Astronomy

Forensic scientists are still working to identify victims of the 9/11 attacks using advancements in technology and techniques developed over the past two decades.

Video: 00:04:29

Watch the second episode of the ExoMars Rosalind Franklin rover mission – Europe’s ambitious exploration journey to search for past and present signs of life on Mars.

This episode starts with Rosalind searching for traces of life below the martian surface using a ground penetrating radar and a set of cameras.

The rover will dig, collect, and investigate the chemical composition of material collected by a drill. Rosalind Franklin will be the first rover to reach a depth of up to two metres deep below the surface, acquiring samples that have been protected from surface radiation and extreme temperatures.

Rosalind Franklin uses the WISDOM radar to help scientists on Earth decide where to drill. Besides identifying the most promising targets for sampling, WISDOM will help the rover avoid potential hazards, such as the presence of buried rocks that could damage the drill.

The scientific eyes of the rover are set on the Panoramic Camera suite known as PanCam. The Close-UP Imager (CLUPI) sits on the side of the drill box, a camera designed to acquire high-resolution, colour, close-up images of outcrops, rocks and soils. PanCam and CLUPI will help scientists find the most promising spots to drill. These instruments can also investigate very fine outcrop details and image drill samples before they are sent into the rover’s laboratory.

After the rover retracts its drill, the sample is in a special chamber at the tip.  Under the reduced martian gravity (38% of Earth’s), the material drops onto a special “hand” that the rover can extend to the front to collect drill samples.

The mission will serve to demonstrate key technologies that Europe needs to master for future planetary exploration missions.

The ExoMars rover series show the rover and martian landscapes as true to reality as possible for a simulation.

Check ESA’s ExoMars website and our frequently asked questions for the latest updates.

 

Credits: ESA

Production: Mlabspace for ESA

3D animation: ESA/Mlabspace

Music composed by Valentin Joudrier

Watch all the videos from the ExoMars Rosalind Frankin mission series.

Access the related broadcst quality video material.

About 70,000 light-years across,

Can you see the bat?

After decades of work, physicists have finally broken into the atom to build the first nuclear clock

The private SpaceX Polaris Dawn crew has now flown farther from Earth than any astronauts have traveled since the last Apollo mission left for the moon.

Galaxy collisions are foundational events in the Universe. They happen when two systems mingle stars in a cosmic dance. They also cause spectacular mergers of supermassive black holes. The result is one very changed galaxy and a singular, ultra-massive black hole.

These colossal events are a major force in the evolution of galaxies. It’s how smaller galaxies combine to form ever-larger ones. Such mergers have been going on since the earliest epochs of cosmic time. Galaxy mergers continue today. Our Milky Way continues to gobble up smaller ones and it will collide with the Andromeda Galaxy in a few billion years. When that happens, both galaxies’ supermassive black holes could also merge.

View of Milkdromeda from Earth “shortly” after the galactic merger of the Milky Way and Andromeda, around 3.85-3.9 billion years from now. Credit: NASA, ESA, Z. Levay and R. van der Marel (STScI), T. Hallas, and A. Mellinger

We don’t see the whole process from start to finish because it takes millions of years to complete. Yet, that doesn’t stop astronomers from looking for—and finding—evidence of galaxy and supermassive black-hole collisions. The latest discovery used the Hubble Space Telescope (HST) to spot three bright, visible light “hot spots” deep inside a pair of colliding galaxies. These targets lie relatively close to us—only about 800 million light-years away. Astronomers followed up with Chandra observations and radio data from the Karl G. Jansky Very Large Array.

Typically, galaxies with bright cores, called “active galactic nuclei” (AGN for short), exist very far away. They’re often seen earlier in cosmic time. The chance to study a galaxy and a pair of supermassive black holes in a collision in the “modern” nearby Universe is a good time to study the mechanics of such an event.

Spotting Incipient Supermassive Black Hole Collisions

The discovery of a future cosmic collision came when HST’s Advanced Camera for Surveys spotted three optical diffraction spikes in the heart of a colliding galaxy called MCG-03-34-64. Two of those “hot spots” appear very close together—only about 300 light-years apart. They trace the presence of oxygen gas in the core. It’s being ionized by something very energetic and the hot spots surprised the astronomers. (The third hot spot isn’t well understood.) “We were not expecting to see something like this,” said Anna Trindade Falcão of the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts. “This view is not a common occurrence in the nearby Universe, and told us there’s something else going on inside the galaxy.”

