium in its filaments, indicates that it’s the result of a rare Type1ax supernova. Since hydrogen and helium make up 90% of the chemicals in the Universe, objects without either of them are immediately interesting.

In this research, the astronomers used the Keck Cosmic Imager Spectrograph (KCIS) to examine the 3D structure and the velocities of the filaments. The KCIS was built to observe the cosmic web, the intricate arrangement of gas, dust, and dark matter that makes up the large-scale structure of the Universe. The gas and dust are extremely dim, and the KCIS was made to perform spectroscopy on these types of low surface brightness phenomena. That makes it a powerful tool for observing the strange filaments coming from Pa 30.

KCIS is a powerful spectrograph that can capture spectral information for each pixel in an image. It can also measure the redshift and blueshift of objects it observes, meaning it can determine their velocity and direction of movement. The researchers were able to show that material in the filaments travelled ballistically at approximately 1,000 kilometres per second.

These three panels from the research are velocity maps of ionized sulphide emissions in Pa 30’s filaments. The upper panel shows the detected redshift and the middle panel shows the blueshift. The bottom panel is a combined velocity map for all the filaments. Image Credit: Cunningham et al. 2024.

“This means that the ejected material has not been slowed down, or sped up, since the explosion,” said lead author Cunningham. “Thus, from the measured velocities, looking back in time allowed us to pinpoint the explosion to almost exactly the year 1181.”

Pa 30 has some unusual features. It’s unusually asymmetrical, while most SN remnants are more spherical. Its filamentary structure displays significant variation in ejecta distribution along the line of sight. Some filaments are more prominent than others and extend further, creating an irregular and lopsided appearance. Some parts of the nebula are travelling at different speeds and in different directions. Elements in the nebula are also distributed unevenly. Iron, for example, is far more concentrated in some regions than others. All of these features suggest that the initial explosion mechanism was asymmetric and that the ejecta in the filaments stem from the initial explosion observed in 1181. Pa 30 also has a very sharp inner edge with an inner gap that surrounds the zombie star.

Two Wide-field Infrared Survey Explorer (WISE) images of Pa 30. The one on the right has the filaments overlain. The inner nebula is compact and surrounds the massive, hot, white dwarf zombie star. The outer nebula is characterized by the wispy filaments that extend out from the central region. Image Credit: Cunningham et al. 2024.

Many of Pa 30’s features suggest an asymmetric explosion as the cause. “The ejecta show a strong asymmetry in flux along the line of sight, which may hint at an asymmetric explosion,” the authors explain. The researchers found that the total flux from redshifted filaments is 40% higher than from blueshifted filaments. “This is tantalizing evidence for asymmetry in the explosion,” they write.

An asymmetric supernova explosion suggests that the underlying physics are complex. Rotation, complex magnetic fields, and the presence of a stellar companion can all contribute to asymmetry. Coupled with the unusually hot white dwarf left behind and its high-velocity stellar wind, the evidence suggests that it was a Type 1ax supernova.

That means the zombie star is likely the remnant of a failed thermonuclear explosion in a white dwarf. The white dwarf could have been just below the Chandrasekhar mass and not exploded completely. Or it could’ve been one of the theoretically possible but elusive super-Chandrasekhar mass white dwarfs. These objects are of great interest because they could be the cause of unusually bright supernovae. If Pa 30’s progenitor was a super-Chandrasekhar mass white dwarf, it could explain some of the remnant’s unusual characteristics.

“Our first detailed 3D characterization of the velocity and spatial structure of a supernova remnant tells us a lot about a unique cosmic event that our ancestors observed centuries ago. But it also raises new questions and sets new challenges for astronomers to tackle next,” said co-author Ilaria Caiazzo.

Some of the questions could be answered with more Keck Cosmic Imager Spectrograph IFU observations.

“Further IFU spectroscopic observations with wider coverage of the nebula will confirm if there exists a global asymmetry in the nebula ejecta, providing important constraints on dynamical models of the ejecta,” the authors conclude.

The post This Ancient Supernova Remnant Looks Like a Stellar Dandelion appeared first on Universe Today.

This idea really is quite a fascinating one. Currently a trip to Mars would require large amounts of air, water and other resources to sustain human life but would also expose travellers to harmful levels of radiation. A wonderful solution has been proposed in a new paper recently published by researchers from Ukraine. They propose that asteroids which already travel relatively close by Earth, Mars and even Venus already could be used to hop between the planets. They are already making the journey anyway and so perhaps the cosmos already provides the solution to interplanetary travel. 

After a return to the Moon, the red planet Mars is next on the list for human exploration. On average it is 225 million km away so a round trip would require astronauts to be away from home for about 3 years! Spending this length of time in space raises a number of serious health risks many of which are caused by prolonged exposure to radiation and microgravity. Over time, muscles and bone density will decline so that the skeletal part of the body will no longer bear enough weight to sustain a return to Earth’s gravity. The cardiovascular system would adjust to microgravity too making heart issues likely upon return. There would be an increased risk of cancer and damage to the nervous system as a result of the prolonged exposure to radiation. The list goes on! 

Mars, Credit NASA

The paper recently authored by A. S. Kasianchuk and V.M. Reshetnyk from the National University of Kyiv in Ukraine they report upon their analysis of the orbit of more than 35,000 near-Earth asteroids. They have been looking for the possibility of successive approaches to all pairs of planets Earth – Venus and Earth – Mars within a time range of 2020 to 2120. If successive passes exist then why not, the team suggest, use the asteroids as interplanetary busses to provide a fast transfer between the planets, possibly even as fast as 180 days. 120 candidates were discovered for Earth-Mars, Earth-Venus, Mars-Earth, Venus-Earth, and even Mars-Venus and Venus-Mars!

