Should Astronauts Be Worried About Mars Dust?

Every Martian year (which last 686.98 Earth days), the Red Planet experiences regional dust storms that coincide with summer in the southern hemisphere. Every three Martian years (five and a half Earth years), these storms grow so large that they encompass the entire planet and are visible from Earth. These storms are a serious hazard for robotic missions, causing electrostatic storms that can mess with electronics and cause dust to build up on solar panels. In 2018 and 2022, the Opportunity Rover and InSight Lander were lost after dust storms prevented them from drawing enough power to remain operational.

But what about crewed missions? In the coming decades, NASA and the Chinese Manned Space Agency (CMS) plan to send astronauts and taikonauts to Mars. These missions will include months of surface operations and are expected to culminate in the creation of long-duration habitats on the surface. According to new research by the Keck School of Medicine at the University of Southern California (USC), Martian dust storms can potentially cause respiratory issues and elevated risk of disease, making them yet another health hazard space agencies need to prepare for.

The research was led by Justin L. Wang, a Doctor of Medicine at USC, along with several of his colleagues from the Keck School of Medicine. They were joined by researchers from the UCLA Space Medicine Center, the Ann and HJ Smead Department of Aerospace Engineering and the Laboratory for Atmospheric and Space Physics at UC Boulder, and the Astromaterials Acquisition and Curation Office at NASA’s Johnson Space Center. The paper detailing their findings appeared on February 12th in the journal GeoHealth.

Sending crewed missions to Mars presents many challenges, including logistics and health hazards. In the past 20 years, the shortest distance between Earth and Mars was 55 million km (34 million miles), or roughly 142 times the distance between the Earth and the Moon. This was in 2003 and was the closest the two planets had been in over 50,000 years. Using conventional methods, it would take six to nine months to make a one-way transit, during which time astronauts will experience physiological changes caused by long-term exposure to microgravity.

These include muscle atrophy, loss of bone density, a weakened cardiovascular system, etc. Moreover, a return mission could last as long as three years, during which time astronauts would spend at least a year living and working in Martian gravity (36.5% that of Earth). There’s also the risk of elevated radiation exposure astronauts will experience during transits and while operating on the surface of Mars. However, there are also the potential health effects caused by exposure to Martian regolith. As Wang described to Universe Today via email:

“There are many potential toxic elements that astronauts could be exposed to on Mars. Most critically, there is an abundance of silica dust in addition to iron dust from basalt and nanophase iron, both of which are reactive to the lungs and can cause respiratory diseases. What makes dust on Mars more hazardous is that the average dust particle size on Mars is much smaller than the minimum size that the mucus in our lungs is able to expel, so they’re more likely to cause disease.”

During the Apollo Era, the Apollo astronauts reported how lunar regolith would stick to their spacesuits and adhere to all surfaces inside their spacecraft. Upon their return to Earth, they also reported physical symptoms like coughing, throat irritation, watery eyes, and blurred vision. In a 2005 NASA study, the reports of six of the Apollo astronauts were studied to assess the overall effects of lunar dust on EVA systems, which concluded that the most significant health risks included “vision obscuration” and “inhalation and irritation.”

Artist’s depiction of a dust storm on Mars. Credit: NASA

“Silica directly causes silicosis, which is typically considered an occupational disease for workers that are exposed to silica (i.e., mining and construction),” said Wang. “Silicosis and exposure to toxic iron dust resemble coal worker’s pneumoconiosis, which is common in coal miners and is colloquially known as black lung disease.”

Beyond causing lung irritation and respiratory and vision problems, Martian dust is known for its toxic components. These include perchlorates, silica, iron oxides (rust), gypsum, and trace amounts of toxic metals like chromium, beryllium, arsenic, and cadmium – the abundance of which is not well understood. On Earth, the health effects of exposure to these metals have been studied extensively, which Wang and his team drew upon to assess the risk they pose to astronauts bound for Mars in the coming decades:

“It’s significantly more difficult to treat astronauts on Mars for diseases because the transit time is significantly longer than other previous missions to the ISS and the Moon. In this case, we need to be prepared for a wide array of health problems that astronauts can develop on their long-duration missions. In addition, [microgravity and radiation] negatively impact the human body, can make astronauts more susceptible to diseases, and complicate treatments. In particular, radiation exposure can cause lung disease, which can compound the effects that dust will have on astronauts’ lungs.”

In addition to food, water, and oxygen gas, the distance between Earth and Mars also complicates the delivery of crucial medical supplies, and astronauts cannot be rushed back to Earth for life-saving treatments either. According to Wang and his colleagues, this means that crewed missions will need to be as self-sufficient as possible when it comes to medical treatment as well. As with all major health hazards, they emphasize the need for prevention first, though they also identify some possible countermeasures to mitigate the risks:

“Limiting dust contamination of astronaut habitats and being able to filter out any dust that breaks through will be the most important countermeasure. Of course, some dust will be able to get through, especially when Martian dust storms make maintaining a clean environment more difficult. We’ve found studies that suggest vitamin C can help prevent diseases from chromium exposure and iodine can help prevent thyroid diseases from perchlorate.”

Austin Langton, a researcher at NASA’s Kennedy Space Center in Florida, creates a fine spray of the regolith simulant BP-1. Credits: NASA/Kim Shiflett

They also stressed that these and other potential countermeasures need to be taken with caution. As Wang indicated, taking too much vitamin C can increase the risk of kidney stones, which astronauts are already at risk for after spending extended periods in microgravity. In addition, an excess of idione can contribute to the same thyroid diseases that it is meant to treat in the first place. For years, space agencies have been actively developing technologies and strategies to mitigate the risks of lunar and Martian regolith.

Examples include special sprays, electron beams, and protective coatings, while multiple studies and experiments are investigating regolith to learn more about its transport mechanisms and behavior. As the Artemis Program unfolds and missions to Mars draw nearer, we are likely to see advances in pharmacology and medical treatments that address the hazards of space exploration as well.

Further Reading: GeoHealth

The post Should Astronauts Be Worried About Mars Dust? appeared first on Universe Today.

DESI Found 300 Candidate Intermediate Mass Black Holes

If Intermediate-Mass Black Holes (IMBHs) are real, astronomers expect to find them in dwarf galaxies and globular clusters. There’s tantalizing evidence that they exist but no conclusive proof. So far, there are only candidates.

The Dark Energy Spectroscopic Instrument (DESI) has found 300 additional candidate IMBHs.