HST’s image of the galaxy MCG-03-34-064 in visible light. Two of the three bright spots at the core are active galactic nuclei sources of light and X-ray emissions. They indicate two supermassive black holes about 300 light-years apart and growing closer. Image credit: NASA, ESA, Anna Trindade Falcão (CfA)

Falcão and her colleagues wanted to know what was going on to cause those bright spots. So, they used the Chandra X-ray observatory to focus on the action. “When we looked at MCG-03-34-64 in the X-ray band, we saw two separated, powerful sources of high-energy emission coincident with the bright optical points of light seen with Hubble. We put these pieces together and concluded that we were likely looking at two closely spaced supermassive black holes,” said Falcão.

The team also found observations of these objects in archival radio telescope data. Those powerful radio emissions proved that the pair of black holes exists and are edging closer together. “When you see bright light in optical, X-rays, and radio wavelengths, a lot of things can be ruled out, leaving the conclusion these can only be explained as close black holes,” noted Falcão. When you put all the pieces together it gives you the picture of the AGN duo.”

The Upcoming Collision

These central supermassive black holes will collide in perhaps a hundred million years. Each is at the core of a single galaxy. As those galaxies draw ever closer together, the black holes in their hearts will start to interact. Eventually, they’ll merge in a powerful event, emitting gravitational waves as part of the process.

This illustration shows the merger of two supermassive black holes and the gravitational waves that ripple outward as the black holes spiral toward each other. Credit: LIGO/T. Pyle

Astronomers suggest (via simulations and observations) that mergers of galaxies with supermassive black holes trigger a lot of activity. As the collisions proceed, interstellar gas flows toward the galactic centers. It also gets compressed in other regions and both activities trigger bursts of star formation. Some gas also accretes onto those central supermassive black holes, causing increased emissions as material spirals through the accretion disk.

These mergers happen continually in the Universe. Models of galaxy evolution, coupled with observational evidence suggest that many AGNs at the hearts of galaxies experience mergers. Colliding supermassive black hole pairs within those AGNs also suggest that those black holes grow through mergers.

Supermassive Black Hole Collisions and Future Detections

Understanding the merger of close-together AGNs such as the ones seen in MCG MCG-03-34-64 offers a unique window into the final stages of what astronomers call “SMBH binary coalescence”. Such events are and will continue to be a major way to measure the effects of these mergers. They’ll offer a rich field of study using observatories sensitive to light across the spectrum, as well as future gravitational wave detectors.

LISA will observe a passing gravitational wave emitted as a result of the collision of two supermassive black holes directly by measuring the tiny changes in distance between freely falling proof masses inside spacecraft with its high precision measurement system. Credit: AEI/MM/exozet

Those detections will require advanced versions of the Laser Interferometer Gravitational-Wave Observatory (LIGO), which made its first detections only a few years ago. Supermassive black hole merger-induced gravitational waves will be the target of future instruments such as LISA (short for Laser Interferometer Space Antenna). It will deploy three space-based detectors millions of miles apart to capture the long-wavelength gravitational waves emitted when black hole behemoths like the ones in MCG-03-34-64 collide. Since those mergers occur throughout the Universe, it’ll be a rich field of study that contributes greatly to our understanding of galaxy mergers as part of cosmic evolution.

For More Information

NASA’s Hubble, Chandra Find Supermassive Black Hole Duo
Resolving a Candidate Dual Active Galactic Nucleus with ~100 pc Separation in MCG-03-34-64

The post Two Supermassive Black Holes on a Collision Course With Each Other appeared first on Universe Today.

Large galaxies like ours are hosts to Supermassive Black Holes (SMBHs.) They can be so massive that they resist comprehension, with some of them having billions of times more mass than the Sun. Ours, named Sagittarius A* (Sgr A*), is a little more modest at about four million solar masses.

Astrophysicists have studied Sgr A* to learn more about it, including its age. They say it formed about nine billion years ago.