Image of Venus taken by NASA’s Pioneer-Venus Orbiter in 1979. (Credit: NASA)

It is a tantalising prospect that instead of mounting a massive rocket based mission to get to Mars or even Venus, that the use of Near Earth Objects (NEO) might provide a natural solution. They would certainly provide a fast transfer between planets but would still require some form of technological solution to radiation protection. The quicker the journey, the lower the risk from radiation so careful selection is an important part of the process. 

The team have produced quite an extensive list of potentials NEO’s for transfers between the inner planets but as new NEO’s are discovered the list will grow. The work provides a snapshot in time of the possible candidates but it requires on going work to keep the list up to date as more asteroids are discovered and orbital elements are refined. NASA’s NEO Surveyor mission has been set the challenge to find more than 90% of all  NEO’s larger than 140 metres in diameter. This will certainly provide a useful resource to the study.

An artist’s conception of an NEO asteroid orbiting the Sun. Credit: NASA/JPL.

Among the asteroids identified, size and proximity to the target planet needs to be considered. Analysis of the overall mission needs to be carefully worked too. If a spacecraft stays in open space for a longer period of time than inside a NEW for example, the effectiveness of the approach must be carefully weighed up. 

It’s an interesting proposition though. With appropriate technological solutions, a carefully selected asteroid can serve not only as a fuel station but also, if shelter is taken beneath the surface for example in caves, could offer radiation protection too. There are significant challenges ahead before this all becomes a reality but with the ever increasing drive to reduce the cost and ecological impact of space flight it is one that most definitely needs further careful analysis. 

Source : The search for NEOs as potential candidates for use in space missions to Venus and Mars

The post Astronauts Could Take an Asteroid Ferry from Earth to Mars appeared first on Universe Today.

To northern sky watchers, Vega is a familiar sight in the summer sky. It’s one of the brightest stars in the sky and in 2013, astronomers detected a large ring of rocky debris surrounding the planet. The prospect of planets suddenly became a real possibility so astronomers turned the James Webb Space Telescope (JWST) on the star. The hunt achieved 10 times the sensitivity of previous ground based searches but alas no planets were discovered. 

Vega lies in the constellation Lyra and is one of the prominent stars that makes up the Summer Triangle along with Aquila in Altair and Deneb in Cygnus. Vega itself likes 25 light years away from Earth so it is, in astronomical terms, relatively close. It’s a hot blue/white star which has a visible surface temperature of around 9,600 degrees. At this temperature it is hotter than the Sun and in size it is about 2.1 times larger in diameter. 

The track of the ISS near Vega in Lyra. From right to left, the station is passing from sunlight into Earth’s shadow. Its color transitions from white to red. Credit: Bob King

Data captured by JWST has recently been used to study Vega. The space telescope is perhaps the most advanced telescope to be placed into orbit. It was launched in December 2021 as part of a partnership between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA.) It orbits the Sun at the second Lagrange point which is about 1.5 million km away from Earth. As telescopes go it’s not the largest (main mirror is 6.5m across) but by being in space it can out perform many ground-based instruments. 

Among the many instruments on board JWST, NIRCam (Near Infrared Camera) and MIRI (Mid Infrared Camera) have been used to probe the secrets of Vega. Interest was piqued when the Infrared Astronomical Satellite (IRAS) detected an excess of long wavelengths which were attributed to a cold dust ring emitting radiation at 25-100 ?m. Further studies revealed the signal was very similar to the signal from the Kuiper Belt. The discovery led astronomers to the conclusion that it must be the remains of planetary formation. 

MIRI, ( Mid InfraRed Instrument ), flight instrument for the James Webb Space Telescope, JWST, during ambient temperature alignment testing in RAL Space’s clean rooms at STFC’s Rutherford Appleton Laboratory, 8th November 2010.

In a paper written by a team of astronomers led by Charles Beichman from NASA’s Exoplanet Science Institute they describe their attempts to hunt down planets in the ring of debris. They were able to utilise data from NIRCam’s coronographic observations of Vega. Within this data, there were 3 sources identified and analysed using supporting data from MIRI. The sources were assessed to see if astrometric data confirmed an association with Vega. If it were part of the Vega system the data would indicate a mass of these sources between 1 and 3 times mass of Jupiter and a temperature in the region of 250K.

Such an object is likely to have disrupted the smooth disk structure but the MIRI data reveals no such effects. It seems then for now at least, that the debris field around Vega is devoid of evidence of planetary formation. Further studies using the instrumentation on board JWST and other new observatories coming on line may change this view but for now it seems, Vega may just be alone without any planetary system. 

Source : Searching for Planets Orbiting Vega with the James Webb Space Telescope

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The TRAPPIST-1 system is a science-fiction writer’s dream. Seven Earth-sized worlds orbit a red dwarf star just 40 light-years away. Three of those worlds are within the habitable zone of the star. The system spans a distance less than 25 times that of the distance from the Earth to the Moon. Oh, what epic tales a TRAPPIST civilization would have! That is, if life in such a system is even possible…

Therein lies the problem. Although the vast majority of potentially habitable worlds orbit red dwarf stars, that doesn’t mean most inhabited worlds have a red dwarf sun. Red dwarfs are known to be violently active in their youth. They emit powerful flares that might strip nearby planets of their atmospheres, and even if a planet can hold on to its sky, it would still be bathed in powerful radiation. Only when a red dwarf matures is it calm and stable. This is very different from larger stars such as our Sun, which are reasonably calm throughout their lives. Since potentially habitable red dwarf planets must orbit very close to their stars, there is a worry that even in the best conditions, life on such a world could never get a foothold. The environment is just too harsh. But a new study gives exobiologists some surprising hope.

