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Reflect Orbital plans to launch a constellation of orbiting mirrors to beam sunlight to solar power plants on Earth after dark.

A set of large, distinctive footprints suggest a raptor dinosaur that lived in East Asia 96 million years ago grew to a length of 5 metres

A set of large, distinctive footprints suggest a raptor dinosaur that lived in East Asia 96 million years ago grew to a length of 5 metres

Yes, but can your volcano do this?

Watch Juno zoom past Jupiter.

Diamonds in the Sky

The Great Carina Nebula

From our vantage point in the

Not one, but two comets appeared near the Sun during

What created this giant X in the clouds?

Six full-body fossils of Ptychodus sharks have been formally analysed for the first time, revealing that they were fast swimmers that preyed on shelled creatures

Six full-body fossils of Ptychodus sharks have been formally analysed for the first time, revealing that they were fast swimmers that preyed on shelled creatures

Ancestors of so-called “soft” corals may have developed bioluminescence in the earliest days of deep-ocean living

NASA's pioneering CloudSat weather and climate mission has come to an end after nearly 18 productive years in Earth orbit.

Climate change’s effects on ocean water temperatures and salinity could shrink sonar detection ranges underwater and make it more challenging to spot submarines

Climate change’s effects on ocean water temperatures and salinity could shrink sonar detection ranges underwater and make it more challenging to spot submarines

Astrobiologists continue to work towards determining which biosignatures might be best to look for when searching for life on other worlds. The most common idea has been to search for evidence of plants that use the green pigment chlorophyll, like we have on Earth. However, a new paper suggests that bacteria with purple pigments could flourish under a broader range of environments than their green cousins. That means current and next-generation telescopes should be looking for the emissions of purple lifeforms.

“Purple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds,” said Lígia Fonseca Coelho, a postdoctoral associate at the Carl Sagan Institute (CSI) and first author of “Purple is the New Green: Biopigments and Spectra of Earth-like Purple Worlds,” published in the Monthly Notices of the Royal Astronomical Society: Letters.

Artist’s concept of Earth-like exoplanets, which strikes the careful balance between water and landmass. Credit: NASA

According to NASA’s Exoplanet Archive, 5612 extrasolar planets have been found so far, as of this writing, and another 10,000 more are considered planetary candidates, but have not yet been confirmed. Of all those, there are just over 30 potentially Earth-like worlds, planets that lie in their stars’ habitable zones where conditions are conducive to the existence of liquid water on surface.

But Earth-like has a broad meaning, ranging from size, mass, composition, and various chemical makeups. While being within a star’s habitable zone certainly means there’s the potential for life, it doesn’t necessarily mean that life could have emerged there, or even if it did, the life on that world might look very different from Earth.

“While oxygenic photosynthesis gives rise to modern green landscapes, bacteriochlorophyll-based anoxygenic phototrophs can also colour their habitats and could dominate a much wider range of environments on Earth-like exoplanets,” Coelho and team wrote in their paper. “While oxygenic photosynthesis gives rise to modern green landscapes, bacteriochlorophyll-based anoxygenic phototrophs can also colour their habitats and could dominate a much wider range of environments on Earth-like exoplanets.”

The researchers characterized the reflectance spectra of a collection of purple sulfur and purple non-sulfur bacteria from a variety of anoxic and oxic environments found here on Earth in a variety of environments, from shallow waters, coasts and marshes to deep-sea hydrothermal vents. Even though these are collectively referred to as “purple” bacteria, they actually include a range of colors from yellow, orange, brown and red due to pigments  — such as those that make tomatoes red and carrots orange.

These bacteria thrive on low-energy red or infrared light using simpler photosynthesis systems utilizing forms of chlorophyll that absorb infrared and don’t make oxygen. They are likely to have been prevalent on early Earth before the advent of plant-type photosynthesis, the researchers said, and could be particularly well-suited to planets that circle cooler red dwarf stars – the most common type in our galaxy.

A collection of bacteria samples in the Cornell University Space Sciences Building. Ryan Young/Cornell University.

That means this type of bacteria might be more prevalent on more and a wider variety of exo-worlds.

On a world where these bacteria might be dominant, it would produce a distinctive “light fingerprint” detectable by future telescopes.

In their paper, Coelho and team presented models for Earth-like planets where purple bacteria might dominate the surface and show the impact of their signatures on the reflectance spectra of terrestrial exoplanets.

“Our research provides a new resource to guide the detection of purple bacteria and improves our chances of detecting life on exoplanets with upcoming telescopes,” the team wrote.

“We need to create a database for signs of life to make sure our telescopes don’t miss life if it happens not to look exactly like what we encounter around us every day,” said co-author Lisa Kaltenegger, CSI director and associate professor of astronomy at Cornell University, in a press release from Cornell.

The post Purple Bacteria — Not Green Plants — Might Be the Strongest Indication of Life appeared first on Universe Today.