SMBHs are the Universe’s most beguiling objects. They’re so massive that their gravitational pull can trap light. They’re surrounded by a rotating ring of material called an accretion disk that feeds material into the hole. When they’re actively feeding, they’re called active galactic nuclei (AGN.) The most luminous AGNs are called quasars, and they can outshine entire galaxies.

How can scientists determine the age of these confounding objects? How can they learn when our black hole, Sgr A*, formed? By gathering data, piecing it together, and running simulations.

This effort started in earnest in April of 2017 when the Event Horizon Telescope (EHT) observed the black hole at the center of galaxy M87. That was the first time we saw an image of a black hole, and it was followed up in 2022 when the EHT observed Sgr A*.

New research published in Nature Astronomy relied on EHT observations to ascertain Sgr A*’s age and origin. It’s titled “Evidence of a past merger of the Galactic Centre black hole.” The authors are Yihan Wang and Bing Zhang, both astrophysicists at the University of Nevada, Las Vegas.

Black holes grow in two ways. They accrete matter over time, and they merge. Astrophysicists believe that it takes a galaxy merger to form an SMBH, and Sgr A* is no different. It likely formed through a merger, though it also accretes material.

This artist’s conception illustrates a supermassive black hole (SMBH) at the core of a young, star-rich galaxy. Black holes grow through two processes: accretion and mergers. Image credit: NASA/JPL-Caltech

Sgr A* is unusual. It spins rapidly and is misaligned relative to the Milky Way. This is evidence of a past merger, according to Wang and Zhang, possibly with a long-gone satellite galaxy called Gaia-Enceladus.

“The Event Horizon Telescope (EHT) provided direct imaging of the SMBH Sgr A* at the Milky Way’s center, indicating it likely spins rapidly with its spin axis significantly misaligned relative to the Galactic plane’s angular momentum,” the authors write in their paper.

The pair of researchers used computer simulations to model what impact a merger would have on the Milky Way’s black hole. “Through investigating various SMBH growth models, here we show that the inferred spin properties of Sgr A* provide evidence of a past SMBH merger,” the authors write.

Their work shows that a 4:1 mass ratio merger with a highly inclined orbital configuration can explain what EHT observations of Sgr A* show. “Inspired by the merger between the Milky Way and Gaia-Enceladus, which has a 4:1 mass ratio as inferred from Gaia data, we have discovered that a 4:1 major merger of SMBH with a binary angular momentum inclination angle of 145-180 degrees with respect to the line of sight (LOS) can successfully replicate the measured spin properties of Sgr A*,” the authors explain in their work.

This figure from the research shows how a black hole merger can create a single, more massive black hole with a spin misaligned with the host galaxy. Image Credit: Wang, Zhang 2024.

“This merger likely occurred around 9 billion years ago, following the Milky Way’s merger with the Gaia-Enceladus galaxy,” said Zhang, a distinguished professor of physics and astronomy at UNLV and the founding director of the Nevada Centre for Astrophysics. “This event not only provides evidence of the hierarchical black hole merger theory but also provides insights into the dynamic history of our galaxy.”

Gaia-Enceladus in a simulation of a galactic merger with the Milky Way matching Gaia data. The remnants of the merger are found throughout the Milky Way. Image Credit: ESA (artist’s impression and composition); Koppelman, Villalobos and Helmi (simulation)

“This discovery paves the way for our understanding of how supermassive black holes grow and evolve,” said lead author Wang in a press release. “The misaligned high spin of Sgr A* indicates that it may have merged with another black hole, dramatically altering its amplitude and orientation of spin.”

“This merger event in our galaxy provides potential observational support for the theory of hierarchical BH mergers in the formation and growth of SMBHs,” the authors write in their conclusion.

When galaxies merge, so do their central black holes. While this has been largely theoretical, gravitational wave observatories are detecting an increasing number of black hole mergers. However, due to our observatories’ frequency range, they’ve only detected stellar mass black hole mergers. SMBH mergers would produce much lower gravitational wave frequencies that are beyond the range of detectors like LIGO/Virgo/KAGRA. The system’s detectors are too close together to detect the lower frequencies.

The authors also point to SMBH merger rates determined in other simulations like the Millenium Simulations, which suggests there could be hundreds or thousands each year in the observable Universe. “The inferred merger rate, consistent with theoretical predictions, suggests a promising detection rate of SMBH mergers for space-borne gravitational wave detectors expected to operate in the 2030s.”