The study focuses on red dwarf superflares and the radiation they emit. These flares emit a great amount of x-rays and ultraviolet radiation. For a young red dwarf planet with an atmosphere, most of the x-rays would never reach the surface, but the young world would still be bathed in UV radiation. The team wanted to know how hostile that UV would be to early life, so they bathed microbes in UV.

The study looked at two types of bacteria. Deinococcus radiodurans is a variety known to be UV tolerant, while Escherichia coli is known to be susceptible to radiation. They bathed each variety in ultraviolet radiation levels that would be typical at the distances of the TRAPPIST worlds e, f, and g, which are the most potentially habitable. The results weren’t good for the E. coli variant, as a simulated flare sterilized them below the limit of detection for the innermost world and some survival for the most distant one. But the D. radiodurans did fairly well. Only about 1 in 600 million survived a simulated flare for the closest world, but given the typical time span between flares, the bacteria would maintain a foothold. And, of course, with regular flares, there would be an evolutionary pressure to become more UV resistant.

So it seems that while early life in the TRAPPIST system might have a tough evolutionary road, the superflares wouldn’t sterilize the planets. Life might be common for red dwarf worlds after all.

Reference: Abrevaya, X C, et al. “An experimental study of the biological impact of a superflare on the TRAPPIST-1 planets.” Monthly Notices of the Royal Astronomical Society (2024): stae2433.

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Exoplanets are a fascinating aspect of the study of the Universe. TRAPPIST-1 is perhaps one of the most intriguing exoplanet systems discovered to date with no less than 7 Earth-sized worlds. They orbit a red dwarf star which can unfortunately be a little feisty, hurling catastrophic flares out into space. These flares could easily strip atmospheres away from the alien worlds rendering them uninhabitable. A new piece of research suggests this may not be true and that the rocky planets may be able to maintain a stable atmosphere after all. 

Exoplanets are alien worlds outside of our solar system orbiting other stars. Their discovery in the 1990’s was just the beginning and to date over 5,000 have been identified. They vary massively in composition from small, rocky Earth-sized planets to gas giants like Jupiter. A few of them orbit in the host star’s habitable zone raising the tantalising possibility that life may exist out there in the universe. 

All manner of techniques and telescopes have been used to hunt for exoplanets and to explore their nature. More recently the James Webb Space Telescope (JWST) which was launched in late 2021 has been engaged to that end. The design of the JWST is such that it is capable of observing nearby exoplanets in greater detail than before. 

Artist impression of the James Webb Space Telescope

TRAPPIST-1 is 40 light years away in the constellation Aquarius. It is one of the most fascinating exoplanetary systems discovered to date with 7 Earth-sized planets in orbit around a cool dwarf star. Like all stars, TRAPPIST-1 has a habitable zone, a region around the star within which, the conditions are likely to be conducive to life for any planet that happens to be orbiting at that distance. TRAPPIST-1 has 3 of the 7 planets orbiting in this zone offering a tantalising possibility of extra-terrestrial life. 

The planets of TRAPPIST-1 are classic rocky objects in orbit around an M-dwarf star. These stars are the most common in the universe but previous studies suggest the intense UV radiation from TRAPPIST-1 would fry any atmosphere or surface water. It has been thought that the hydrogen molecules would escape, leaving behind significant quantities of reactive oxygen which would likely inhibit the development of organic chemistry. 

Illustration of the tidally locked world TRAPPIST-1f. Credit: NASA/JPL-Caltech

A recent study led by the University of Washington has been published in the journal Nature Communications which suggests an alternative theory. The team led by Joshua Krissansen-Totton suggest that instead, a stable atmosphere can be created and sustained following an alternative sequence of events. 

During the evolution of the planet, and following its molten state, millions of years of cooling lead to the solid rocky planets we see today. They report that their data shows hydrogen and other light gasses escaped out into space for planets near to the star. For those that are further away where things are a little cooler, the hydrogen reacted with oxygen and iron deep inside the planet producing water and other heavier gasses. These processes may have created a stable atmosphere after all. 

Observations from the JWST can detect higher levels of thermal infrared energy from the inner planets and they reveal the absence of a thick atmosphere. The team suggest more distant planets may have a more stable environment that might even produce a habitable environment. JWST has to date, been unable to detect atmospheres but with new ground based telescopes coming online and with new imaging techniques, the TRAPPIST-1  planets in the habitable zone may soon reveal their mysteries. 

Source : Rocky planets orbiting small stars could have stable atmospheres needed to support life

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Infrared astronomy has revealed so much about the Universe, ranging from protoplanetary disks and nebulae to brown dwarfs, aurorae, and volcanoes on together celestial bodies. Looking to the future, astronomers hope to conduct infrared studies of supernova remnants (SNRs), which will provide vital information about the physics of these explosions. While studies in the near-to-mid infrared (NIR-MIR) spectrum are expected to provide data on the atomic makeup of SNRs, mid-to-far IR (MIR-FIR) studies should provide a detailed look at heated dust grains they eject into the interstellar medium (ISM).

Unfortunately, these studies have been largely restricted to the Milky Way and the Magellanic Clouds due to the limits of previous IR observatories. However, these observational regimes are now accessible thanks to next-generation instruments like the James Webb Space Telescope (JWST). In a recent study, a team led by researchers from Ohio State University presented the first spatially resolved infrared images of supernova remnants (SNRs) in the Triangulum Galaxy (a.k.a. Messier 33). Their observations allowed them to acquire images of 43 SNRs, thanks to the unprecedented sensitivity and resolution of Webb’s IR instruments.

