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Most atoms are made from positively charged protons, neutral neutrons and negatively charged electrons. Positronium is an exotic atom composed of a single negative electron and a positively charged antimatter positron. It is naturally very short-lived, but researchers have now successfully cooled and slowed down samples of positronium using carefully tuned lasers. They hope this research will help others explore exotic forms of matter, and that such research might unlock the secrets of antimatter.

Astronomers have captured images of a star other than the Sun in enough detail to track the motion of bubbling gas on its surface. The images of the star, R Doradus, were obtained in July and August 2023. They show giant, hot bubbles of gas, 75 times the size of the Sun, appearing on the surface and sinking back into the star's interior faster than expected.

Neuroscientists have revealed how sensory input is transformed into motor action across multiple brain regions in mice. The research shows that decision-making is a global process across the brain that is coordinated by learning. The findings could aid artificial intelligence research by providing insights into how to design more distributed neural networks.

With maps of the connections between neurons and artificial intelligence methods, researchers can now do what they never thought possible: predict the activity of individual neurons without making a single measurement in a living brain.

There were at least two op-eds in the New York Times in the last few days arguing that if Harris was to win last night’s debate, she could not spend her time attacking Trump but had to show that she had tangible policy proposals for the American people.  Well, Harris did win the debate (I’m not aware of anybody who disagrees with this, including conservative websites like the National Review), but it was not because of her policy proposals. (Fortunately, I managed to stay awake to watch the whole thing.)

The NYT was wrong: Harris won the debate hands down, not by presenting tangible policies (she did mention a few), but by doing what she was told not to do: baiting and attacking Trump. She did it calmly but persistently, to the point where Trump became so baffled and enraged that he simply lost it, becoming unhinged and yes, almost deranged. And when that happened, his narcissism and lying became uncontrollable. In fact, at some points I thought that, like Biden, he had simply lost his ability to think. It seems to me now that Trump is showing signs of age, in a manner different in degree but not in kind from the kind of fogginess that brought down Biden in his last debate with Trump.

If you didn’t see the debate, it’s below.

I suspect that some of Harris’s debate practice involved confecting statements that would unsettle Trump, and, sure enough, they worked, like a red cape shown to a bull.  Perhaps the most effective was Harris’s assertion that people got bored at Trump rallies, which were insubstantial and full of pop culture, and simply left them early.

That was enough to unsettle Trump, who claims that his rallies were, like everything else he does, the greatest in the history of America. And he never recovered his equilibrium.  The lies and misstatements spouted forth like water from a fountain.  There was the statement that Haitians were eating pets in Ohio, the claim that Harris met both Putin and Zelensky and failed to secure a peace (she never met Putin), the false claim that tariffs on foreign goods wouldn’t result in higher prices for consumers, that if was elected he could settle the Ukraine/Russia war before he took office, that Harris was a Marxist, that some Democrats support the execution of children after birth, and so on. None of that is true. When Harris said that world leaders were laughing at Trump’s ineptitude (another statement guaranteed to bait him), his response was to quote Hungarian President Viktor Orbán, a minor figure who admires Trump but also admires Putin. Was that the best he could do?

The WaPo and other sites have compiled a list of Trump’s lies and exaggerations, and it’s long.  Now Harris wasn’t immune to misstatements, either, but they were far fewer, and included her statement that “And as of today, there is not one member of the United States military who is in active duty in a combat zone, in any war zone around the world, the first time this century,”, which isn’t true. She claimed that the Biden administration created over 800,000 manufacturing jobs (the true number is close to 625,00).  But these are trivial compared to Trump’s fulminating and arrant lying.

I don’t know how many undecided voters would have been swayed by Trump’s performance to vote for him, but I doubt that it’s anywhere close to half.  The debate was really a contrast in likability and personality, and Harris’s cool demeanor and failure to get flustered made her look far better than Trump, whom I’ve always said suffers from a form of personality disorder.  And voters want to like the person whose box they check on the Presidential ballot.

Both candidates evaded some questions, including Trump’s denial of any responsibility for Project 2025, his failure to own up to the “fine people on both sides” statements he said after the far-right rally in Charlottesville, and his failure to specify how he’d rid the country of 11 million illegal immigrants. For her part, Harris didn’t really explain how her policies could change if her values didn’t, and she didn’t own up to her change of policy on fracking nor admit the seriousness of the immigration issue. This was balanced by two statements by Harris that were eloquent and, at least to me, somewhat moving: her defense of abortion rights for women and her rebuke of Trump for failing to stand for America’s democratic values by not supporting Ukraine.

No, Harris wasn’t strong on presenting policies (she did outline some, like her $6,000 tax credit to parents with newborns and a reduction in tax credits, and her website now outlines specific plans, including giving $25,000 to first-time home buyers). Whether her plans are financially viable is another question, but neither she nor Trump were asked that. (Note that, according to the New Republic, many of Harris’s policies were lifted directly from Biden’s campaign website).

The one issue on which I strongly disagree with Harris is the stand on Israel she espoused. While she said she strongly supported Israel and its right to defend itself, she also argued that the death toll of civilians in Gaza (something that’s been lifted from Hamas’s figures) is too high, and that we need both an immediate cease-fire and especially a two-state solution.  Both of those policies explicitly deny Israel the right to defend itself: a cease-fire now is a loss for Israel and a victory for Hamas, and we simply cannot have a two-state solution now. There are not honest brokers on either side, and of course neither Israel nor the Palestinians really want a two-state “solution”, which won’t solve any problems. (Israel now has no faith that a Palestinian state will be peaceful, and the Palestinians want the erasure of the state of Israel far more than they want their own state alongside Israel.)  I have little faith that Harris will conduct an israeli policy to my liking, but of course many Americans are far less pro-Israel than I.