There are plans to build facilities that can detect these lower SMBH merger frequencies. The ESA and NASA are planning a mission called LISA (Laser Interferometer Space Antenna) that can detect these waves. LISA will consist of three spacecraft working together as an interferometer. Each spacecraft would be 2.5 million km long.

Artist Impression of LISA, the Laser Interferometer Space Antenna. Image Credit: NASA

SMBHs are some of the most puzzling objects in the Universe and are daunting to study. However, even in the absence of any gravitational wave evidence of SMBH mergers, this research helps set the stage for deepening our understanding of these mergers when they do occur.

The post The Milky Way’s Supermassive Black Hole Might Have Formed 9 Billion Years Ago appeared first on Universe Today.

The Boeing Starliner module has been plagued with issues despite what seemed to be the dawning of a new commercial space giant. The module detached from the International Space Station on 7 September but without its crew! Butch Wilmore and Suni Williams journeyed to the ISS in June this year in what was supposed to be a mission lasting just a week. They are still there! Just a few days ago, their module returned under remote control while they stay in orbit until February! 

I think the two astronauts stuck up in the ISS (although NASA and Boeing try and contain the use of the term ‘stuck’) would agree, space exploration is unpredictable! We are only just scraping the surface of the physics of the cosmos and the extreme conditions beyond the safe confines of Earth’s atmosphere.

NASA’s Boeing Crew Flight Test astronauts (from top) Butch Wilmore and Suni Williams pose on June 13, 2024 for a portrait inside the vestibule between the forward port on the International Space Station’s Harmony module and Boeing’s Starliner spacecraft. Credit: NASA

Spacecraft like the Boeing Starliner must protect the crew from the hostile environment that includes high levels of radiation, and micrometeoroids to name just tow of them. Even with the extreme levels of planning that go into space missions, sometimes things go wrong! Human error, equipment malfunction and even cosmic events can all transpire to make space exploration one of the trickiest endeavours our species has undertaken. 

The Starliner module was developed by Boeing as one of a new generation of spacecraft designed to transport astronauts to the ISS. It was developed as part of NASAs Commercial Crew Program as an independent, re-usable module. The module is equipped with touch screen controls to give it a real ‘Star-Trek’ appeal, a streamlined suite of instruments that enable it to be either manually or automatically controlled. It has been designed for land-based recoveries like most others that splash down on their return to Earth.

The Starliner spacecraft is pictured docked with the Harmony module at the International Space Station high above the Mediterranean Sea. Credit: NASA

The Boeing contract with NASA was secured in September 2014 and, after a few test failures, finally launched its first crew to the ISS on 5 June 2024. The intention was for them to stay on board for a week but as history shows, that hasn’t quite gone to plan. Before they had even left a helium leak had been identified in the propulsion system but was considered to be isolated. During the flight, another four leaks were identified. 

What do these dates have in common; 14 June, 18 June and 24 August? They are all dates that NASA and Boeing a delay for the return of Willliams and Wilmore. Now it looks likely that their return won’t be until February next year hitching a ride on board the SpaceX Dragon module instead. 

Crew Dragon docking with ISS

The decision was taken to return the Starliner module to Earth autonomously for safety concerns. Now it is back on Earth teams of engineers will begin work to understand what has been plaguing the propulsion system. It touched down on 7 September landing at the White Sands Space Harbour in New Mexico in what has been described as a text book landing, unfortunately Williams and Wilmore had to watch from the comfort of the ISS!

Source : Starliner Lands in New Mexico

The post Starliner Comes Home Empty appeared first on Universe Today.

We recently reported on the successful deployment of the solar sail of the Advanced Composite Solar Sail System (ACS3) technology demonstration mission. That huge achievement advances one of the most important technologies available to CubeSats – a different form of propulsion. But getting there wasn’t easy, and back in May, a team of engineers from NASA’s Langley Research Center who worked on ACS3 published a paper detailing the trials and tribulations they went through to prepare the mission for prime time. Let’s take a look at what they learned.

ACS3 was only a technology demonstration mission—it had no science payload to deal with. And that’s a good thing, too, because fitting the solar sail into the housing of a CubeSat was a challenge even without any scientific equipment.

