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A framework based on advanced AI techniques can solve complex, computationally intensive problems faster and in a more more scalable way than state-of-the-art methods, according to a new study.

Astronomers have used new data from NASA's Hubble Space Telescope and the retired SOFIA (Stratospheric Observatory for Infrared Astronomy) as well as archival data from other missions to revisit one of the strangest binary star systems in our galaxy -- 40 years after it burst onto the scene as a bright and long-lived nova. A nova is a star that suddenly increases its brightness tremendously and then fades away to its former obscurity, usually in a few months or years.

Researchers have demonstrated the first chip-based 3D printer, a tiny device that emits reconfigurable beams of visible light into a well of resin that rapidly cures into a solid shape. The advance could enable a 3D printer small enough to fit in the palm of a person's hand.

Researchers have demonstrated the first chip-based 3D printer, a tiny device that emits reconfigurable beams of visible light into a well of resin that rapidly cures into a solid shape. The advance could enable a 3D printer small enough to fit in the palm of a person's hand.

Observing the earliest stars is one of the holy Grails of astronomy. Now, a team at the University of Hong Kong led by astronomer Jane Lixin Dai is proposing a new method for detecting them. If it works, the approach promises to open a window on the origin of the cosmos itself.

The earliest stars in the Universe formed very soon after the Big Bang. Astronomers call them “Population III” (or Pop III) stars. They’re different from the Sun and other stars in the modern cosmos for a variety of reasons. They formed mainly from the hydrogen and helium in the newborn cosmos. From there, they grew to outrageous sizes and masses very quickly. That growth had a price. Those stars had very short lives because they blew through their core fuels very quickly. However, fusion at their cores and the circumstances of their deaths created the first elements heavier than hydrogen and helium. Those new elements seeded the next generations of stars.

Population III stars were the Universe’s first stars. They were extremely massive, luminous stars, and many of them exploded as supernovae. Image Credit: DALL-E

So, why can’t we detect these early stellar behemoths? For one thing, they existed too far away, too early in history, and their light is very faint. That’s not to say they are undetectable. Astronomers just need advanced methods and technology to spot them.

How to “See” the First Stars

Professor Dai’s team just published a study that suggests a connection between these first stars and nearby black holes. In short, they looked at what happens when a Pop III star interacts with a black hole. Essentially, it gets torn to shreds and gobbled up. For example, the supermassive one at the heart of our Milky Way Galaxy—called Sagittarius A*— does this. It has a regular habit of ripping apart stars that wander too close. When such a tidal disruption event (TDE) happens, it releases huge amounts of radiation. If the same thing happens in another galaxy—no matter how far away—the light from the event is detectable. As it turns out these tidal disruption event flares have interesting and unique properties used to infer the existence of the ancient Pop III stars.

The alien star S0-6 is spiraling toward Sagittarius A*, the Milky Way’s central supermassive black hole. S0-6 likely came from another galaxy and it may get gobbled up or torn up by interactions with the supermassive black hole. Courtesy: Miyagi University of Education/NAOJ.

“As the energetic photons travel from a very faraway distance, the timescale of the flare will be stretched due to the expansion of the Universe. These TDE flares will rise and decay over a very long period of time, which sets them apart from the TDEs of solar-type stars in the nearby Universe,” said Dai.

In addition, the expansion of the Universe stretches the wavelengths of light from the flares, according to Dai’s colleague, Rudrani Kar Chowdhury. “The optical and ultraviolet light emitted by the TDE will be transferred to infrared emissions when reaching the Earth,” Chowdhury said. Those emissions are exactly the kind of light new generations of telescopes are built to observe.

Searching for First Stars with Advanced Telescopes

This detection method is right up the alley of the JWST and the upcoming Nancy Grace Roman telescopes. Both are optimized to sense dim, distant objects via infrared wavelengths. They should be able to search out the stretched light from those long-gone Pop III stars unfortunate enough to encounter a black hole. In particular, the Roman telescope will use its wide-field instrument to gather the faint infrared light from stars born at the earliest epochs of cosmic time.

Artist’s impression of the Nancy Grace Roman space telescope (formerly WFIRST). Credit: NASA/GSFC

Astronomers generally accept that these first stars formed perhaps as early as a hundred million years after the Big Bang. That’s when overly dense regions filled with hydrogen and helium began to experience gravitational collapse. The stars that formed in those first birth crèches were purely hydrogen and helium—in other words, they were “metal-free”. They lived perhaps a few million years before exploding as cataclysmic supernovae. (By comparison, the Sun has existed for some 4.5 billion years and has another few billion years left before it becomes a red giant and then a white dwarf.) The heavier elements created inside those first stars got blasted out to space, enriching the nearby molecular clouds with infusions of carbon, oxygen, nitrogen, and other elements. Some of the largest first stars could have collapsed directly to form black holes.