As for the moderators, they were pretty good, though David Muir dominated the questions over Linsey Davis, which seems to me a bit sexist. However, the questions were generally good, and I thought the policy of fact-checking false claims during the live debate was a good one (and probably threw Trump off even more).

I believe that the Democrats, flush with victory, are now calling for a second debate, but I’m not sure there will be one. If the polls show that voters (and the electoral college) have moved towards Harris, Trump will surely not agree to a second debate.

When I discussed this with Luana today, she came to a conclusion that is hers. And here it comes. There is one good outcome of this debate: whichever side loses will have to recalibrate. If Trump loses, then MAGA is gone and Trump has lost most of his influence in the GOP. If Harris loses, then the Democrats have to become yet more centrist (though I have to add that Harris has deliberately become more centrist recently as a pragmatic issue to win).

We don’t know who will win the election, and the next few days will show how much Trump’s embarrassing performance will cost the GOP. (Remember, he’s always been an awful debater but has nevertheless come out on top twice.)  But regardless of that, there’s no question that the winner of the debate was Kamala Harris. I’m still not a big fan of hers, but was reminded last night why I’ve always regarded Trump as a joke—but a very dangerous joke.

Now, of course, it’s your turn to weigh in, and I ask you to do so in the comments. (There was some weighing in after my livestream post on the debate last night.)

And we’re back, with a batch of insect and spider photos from regular Mark Sturtevant. Mark’s comments are indented, and you can enlarge his photos by clicking on them.

Here are more pictures of arthropods that were taken last summer from eastern Michigan, which is where I live. They include both pictures from the field along with staged shots from the ‘ol dining room table.

First up are two bee- or wasp-mimicking Syrphid flies. The first one is Somula decora and the second is Temnostoma alternans. An issue that Syrphid flies will have when mimicking Hymenopterans is that because they are descended from flies with shortened antennae, they lack the long antennae of their models. The first one tries to fix that with antennae that are placed out on a stalk on the head.

The second one (which is doing a great job looking like a Yellowjacket, btw), instead tends to wave its darked front legs up and down as wasps will do with their antennae. The provided link is worth viewing, as it shows one of these flies using its legs. It really sells it! We often see that mimics not only take on the appearance of their models, but they will also imitate some of their identifying behaviors as well.

Next up is a simple Asian Lady Beetle larva Harmonia axyridis. This predatory larva will graze on aphids and then pupate to later become the ubiquitous Lady Beetle that everyone sees everywhere. In case anyone is wondering, the terms Lady Beetle, Ladybird Beetle, and Ladybug (one word) are all widely used, but it is technically more correct to use a reference that they are beetles (Coleoptera), and not bugs (Hemiptera). I will try to remember that.

It has been many years since I’ve seen the beetle shown in the next picture. This is an Elm Borer, Saperda tridentata. The common name of course tells you something about the biology of this insect.

Let’s wrap up this set with some Jumping Spiders, which belong to the family Salticidae (referring to their habit of jumping, or saltating). I am lucky in that many species from this charming family are commonly seen in and around the house. There quite a few more besides the three shown here.

First up is a male Tan or Familiar Jumping Spider, Platycryptus undatus. These are our largest Salticid, and I can always find a few out on the shed. They are distinctly flatter than many members of this family, and they use that to quickly hide inside crevices on the shed. One has to be fast when trying to catch them.

Next is a female Dimorphic jumping spider, Maevia inclemens. They have this name since males come in two color morphs that look completely different. I showed one here a couple posts back. Jumping spiders are usually fidgety to photograph, but a common trick is to calm them down with a little snack.

Last, here is a female Zebra Jumping Spider, Salticus scenicus. These are one of our smallest Salticids. Males sport very large chelicerae and fangs, and I have not managed to get WEIT-worthy pictures of one since (for me) they are always dialed up to eleven. Save it for next season, I always say. Anyway, the last Zebra picture shows a new post-processing trick where I add Dramatic Lighting by using layer masks to apply darkened gradients above and below. This is to add greater depth to the surroundings and to emphasize the subject.

It seems there is an endless stream of artificial intelligence (AI) news coming out, and this includes the field of medicine. There also continues to be a debate about the true impact of AI – how much is hype, and how much is a genuine advance that can transform our technology? As with many technological advances, it’s both. New tech, perhaps especially […]

The post Update on AI in the Clinic first appeared on Science-Based Medicine.

In between two spacecraft visiting Jupiter’s moon Io, a volcano spreading material over hundreds of kilometres has appeared

Cleaner wrasse use their reflection to build a mental image of their body size, which they use to compare themselves to rivals before picking a fight

Join the Skeptoid Flash Mob at CSICon 2024 in Las Vegas. Visit skeptoid.com/store to get your shirts.

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.

This may be the only debate between America’s two Presidential candidates so it would behoove us to listen to it. It’s beginning in about three minutes so, if you’re watching, put your comments below.

The candidates have two minutes to answer the question, two minutes for a rebuttal by the other candidates, and then back to the questioned candidate for a one-minute rebuttal.

The debate is actually on all three major channels, but the moderators are from ABC.

Oh, and I have pretty bad jet lag, so I’ll last until my eyes start closing.

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.

A new article examines how the flexibility of containers affect how fast they drain.

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.

Phase separation, when molecules part like oil and water, works alongside oxygen diffusion to help memristors -- electrical components that store information using electrical resistance -- retain information even after the power is shut off, according to a recent study.

Phase separation, when molecules part like oil and water, works alongside oxygen diffusion to help memristors -- electrical components that store information using electrical resistance -- retain information even after the power is shut off, according to a recent study.

Demand for cancer genetic testing is on the rise, but there's not enough genetic counselors to guide patients through the process. Researchers say chatbots could be the answer.

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.

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