Logic says that IMBHs should exist. We know of stellar-mass black holes, and we know of supermassive black holes (SMBHs). Stellar-mass black holes have between five and tens of solar masses, and SMBHs have at least hundreds of thousands of solar masses. Their upper limit is not constrained. Astrophysicists think these black holes are linked in an evolutionary sequence, so it makes sense that there’s an intermediate step between the two. That’s what IMBHs are, and their masses should range from about 100 to 100 thousand solar masses. IMBHs could also be relics of the very first black holes to form in the Universe and the seeds for SMBHs.

The problem is that there are no confirmed instances of them.

Omega Centauri, the brightest globular cluster in the Milky Way, is one of the prime candidates for an IMBH. There’s an ongoing scientific discussion about the cluster and the potential IMBH in its center. Stars in the cluster’s center move faster than other stars, indicating that a large mass is present. Some scientists think it’s an IMBH, while others think it’s a cluster of stellar-mass black holes.

This is Omega Centauri, the largest and brightest globular cluster that we know of in the Milky Way. An international team of astronomers used more than 500 images from the NASA/ESA Hubble Space Telescope spanning two decades to detect seven fast-moving stars in the innermost region of Omega Centauri. These stars provide compelling new evidence for the presence of an intermediate-mass black hole. Image Credit: ESA/Hubble & NASA, M. Häberle (MPIA)

Other evidence for IMBHs comes from a gravitational wave detection in 2019. The wave was generated by two black holes merging. The pair of black holes had masses of 65 and 85 solar masses, and the resulting black hole had 142 solar masses. The other 8 solar masses were radiated away as gravitational waves.

By adding 300 more IMBH candidates to the list, DESI may be nudging us toward a definitive answer about the existence of these elusive black holes.

The 300 new candidates are presented in a paper soon to be published in The Astrophysical Journal. It’s titled “Tripling the Census of Dwarf AGN Candidates Using DESI Early Data” and is available at arxiv.org. The lead author is Ragadeepika Pucha, a postdoctoral researcher at the University of Utah.

The 300 candidate IMBHs are the largest collection to date. Until now, there were only 100 to 150 candidates. This is a massive leap in the amount of available data, and future research will no doubt rely on it to make progress on the IMBH issue.

“Our wealth of new candidates will help us delve deeper into these mysteries, enriching our understanding of black holes and their pivotal role in galaxy evolution.”

Ragadeepika Pucha, University of Utah

The new candidates were identified in DESI’s early data release, which contains data from 20% of DESI’s first year of operations. The data included more than just IMBH candidates. DESI also found about 115,000 dwarf galaxies and spectra from about 410,000 galaxies, a huge number.

This mosaic shows a series of images featuring candidate dwarf galaxies hosting an active galactic nucleus, captured with the Subaru Telescope’s Hyper Suprime-Cam. Image Credit: Legacy Surveys/D. Lang (Perimeter Institute)/NAOJ/HSC Collaboration/D. de Martin (NSF NOIRLab) & M. Zamani (NSF NOIRLab)

The data allowed lead author Pucha and her colleagues to explore the relationship between the evolution of dwarf galaxies and black holes.

Despite their extreme masses, black holes are difficult to find. Their presence is inferred from their effect on their environment. In their presence, stars are accelerated to high velocities. Fast-moving stars were one of the clues showing that the Milky Way has an SMBH.

Astronomers are pretty certain that all massive galaxies like ours host an SMBH in their centers, but this certainty fades when it comes to dwarf galaxies. Dwarf galaxies are so small that our instruments struggle to observe them in detail. Unless the black hole is actively feeding.

When a black hole is actively consuming material, it is visible as an active galactic nucleus (AGN.) AGNs are like beacons that alert astronomers to the presence of a black hole.

“When a black hole at the center of a galaxy starts feeding, it unleashes a tremendous amount of energy into its surroundings, transforming into what we call an active galactic nucleus,” lead author Pucha said in a press release. “This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies.”

The team found 2,500 dwarf galaxies containing an active galactic nucleus, an astonishing number. Like the new IMBH candidates, this is the largest sample ever discovered. The researchers determined that 2% of the dwarf galaxies hosted AGN, a big step up from the 0.5% gleaned from other studies.

“This increase can be primarily attributed to the smaller fibre size of DESI compared to SDSS <Sloan Digital Sky Survey>, which aids with the identification of lower luminosity AGN within the same magnitude and redshift range,” the authors explain in their paper.

This artist’s illustration depicts a dwarf galaxy that hosts an active galactic nucleus — an actively feeding black hole. In the background are many other dwarf galaxies hosting active black holes, as well as a variety of other types of galaxies hosting intermediate-mass black holes. Image Credit: NOIRLab/NSF/AURA/J. da Silva/M. Zamani

Astronomers think that black holes found in dwarf galaxies should be within the intermediate-mass range. However, only 70 of the newly discovered IMBH candidates overlap with dwarf AGN candidates. This is unexpected and raises yet more questions about black holes, how they form, and how they evolve within galaxies.

This scatter plot, adapted from the research, shows the number of candidate dwarf galaxies hosting active galactic nuclei (AGN) from previous surveys compared with the number of new dwarf galaxy AGN candidates discovered by the Dark Energy Spectroscopic Instrument (DESI). Image Credit: NOIRLab/NSF/AURA/R. Pucha/J. Pollard

“For example, is there any relationship between the mechanisms of black hole formation and the types of galaxies they inhabit?” Pucha said. “Our wealth of new candidates will help us delve deeper into these mysteries, enriching our understanding of black holes and their pivotal role in galaxy evolution.”

DESI is only getting started. These discoveries were made with only a small portion of data from the instrument’s first year of operation, and there are several more years of operation to come.

“The anticipated increase in the sample of dwarf AGN candidates over the next five years with DESI will accelerate studies of AGN in dwarf galaxies,” the authors write in their research. “The statistical sample of dwarf AGN candidates will be invaluable for addressing several key questions related to galaxy evolution on the smallest scales, including accretion modes in low-mass galaxies and the co-evolution of galaxies and their central BHs,” they conclude.

• Press Release: DESI Uncovers 300 New Intermediate-Mass Black Holes Plus 2500 New Active Black Holes in Dwarf Galaxies
• Research: Tripling the Census of Dwarf AGN Candidates Using DESI Early Data
• Research: Properties and Astrophysical Implications of the 150 M? Binary Black Hole Merger GW190521
• Research: New constraints on the central mass contents of Omega Centauri from combined stellar kinematics and pulsar timing

The post DESI Found 300 Candidate Intermediate Mass Black Holes appeared first on Universe Today.

Did Astronomers Just Witness the Formation of a “Strange Star”?

There are plenty of types of stars out there, but one stands out for being just a little weirder than the others. You might even say it’s strange. According to a paper from researchers at Guangxi University in China, the birth of one might have recently been observed for the very first time.