Finding these first stars and their emitted light (particularly from possible interactions with early black holes) will give astronomers amazing insight into conditions in the early Universe. Even though those stars are long gone, JWST, Roman, and other telescopes can look back in time and see their dim, infrared light. If Dai’s method works, those telescopes could be responsible for the discovery of tens of Pop III stars each year.

For More Information

HKU Astrophysicists Discover a Novel Method for Hunting the First Stars
Detecting Population III Stars through Tidal Disruption Events in the Era of JWST and RomanNancy Grace Roman Space Telescope

The post A New Way to Search for the First Stars in the Universe appeared first on Universe Today.

There are plenty of crazy ideas for missions in the space exploration community. Some are just better funded than others. One of the early pathways to funding the crazy ideas is NASA’s Institute for Advanced Concepts. In 2017 and again in 2021, it funded a mission study of what most space enthusiasts would consider only a modestly ambitious goal but what those outside the community might consider outlandish—landing on Pluto.

Two major questions stand out in the mission design: How would a probe arriving at Pluto slow down, and what kind of lander would be useful on Pluto itself? The answer to the first is one that is becoming increasingly common on planetary exploration missions: aerobraking.

Pluto has an atmosphere, albeit sparse, as confirmed by the New Horizons mission that whizzed past in 2015. One advantage of the minor planet’s relatively weak gravity is that its low-density atmosphere is almost eight times larger than Earth’s, providing a much bigger target for a fast incoming aerobraking craft to aim for.

Fraser discusses future missions to Pluto.

Much of the NIAC Phase I project was focused on the details of that aerobraking system, called the Enveloping Aerodynamic Decelerator (EAD). Combined with a lander, that system makes up the “Entrycraft” that the mission is designed around. Ostensibly, it could alternatively contain an orbiter, and there are plenty of other missions discussing how to insert an orbiter around Pluto. Hence, the main thrust of this paper is to focus on a lander.

After aerobraking and slowing down to a few tens of meters a second, from 14 km/s during its interplanetary cruise phase, the mission would drop its lander payload, then rest on the surface, only to rise again under its own power. The answer to the second question of what kind of lander would be useful on Pluto is – a hopper.

Hoppers have become increasingly popular as an exploration tool everywhere, from the Moon to asteroids. Some apparent advantages would include visiting a wide array of interesting scientific sites and not having to navigate tricky land-based obstacles. Ingenuity, the helicopter that accompanied Perseverance paved the way for the idea, but in other words, the atmosphere isn’t dense enough to support a helicopter. So why not use the current favorite method of almost all spacecraft – rockets?

Fraser discusses the results from New Horizons.

A hopper would fire its onboard thrusters to reach the area on Pluto’s surface and then land elsewhere. It could then do some science at its new locale before taking off and doing so again somewhere else. The NIAC Phase I Final Report describes five main scientific objectives of the mission, including understanding the surface geomorphology and running some in-situ chemical analysis. A hopper structure would enable those goals much better than a traditional rover at a relatively low weight cost since Pluto’s gravity is so weak.

Other objectives of the report include mathematical calculations of the trajectory, including the aerobraking itself and the stress and strain it would have on the materials used in the system. The authors, who primarily work for Global Aerospace Corporation and ILC Dover, two private companies, also updated the atmospheric models of Pluto with new New Horizons data, which they then fed into the aerobraking model they used. Designing the lander/hopper, integrating all the scientific and navigation components, and estimating their weights were also part of Phase I.

The original launch window for the mission was planned as 2029 back in 2018, though now, despite receiving a Phase II NIAC grant in 2021, that launch window seems wildly optimistic. Since the mission would require a gravity assist from Jupiter, the next potential launch window would be 2042, with a lander finally reaching the surface of Pluto in the 2050s. That later launch window is likely the only feasible one for the mission, so we might have to wait almost 30 years to see if it will come to fruition. Sometimes crazy ideas take patience – we’ll see if the mission team has enough of that to push it onto the surface of one of the most interesting minor planets in the solar system.

Learn More:
B. Goldman – Pluto Hop, Skip, and Jump
UT – NASA is Now Considering a Pluto Orbiter Mission
UT – Should We Send Humans to Pluto?
UT – New Horizons Team Pieces Together the Best Images They Have of Pluto’s Far Side

Lead Image:
Artist’s depiction of the Pluto Lander mission design.
Credit- B. Goldman / Global Aerospace Corporation

The post Landing on Pluto May Only Be A Hop Skip and Jump Away appeared first on Universe Today.