The team was led by Dr. Sumit K. Sarbadhicary, a former Postdoctoral Fellow with OSU’s Center for Cosmology & Astro-Particle Physics (CCAP) and current Assistant Research Scientist at Johns Hopkins University (JHU). He was joined by multiple astronomers and physicists from OSU, the Harvard & Smithsonian Center for Astrophysics, the Flatiron Institute’s Center for Computational Astrophysics, the University of Heidelberg’s Institute for Theoretical Astrophysics, the National Radio Astronomy Observatory (NRAO), and the Space Telescope Science Institute (STScI). The paper that describes their findings is being reviewed for publication in The Astrophysical Journal.

The Crab Nebula, a supernova remnant, observed by the JWST. Credit: NASA/ESA/JWST

As they explain in their study, SNRs in the Milky Way and Magellanic clouds are the best studied in the Universe because they are the closest. This has allowed astronomers to conduct detailed studies that revealed their structures at most wavelengths, including infrared. As Dr. Sarbadhicary told Universe Today via email, studies of these SNRs have taught astronomers a great deal. This includes dust production, the composition of supernova explosions, and the physics of astrophysical shock waves – particularly those that travel through dense gas clouds where new stars could be forming. 

However, as Sarbadhicary explained, these studies have still been confined to our galaxy and its satellites, which has limited what astronomers can learn about these major astronomical events:

“[The] only thing is, we haven’t quite been able to step outside the Magellanic Clouds and explore SNRs in more distant galaxies in the infrared. We know that other Local Group galaxies such as Andromeda (M31), and Triangulum (M33) have several hundreds of SNRs, so there is a tremendous potential for building statistics. Additionally, infrared-emitting SNRs are a somewhat rare breed, found mostly in explosions that happened close to dense molecular gas that is either part of the interstellar medium, or material lost by the progenitor star before explosion. So having more objects would be really helpful.”

The first generation of SNR studies at infrared wavelengths were conducted with NASA’s Infrared Astronomical Satellite (IRAS) and the ESA’s Infrared Space Observatory (ISO). Despite their limited spatial resolution and the confusion of peering through the Galactic plane, these observatories managed to identify about 30% of SNRs in the Milky Way between 10 and 100 micrometers (?m), which corresponds to parts of the Medium and Far-Infrared (MIR, NIR) spectrum.

Artist’s impression of the Herschel Space Telescope. Credit: ESA/AOES Medialab/NASA/ESA/STScI

In recent decades, IR astronomy has benefitted immensely from missions like NASA’s Spitzer Space Telescope and the ESA’s Herschel Space Observatory. These observatories boast higher angular resolutions and can conduct surveys in broader parts of the IR spectrum – 3 to 160 ?m for Spitzer and 70 to 500 ?m for Herschel. Their observations led to wide-field Galactic surveys – the Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE), the MIPS Galactic Plane Survey (MIPSGAL), and the Herschel infrared Galactic Plane Survey (Hi-GAL) – and the first high-quality extragalactic IR surveys of SNRs.

“Unfortunately, the angular resolution of the Spitzer telescope (JWST’s predecessor) was just not good enough to recover the same spatial detail in more distant galaxies,” added Sarbadhicary. “While you might see a faint blip with Spitzer, it would be hard to tell (at these distances) if it’s from the SNR or some blend of stars and diffuse emission.” Fortunately, the situation has improved even more with the deployment of the James Webb Space Telescope (JWST). According to Sarbadhicary, Webb’s increased resolution and advanced IR instruments are providing deeper and sharper views of SNRs in the near- and mid-infrared wavelengths:

“We had already seen JWST’s potential for revolutionizing studies of SNRs from crisp new images of known SNRs such as Cassiopeia A in our Galaxy and 1987A in the Large Magellanic Cloud, published in recent papers. The images revealed an unprecedented amount of detail about the explosion debris, material lost by the star prior to the explosion, and much more.

“This superior combination of sensitivity and angular resolution also now enables JWST to recover images of SNRs in galaxies nearly 20 times farther than the Magellanic Clouds (e.g., M33 in our paper), with the same level of detail found by Spitzer in SNRs in the Magellanic Clouds. What is particularly helpful because of JWST’s high angular resolution is that we are less likely to confuse SNRs with overlapping structures such as HII regions (gas photoionized by massive stars).” 

JWST’s near-infrared view of the star-forming region NGC 604 in the Triangulum galaxy. Credit: NASA, ESA, CSA, STScI

For their study, Sarbadhicary and his team leveraged archival JWST observations of the Trangulum Galaxy (M33) in four JWST fields. Two of these covered central and southern regions of M33 with separate observations using Webb’s Near-Infrared Camera (NIRCam) and its Mid-Infrared Imager (MIRI). The third involved MIRI observations of a long radial strip measuring about 5 kiloparsecs (~16,300 light-years), one covering the giant emission nebula in M33 (NGC 604) with multiple NIRCam and MIRI observations. They then overlapped these observations with previously identified SNRs from multi-wavelength surveys.