A strange star is a (so far theoretical) compact star that is so dense it literally breaks down regular parts of atoms (like neutrons) into their constituent quarks. Moreover, even those quarks (the up and down that comprise a neutron) get compressed into an even rarer type of quark called a strange quark – hence the name strange star.

Technically, the “strange” matter that a strange star would be composed of is a combination of up, down, and strange quarks. But, at least in theory, this mix of sub-hadronic particles could even be more stable than a traditional neutron star, which is similar to a strange star but doesn’t have enough gravity to break down the neutrons.

Fraser discusses strange stars.

Strange stars, though they exist in theory, are exceedingly rare. No one has ever proven that one exists. But Xiao Tian and his co-authors think they might have found evidence of one.

Their paper describes a recent gamma-ray burst known as GRB 240529A that they think holds the clues to finding a strange star. Gamma-ray bursts, the gigantic implosions that sometimes result from creating a black hole, could also have other causes – or “central engines,” as they are called in the literature. One such central engine is the creation of a magnetar.

Magnetars are another type of neutron star that is even more extreme. Their magnetic fields could be up to 1,000 times that of a typical neutron star, giving them the largest magnetic fields in the known universe. In them, electrons and protons are forced together to create neutrons, hence the name neutron star.

Fraser discusses magnetars, the type of star that would theoretically collapse into a strange star.

However, they could also collapse upon themselves, as a part of cosmological theory allows for a magnetar to collapse into an even more dense form, which would be something akin to a strange star with the requisite mix of quarks. Doing so would undoubtedly produce a gamma-ray burst, which Dr. Tian and his co-authors believe they found in GRB 240529A.

The details of that particular GRB hold the clues. There were three distinct “emission episodes” that represented different phases of the collapse to a magnetar, then to a strange star, and then the spin-down of the strange star. A different spectrum of gamma rays represents each as part of the burst, and each episode was separated by a few hundred seconds of relative calm, which seems like an exceedingly short time considering how massive the objects were collapsing. 

Moreover, in the X-ray spectrum, another part of the light curve could be described as containing “plateaus.” According to the authors, each of these plateaus could represent a stage in the birth of the strange star, with the first representing its cooling and the second representing its “pin down” phase.

According to their calculations, the observed data best matches the theoretical values that would be seen if GRB represented the birth of a strange star. So it seems likely that, for the first time, astronomers have garnered some evidence to support a theory that was initially developed in the 1980s. But, as always, more testing is needed, and other researchers should confirm the authors’ calculations. But if they do, it would be a significant leap forward in experimental astrophysics – and may herald many more strange findings to come.

Learn More:
Tian et al – Signature of strange star as the central engine of GRB 240529A
UT – It Takes Very Special Conditions to Create This Bizarre Stellar Spectacle
UT – SLS Hurricanes, James Webb Fixed, Strange Quark Star
UT – The Mysterious Case of the Resurrected Star

Lead Image:
Illustration of the interior of a neutron star and a strange quark star
Credit – NASA/SAO/CXC/J.Drake et al.

The post Did Astronomers Just Witness the Formation of a “Strange Star”? appeared first on Universe Today.

NASA’s SPHEREx Launches Soon and Will Search For Water in Molecular Clouds

As far as we can tell, life needs water. Cells can’t perform their functions without it. Some have suggested that other exotic liquids, like liquid methane, could do the job on worlds like Saturn’s moon Titan. That idea is highly speculative, though.

So, it makes sense that NASA is launching a spacecraft dedicated to the search for water.

SPHEREx stands for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer. It’s scheduled to launch on February 27th. It has a single instrument and one observing mode. Part of its mission is to map the sky in near-infrared and measure the spectra of 450 million galaxies. The results will help scientists understand the expansion of the Universe and the origin and evolution of galaxies.

This image shows a semi-frontal view of the SPHEREx observatory during integration and testing at BAE Systems (Boulder, CO). Image Credit: NASA/JPL-Caltech.

Its other scientific goal is to probe molecular clouds for water ice and other frozen pre-biotic molecules. These ices are frozen onto the surface of dust grains in molecular clouds, and somehow, through a long journey, they become part of planets, where they can form oceans and potentially foster the appearance of life.

Infrared observations show that in cold, dense regions of space in molecular clouds, chemicals critical to life are locked into dust grains. Water is the primary one, of course, but there are other pre-biotic molecules as well: carbon dioxide (CO2), carbon monoxide (CO), methanol (CH3OH), the nitrogen-bearing molecule ammonia (NH3) plus various carbon-nitrogen stretch molecules (XCN), and the important sulphur-bearing molecule, carbonyl sulphide (COS). Carbon-nitrogen stretch molecules are everywhere in organic and biological molecules and play critical roles in biological processes. Carbonyl-sulphide plays a role in the formation of peptides, which are the building blocks of proteins.

There’s a vast amount of water frozen in dust grains in molecular clouds, and scientists think this is where the bulk of the water in the galaxy and even in the Universe resides. These grains are the source of water for Earth’s oceans and for any exoplanets or moons that might harbour oceans.

SPHEREx will examine molecular clouds and try to understand how much water they contain. It will also examine stars in those clouds and the rings of material that form around them, out of which planets form.

Put succinctly, SPHEREx is trying to answer this question: How does ice content evolve from diffuse clouds to dense clouds to planetary disks and then to planets?

This photo by renowned astrophotographer Rogelio Bernal Andreo shows the Orion constellation and the surrounding nebulas of the Orion Molecular Cloud complex. The clouds in the complex hold frozen water and other chemicals critical to life. Image Credit: By Rogelio Bernal Andreo – https://ift.tt/mJMoTX1, CC BY-SA 3.0, https://ift.tt/YBJcjl9

There’s little doubt that ices play an important role in the formation of planetesimals in disks around young stars. Likewise, there’s little doubt that these ices are sources of water and organic molecules, too. But how does it all happen? Ice’s journey from translucent to dense molecular clouds and then to protoplanetary disks is not well understood. Scientists want to know if the ices in the disks are simply inherited from the interstellar medium or if they’re altered in the disks somehow.

The SPHEREx mission hopes to answer this question and others with its infrared absorption spectroscopy.

SPHEREx will generate spectra for between 8 and 9 million sources and should transform our understanding of ices in molecular clouds, young stellar objects, and protoplanetary disks.

In infrared wavelengths, ices have unique spectral signatures. Prior to the JWST, scientists had only about 200 ice absorption spectra available. The JWST is changing that, but it has lots of other important work to do.

The JWST is already advancing our understanding of these ices. Like other infrared observatories, it can see through dust, but it is far more powerful and sensitive. A key to SPHEREx’s design and performance is its ability to be as accurate as the JWST.