The technology demonstrated was the deployable boom system that created an 81 square meter surface of solar sail to catch the photon particles used to propel the mission forward. That sounds much easier than it was, as is evident from the descriptions of the problems the team had to overcome.

Fraser describes how useful solar sails are.

Eventually, the mission launched in a 12U CubeSat configuration, weighing about 16 kg (36 lbs) in total mass. However, the mission was initially prototyped to fit into a 6U configuration—about half the size and weight of the 12U. With the amount of deployable material and the necessary motors to drive their deployment, the engineers couldn’t fit other essential components, like reaction wheels, to steady the CubeSat’s orientation.

However, the 12U design “came with several technical challenges,” according to the paper. One was whether to use four independent spools of material, each tied to an independent boom or one central hub spool with all four booms coiled around a central axis. As was the case with almost all engineering projects, the team’s decision wasn’t based on what was technically best. They decided to use the four independent spools since that required the least modification from the original 6U design.

Another lesson described in the paper was the timing of the launch coordination. Both the “dispenser” (i.e., the system that sends the CubeSats out into space after a successful launch) and the launch contract weren’t submitted until ACS3 was already in testing. By then, modifications had been made to the design, which made it difficult to integrate into an existing dispenser, as the team had modified the edges of the satellite to fit the sails better. But doing so messed up one of the critical touchpoints for standard CubeSat dispensers.

Here’s Fraser’s overview of what a solar sail is.

To make matters worse, without a known launch date and inclination, the team had to overengineer many of the CubeSat systems. They had to meet a much wider range of temperatures and shock/vibration environments. But when they finally got their launch date of April 23rd on an Electron rocket from New Zealand, the system had been engineered for an environment much harsher than what it was subjected to, causing increased cost and delays in the delivery.

To meet these challenges, the team took the approach of rapidly prototyping, including developing several different 3D-printed prototypes before finally making the full system out of metal. At one point, a management decision was made not to replace any insert fasteners that were never intended to be used on the final flight but ended up being included anyway because of the cost of replacing them.

Again, these kinds of management decisions are commonplace to anyone involved in an engineering project. However, it’s nice to see that, in this case, it didn’t affect the project’s overall success. Despite some indications that it might be either tumbling or wobbling, ACS3 undoubtedly achieved its primary objective of deploying its solar sail. So, after all the effort and compromises that the team at Langley and elsewhere at NASA put into it, now you just need to look up into the night sky, and you might see the fruits of their labor streaking across it.

Learn More:
Schneider et al. – Advanced Composite Solar Sail System (ACS3): Mechanisms and Lessons Learned from a CubeSat Solar Sail Deployer
UT – NASA’s New Solar Sail Extends Its Booms and Sets Sail
UT – NASA’s Next Solar Sail is About to Go to Space
UT – NASA’s Putting its Solar Sail Through its Paces

Lead Image:
CAD image of the ACS3 spacecraft.
Credit – Schneider et al

The post What Did We Learn From Manufacturing the ACS3 Solar Sail Mission? appeared first on Universe Today.

Watch new exclusive clip for Season 5 of "Star Trek: Lower Decks," the final season of Paramount+'s sci-fi comedy animated series that premieres Oct. 24.

NASA's oldest active astronaut, Don Pettit, is set to return to space on Sept. 11. In his spare ISS time, he is known for stunning photography and tinkering with engineering.

NGC 1333 is a nearby star-forming region in the Perseus constellation. NASA's James Webb Space Telescope surveyed a large portion of NGC 1333, identifying planetary objects using the observatory’s Near-InfraRed Imager and Slitless Spectrograph.

The tag team of NASA space telescopes Hubble and Chandra has demonstrated that two is definitely better than one when it comes to pairings of supermassive black holes and hunting for them.

An ancient passerby may have visited the Sun and inadvertently helped shape the Solar System into what it is today. It happened billions of years ago when a stellar drifter came to within 110 astronomical units (AU) of our Sun. The effects were long-lasting and we can see evidence of the visitor’s fleeting encounter throughout the Solar System.

Neptune is the outermost planet in the Solar System, and by a simple definition, that can mark the edge of the Solar System. There’s an entire realm of other objects beyond Neptune called the Kuiper Belt. It’s the home of Pluto, most of the dwarf planets, and some comets. Astronomers aren’t certain how large the Kuiper Belt population is, but it could contain tens of thousands of objects larger than 100 km in diameter.