They also considered the volumes of multi-wavelength data previous missions have obtained of this galaxy. This includes images of stars acquired by the venerable Hubble and cold neutral gas observations conducted by the Atacama Large Millimeter-submillimeter Array (ALMA) and the Very Large Array (VLA). As Sarbadhicary indicated, the results revealed some very interesting things about SNRs in the Triangulum Galaxy. However, since their survey covered only 20% of the SNRs in M33, he also noted that these results are just the tip of the iceberg:

“The most surprising finding was the presence of molecular hydrogen emission in two out of the three SNRs where we had F470N observations (a narrowband filter centered on the 4.7-micron rotational line of the hydrogen molecule). Molecular hydrogen is by far the most abundant molecule in interstellar gas, but because of the symmetry of the molecule, it cannot produce visible radiation at the typical cold temperatures of interstellar gas. Only when heated by shocks or ultraviolet emission does H2 emit radiation (such as at 4.7 microns), so it is a very useful tracer of shocks hitting dense molecular gas, where star formation occurs.”

While astronomers have seen this emission in several SNRs within the Milky Way, this was the first time such observations have been made of an extragalactic source. “The JWST data also revealed that between 14-43% of the SNRs show visible infrared emission,” added Sarbadhicary. “The brightest infrared SNRs in our sample are also some of the smallest in M33 and the brightest at other wavelengths, especially X-ray, radio, and optical. This means that the shocks in these SNRs are still traveling relatively fast and hitting high-density material in the environment, leading to a substantial amount of the shock energy being radiated into infrared lines and dust that are illuminating the emission seen in our broadband images.”

JWST observations of 80 objects (circled in green) that changed in brightness over time, most of which are supernovae. Credit: NASA/ESA/CSA/STScI/JADES Collaboration

The results show how Webb’s high angular resolution will allow astronomers to conduct highly accurate infrared observations of large populations of SNRs in galaxies beyond the Magellanic Clouds. This includes M33, the Andromeda Galaxy (M31), and neighboring Local Group galaxies like the Southern Pinwheel Galaxy (M83), the Fireworks Galaxy (NGC 6946), the Whirlpool Galaxy (M51), multiple dwarf galaxies in the Local Group, and many more! Said Sarbadhicary:

“Personally, I am quite excited about being able to study the population of SNRs impacting dense gas with JWST since the physics of how shocks impact dense gas and regulate star formation in galaxies is a major topic in astronomy. The infrared wavelengths have a treasure trove of ionic and molecular lines (like H2 we found) that are excited in warm, high-density gas clouds by shocks, so these observations can be really useful.

“There are also some rare Cassiopeia A-like SNRs in these galaxies that are very young and rich in ejecta material from the explosion, and JWST can provide a lot of new information from emission lines in the infrared. Another big area of study is dust and how they are produced and destroyed in shocks.”

Further Reading: arXiv

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Moons are the norm in our Solar System. The International Astronomical Union recognizes 288 planetary moons, and more keep being discovered. Saturn has a whopping 146 moons. Every planet except Mercury and Venus has moons, and their lack of moons is attributed to their small size and proximity to the Sun.

It seems reasonable that there are moons around exoplanets in other Solar Systems, and now we’re going to start looking for them with the James Webb Space Telescope.

The Cool Worlds Lab is part of the Columbia University Astronomy Department and is led by assistant professor David Kipping, a well-known British/American astronomer. The Lab focuses on cool exoplanets with wide orbits around stars. “In this regime, orbital dynamics and atmospheric chemistry diverge from their hot counterparts, and the potential for satellites, rings, and habitability become enhanced,” the Lab’s website says. Exomoons around these planets are part of the Lab’s focus, and Kipping is an author and co-author of several papers about exomoons.

There’s a lot of active discussion in the astronomy world about exomoons, how to find them, and how to confirm them. Currently, there are no confirmed exomoons, only a list of candidates, some of which should be in habitable zones if they’re real.

Kipping and his team have succeeded in getting some JWST observation time to look for an exomoon. Back in February, his proposal was selected. “We have been hoping to find exomoons for a very long time,” Kipping says in a YouTube video announcing the beginning of their JWST observations, adding that exomoons have been “a continuous thread in my career.”

Now, Kipping and the Cool Worlds Lab is being given a chance to use the world’s most powerful space telescope to observe an exoplanet named Kepler-167e. Kipping himself found this planet about 10 years ago, and there’s something special about it. It’s a Jupiter analogue and a very rare example of a long-period transiting gas giant. Because Jupiter has so many moons, Kipping and others argue that Kepler-167e is a strong candidate to also have moons.

An artist’s illustration of Kepler-167e, a Jupiter analogue in a distant solar system. At the time of writing, the JWST is observing this planet and looking for signs of an exomoon. Image Credit: NASA Eyes On Planets

The planet only transits its star once every three years, and the next transit is happening right now. In fact, it started yesterday morning, and the JWST was watching on behalf of the Cool Worlds Lab. The JWST has given the Lab 60 hours—2 and a half days— of observing time. Those observations are happening right now, and if all goes well, we may have our first strong detection of an exomoon.

The data from these observations is exclusive to the Cool Worlds Lab for one year. “We have a year before the data goes public, and that’s fairly normal with JWST data,” Kipping said.

Kipping says they have to be cautious when they get their initial results. “I’ve been in this situation many times. You get the data on the first day. You see a dip and you’re like ‘That’s it. We’re there. We’ve got a moon.’ ” But a few weeks or months later, it could turn out to not be real. “So we don’t want to get people’s excitement up prematurely,” he said.

Looking for exomoons is extremely challenging and Kipping led an effort to find some in Kepler’s data. “We surveyed probably on the order of 300 or 350 exoplanets during our time, and only two real candidates popped up over this entire analysis,” Kipping said in an interview with Fraser Cain earlier this year. One of the candidates was Kepler-1625 b, and even then, they only had the “smallest of hints from the Kepler data that there was something there,” he said.

