Astronomy
Inside the Hubble Space Telescope's 23-year-long look at a beautiful blue galaxy
Why ‘Brain Rot’ Is 2024’s Word of the Year
The phrase “brain rot” spiked 230 percent from 2023 to 2024, according to the makers of the Oxford English Dictionary
Directive 8020: Everything we know about Supermassive's sci-fi horror game
Could Primordial Black Holes Be Hiding in Plain Sight?
Are Primordial Black Holes real? They could’ve formed in the unusual physics that dominated the Universe shortly after the Big Bang. The idea dates back to the 1960s, but so far, the lack of evidence makes them purely hypothetical.
If they do exist, a new paper suggests they may be hiding in places so unlikely that nobody ever thought to look there.
Black holes form when massive stars reach the end of their lives and suffer gravitational collapse. However, Primordial Black Holes (PBHs) didn’t involve stars. Physicists hypothesize that PBHs formed in the early Universe from extremely dense pockets of sub-atomic matter that collapsed directly into black holes. They could form part or all of what we call dark matter.
However, they remain hypothetical because none have been observed.
New research in Physics of the Dark Universe suggests researchers are not looking in the right places. It’s titled “Searching for small primordial black holes in planets, asteroids and here on Earth.” The co-authors are De-Chang Dai and Dejan Stojkovic, from Case Western Reserve University and the State University of New York, respectively.
The authors claim that evidence for PBHs could be found in objects as large as hollowed out planetoids or asteroids and objects as small as rocks here on Earth.
“Small primordial black holes could be captured by rocky planets or asteroids, consume their liquid cores from inside and leave hollow structures,” the authors write. “Alternatively, a fast black hole can leave a narrow tunnel in a solid object while passing through it. We could look for such micro-tunnels here on Earth in very old rocks,” the authors claim, explaining that the search wouldn’t involve specialized, expensive equipment.
The authors work leans heavily on other research suggesting that PBH masses between 1016 and 1010 solar masses could be candidates for dark matter. These PBHs could be captured by stars or trapped in their interiors upon formation. The PBH would slowly consume gas inside the stars.
However, these authors take it in a different direction. “We extend this idea to planets and asteroids, which can also be expected to host PBHs,” they write, explaining that the PBHs could be captured by these objects either during their creation or after their creation. Once inside a rocky body, the PBH would consume the liquid core, hollowing it out and leaving it empty.
“We have to think outside of the box because what has been done to find primordial black holes previously hasn’t worked.”
Dejan Stojkovic, SUNY“If the object has a liquid central core, then a captured PBH can absorb the liquid core, whose density is higher than the density of the outer solid layer,” Stojkovic said.
This figure from the research illustrates what could happen when a PBH is inside a rocky body. (A) A planet is formed around a small primordial black hole (or alternatively a planet captures a black hole in its center) (B) The central core gets slowly absorbed by the black hole. If the outer shell has a strong enough compressive strength, then the shell can support itself leading to a hollow object. (C) If the liquid core becomes solid before it is completely eaten by the black hole, there will exist an empty shell between the outer layer and central core. Image Credit: Stojkovic et al. 2024.If the asteroid or other body suffers an impact, the PBH could escape, leaving nothing but a hollow shell behind, which could be detectable.
“If the object’s density is too low for its size, that’s a good indication it’s hollow,” Stojkovic said. Studying an object’s orbit with a telescope is enough to reveal hollowness.
Another possibility the authors present is fast-moving tiny PBHs that leave microscopic tunnels in objects. “Since the cross-section of a small PHBs is very small, a fast enough PBH will most likely create a straight tunnel after passing through the asteroid,” the authors explain. In that case, a straight tunnel through an asteroid could be evidence of a PBH.
A rapidly moving PBH could leave a straight tunnel the size of its Schwarzschild radius. If the asteroid’s composition is strong, the tunnel wouldn’t collapse immediately. Image Credit: Stojkovic et al. 2024.PBHs could also leave microscopic tunnels in rocks and other objects on Earth. “The same effect could allow detection of a PBH here on Earth if we look for sudden appearance of narrow tunnels in metal slabs,” the authors write.
What’s different about these hypothesized PBHs is detection. In other scenarios, space telescopes, gravitational wave observatories, or even monitoring distant quasars in microwaves are required to detect them. But in this work, detection is potentially much cheaper and easier.
The James Webb Space Telescope or the Laser Interferometer Space Antenna are proposed ways of detecting PBHs. Image Credit: European Space Agency CC BY-SA 4.0“The chances of finding these signatures are small, but searching for them would not require much resources and the potential payoff, the first evidence of a primordial black hole, would be immense,” said Stojkovic. “We have to think outside of the box because what has been done to find primordial black holes previously hasn’t worked.”