Astronomers have captured what appears to be a snapshot of a massive collision of giant asteroids in Beta Pictoris, a neighboring star system known for its early age and tumultuous planet-forming activity.

Scientists have created innovative soft robots equipped with electronic skins and artificial muscles, allowing them to sense their surroundings and adapt their movements in real-time.

Scientists have created innovative soft robots equipped with electronic skins and artificial muscles, allowing them to sense their surroundings and adapt their movements in real-time.

Boys are good at math, girls not so much? A study has analyzed the social mechanisms that contribute to the gender gap in math confidence. While peer comparisons seem to play a crucial role for boys, girls' subjective evaluations are more likely to be based on objective performance.

Astrophysicists calculate the likelihood that Earth was exposed to cold, harsh interstellar clouds, a phenomenon not previously considered in geologic climate models.

Scientists have successfully miniaturized a powerful erbium-based biber laser on a silicon-nitride photonic chip. Since typical erbium-based fiber lasers are large and difficult to scale down, the breakthrough promises major advances in optical communications and sensing technologies.

Scientists have successfully miniaturized a powerful erbium-based biber laser on a silicon-nitride photonic chip. Since typical erbium-based fiber lasers are large and difficult to scale down, the breakthrough promises major advances in optical communications and sensing technologies.

Academics are often accused of 'splitting hairs', but a team has now devised a machine to do just that. We all have a bad hair day from time to time, and split ends are a common problem. However, the science behind this kind of hair damage is poorly understood, which is why scientists are investigating this knotty problem.

Antibody drug discovery is an extremely laborious and tedious process. Epitope Binning-seq, a novel method, introduces a groundbreaking approach by enabling simultaneous analysis of multiple antibodies. Using a fluorescently labeled reference antibody (rAb), this method employs flow cytometry to identify similar epitope-binding query antibodies (qAbs). Next-generation sequencing of fluorescence-negative cells then groups qAbs with epitopes akin to the rAb into epitope bins. This innovative technique holds immense potential in enhancing antibody drug discovery process.

A multi-institutional team has created atomic optical antennas in solids. The team used germanium vacancy centers in diamonds to create an optical energy enhancement of six orders of magnitude, a regime challenging to reach with conventional atomic antenna structures.

An international team of planetary scientists has detected patches of water frost sitting atop the Tharsis volcanoes on Mars, which are not only the tallest volcanic mountains on the Red Planet but in the entire solar system.

Astronomers have deciphered the formation history of young star clusters, some of which we can see with the naked eye at night. The team reports that most nearby young star clusters belong to only three families, which originate from very massive star-forming regions. This research also provides new insights into the effects of supernovae (violent explosions at the end of the life of very massive stars) on the formation of giant gas structures in galaxies like our Milky Way.

Astronomers observing exoplanet GJ 3470 b saw evidence of water, carbon dioxide, methane and sulfur dioxide. Astronomers hope the discovery of this exoplanet's sulfurous atmosphere will advance our understanding of how planets forms.

The Milky Way is only as massive as it is because of collisions and mergers with other galaxies. This is a messy process, and we see the same thing happening with other galaxies throughout the Universe. Currently, we see the Milky Way nibbling at its two satellite galaxies, the Large and Small Magellanic Clouds. Their fate is likely sealed, and they’ll be absorbed into our galaxy.

Researchers thought the last major merger occurred in the Milky Way’s distant past, between 8 and 11 billion years ago. But new research amplifies the idea that it was much more recent: less than 3 billion years ago.

This new insight into our galactic history comes from the ESA’s Gaia mission. Launched in 2013, Gaia is busily mapping 1 billion astronomical objects, mostly stars. It measures them repeatedly, establishing accurate measurements of their positions and motions.

A new paper published in the Monthly Notices of the Royal Astronomical Society presents the findings. It’s titled “The Debris of the ‘Last Major Merger’ is Dynamically Young.” The lead author is Thomas Donlon, a post-doctoral researcher in Physics and Astronomy at the University of Alabama, Huntsville. Donlon has been studying mergers in the Milky Way for several years and has published other work on the matter.

Each time another galaxy collides and merges with the Milky Way, it leaves wrinkles. ‘Wrinkles’ obviously isn’t a scientific term. It’s an umbrella term for several types of morphologies, including phase space folds, caustics, chevrons, and shells. These wrinkles move through different groups of stars within the Milky Way, affecting how the stars move through space. By measuring the positions and velocities of these stars with great precision, Gaia can detect the wrinkles, the imprint of the last major merger.

“We get wrinklier as we age, but our work reveals that the opposite is true for the Milky Way. It’s a sort of cosmic Benjamin Button, getting less wrinkly over time,” said lead author Donlon in a press release. “By looking at how these wrinkles dissipate over time, we can trace when the Milky Way experienced its last big crash—and it turns out this happened billions of years later than we thought.”