In 2018, researchers presented evidence in support of an exomoon orbiting Kepler-1625b, a super Jupiter 8,200 light-years away. Subsequent research poured cold water on the moon’s existence. Image Credit: By ESA/Hubble, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=73369715

Kipping told Universe Today that “we’re really pushing these data sets to their limits to even get these signals.”

But the JWST’s data should be more robust than Kepler’s. Kepler was an automated survey, while the JWST is a different beast. Kepler had a fixed field of view and a primary mirror only 0.95 meters in diameter. Its sole job was to detect exoplanets that transited in front of their stars. The JWST has a 6.5-meter mirror, multiple instruments, including cameras and spectrographs, and a system of filters. It’s far more capable than Kepler, as almost everyone knows.

Kipping is hopeful that the JWST will be able to detect moons as small as Ganymede and Callisto. There’s a chance that the JWST will detect a slam-dunk exomoon and that it’ll be clear to everyone. “That’s the dream scenario,” Kipping says. However, this set of observations will be scientifically rich whether they detect an exomoon or not because the JWST will be able to measure other things about the planet.

“But there’s also a scenario where we don’t see anything,” Kipping said. If that happens, it would also be a significant finding. “We would essentially have to rip up the textbook,” Kipping said. “If we don’t see a Titan, if we don’t see a Ganymede, we don’t see a Callisto, that is telling us something quite profound about Moon formation, maybe that our Solar System’s kind of special.”

Enhanced image of Ganymede taken by the JunoCam during the mission’s flyby on June 7th, 2021. Ganymede is our Solar System’s largest moon and potentially holds a subsurface ocean. Ganymede and other moons in our Solar System are suspected of having warm, potentially life-supporting oceans under layers of ice. It seems highly likely that some exomoons will also have oceans and be potentially habitable. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Kalleheikki Kannisto

This mirrors what we used to say about exoplanets. Prior to the Kepler mission, which found over 2,500 exoplanets, we weren’t certain if our Solar System’s planet population was normal or extraordinary. Now we know that exoplanets are likely orbiting every star. (Though our Solar System is still special.)

We may be on the verge of an age of exomoon discovery, just as we were prior to Kepler’s launch. The Cool Worlds Lab exomoon observations are just one of five exomoon observing efforts the JWST has approved, and the JWST isn’t the only telescope that will be searching for them. The ESA’s upcoming PLATO (PLAnetary Transits and Oscillations of stars) mission will study exoplanets in habitable zones around Sun-like stars, and it will also discover exomoons.

Kipping is boiling over with enthusiasm about the JWST’s observations of Kepler-167e. He discovered the planet, and if he and his team were able to find the first confirmed exomoon around it, it would be quite an achievement.

“It’s an amazing opportunity that we have to potentially test some long-standing theories,” Kipping said, adding that it’s also a “dream I’ve had for my entire career.”

For updates on the observations, follow Cool Worlds on YouTube.

The post The Search for Exomoons is On appeared first on Universe Today.

Remember that amazing “first image” of Sagittarius A* (Sgr A) black hole at the heart of the Milky Way? Well, it may not be completely accurate, according to researchers at the National Astronomical Observatory of Japan (NAOJ). Instead, the accretion disk around Sgr A* may be more elongated, rather than the circular shape we first saw in 2022.

Scientists at NAOJ applied different analysis methods to the data of Sgr A* first taken by the Event Horizon Telescope (EHT) team. The EHT data came from a network of eight ground-based radio telescopes. The original analysis showed a bright ring structure surrounding a dark central region. The re-analysis resulting in a different shape implies something about the motions and distribution of matter in the disk.

In fairness to both teams, radio interferometry data is notoriously complex to analyze. According to NAOJ astronomer Miyoshi Mikato, the rounded appearance may be due to the way the image was constructed. “We hypothesize that the ring image resulted from errors during EHT’s imaging analysis and that part of it was an artifact, rather than the actual astronomical structure,” Miyoshi suggested.

This is the first image of Sgr A*, the supermassive black hole at the center of our galaxy. A reanalysis of EHT data by NAOJ scientists suggests its accretion disk may be more elongated than circular. Credit: EHT Explaining the Black Hole Appearance

So, what does Sgr A* look like in the NAOJ re-analysis? “Our image is slightly elongated in the east-west direction, and the eastern half is brighter than the western half,” said Miyoshi. “We think this appearance means the accretion disk surrounding the black hole is rotating at about 60 percent of the speed of light.”

The accretion disk is filled with superheated material “circling the drain” as it were. It’s funneling into the 4-million-solar-mass black hole. As it cycles through the accretion disk, friction and the action of magnetic fields heat the material. That causes it to glow, mostly in x-rays and visible light as well as giving off radio emissions.

Various factors also influence the shape of the accretion disk, including the spin of the black hole itself. In addition, the accretion rate (that is, how much material falls into the disk), as well as the angular momentum of the material, all affect the shape. The gravitational pull of the black hole also distorts our view of the accretion disk. That sort of “funhouse mirror” distortion makes it incredibly difficult to image. As it turns out, either view of the disk’s actual shape—the original EHT “circular” view or the NAOJ elongated view—could be accurate.

So, Why the Different Views of the Black Hole?

How did the teams come up with two slightly different views of Sgr A* using the same data? “No telescope can capture an astronomical image perfectly,” Miyoshi pointed out. For the EHT observations, it turns out that interferometric data from the widely linked telescopes can have gaps. During data analysis, scientists have to use special techniques to construct a complete image. That’s what the EHT team did, resulting in the “round black hole” image.