Some of these objects have unusual orbits and are called Trans-Neptunian objects (TNO). In new research, a team of astronomers suggest that these orbits, and some other evidence in the Solar System, support the idea that another star passed by our Solar System and drove these objects into their current orbits. The star may have disturbed some objects so strongly that they were driven into the inner Solar System and took up residence as moons around the giant planets.

These results are in two new papers. One is published in the journal Nature and is titled “Trajectory of the Stellar Flyby Shaping the Outer Solar System.” The second is published in the Astrophysical Journal Letters and is titled “Irregular moons possibly injected from the outer solar system by a stellar flyby.” Susanne Pfalzner, the lead author of both, is from Jülich Supercomputing Centre, Forschungszentrum (Research Center) Jülich, Jülich, Germany.

“The beauty of this model lies in its simplicity. It answers several open questions about our solar system with just a single cause.”

Susanne Pfalzner, Jülich Supercomputing Centre, Forschungszentrum Jülich, Germany

While Neptune marks the outermost boundary of planets in our Solar System, an entire population of objects exists beyond it. “However, several thousand celestial bodies are known to move beyond the orbit of Neptune,” said Pfalzner. “Surprisingly, many of these so-called trans-Neptunian objects move on eccentric orbits that are inclined relative to the common orbital plane of the planets in the solar system. “

Pluto is the most well-known TNO because it used to be considered a planet. Its orbit is inclined by 17 degrees relative to the ecliptic, an imaginary plane that Earth follows as it orbits the Sun. In the ecliptic, Earth is considered to orbit the Sun at zero degrees, and none of the other planets are inclined by more than only seven degrees.

Pfalzner and her co-researchers used simulations to try to understand how some objects are inclined. They ran more than 3,000 supercomputer simulations in their effort. They wanted to investigate the idea that a passing star could be responsible, and their work showed that it could.

“Our exhaustive numerical parameter study consists of over 3,000 individual simulations modelling the effect of a stellar flyby on a planetesimal disk surrounding the Sun extending to 150?au and 300?au, respectively,” the authors write in their research.

There are three distinct populations of TNOs:

• the cold Kuiper belt objects moving on nearly circular orbits close to the plane,
• the Sedna-like TNOs orbiting at large distances (rp?>?60?au) on highly eccentric orbits (e?>?0.5),
• TNOs with high inclination (i?>?60°).

Any theory on the formation of the Solar System has to explain these three groups, according to the authors. “While only three Sedna-like objects and few highly inclined TNOs are known so far, they are the make-or-break test for any outer Solar System formation theory,” they write.

This isn’t the first time scientists have wondered if a stellar flyby can explain these puzzling parts of our Solar System. But this question has been dismissed because stellar flybys were thought to be rare. However, as we get more powerful telescopes, we’re discovering that they’re more commonplace. “However, recent Atacama Large Millimeter Array observations reveal that close stellar flybys seem to be relatively common,” the authors write.

The flyby hypothesis has gained renewed interest, but it’s difficult to study because the flyby parameter space is so large, and predictions are vague.

These researchers have made important progress, though, and their simulations can explain a lot.

“Even the orbits of very distant objects can be deduced, such as that of the dwarf planet Sedna in the outermost reaches of the solar system, which was discovered in 2003. And also objects that move in orbits almost perpendicular to the planetary orbits,” Pfalzner said. Sedna has an extremely wide orbit and takes 11,400 years to complete one orbit around the Sun. Its orbit is also wildly eccentric.

According to Pfalzner and her colleagues, a stellar flyby can also explain two Solar System objects with very oddball orbits. 2008 KV42 has a retrograde orbit, meaning it orbits in the opposite direction than the planets. 2011 KT19‘s orbit is tilted 110 degrees, meaning it effectively follows a polar retrograde orbit.

What kind of star could’ve shaped these objects’ orbits?

This table from the paper shows the trajectory of the stellar flyby that shaped the outer Solar System. Columns: solar masses, AU, inclination, angle of periastron, and assumed pre-flyby disk size. Image Credit: Pfalzner et al. 2024.