The black line is the JWST spectrum of a source seen through a thick molecular cloud of interstellar dust, showing the strong features of the interstellar ice species H2O, CO2, and CO at wavelengths of 3.05, 4.27, and 4.67 microns (McClure et al. 2023, Nature Astronomy, 7, 431). Overlaid in red is a simulated spectrum, taken with SPHEREx’s lower spectral resolving power, of a background source with 100x the JWST brightness in the SPHEREx range that shows the same absorption features as seen by JWST. Note that SPHERE reproduces almost all of the spectral structure apparent in the JWST spectrum. Image Credit: NASA/JPL

There is no shortage of targets for SPHEREx. Some research shows that there are over 8,000 molecular clouds in the Milky Way. Not all of them are great targets for SPHEREx, but many are.

SPHEREx has a catalogue of targets that includes molecular clouds in the Large and Small Magellanic Clouds and several constellations, including Monoceros, home of the Monoceros R2 Molecular Cloud.

The Monoceros R2 Molecular Cloud is one of SPHEREx’s targets. This image shows only a portion of the cloud, which is a large cloud with lots of active star formation. Star formation is particularly active in the location of the bright red nebula just below the center of the image. This image was obtained with the wide-field view of the Mosaic II camera on the Blanco 4-meter telescope at Cerro Tololo Interamerican Observatory on January 11th, 2012. Image Credit: T.A. Rector (University of Alaska Anchorage) and N.S. van der Bliek (NOIRLab/NSF/AURA)

It’s axiomatic that stars and planets have the same compositions as the molecular clouds that fostered them. But the specifics of planet formation are mysterious and the study of the processes has produced some surprises.

In 1998, NASA launched the Submillimeter Wave Astronomy Satellite (SWAS). Similar to SPHEREx, it studied the chemical composition of interstellar clouds and surveyed the galaxy to determine how much water vapour was present in molecular clouds. Surprisingly, it found far less than expected.

“This puzzled us for a while,” said Gary Melnick, a senior astronomer at the Center for Astrophysics | Harvard & Smithsonian and a member of the SPHEREx science team. “We eventually realized that SWAS had detected gaseous water in thin layers near the surface of molecular clouds, suggesting that there might be a lot more water inside the clouds, locked up as ice.”

The SWAS team figured out that hydrogen and oxygen atoms were being frozen onto the surfaces of ice grains where they formed water ice. Subsequent research confirmed their suspicions. On the unprotected surfaces of molecular clouds, cosmic radiation can break the H2O molecules apart, but protected inside molecular clouds, the molecules persisted.

The water ice and other ices create spectroscopic signatures separate from their liquid counterparts, and SPHEREx is designed to detect them.

It will do more than detect them, though. The spacecraft will also determine how deep inside the clouds the ices form, how their abundance changes with cloud density, and how the abundance changes when a star forms.

SPHEREx will also cooperate with other telescopes, including the JWST, which will perform more powerful follow-up observations when merited.

“If SPHEREx discovers a particularly intriguing location, Webb can study that target with higher spectral resolving power and in wavelengths that SPHEREx cannot detect,” said Melnick. “These two telescopes could form a highly effective partnership.”

SPHEREx will launch on February 27th in a Falcon Heavy rocket from Vandenberg Air Base. It will follow a Sun-Synchronous orbit at about 700 km altitude. In its nominal 25-month mission, SPHEREx will map the entire sky four times.

• Press Release: NASA’s SPHEREx Space Telescope Will Seek Life’s Ingredients
• CalTech SPHEREx Science
• An All-Sky Spectral Survey
• The Astrophysical Journal: The SPHEREx Target List of Ice Sources (SPLICES)
• JPL: The Origin of Water – and Other Pre-biotic Molecules – in Planetary Systems

The post NASA’s SPHEREx Launches Soon and Will Search For Water in Molecular Clouds appeared first on Universe Today.

What Would Actual Scientific Study of UAPs Look Like?

For those who missed the memo, UFOs (Unidentified Flying Objects) are now called UAPs (Unidentified Aerospace-Undersea Phenomena). The term UFO became so closely tied to alien spacecraft and fantastical abduction stories that people dismissed the idea, making any serious discussion difficult. The term UAP is a broader term that encompasses more unexplained objects or events without the alien spaceship idea truncating any useful or honest discussion.

While the name change is helpful, it’s just the beginning. We need a way to study UAPs scientifically, and new research shows us how.

Though the idea of alien spacecraft visiting us isn’t always taken very seriously, the effort to document UAP and understand them goes back decades. In current times, governments around the world have made more serious efforts to understand what’s behind the phenomena. Most notably, NASA recently initiated a study into UAP called the Unidentified Anomalous Phenomena Independent Study and released its final report in September 2023.

New research aims to explore past efforts, dispel some misunderstandings, and enable future research into UAP.

The research is titled “The New Science of Unidentified Aerospace-Undersea Phenomena (UAP).” The lead author is Kevin Knuth from the Department of Physics at the State University of New York at Albany. The research is available on the pre-press site arxiv.org.

“After decades of dismissal and secrecy, it has become clear that a significant number of the world’s governments take Unidentified Aerospace-Undersea Phenomena (UAP), formerly known as Unidentified Flying Objects (UFOs), seriously–—yet still seem to know little about them,” the authors write. “As a result, these phenomena are increasingly attracting the attention of scientists around the world, some of whom have recently formed research efforts to monitor and scientifically study UAP.”

Many UAP have good explanations, like this image from the Apollo 16 mission to the moon that shows what may look like a flying saucer. In 2004, NASA said it was the spacewalk floodlight/boom that was attached to the Apollo spacecraft. Image Credit: NASA

The authors review about 20 historical studies, some done by governments and others by private researchers, between 1933 and the present. Countries include the USA, Canada, France, Russia, and China. Their goal is to summarize and clarify the scientific narrative around UAPs. “Studies range from field station development and deployment to the collection and analysis of witness reports from around the world,” the authors write.

The main obstacle to studying UAPs is that they’re neither repeatable nor controllable. Another problem is that witness reports are unreliable, often explained away as natural phenomena, or dismissed outright by citizens, scientists, and governments. This has dissuaded serious discussion and study and left us in “a rather disconcerting state of ignorance,” the authors write.

Ignorance is seldom desirable, though it can sometimes provide a false sense of relief. Being disconcerted is likewise undesirable. What can be done?

“The problem and opportunity that we face today is that the situation has changed dramatically,” according to the authors. We now know that the US Defense Intelligence Agency (DIA) conducted a covert, six-year program called the Advanced Aerospace Threat Identification Program (AATIP) to study UAP. With 50 full-time investigators, the AATIP dwarfed other UAP efforts. The AATIP focused on military-only encounters and considered things like psychic and paranormal phenomena correlated with UAP events. The AATIP created a massive amount of data on UAP that encompassed more than 200,00 cases. (Alarmingly, the effort also produced more than 200 research papers, some over 100 pages long, and none of them have ever been seen by the public or by the US Congress.)