Miyoshi’s team published a paper describing their results. In it, they propose that the “ring” structure in the 2022 image released by EHT is an artifact caused by the bumpy point-spread function (PSF) of the EHT data. The PSF describes how an imaging system deals with a point source in the region it’s looking at. It helps give a measure of the amount of blurring that occurs because of imperfections in the optics (or in this case, the gaps in the interferometric data). In other words, it had problems with “filling” in the gaps.

The NAOJ team reanalyzed the data and used a different mapping method to smooth over the gaps in the data. That resulted in an elongated shape for the Sgr A* accretion disk. One-half of the disk is brighter and they suggest it’s due to a Doppler boost as the disk rotates rapidly. They suggest that the newly analyzed data and elongated image shows a portion of the disk that lies a few Schwarzschild radii away from the black hole, rotating extremely fast, and viewed from an angle of 40°-45°.

What’s Next?

This reanalysis should help contribute to a better understanding of what the Sgr A* accretion disk actually looks like. The EHT study of Sgr A* resulting in the 2022 image release was the first detailed attempt to map the region around the black hole. The EHT consortium is working on improvements to produce better and more detailed interferometry images of this and other black holes. Eventually, that should result in more accurate views. Follow-up studies should help fill in any gaps in the observations of the accretion disk. In addition, detailed studies of the near environment around the black hole should give more clues to the black hole hidden inside the disk. I

For More Information

First Picture of Milky Way Black Hole ‘May Not Be Accurate’
An Independent Hybrid Imaging of Sgr A* from the Data in EHT 2017 Observations

The post The Milky Way’s Supermassive Black Hole Photo Might Need a Retake appeared first on Universe Today.

The odds are good that we are not alone in the Universe. We have found thousands of exoplanets so far, and there are likely billions of potentially habitable planets in our galaxy alone. But finding evidence of extraterrestrial life is challenging, and even the most powerful telescopes we currently have may not produce definitive proof. But there are telescopes in the pipeline that may uncover life. It will be decades before they are built and launched, but when they are, which systems should they target first? That’s the question answered in a recent paper.

There are two major projects in the pipeline with the specific goal of searching for life. One is NASA’s Habitable Worlds Observatory (HWO), and the other is the Large Interferometer For Exoplanets (LIFE). Both would use high-resolution spectroscopy to map the chemical composition of exoplanet atmospheres and identify potential biosignatures. But both are in the early design and proposal stages, and it will be at least the 2040s before either are launched. Both also have a downside, in that they will need long observing times to capture detailed spectra. So when they are launched, they won’t be able to look at exoplanets willy-nilly. They will need a specific plan.

This is where this new paper comes in. In it, the team outlines the criteria for prioritizing targets. Drawing from a range of sources, they filter known exoplanet systems into some best-case groups. The first consists of main-sequence stars within 30 parsecs of Earth. But rather than considering all nearby stars, the list only includes stars that are either single stars or wide binaries. The idea is that these are most likely to have planetary systems with stable orbits. The group also excludes red dwarfs, since red dwarfs are likely to produce large flares and x-rays hostile to life.

The second group consists of star systems that are positioned in a region of the sky best suited for observation by LIFE and HWO. For example, if a system is aligned with the orbital plane of Earth, it will be more difficult to study since the Sun will be in the way for part of the year.

The third group consists of the “Golden Targets.” These are systems known to have potentially habitable planets with atmospheres and excellent observing conditions. There are currently about ten systems in this group, but future observations are likely to add more to the list before LIFE and HWO are launched. This group represents the priority targets for these missions.

If you are curious, you can see which systems are in each group at the LIFE Target Star Database.

Reference: Menti, Franziska, et al. “Database of Candidate Targets for the LIFE Mission.” Research Notes of the AAS 8.10 (2024): 267.

The post Here are Some Potentially Habitable World Targets for the Upcoming LIFE Mission appeared first on Universe Today.

China has some bold plans for space research and exploration that will be taking place in the coming decades. This includes doubling the size of their Tiangong space station, sending additional robotic missions to the Moon, and building the International Lunar Research Station (ILRS) around the lunar south pole. They also hope to begin sending crewed missions to Mars by 2033, becoming the first national space agency to do so. Not to be left behind in the commercial space sector, China is also looking to create a space tourism industry that offers suborbital flights for customers.

One of the companies offering these services is Jiangsu Deep Blue Aerospace Technology, a private launch company founded in November 2016 by Chinese entrepreneur Huo Liang. On October 24th, at 6:00 pm local time (03:00 am PDT; 06:00 am EDT), during a “Make Friends” Taobao live broadcast, Huo shared the companies’ latest progress on their commercial spacecraft. He also announced the pre-sale of tickets for the first suborbital launch in 2027. The company also posted an infographic with the details of the flight on the Chinese social media platform Weixin (WeChat).

Commercial space travel has advanced considerably in the U.S. and other countries in recent years. In 2021, Virgin Galactic launched its first commercial space mission from Spaceport America near Las Cruces, New Mexico, ferrying Sir Richard Branson and selected passengers to space. A few weeks later, Blue Origin conducted the first crewed mission of its New Shepard rocket, with CEO Jeff Bezos and a crew of five taking off from the company’s launch site near El Paso, Texas. Later that year, SpaceX’s Dragon spacecraft took four passengers to orbit as part of the mission, Inspiration4, first all-civilian spaceflight.