“While our estimate gives a very small probability of finding such tunnels, looking for them does not require expensive equipment and long preparation, and the payoff might be significant,” the authors explain.
“You have to look at the cost versus the benefit. Does it cost much to do this? No, it doesn’t,” Stojkovic said in a press release.
This is thinking outside the box, or outside the standard model in any case. Cosmology is kind of at a standstill while we wrestle with the idea of dark matter. Could PBHs be dark matter? Could they behave like the authors suggest, and be detected in this manner?
“The smartest people on the planet have been working on these problems for 80 years and have not solved them yet,” Stojkovic said. “We don’t need a straightforward extension of the existing models. We probably need a completely new framework altogether.”
The post Could Primordial Black Holes Be Hiding in Plain Sight? appeared first on Universe Today.
Astronaut Suni Williams and Astrobee
NASA Wants Students’ Help Designing Missions to Other Moons
One of NASA’s primary missions is to inspire the next generation of scientists and engineers to join the STEM field. It does so by producing inspirational and educational content on various platforms. But sometimes, it takes a more direct approach by rewarding students for their contributions to solving a particular problem NASA is facing. Recently, the organization announced such a challenge – the Power to Explore Challenge, which is open to submission from K-12 students until the end of January.
This challenge is part of an ongoing series of challenges that NASA has released to encourage kids to utilize a radioisotope power system (commonly known as a radioisotope thermal generator—or RTG) to enable future missions. Last year, the challenge involved coming up with a mission to a “dark, dusty, or far away place” where the benefits of RTGs, which don’t rely on solar power, would be the most obvious.
A winner was then selected in three separate age categories, detailing missions to Enceladus (Rainie Lin from Kentucky), Tethys (Aadya Karthik from Washington), and Ariel (Thomas Liu from New Jersey). The three winners received a behind-the-scenes tour of the research facilities at NASA’s Glenn Research Center in Cleveland, where much of NASA’s RTG research occurs.
Video Announcing the Challenge.Credit – ScienceatNASA YouTube Channel
This year, there is again a call to develop missions powered by an RTG, but with a more explicit call to visit a moon somewhere in the solar system. There are plenty to choose from—the International Astronomical Union recognizes 288 orbiting planets, while there are over 470 orbiting smaller objects, like Dimorphos around Didymos, the asteroid targeted by NASA’s DART redirect mission.
The challenge is once again run by Future Engineers, an organization that emphasizes engineering education for kids. They provide the judges, who will focus on details like how feasible it is to use an RTG at the location the entrant selected, and what their “special human power” that they describe in their essay would bring to the mission.
Submissions must be a maximum of 275 words and will go through three rounds of judging. Semifinalists, finalists, and grand prize winners will be selected in March, April, and May, respectively. Once again, the grand prize winners will receive a tour of the Glenn Research Center. Semifinalists will receive a gift pack, and finalists will receive both a gift pack and a teleconference with a NASA mission expert.
Fraser discusses some challenges facing missions to other moons – especially their budgets.Applications are open until the end of January, so if you or someone you know is interested in applying, there’s still plenty of time to conceive of a mission and polish up a 275-word essay. Who knows, you might even win a trip to Cleveland – and I can attest to it being pretty nice here in the summer – but more importantly, you might inspire the next NASA mission to one of the solar system’s numerous moons.
Learn More:
NASA – Power to Explore Student Challenge
Future Engineers – Power to Explore
UT – An Improved Radioisotope Thermoelectric Generator Could Dramatically Reduce The Weight Of Interplanetary Missions
UT – NASA is Getting the Plutonium it Needs for Future Missions
Lead Image:
Power To Explore Logo
Credit – NASA / Future Engineers
The post NASA Wants Students’ Help Designing Missions to Other Moons appeared first on Universe Today.
Get a sneak peek at 'Star Trek' illustrated short story anthology beaming up later this month (exclusive)
New forms of animals made by fusing several comb jellies together
New forms of animals made by fusing several comb jellies together
Plate Tectonics May Be the Surprising Solution to the Mystery of Earth’s Origins
Plate tectonics, or the recycling of Earth's crust, may have begun much earlier than previously thought—and may be a big reason that our planet harbors life
'Galaxy Quest' blasts back onto our screens with 25th anniversary Blu-ray release
Health Care Isn’t Working for Homebound Older Adults Living Alone
There is a large population of older adults with physical problems that prevent them from leaving home. Many have significant medical and practical needs that go unmet
Are planet-killing black holes hiding inside your cat?
Antarctica Has Gotten 10 Times Greener in 35 Years
Our satellites are dispassionate observers of Earth’s climate change. From their vantage point they watch as pack ice slowly loses its hold on polar oceans, ice shelfs break apart, and previously frozen parts of the planet turn green with vegetation.
Now, scientists have compiled 35 years of satellite data showing that Antarctica is slowly, yet perceptibly, becoming greener.