“The best match for today’s outer solar system that we found with our simulations is a star that was slightly lighter than our Sun – about 0.8 solar masses, “explained Pfalzner’s colleague Amith Govind. “This star flew past our sun at a distance of around 16.5 billion kilometres. That’s about 110 times the distance between Earth and the Sun, a little less than four times the distance of the outermost planet Neptune.”

The irregular moons are one of the Solar System’s puzzles. Everything in the Solar System formed from the solar nebula, which means barring outside influence, everything should share orbital similarities. “The origin of these irregular moons is still an open question, but these moons have a lot in common with the objects beyond Neptune (trans-Neptunian objects—TNOs), suggestive of a common origin,” the authors write.

The passing star could’ve disrupted distant objects and sent them careening into the inner Solar System, where the giant planets captured them into their orbits.

“Some of these objects could have been captured by the giant planets as moons,” says co-author Simon Portegies Zwart from Leiden University. “This would explain why the outer planets of our solar system have two different types of moons.”

This table from the research shows the Solar System’s irregular moon population. The majority of the irregular moons follow retrograde orbits. Image Credit: Pfalzner et al. 2024.

Irregular moons have unusual orbits that can be inclined, “highly elliptical, sometimes retrograde, and sometimes at great distances from their planet. All four giant planets host irregular moons, like Saturn’s Phoebe and Neptune’s Triton. “The beauty of this model lies in its simplicity,” says Pfalzner. “It answers several open questions about our solar system with just a single cause.”

This Cassini image shows Saturn’s moon, Phoebe. It’s an example of the unusual properties of irregular moons. Like many others, it orbits Saturn in the opposite direction. Image Credit: NASA/JPL

“A stellar flyby can simultaneously reproduce the complex TNO dynamics quantitatively while explaining the origin of the irregular moons and the colour distributions of both populations,” the authors write. Their simulations show that the flyby would’ve sent 7.2% of the TNO population into the inner Solar System. Many of them would’ve followed retrograde orbits, though most would’ve been subsequently ejected from the Solar System, and only a handful were captured by planets.

Could this flyby have impacted the appearance of life? That’s a purely speculative question, but since life is so rare and unexplained, it needs to be asked. It’s possible that some objects disturbed by the flyby crashed into Earth or other planets, possibly delivering prebiotic material and volatiles. At the same time, Earth’s orbit could’ve remained undisturbed. “However, how much prebiotic material originally contained in an injected TNO would survive impact on a terrestrial planet would require further studies,” the authors write.

The simulations were able to explain critical things about the Solar System that are in need of explanations. However, there needs to be more evidence before the work is conclusive.

The team’s predictions may be verified when the Vera Rubin Observatory (VRO)comes online. The VRO is expected to discover around 40,000 TNOs.

The post A Stellar Flyby Jumbled Up the Outer Solar System appeared first on Universe Today.

An obituary for legendary actor James Earl Jones.

Ancient humans are said to have evolved to leave the trees, where our primate ancestors lived, in favour of open grassy savannahs – but we may have this idea wrong

Ancient humans are said to have evolved to leave the trees, where our primate ancestors lived, in favour of open grassy savannahs – but we may have this idea wrong

Warhammer 40K: Space Marine 2 is out now. If you don't know anything about the universe or haven't played the original, we've got you covered.

Three amazing recent asteroid finds show what’s possible in terms of astronomy online.

Practical astronomy is increasingly becoming an online affair. In 2023, we wrote about this trend, and highlighted how Russian observer and amateur astronomer Filipp Romanov used time on a remote observatory to successfully discover two asteroids, which he named 623826 Alekseyvarkin and 623827 Nikandrilyich after his great-grandfathers. Now, Filipp has repeated this feat and pushed the limit of what’s possible online with the discovery of a trio of asteroids, including a rare near-Earth asteroid discovery found using a remote system.

Universe Today caught up with Filipp to explain how he did it:

“I have been searching for asteroids in images from remote telescopes from time to time for almost two years, and I have discovered four asteroids that have received their names, but on August 26th, 2024, I made a great find—I found a near-Earth asteroid in the images obtained using the 0.51-meter f/6.8 remote telescope T59 located at the Siding Spring Observatory of the iTelescope network, which is visible in all eight (300 second exposure) photos of one of the fields of the sky.”