Deep Blue Aerospace's new hop test (5-10 km level) failed in the final stages today in Inner Mongolia, according to this news report. Waiting for video of the attempt. https://t.co/bexXAZzWwo https://t.co/OEWrwKu0ro

— Andrew Jones (@AJ_FI) September 22, 2024

In addition to Deep Blue Aerospace, multiple commercial space startups have emerged in China since 2014, including Galactic Energy, LandSpace, LinkSpace, ExPace, OneSpace, and Orienspace. For several years, these companies have been researching reusable rockets and engines to realize domestic commercial launch capability. During this time, Deep Blue Aerospace has accomplished many milestones that will make commercial launches possible. Between 2021 and 2022, the company completed “hop tests” using its Nebula-1 reusable rocket, which achieved China’s first vertical takeoff and landing (VTOL).

The first test occurred on October 13th, 2021, and saw the Nebula-1 complete a 100-meter (328 ft) flight, followed by a 1-km (0.62 mi) flight on May 6th, 2022. Unfortunately, the company experienced an accident during a 5 to 10 km (3 to 6.2 mi) test flight in September when a Nebula-1 first stage exploded while attempting to land. As the company stated in their infographic:

“In order to ensure the comprehensive maturity and stability of the technology, Deep Blue Aerospace is intensively preparing for the next high-altitude recovery test, striving for perfection in every detail. The improvement of rocket recovery technology will lay a solid foundation for Deep Blue Aerospace to promote suborbital travel projects and open a new chapter in human exploration of space.”

According to the company, the first high-altitude vertical recovery flight of Nebula-1’s first stage will take place in November 2024. This will be followed by the rocket’s first orbital reentry and recovery test in the first quarter of 2025 and multiple recovery and reuse tests throughout the year. The company intends to conduct dozens of tests using a fully stacked Nebula-1 rocket and crewed spacecraft in 2026. If all goes according to plan, the company will commence suborbital flights in 2027.

A side-by-side comparison of the SpaceX Dragon and Deep Blue Space space capsules.
Credit: SpaceX/Deep Blue Space

The infographic also previews what the launch vehicle and spacecraft will look like, which have some notable similarities to SpaceX and Blue Origin vehicles. For instance, the crew capsule strongly resembles the SpaceX’s Crew Dragon vehicle, which includes the launch abort system consistsing of eight thrusters distributed into four clusters. However, the Dragon space capsule has only two viewports, whereas the Nebula-1 reportedly has five (though eight can be seen in the infographic), which is more akin to Blue Origin’s New Shepard space capsule, which has six large viewports.

In addition, the Nebula-1 launch vehicle is also similar in design to the SpaceX Falcon 9 rocket. This includes the payload fairing, the chassis, the grid fins on the interstage structure, and the fold-out landing legs. The Nebula-1 also has nine Thunder-R1 engines arranged in a circle around a single engine. This is very similar to the Falcon 9‘s arrangement of eight Merlin thrusters (which fire during takeoff) surrounding a single thruster used for landing. According to the rocket specifications, the Nebula-1 weighs 7,900 kg (8.7 U.S. tons) fully fueled and has a payload capacity to LEO of almost 2,000 kg (2.2 U.S. tons) – though they plan to increase this to 8,000 kg (8.8 U.S. tons)

The specs also note that the rocket has a maximum flight altitude of 100 to 150 km (62 to 93 mi) and can be reused a maximum of 50 times. This is a far cry from Falcon 9′s takeoff mass of 549,054 kg (605 U.S. tons) and a payload capacity of 22,000 kg (24.25 U.S. tons), and the number of times it can be reused is likely an inflated estimate. But the appearances still suggest that the Nebula-1’s design was inspired by the Falcon 9, which has set the standard for rocket retrieval and reusability.

Meanwhile, the spacecraft reportedly measures 4 m (13 ft) in height and 3.5 m (11.5 ft) in diameter and can carry six passengers in a single flight. This is comparable to the New Shepard space capsule and falls just short of the Dragon’s capacity of up to 7 passengers. However, the inaugural flight will consist of three crewmembers spending a total of 12 minutes in flight and 5 minutes experiencing weightlessness. The rocket will fly to an altitude of 100 km (62 mi) – aka. the Karman Line, the official boundary between Earth and space. As the company indicated:

“During the suborbital flight of Deep Blue Spacecraft, passengers will experience much more than a brief weightlessness experience. They will experience the vastness and mystery of the universe and witness the magnificent landscape beyond the earth. This will be an all-round, multi-sensory space journey that will be unforgettable for a lifetime.”

Side-by-side comparison of the Nebula-1 and Falcon 9 rockets. Credit: Deep Blue Space/SpaceX

Per the pre-sale, two tickets are being offered for 1.5 million yuan, with a ticket deposit price of 50,000 yuan. This is equivalent to roughly $200,000 and $7,000, respectively. Presumably, the third seat will be occupied by Huo, who may be hoping to follow Branson and Bezos’ example by participating in the inaugural flight. The people purchasing the tickets will also receive a “1,000-yuan Cultural and Creative Gift Package” and a commemorative model of the Nebula-1 rocket. According to the infographic and statement, they will also be given the chance to view the launch of a Long March rocket from a launch center of their choice – Jiuquan, Wenchang, or Xichang.

Potential ticket buyers must also meet certain health requirements, undergo a medical evaluation, be 18 to 60 years old, and participate in pre-flight safety training a month before the flight. Because certain “technical details and specific information” will be revealed during the flight, passengers must also sign a confidentiality agreement. Additional details are provided on Deep Blue Aerospace’s Taobao official store page.

The company also plans to unveil the Nebula-2, a medium to heavy-lift launch vehicle powered by liquid oxygen and kerosene. This rocket will reportedly be capable of lifting payloads of up to 20,000 kg (22 U.S. tons) to LEO (comparable to the Falcon 9) and has an inaugural launch planned for late 2025.

Further Reading: Weixin

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