This proves that the effort to study and understand UAP has gained traction and moved from the fringe to the mainstream. It’s a signal that UAP research could see increased funding and resources. According to the researchers, that means there needs to be a coordinated effort. The effort needs to be scientific, and data needs to be shared among researchers.

The geographic distribution of UFO sightings. One of the puzzling things about sightings is that they’re not distributed in any way that makes sense. Does culture play a role? Image Credit: sammonfort3

Enough research has been done to make the next steps clear.

“It is generally agreed that the optimal methodology to study UAP relies on many different types of instruments, spatially separated, to dramatically reduce the possibility of error,” the authors write. “This is the only way in which the scientific community will recognize truly anomalous data.” The authors say that multi-messenger astronomy, in which objects are studied across wavelengths with multiple telescopes, is a good model for the future study of UAP.

Rigor is required for UAP studies and data to be taken seriously. One group arguing in favour of more UAP scientific research is the UAlbany-UAPx Collaboration, an organization that the lead author of this research, Kevin Knuth, is involved with. They developed rigorous definitions of what detections constitute a UAP and recommended that “at least two of each type of sensor and 2+ distinct sensor types” be used in the effort to study UAP.

The future effort to understand UAP must migrate in from the fringes and adhere to scientific standards in other disciplines. “This way, one rigorously quantifies the meaning of extraordinary evidence, in the same way it has been done historically by particle physicists, who have established a very high bar to clear,” the authors write.

The researchers also explain how our burgeoning fleet of satellites could play a larger role in the study of UAP. “UAP researchers are now considering the air and space domains as open-air laboratories, utilizing these vast environments for systematic scientific inquiry,” they write.

Throughout most of history, satellite data has been restricted to large governments and their defence and military organizations. But their monopoly on the data is withering away. Satellite imagery and data are routinely shared with the public and are freely available for scientific use. Coinciding with greater accessibility is greater quality. “Thanks to significant technological advancements and the proliferation of commercial satellite services, access to satellite data has expanded dramatically. In addition, rapid advances in information and communication technologies have opened new avenues for many more actors,” the authors explain.

This image shows one of the NOAA’s Geostationary Operational Environmental Satellites (GOES)–R Series. It’s the Western Hemisphere’s most sophisticated weather-observing and environmental monitoring system. The GOES-R Series provides advanced imagery and atmospheric measurements, real-time mapping of lightning activity, and monitoring of space weather. Could satellites like it be used in the scientific study of UAPs? Image Credit: NOAA

Though current satellites aren’t aimed at studying UAP, their sensors can be used to examine environments near reported UAP. This brings up another parallel between astronomy and UAP. We have telescopes that scan the sky for transients and when they detect one, they send out urgent messages to other telescopes suited for follow-up observations. The same arrangement could work in the study of UAP.

Advancements in science and astronomy can also benefit the study of UAP. Tools such as cloud computing, artificial intelligence (AI), and machine learning (ML) now enable scientists to gather, store, transmit, and analyze data more efficiently than ever before,” the authors write. There’s an ongoing democratization of data sharing that can be leveraged in the study of UAP.

UAP are not one thing. Only a dedicated, serious effort to understand them as they appear can determine if there’s something there deserving of deeper study. The authors argue that a “paradoxical loop of dismissal in mainstream science” is preventing progress. The paper outlines a way to cancel that paradox based on the sound methods of the scientific method.

The problem is that detecting them scientifically requires a very wide net of detectors and significant resources over long periods of time. That, again, parallels how we do other science. “Only long-term, transgenerational research programs, such as enjoyed by many research programs well established and stabilized within academic science now for many decades, can possibly yield the proper data on which a potential resolution to UAP can be founded,” the authors write.

However, we’re not starting from scratch.

“Our aim here is to enable future studies to draw on the great depth of prior documented experience,” the researchers explain.

Research: The New Science of Unidentified Aerospace-Undersea Phenomena (UAP)

The post What Would Actual Scientific Study of UAPs Look Like? appeared first on Universe Today.

This Ancient Galaxy Cluster is Still Forming Stars When it Should be ‘Red and Dead’

The Phoenix Cluster is one of the most massive galaxy clusters known. Astronomers have identified 42 member galaxies so far, yet there could be as many as 1,000 in the cluster. Because of its size and its age, it should be finished with the vigorous star formation characteristic of young galaxies.

But it’s not.

Star formation needs cold, dense gas. Hot gas resists collapsing into stellar cores, which become protostars and then main sequence stars. Old galaxies and clusters have either used up their cold gas or had it stripped away. These are called ‘quenched’ galaxies. In terms of star formation, galaxies can be classified as red sequence, meaning old and quenched, or blue cloud, meaning there’s more active star formation.

The Phoenix Cluster’s central galaxy is about 5.8 billion light-years away and should be mostly done with star formation. Many galaxy clusters have a region of hot gas in the intracluster medium (ICM). In a typical galaxy, this gas cools down and feeds star formation. However, observations show that the rate of star formation in these galaxies is remarkably low, and there’s no evidence of the cold gas. Astronomers call this discrepancy the “cooling flow problem,” and it leads to this question: Why isn’t the ICM cooling and forming new stars?

The dominant answer to this is that black hole jets from active galactic nuclei are heating the gas and preventing it from forming stars.

The Phoenix Cluster’s central galaxy should be mostly done with star formation. Yet it has an intensely bright core typical of vigorous star formation. Somehow, the Phoenix Cluster has a source of cold gas that’s fuelling the star birth. Did it generate itself somehow? Is it funnelling in from younger galaxies?

In new research, scientists used the JWST to probe the cluster’s heart. They did so because previous observations with other telescopes showed that the core was extraordinarily bright, indicating ferocious star birth. Since this contradicted what astronomers think they know about clusters like this, their curiosity was piqued.

The research, published in Nature, is titled “Directly imaging the cooling flow in the Phoenix cluster.” The lead author is Michael Reefe, a physics graduate student at MIT’s Kavli Institute for Astrophysics and Space Research.

This older image of the Phoenix Cluster (SPT-CLJ2344-4243) combines Chandra and Hubble’s X-ray, ultraviolet, and optical wavelengths. In this new research, the team of scientists used the JWST’s infrared capabilities to try to understand Phoenix better. Image Credit: By X-ray: NASA/CXC/MIT/M.McDonald et al; Optical: NASA/STScI – https://ift.tt/WRAGNXo (image link), Public Domain, https://ift.tt/ES6jcAO

Michael McDonald, associate professor of physics at MIT and co-author of this research, led the research team that discovered the Phoenix Cluster in 2010 using the South Pole Telescope. Two years later, they observed it again with multiple telescopes. They found that the central galaxy in the cluster was unexpectedly bright due to extreme star formation. The researchers said that up to 1,000 stars could be forming each year, an astounding number compared to the Milky Way, which forms fewer than 10 stars per year according to some research.