NASA and the United States Geological Survey sent the first Landsat into space in 1975. Since then, they’ve launched eight more Landsats, with Landsat 9 being the most recent launch in 2021. Landsat data is a unique treasure trove of data about Earth and the changes it goes through, including millions of images.
Landsats have watched as forest fires burn, as urban regions expand, as glaciers melt, and as Earth goes through many other changes.
Recent research published in Nature Geoscience used 35 years of Landsat data, from Landsat 5 through Landsat 8, to measure the spread of vegetation into Antarctica. It’s titled “Sustained greening of the Antarctic Peninsula observed from satellites.” The research was co-led by Thomas Roland, an environmental scientist University of Exeter, and by remote sensing expert Olly Bartlett of the University of Hertfordshire.
“This study aimed to assess vegetation response to climate change on the AP <Antarctic Peninsula> over the past 35 years by quantifying rates of change in the spatial extent and ‘direction’ (greening versus browning), which have not yet been quantified,” the paper states.
The Antarctic Peninsula is about 1300 km (810 mi) long and is part of the larger West Antarctica Peninsula. It covers about 522,000 square kilometers (202,000 sq mi) and is the northern-most part of Antarctica. Image Credit: By krill oil – Krilloil.com, CC0, https://commons.wikimedia.org/w/index.php?curid=23043354The research shows that the amount of land covered in vegetation on the Antarctic Peninsula has increased by more than 10x since 1986. The area of vegetated land rose from 0.86 sq. km. (0.33 sq. mi.) in 1986 to 11.95 sq. km (4.61 sq. mi.) in 2021. The coverage is restricted to the warmer edges of the peninsula, but it still indicates a shift in the region’s ecology, driven by our carbon emissions.
This vegetative colonization of Earth’s coldest region begins with mosses and lichens. Mosses are pioneer species, the first organisms to move into a newly-available habitat. These non-vascular plants are tough and hardy, and can grow on bare rock in low-nutrient environments. They create a foundation for the plants that follow them by secreting acid that breaks down rock and by providing organic material when they die.
This image shows moss hummocks on Ardley Island just off the coast of the Antarctica Peninsula. Image Credit: Roland et al. 2024.The map makes the results of the research clear. Each of the four panels show the amount of green vegetation on the Antarctic Peninsula’s ice-free land below 300 meters (1000 ft) altitude. Each hexagon is shaded depending on how many sq. km. of it are covered in vegetation. That’s determined by the satellite-based Normalized Difference Vegetation Index (NDVI). The NDVI is based on spectrometric data gathered by the Landsat satellites during cloud-free days every March, the end of the growing season in Antarctica.
Mosses dominate the green areas, growing in carpets and banks. In previous research, Roland and co-researchers collected carbon-dated core samples from moss banks on the western side of the AP. Those showed that moss had accumulated more rapidly in the past 50 years and that there’s been a boost in biological activity. That led them to their current research, where they wanted to determine if moss was not only growing upward to higher elevations, but outward, too.
“Based on the core samples, we expected to see some greening,” Roland said, “but I don’t think we were expecting it on the scale that we reported here.”
A moss bank grows on bare rock on Norsel Point on Amsler Island. Carbon-core samples from moss banks showed an increase in growth in the past few decades. Image Credit: Roland et al. 2024.“When we first ran the numbers, we were in disbelief,” Bartlett said. “The rate itself is quite striking, especially in the last few years.”
The Western Antarctica Peninsula is warming up faster than other parts of Earth. Not only are its glaciers receding, but the extent of the sea ice is shrinking and there’s more open water. The authors point out that changing wind patterns due to GHG emissions could be contributing.
What will happen as the ice continues to retreat and pioneer species colonize more of Antarctica? The continent has hundreds of native species, mostly mosses, lichens, liverworts, and fungi. The continent has only two species of flowering plants, Antarctic Hair Grass and Antarctic Pearlwort. What does it mean for them?
Left: Antarctic Hair Grass. Right: Antarctic Pearlwort Image Credit Left: By Lomvi2 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10372682. Image Credit Right: By Liam Quinn – Flickr: Antarctic Pearlwort, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=15525940“The narrative in these places has been dominated by glacial retreat,” Roland said. “We’re starting to think about what comes next, after ice recession.”
After moss gains a foothold in a region, soil is created where there was none. That provides an opening for other organisms, both native and non-native. The risk is that the inherent biodiversity will be undermined. Tourism and other human activity can inadvertently introduce new species, and wind-borne seeds and spores can do the same. If robust organisms arrive, they can outcompete the native species. There are already a few documented instances of this happening.