A Surreptitious Find

Timing and planning is crucial in the hunt for asteroids, as Filipp elaborates: “I reserved in advance the necessary time on this telescope (when the waning gibbous Moon did not illuminate the sky above this observatory, and when the Moon was still below the horizon) for imaging, calculated the celestial coordinates, and requested specifically for the searching of main-belt asteroids and photography of two areas of the sky near the near the ecliptic and in the opposition region.”

The region is crucial, as asteroids coming into opposition ‘opposite’ to the Sun as seen from Earth are also at their brightest. Also, the area in the constellation Pisces where asteroids are reaching this point in late August into September is also relatively vacant, and far from the densely packed plane of the Milky Way Galaxy. In the era of visual astronomy in the mid-19th century, more asteroids were discovered in September than any other month.

It was in the same constellation than Filipp made a surprise discovery.

“I found an asteroid with a fast movement. In the images, this astronomical object looked like lines, unlike star-shaped (point source) main-belt asteroids, and I thought that it might be a near-Earth asteroid.” This fast motion leaving trails in the images is a clue that the object is also closer to the Earth.

Still, Filipp had to be sure that the asteroid wasn’t a known space rock. “I checked that there were no matches with known astronomical objects from the Minor Planet Center (MPC) database and sent the data of my astronomic measurements to the NEO Confirmation Page (NEOCP) so that they appear there for the attention of astronomers around the world.”

Pinning Down an Asteroid Find

This stage is crucial, in order to confirm the discovery and refine the position and orbit of the asteroid… and the more observations the better. Bad weather over key sites or losing the asteroid in the Sun’s glare can mean a discovery can go missing for months, or even years. “I immediately wrote to a number of astronomers with a request to confirm this astronomical object, but some of the astronomers did not have clear weather for observations (or were) not online at the time. Only one amateur astronomer immediately responded.” Filipp then made a quick decision to use precious observing time to make a follow up observation, using an iTelescope in Chile. “As a result, we both managed to confirm this asteroid and each of us sent results of our astrometric measurements to the MPC.”

Automatic sky surveys have since picked up asteroid 2024 QS, including the Mount Lemmon Survey on September 3rd, and the ATLAS-HKO and -MLO surveys in Hawaii on September 5th.

Asteroid 2024 QS, captured September 1st, days before closest approach to the Earth. Credit: Filipp Romanov.

The discovery became known as 2024 QS, a 43-meter asteroid on a 1.8 year orbit around the Sun, passing 12.1 LD (lunar distances, or slightly less than 4.7 million kilometers) from the Earth yesterday on September 9th at 00:39 Universal Time (UT). This pass ejected the asteroid from the near-Earth vicinity. About 35,000 Near-Earth Objects (NEOs) are known of though certainly, amateur astronomers finding one is rare.

…And Something More Asteroids 679996 (left) and 679999 (right). Credit: Filipp Romanov.

Two more recent discoveries were also made by Filipp:

The first was asteroid 2023 PS3, found on August 9th, 2023 using the the 2-meter Liverpool Telescope. This small (150-170 meter in diameter) asteroid is on a 2.56 year orbit. 2023 PS3 is a member of the Hungaria Group. Astronomers only know of about 30,000 Hungaria Group asteroids. This asteroid was later named 679996 Mariyafilippovna, after Filipp’s great-grandmother.

M.F. Romanova (left) and M.M. Varkina (right), the two great grandmothers of Filipp Romanov.

Mariya Filippovna Romanova (1919-1979) lived in Chugueka and worked as a secretary-typist and as a clerk. She was awarded the Veteran of Labour medal.

Next was asteroid 2023 SJ76, found on September 16th, 2023 using the T11 iTelescope located at the Utah Desert Remote Observatory located at Great Basin desert in Beryl Junction, Utah.

This main-belt asteroid is several hundred meters across, and has an orbital period of 3.57 years. It later received the name of 679999 Mariyavarkina after Filipp’s great-grandmother Mariya Maksimovna Varkina, who tragically died while pregnant in a bus accident in Primorsky Krai, Russia in 1962. She was Mordvin (by nationality), and from Sabanovo (near Penza, Russia).

Filipp Romanov at his laptop.

Congrats to Filipp on these amazing finds, and showing us all what’s possible, with a little dedication and persistence.

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