The effort to understand the Milky Way’s (MW) last major merger involves different pieces of evidence. One of the pieces of evidence, along with wrinkles, is an Fe/H-rich region where stars follow a highly eccentric orbit. A star’s Fe/H ratio is a chemical fingerprint, and when astronomers find a group of stars with the same fingerprint and the same orbits, it’s evidence of a common origin. This group of stars is sometimes called ‘the Splash.’ The stars in the Splash may have originated in a Fe/H-rich progenitor. They have odd orbits that stand out from their surroundings. Astronomers think they were heated and their orbits altered as a by-product of the merger.

There are two competing explanations for all of the merger evidence.

One says that a progenitor dwarf galaxy named Gaia Sausage/Enceladus (GSE) collided with the MW proto-disk between 8 and 11 billion years ago. The other explanation is that an event called the Virgo Radial Merger (VRM) is responsible for the stars in the inner halo. That collision occurred much more recently, less than 3 billion years ago.

This is a Hubble Space Telescope image of the globular cluster NGC 2808. It might be the old core of the Gaia Sausage. Image Credit: By NASA, ESA, A. Sarajedini (University of Florida) and G. Piotto (University of Padua (Padova)) – http://hubblesite.org/newscenter/archive/releases/2007/2007/18/image/a/ (direct link), Public Domain, https://commons.wikimedia.org/w/index.php?curid=2371715

“These two scenarios make different predictions about observable structure in local phase space because the morphology of debris depends on how long it has had to phase mix,” the authors explain in their paper.

The wrinkles in the MW were first identified in Gaia data in 2018 and presented in this paper. “We have observed shapes with different morphologies, such as a spiral similar to a snail’s shell. The existence of these substructures has been observed for the first time thanks to the unprecedented precision of the data brought by Gaia satellite, from the European Space Agency (ESA)”, said Teresa Antoja, the study’s first author, in 2018.

This AI-generated image illustrates the MW’s ‘wrinkles’ from the last major merger event. Image Credit: University of Barcelona.

But Gaia has released more data since 2018, and it supports the more recent merger scenario, the Virgo Radial Merger. That data shows that the wrinkles are much more prevalent than the earlier data and the studies based on it suggest.

“For the wrinkles of stars to be as clear as they appear in Gaia data, they must have joined us less than 3 billion years ago—at least 5 billion years later than was previously thought,” said co-author Heidi Jo Newberg, from the Rensselaer Polytechnic Institute. If the wrinkles were much older and conformed to the GSE merger scenario, they’d be more difficult to discern.

“New wrinkles of stars form each time the stars swing back and forth through the center of the Milky Way. If they’d joined us 8 billion years ago, there would be so many wrinkles right next to each other that we would no longer see them as separate features,” Newberg said.

This doesn’t mean there’s no evidence for the more ancient GSE merger. Some of the stars that hint at the ancient merger may be from the more recent VRM merger, and some may still be associated with the GSE merger. It’s challenging to figure out, and simulations play a large role. The researchers in previous work and in this work ran multiple simulations to see how they matched the evidence. “Our goal is to determine the time that has passed since the progenitor of the local phase-space folds collided with the MW disc,” the authors write in their paper.

“We can see how the shapes and number of wrinkles change over time using these simulated mergers. This lets us pinpoint the exact time when the simulation best matches what we see in real Gaia data of the Milky Way today—a method we used in this new study too,” said Thomas.

“By doing this, we found that the wrinkles were likely caused by a dwarf galaxy colliding with the Milky Way around 2.7 billion years ago. We named this event the Virgo Radial Merger.” Those results and the name come from a previous study from 2019.

As Gaia delivers more data with each release, astronomers are getting a better look at the evidence of mergers. It’s becoming clear that the MW has a complex history.

The VRM likely involved more than one entity. It could have brought a whole group of dwarf galaxies and star clusters into the MW at around the same time. As astronomers research the MW’s merger history in greater detail, they hope to determine which of these objects are from the more recent VRM and which are from the ancient GSE.

“The Milky Way’s history is constantly being rewritten at the moment, in no small part thanks to new data from Gaia,” adds Thomas. “Our picture of the Milky Way’s past has changed dramatically from even a decade ago, and I think our understanding of these mergers will continue to change rapidly.”

“This finding improves what we know of the many complicated events that shaped the Milky Way, helping us better understand how galaxies are formed and shaped—our home galaxy in particular,” said Timo Prusti, Project Scientist for Gaia at ESA.

The post The Milky Way’s Last Merger Event Was More Recent Than Thought appeared first on Universe Today.