In previous observations, astronomers have found some very hot gas and some very cold gas in the Phoenix Cluster. They have observed pockets of ultrahot gas measuring about 1 million degrees Fahrenheit and regions of extremely cold gas measuring only 10 kelvins, or 10 degrees above absolute zero. Hot gas is not unusual since supermassive black holes (SMBHs) can emit extremely energetic jets that can heat gas. When a galaxy is young, some of this gas cools and forms stars. The Phoenix Cluster’s central galaxy also has some cool gas. Previous observations showed that there was no in-between warm gas, which is odd. Is there an answer to the cooling flow problem in the Phoenix Cluster?

The researchers reasoned that if the Phoenix central galaxy is somehow generating the detected cold gas, then there must be warm gas that’s intermediate between the hot gas and the cold gas. This is where the JWST enters the picture.

The JWST, with its powerful infrared capabilities, did find some warm gas. That shows that the cluster is able to generate the cold gas needed for star formation because the warm gas is evidence of a transition between temperature extremes.

New JWST observations, based on neon emissions, provided the first large-scale map of gas at temperatures between 100,000 and 1,000,000 Kelvin in the Phoenix Cluster. They used the Medium-Resolution Spectrometer on MIRI and collected 12 hours of infrared data. They were looking for a specific wavelength of light emitted by neon at around 300,000 K, or 540,000 F. This shows the presence of the intermediate warm gas that would be evidence of cooling.

Critically, the neon is co-spatial with other features like the coolest gas and the sites of active star formation. This is evidence supporting a direct link between intermediate gas, its cooling, and star formation.

“This 300,000-degree gas is like a neon sign that’s glowing in a specific wavelength of light, and we could see clumps and filaments of it throughout our entire field of view,” lead author Reefe said in a press release. “You could see it everywhere.”

The three panels in this figure from the study go to the heart of the research. They’re maps of the [Ne VI]-emitting coronal gas in the central galaxy of the Phoenix cluster overlaid with the hotter and colder gas phases and starlight. (a) shows Ne VI flux, which indicates cooling gas. (b) shows an [O II] image of the central galaxy of the Phoenix cluster in the greyscale using data from the HST Advanced Camera for Surveys. It indicates star formation. (c) shows young, actively star-forming regions in blue. Image Credit: Reefe et al. 2025

“For the first time, we have a complete picture of the hot-to-warm-to-cold phase in star formation, which has really never been observed in any galaxy,” said Reefe. “There is a halo of this intermediate gas everywhere that we can see.”

The fact that astronomers were unable to see the telltale warm gas in the Phoenix Cluster doesn’t mean it wasn’t there. The JWST gives researchers their best look at galaxies, uncovering details that were previously hidden. Still, the question that has to be asked is whether Phoenix is special. Will the JWST find the telltale warm gas in other galaxies?

“The question now is, why this system?” added co-author McDonald. “This huge starburst could be something every cluster goes through at some point, but we’re only seeing it happen currently in one cluster. The other possibility is that there’s something divergent about this system, and the Phoenix went down a path that other systems don’t go. That would be interesting to explore.”

“Previous to the Phoenix, the most star-forming galaxy cluster in the universe had about 100 stars per year, and even that was an outlier. The typical number is one-ish,” McDonald said. “The Phoenix is really offset from the rest of the population.”

This brings us to one of the unanswered questions about old galaxies. They should be quenched or “red and dead,” but all of them aren’t. Where did this cold gas come from? Did it come from outside these galaxies?

“The question has been: Where did this cold gas come from?” McDonald said. “It’s not a given that hot gas will ever cool, because there could be black hole or supernova feedback. So, there are a few viable options, the simplest being that this cold gas was flung into the center from other nearby galaxies. The other is that this gas somehow is directly cooling from the hot gas in the core.”

The fact that the [Ne VI] emissions are cospatial with the sites of active star formation suggests a recent episode of rapid gas cooling, creating a spike in cooling. The researchers say this extreme cooling us generating 20,000 solar masses of cold gas each year. That shows that the galaxy is able to supply its own cold gas for star formation and that it’s not coming from elsewhere. The question is, how?

The results suggest that somehow, the central black hole is actually promoting cooling the gas rather than heating it. “These data provide a large-scale map of gas at temperatures between 10⁵ kelvin and 10⁶ kelvin in a cluster core and highlight the critical role that black hole feedback has in not only regulating cooling but also promoting it,” the authors write. “

An artist’s conception of a supermassive black hole’s jets. These jets may play a role in cooling gas rather than heating it. Image Credit: NASA / Dana Berry / SkyWorks Digital

The research answers part of the question that the Phoenix Cluster poses.

“If short-lived cooling episodes are common in the galaxy cluster population, providing the necessary fuel for ongoing AGN feedback, then Phoenix provides a unique window into this critically important, but rarely captured, process for understanding the formation of the most massive galaxies in the Universe,” the authors write in their conclusion.

“I think we understand pretty completely what is going on, in terms of what is generating all these stars,” McDonald said. “We don’t understand why. But this new work has opened a new way to observe these systems and understand them better.”

• Press Release: Study reveals the Phoenix galaxy cluster in the act of extreme cooling
• Research: Directly imaging the cooling flow in the Phoenix cluster

The post This Ancient Galaxy Cluster is Still Forming Stars When it Should be ‘Red and Dead’ appeared first on Universe Today.

A Spiral Structure in the Inner Oort Cloud

We typically think of the Oort cloud as scattered ice balls floating far from the Sun, yet still tied to it gravitationally. Occasionally, some wayward gravitational perturbation will knock one of them a weird way and create a long-period comet, which might briefly delight us lowly humans by providing something interesting in the sky to look at. But what the Oort cloud actually looks like and how it is affected by forces greater than just our solar system has remained somewhat of a mystery. A new paper from researchers at the Southwest Research Institute and the American Museum of Natural History tries to shine a light on what this invisible part of the solar system looks like – at least the part that is only 1,000 to 10,000 times farther away from the Sun as Earth is.

That part called the “inner” Oort cloud is considered slightly more populated than the “outer” Oort cloud, which ranges from 10,000 AU to 100,000 AU. Overall, potentially trillions of icy bodies are thought to be floating deep in space, though we only ever see the ones that show up in the inner solar system as long-period comets. 