Scientists turned into cosmic crime scene investigators to reconstruct the impact that sent Earth's "quasi-moon" Kamo'oalewa rocketing from the lunar surface millions of years ago.

Planetary nebula are some of nature’s most stunning visual displays. The name is confusing since they’re the remains of stars, not planets. But that doesn’t detract from their status as objects of captivating beauty and intense scientific study.

Like all planetary nebula, the Southern Ring Nebula is the remnant of a star like our Sun. As these stars age, they will eventually become red giants, expanding and shedding layers of gas out into space. Eventually, the red giant becomes a white dwarf, a stellar remnant bereft of fusion that emanates whatever residual thermal energy it has without ever generating anymore. The white dwarf lights up the shells of gas expelled earlier, and we get to enjoy the show.

When the long-awaited JWST started delivering images, the Southern Ring Nebula (NGC 3132) was one of its first targets. It was one of five objects that made up the telescope’s first science results. The JWST’s images revealed something surprising about NGC 3132: it has two stars. The white dwarf is in the center of NGC 3132 and its companion is between 40 to 60 AU away, about the same distance as Pluto is from the Sun.

Researchers wanted to understand more about the Southern Ring Nebula’s structure. The JWST works in the infrared and can image warm hydrogen in the nebula. But to get a more complete image of the nebula, a team of researchers from the Rochester Institute of Technology (RIT) turned to the Submillimeter Array (SMA). The SMA can sense the cooler CO (carbon monoxide) in the nebula beyond the JWST’s reach. It sensed CO’s presence and measured its velocity and the velocities of other molecules.

The research is published in The Astrophysical Journal titled “The Molecular Exoskeleton of the Ring-like Planetary Nebula NGC 3132.” Professor Joel Kastner from the RIT School of Physics and Astronomy is the lead author.

The new observations showed that most of the nebula’s hydrogen gas is in a large expanding ring and that a second expanding ring lies almost perpendicular to the first.

“JWST showed us the molecules of hydrogen and how they stack up in the sky, while the Submillimeter Array shows us the carbon monoxide that is colder that you can’t see in the JWST image,” explained Kastner.

This figure from the study shows the velocities of three molecules in NGC 3132 as measured by the SMA. From left to right: 12CO, 13CO, and CN (cyanide.) The images clearly show the primary ring in the nebula. Image Credit: Kastner et al. 2024.

“The extra velocity dimension from the array’s radio wavelength observations then effectively allows us to see the nebula in 3-D. When we started to turn the whole nebula around in 3-D, we immediately saw it really was a ring, and then we were amazed to see there was another ring,” Kastner said.

“Surprisingly, the data further reveal that the nebula also appears to harbor a second, dust-rich molecular ring (Ring 2)—detected in (dust) absorption, in low-excitation emission lines, in H2, and (now) in 12CO(2–1)—that appears to lie nearly perpendicular to Ring 1,” the authors explain in their published research.

This figure from the study shows the SMA observations of NGC 3132 in the left column and the JWST infrared image in the right column. The bottom images show the different velocities of molecules in the nebula. The light blue velocity shows the presence of the main ring, but the red and pink high-velocity clumps show the presence of a second ring. Image Credit: Kastner et al. 2024.

The rings are offset from one another, which explains why the 3D view made the second one more visible. The team matched their observations to a geometric model that showed inclinations of 45° for Ring 1 and 78° for Ring 2.

These panels from the published research show the two rings around NGC 3132. The left panel shows the rings with a 45° for Ring 1 and 78° for Ring 2. The right panel shows the two rings with a 15° for Ring 1. Image Credit: Kastner et al. 2024.

Why does the Southern Ring Nebula have two offset rings?

The authors say we have a pole-on view of a bipolar nebula shaped by the presence of a second star. There are many bipolar nebulae, including well-known ones like the Butterfly Nebula.

The Butterfly Nebula as imaged by the Hubble Space Telescope. Image Credit: By NASA, ESA and the Hubble SM4 ERO Team – http://www.hubblesite.org/newscenter/archive/releases/2009/25/image/f/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7777740

However, the presence of a second star has complicated NGC 3132’s shape. “We suggest that this apparent two-ring structure may be the remnant of an ellipsoidal molecular envelope of AGB ejecta that has been mostly dispersed by a series of rapid-fire but misaligned collimated outflows or jets,” the authors explain in their research. “Such a scenario would be consistent with the hypothesis that the mass-losing AGB progenitor of NGC 3132 was a member of an interacting triple star system.”

It would be consistent, but the authors say there’s no way to conclude that a third star was involved with current research. “Detailed simulations of the dynamical effects of such multiple-star toppling jets systems on AGB molecular envelopes are required to test this speculative scenario for the shaping of the molecular exoskeleton of NGC 3132,” the authors explain.

The presence of all that molecular gas in the nebula surprised scientists. The intense UV from the white dwarf should break up the carbon monoxide and the molecular hydrogen. But it hasn’t.