This image shows a moss lawn or carpet on Barrientos Island. Image Credit: Roland et al. 2024.The carbon-core and Landsat data is just the beginning for Roland, Bartlett, and their fellow researchers. Up-close fieldwork is the next step. “We’re at the point that we’ve said the best we can say with the Landsat archives,” Roland said. “We need to go to these places where we’re seeing the most distinctive changes and see what’s happening on the ground.”
The researches want to know what types of plant communities are establishing themselves, and what shifts are playing out in the environment.
The post Antarctica Has Gotten 10 Times Greener in 35 Years appeared first on Universe Today.
The Arctic Could Be Functionally Ice-Free in Just a Few Years
The Arctic is likely to become “ice-free” by midcentury—and could pass that grim milestone much sooner—unless much more is done to combat climate change
Building blocks: How China plans to make bricks on the moon for lunar habitats
Tiny asteroid detected hours before hitting Earth to become 4th 'imminent impactor' of 2024
White Dwarfs Could Have Habitable Planets, Detectable by JWST
In a few billion years, our Sun will die. It will first enter a red giant stage, swelling in size to perhaps the orbit of Earth. Its outer layers will be cast off into space, while its core settles to become a white dwarf. Life on Earth will boil away, and our planet itself might be consumed by the Sun. White dwarfs are the fate of all midsize stars, and given the path of their demise, it seems reasonable to assume that any planets die with their sun. But the fate of white dwarf planets may not be lifeless after all.
More than a dozen planets have been discovered orbiting white dwarf stars. That’s a small fraction of the known exoplanets, but it tells us that planets can survive the red giant stage of a Sun-like star. Some planets may be consumed, and the orbits of survivors might be dramatically affected, but some planets retain a stable orbit. Any planets that were in the habitable zone of the star would die off, but a new study suggests that some white dwarf planets might give life the foothold it needs to evolve again.
Although white dwarfs don’t undergo nuclear fusion, they do remain warm for billions of years. Young white dwarfs can have a surface temperature of 27,000 K or more, and it takes billions of years for them to cool. Since the simple definition of a star’s habitable zone is simply the range where a planet is warm enough for liquid water, this means all white dwarfs have a habitable zone. Unlike main sequence stars, however, this region would migrate inward as the star cools. But in this new work, the authors show that white dwarfs have a habitable zone that would be warm enough for life across billions of years. For a white dwarf of about 60% of the Sun’s mass, part of the habitable zone would persist for nearly 7 billion years, which is more than enough time for life to evolve and thrive on a world. In comparison, the Earth is less than 5 billion years old.
Habitable zone of a white dwarf over time. Credit: Whyte, et alOf course, for life to appear on a white dwarf planet, simply being warm isn’t enough. To have the kind of complex life we see on Earth, the spectrum of starlight would need to provide the right kind of energy for things like photosynthesis without ionizing the planet’s atmosphere. The spectra of white dwarfs are shifted much more to the ultraviolet than the visible and infrared, but the authors show that ionizing radiation would not be severe, and the amount of UV would allow for Earth-like photosynthesis. The optimal habitable zone would be close to the white dwarf, similar to the habitable zone of the TRAPPIST-1 red dwarf.
Just because a white dwarf planet might be home to life, that doesn’t mean they are. We know life can exist around a Sun-like star, but we’d need clear evidence to say the same is true for white dwarfs. That’s where the second part of this work comes in. Since white dwarfs are bright for their size and habitable planets would need to orbit them closely, our ability to gather evidence on them is good. The James Webb Space Telescope (JWST), for example, is sensitive enough to observe the atmospheric spectra of white dwarf planets as they transit. A few hours of observational time could be enough to get a spectrum sharp enough to detect biosignatures.
All that said, finding life on a white dwarf planet is a long shot. The planets would likely have to migrate inward during the latter part of the red dwarf stage, maintain a stable orbit, and somehow retain or recapture the kind of water-rich atmosphere you need for terrestrial life. That’s a big ask. But given how easy it might be to detect biosignatures, it’s worth taking a look.
Reference: Whyte, Caldon T., et al. “Potential for life to exist and be detected on Earth-like planets orbiting white dwarfs.” arXiv preprint arXiv:2411.18934 (2024)
The post White Dwarfs Could Have Habitable Planets, Detectable by JWST appeared first on Universe Today.
Creating artificial eclipses to study the Sun | Proba-3 explained
Proba-3 is such an ambitious mission that it needs more than one single spacecraft to succeed. In order for Proba-3’s Coronagraph spacecraft to observe the Sun’s faint surrounding atmosphere, its disk-bearing Occulter spacecraft must block out the fiery solar disk. This means Proba-3’s Occulter ends up facing the Sun continuously, making it a valuable platform for science in its own right.
Proba-3 is scheduled for launch on a PSLV-XL rocket from Satish Dhawan Space Centre in Sriharikota, India, on Wednesday, 4 December, at 11:38 CET (10:38 GMT, 16:08 local time).