Estimating the cloud’s structure requires more than understanding the planet’s gravitational forces. While they still have an impact, there is a larger player in the orbital mechanics of these icy rocks—the galaxy itself.

There’s a concept known as the “Galactic tide”. As our solar system moves through the galaxy, it is subjected to gravitational forces of other objects, like stars and black holes, that are closer or farther away from it. Like Earth’s Moon forces the water on the surface towards it due to its gravity, the galactic center, where most of the galaxy’s mass is, affects large objects in our solar system.

Fraser discusses the Oort cloud, the mysterious region where comets come from.

For the planets, this influence is drowned out by their gravitational bond to the Sun. But for Oort cloud objects, it plays a major role in determining their positioning. New long-period comets are formed when a nuance in the galactic tide either forces them into the inner solar system itself or causes them to collide with one another, sending one off on a trajectory toward the Sun.

Modeling this complex dynamic is hard, and the researchers, including lead author David Nesvorný, had to rely on a supercomputer at NASA to run their analytical model and compare it to previous simulations of the structure of the Oort cloud. They found something intriguing hiding in the data.

According to their model, the Oort cloud looks like a spiral disk about 15,000 au across, offset by the ecliptic by about 30 degrees. But more interestingly, it has two spiral arms that almost make it look like a galaxy.

Spiral arms of the Oort cloud in relation to the ecliptic and galactic planes.
Credit – Nesvorný et al.

These spiral arms, which are located nearly perpendicular to the galaxy’s center, resulting from the influence of the Galactic tide, are represented in the mathematical model by a phenomenon known as the Kozai-Lidov effect. In this quirk of celestial mechanics, large bodies are affected by “Kozai oscillations” that result from the gravitational influence of objects that are much farther away but, in the aggregate, still have an impact on the mechanics of a body.

The changes those oscillations make take a long time, but according to the researcher’s analysis, they almost solely determine the shape of the inner Oort cloud. The gravitational pull of the solar system’s planets or nearby passing stars doesn’t seem to have much effect.

According to the paper, taking a picture of this two-armed spiral will be exceedingly difficult. The authors suggest doing so would either require direct observation of a large number of objects in that space (which is unlikely in the near term) or separation of radiation from those objects that eliminates background and foreground sources so it could track the specific structure.

As of now, neither observational method has any resources dedicated to it. But, if we want to learn more about the home of any potential new comets and their impact on us, it wouldn’t be a bad idea to start planning how to look.

Learn More:
Nesvorný et al – A Spiral Structure in the Inner Oort Cloud
UT – The Oort Cloud Might be More Active Than We Thought
UT – A Star Passed Through the Oort Cloud Less Than 500,000 Years Ago. It Wasn’t the Only One.
UT – There Could Be Captured Planets in the Oort Cloud

Lead Image:
Illustration of the Oort Cloud.
Credit – NASA

The post A Spiral Structure in the Inner Oort Cloud appeared first on Universe Today.

Huge Release of Type 1a Supernovae Data

Type 1a supernovae are extremely powerful events that occur in binary systems containing at least one white dwarf star – the core remnant of a Sun-like star. Sometimes, the white dwarf’s powerful gravity will siphon material from its companion star until it reaches critical mass and explodes. In another scenario, a binary system of two white dwarfs will merge, producing the critical mass needed for a supernova. Unlike regular supernovae, which occur every fifty years in the Milky Way, Type Ia supernovae happen roughly once every five hundred years.

In addition to being incredible events, Type 1a supernovae are useful astronometric tools. As part of the Cosmic Distance Ladder, these explosions allow astronomers to measure the distances to objects millions or billions of light-years away. This is vital to measuring the rate at which the Universe is expanding, otherwise known as the Hubble Constant. Thanks to an international team of researchers, a catalog of Type 1a Supernovae has just been released that could change what we know of the fundamental physics of supernovae and the expansion history of the Universe.

This new catalog constitutes the second data release (DR2) from the Zwicky Transient Facility (ZTF), a wide-field astronomical survey that began in 2018. This survey relies on the ZTF camera on the 1.2-meter (4-foot) Samuel Oschin Telescope at the Palomar Observatory near San Diego, California. It has classified over 8,000 supernovae, including 3628 nearby Type 1a supernovae (SNe Ia), more than doubling the number of known SNe Ia’s discovered in the past 30 years. Despite being rare, the ZTF’s depth and survey strategy have allowed the ZTF Collaboration to detect nearly four per night.

This catalog contains 3628 nearby SNe Ia and is the first large and homogenous dataset astrophysicists can access. The release is detailed in a paper released on February 14th in Astronomy & Astrophysics, alongside a Special Issue containing 21 related publications. The paper’s lead authors are Dr. Mickael Rigault, head of the ZTF Cosmology Science working group and a Research Scientist at the Centre National de la Recherche Scientifique (CNRS), the Université Claude Bernard Lyon, and Dr. Matthew Smith, a Lecturer in Astrophysics at Lancaster University. As Dr. Rigault said:

“For the past five years, a group of thirty experts from around the world have collected, compiled, assembled, and analyzed these data. We are now releasing it to the entire community. This sample is so unique in terms of size and homogeneity that we expect it to significantly impact the field of Supernovae cosmology and to lead to many additional new discoveries in addition to results we have already published.”

The key component of the ZTF system is its 47-square-degree, 600-megapixel cryogenic CCD mosaic science camera. The camera scans the entire northern sky daily in three optical bands with a magnitude of 20.5, allowing it to detect nearly all supernovae within 1.5 billion light-years of Earth. Co-author Prof. Kate Maguire of Trinity College Dublin said, “Thanks to ZTF’s unique ability to scan the sky rapidly and deeply, we have captured multiple supernovae within days—or even hours—of [the] explosion, providing novel constraints on how they end their lives.”

The ultimate purpose of the survey is to determine the expansion rate of the Universe (aka. the Hubble Constant). Since the late 1990s and the Hubble Deep Fields observations, which used SNe Ia to measure cosmic expansion, astronomers have known that the expansion rate is accelerating. This effectively demonstrated that the Hubble Constant is not constant and gave rise to the theory of Dark Energy. In addition, the ability to observe the Universe all the way back to roughly 1 billion years after the Big Bang led to the “Crisis in Cosmology.”

Also known as the “Hubble Tension,” astronomers noted that distance measurements along the Cosmic Ladder produced different values. Since then, cosmologists have been looking for explanations for this Tension, which include the possibility of Early Dark Energy (EDE). A key part of this is obtaining truly accurate measurements of cosmic distances. Co-author Professor Ariel Goobar, the Director of the Oskar Klein Centre in Stockholm and one of the founding institutions of ZTF, was also a member of the team that discovered the accelerated expansion of the Universe in 1998.