“Where does the carbon and the oxygen and the nitrogen in the universe come from?” said Kastner. “We’re seeing it generated in the sun-like stars that are dying, like the star that’s just died and created the Southern Ring. A lot of that molecular gas could wind up in planetary atmospheres and atmospheres can enable life.”

The post See the Southern Ring Nebula in 3D appeared first on Universe Today.

The venerable Hubble Space Telescope is like a gift that keeps on giving. Not only is it still making astronomical discoveries after more than thirty years in operation. It is also making discoveries by accident! Thanks to an international team of citizen scientists, with the help of astronomers from the European Space Agency (ESA) and some machine learning algorithms, a new sample of over one thousand asteroids has been identified in Hubble‘s archival data. The methods used represent a new approach for finding objects in decades-old data that could be applied to other datasets as well.

The research team was led by Pablo García-Martín, a researcher with the Department of Theoretical Physics at the Autonomous University of Madrid (UAM). It included members from the ESA, NASA’s Jet Propulsion Laboratory (JPL), the Astronomical Institute of the Romanian Academy, the University of Craiova, the Université Côte d’Azur, and Bastion Technologies. The paper that describes their findings, “Hubble Asteroid Hunter III. Physical properties of newly found asteroids,” recently appeared in Astronomy & Astrophysics.

Ask any astronomers and they will tell you that asteroids are material left over from the formation of the Solar System ca. 4.5 billion years ago. These objects come in many shapes in sizes, ranging from peddle-sized rocks to planetoids. Observing these objects is challenging since they are faint and constantly in motion as they orbit the Sun. Because of its rapid geocentric orbit, Hubble can capture wandering asteroids thanks to the distinct curved trails they leave in Hubble exposures. As Hubble orbits Earth, its point of view changes while observing asteroids following their orbits.

Hubble image of the barred spiral galaxy UGC 12158, with streaks left by photobombing asteroids. Credit: NASA, ESA, P. G. Martín (AUM)/J. DePasquale (STScI)/A. Filippenko (UC Berkeley)

Asteroids have also been known to “photobomb” images acquired by Hubble of distant cosmic objects like UGC 12158 (see image above). By knowing Hubble’s position when it took exposures of asteroids and measuring the curvature of the streaks they leave, scientists can determine the asteroids’ distances and estimate the shapes of their orbits. The ability to do this with large samples allows astronomers to test theories about Main Asteroid Belt formation and evolution. As Martin said in a recent ESA Hubble press release:

“We are getting deeper into seeing the smaller population of main-belt asteroids. We were surprised to see such a large number of candidate objects. There was some hint that this population existed, but now we are confirming it with a random asteroid population sample obtained using the whole Hubble archive. This is important for providing insights into the evolutionary models of our Solar System.”

According to one widely accepted model, small asteroids are fragments of larger asteroids that have been colliding and grinding each other down over billions of years. A competing theory states that small bodies formed as they appear today billions of years ago and have not changed much since. However, astronomers can offer no plausible mechanism for why these smaller asteroids would not accumulate more dust from the circumstellar disk surrounding our Sun billions of years ago (from which the planets formed).

In addition, astronomers have known for some time that collisions would have left a certain signature that could be used to test the current Main Belt population. In 2019, astronomers from the European Science and Technology Centre (ESTEC) and the European Space Astronomy Center’s Science Data Center (ESDC) came together with the world’s largest and most popular citizen-science platform (Zooniverse) and Google to launch the citizen-science project Hubble Asteroid Hunter (HAH) to identify asteroids in archival Hubble data.

This graph is based on Hubble Space Telescope archival data that were used to identify a largely unseen population of very small asteroids. Credit: NASA/ESA/P. G. Martín (AUM)/E. Wheatley (STScI)

The HAH team comprised 11,482 citizen-science volunteers who perused 37,000 Hubble images spanning 19 years. After providing nearly two million identifications, the team was given a training set for an automated algorithm to identify asteroids based on machine learning. This yielded 1,701 asteroid trails, with 1,031 corresponding to previously uncatalogued asteroids – about 400 of which were below 1 km (~1090 ft) in size. Said Martin:

“Asteroid positions change with time, and therefore you cannot find them just by entering coordinates, because they might not be there at different times. As astronomers we don’t have time to go looking through all the asteroid images. So we got the idea to collaborate with more than 10,000 citizen-science volunteers to peruse the huge Hubble archives.”

This pioneering approach may be effectively applied to datasets accumulated by other asteroid-hunting observatories, such as NASA’s Spitzer Space Telescope and Stratospheric Observatory for Infrared Astronomy (SOFIA). Once the James Webb Space Telescope (JWST) has accumulated a large enough dataset, the same method could also be applied to its archival data. As a next step, the HAH project will examine the streaks of previously unknown asteroids to characterize their orbits, rotation periods, and other properties.

Further Reading: ESA Hubble, Astronomy & Astrophysics

The post Hubble Has Accidentally Discovered Over a Thousand Asteroids appeared first on Universe Today.