“Ultimately, the aim is to address one of our time’s biggest questions in fundamental physics and cosmology, namely, what is most of the Universe made of?” she said. “For that, we need the ZTF supernova data.” One of the biggest takeaways from this catalog and the studies that went into creating it is that more than previously thought, Type Ia Supernovae vary based on their host environment. As a result, the correction mechanism used to date needs revising, which could change how we measure the expansion rate of the Universe.

This could have consequences for the Standard Model of Cosmology – aka. the Lambda Cold Dark Matter (Lambda-CDM) model – and issues arising from it like the Hubble Tension. This data will be essential when the Nancy Grace Roman Space Telescope (RST) launches into space and begins making observations leading to the first wide-field maps of the Universe. Combined with observations by the ESA’s Euclid mission, these maps could finally resolve the mystery of Dark Matter and cosmic expansion. As Dr Rigault said:

“With this large and homogeneous dataset, we can explore Type Ia supernovae with an unprecedented level of precision and accuracy. This is a crucial step toward honing the use of Type Ia Supernovae in cosmology and assess[ing] if current deviations in cosmology are due to new fundamental physics or unknown problem[s] in the way we derive distances.”

Further Reading: Lancaster University, Astronomy & Astrophysics

The post Huge Release of Type 1a Supernovae Data appeared first on Universe Today.

The Moon Solidified 4.43 Billion Years Ago

What’s the story of our Moon’s early history? Despite all we know about our closest natural satellite, scientists are still figuring out bits of its history. New measurements of rocks gathered during the Apollo missions now show it solidified some 4.43 billion years ago. It turns out that’s about the time Earth became a habitable world.

University of Chicago scientist Nicolas Dauphas and a team of researchers made the measurements. They looked at different proportions of elements inside Moon rocks. They provide a window into the Moon’s early epochs. It started out as a fully molten blob after a collision between two early solar system bodies.

As it cooled and crystallized, the molten proto-moon separated into layers. Eventually, about 99% of the lunar magma ocean had solidified. The rest was a unique residual liquid called KREEP. That acronym stands for the elements potassium (K), rare earth elements (REE), and phosphorus (P).

Dauphas and his team analyzed this KREEP and found that it formed about 140 million years after the birth of the Solar System. It’s in the Apollo rocks and scientists hope to find it in samples from the South Pole-Aitken basin. This is the region where Artemis astronauts will eventually explore. If analysis confirms it there, then it indicates a uniform distribution of this KREEP layer across the lunar surface.

Understanding KREEP’s History on the Moon

The clues to the Moon’s ultimate “cooling off period” lie in a faintly radioactive rare earth element called “lutetium”. Over time, it decays to become hafnium. In the early Solar System, all rocks had about the same amounts of lutetium. Its decay process helps determine the age of the rocks where it exists.

However, the Moon’s solidification and subsequent formation of KREEP reservoirs didn’t result in a lot of lutetium compared to other rocks created at the same time. So, the scientists wanted to measure the proportions of lutetium and hafnium in Moon rocks and compare them to other bodies created around the same time—such as meteorites. That would allow them to calculate a more precise time for when the KREEP formed on the Moon.

They tested tiny samples of Moon rocks and looked at the ratio of hafnium in embedded lunar zircons. Through that analysis, they found that the rock ages are consistent with formation in a KREEP-rich reservoir. Those ages are consistent with the formation of KREEP reservoirs about 140 million years after the birth of the solar system, or about 4.43 billion years ago. “It took us years to develop these techniques, but we got a very precise answer for a question that has been controversial for a long time,” said Dauphas.

Placing KREEP in Perspective

Interestingly, the team’s results showed that lunar magma ocean crystallization occurred while leftover planetary embryos and planetesimals bombarded the Moon. Those objects were the birth “seeds” of the planets and Moon, which began after the Sun coalesced starting some 4.6 billion years ago. What remained from the formation of the planets continued to batter the already-formed planets.

The formation of the Moon itself began some 60 million years after the solar system itself was born. The most likely event was the collision of a Mars-sized world called Theia with the infant Earth. That sent molten debris into space and it began to coalesce to make the Moon. “We must imagine a big ball of magma floating in space around Earth,” said Dauphas. Shortly thereafter, that ball began to cool. That process eventually resulted in the formation of the lunar KREEP layers.

An artist’s conception of the cooling lunar magma ocean. Courtesy ESA.

The study of the decay of lutetium to hafnium in samples of those KREEP rocks is a big step forward in understanding the most ancient epoch of lunar history. More rock samples brought back from the South Pole-Aitken basin will help fill in the remaining blanks and help researchers clarify the timeline of both the cooling of the lunar rock and the subsequent creation of such rock deposits as the mare basalts. Those rock layers were created when impactors slammed into the lunar surface, generating lava flows that filled the impact basins.

The mare formed as a result of impacts later in the early history of the Moon, some 240 million years after the birth of the Solar System formation. Those impacts stimulated lava flows that covered less than 20 percent of the lunar surface and engulfed the oldest surfaces.

Timing is Everything

Fixing the dating of lunar cooling not only tells us about the history of the Moon but helps scientists understand Earth’s evolution. That’s because the impact that formed the Moon was probably also the last major impact on Earth. It could well mark a time when the Earth may have begun its transformation into a stable world. That’s an important step toward evolving into a place hospitable for life.

“This finding aligns nicely with other evidence—it’s a great place to be in as we prepare for more knowledge about the Moon from the Chang’e and Artemis missions,” said Dauphas. “We have a number of other questions that are waiting to be answered.”

For More Information

Lunar Rocks Help Scientists Pinpoint When the Moon Crystallized
Completion of Lunar Magma Ocean Solidification at 4.43 Ga
Moon Formation

The post The Moon Solidified 4.43 Billion Years Ago appeared first on Universe Today.

What Would Happen if a Tiny Black Hole Passed Through Your Body?

In 1974, science fiction author Larry Niven wrote a murder mystery with an interesting premise: could you kill a man with a tiny black hole? I won’t spoil the story, though I’m willing to bet most people would argue the answer is clearly yes. Intense gravity, tidal forces, and the event horizon would surely lead to a messy end. But it turns out the scientific answer is a bit more interesting.

On the one hand, it’s clear that a large enough black hole could kill you. On the other hand, a black hole with the mass of a single hydrogen atom is clearly too small to be noticed. The real question is the critical mass. At what minimum size would a black hole become deadly? That’s the focus of a new paper on the arXiv.

The study begins with primordial black holes. These are theoretical bodies that may have formed in the earliest moments of the Universe and would be much smaller than stellar-mass black holes. Anywhere from atom-massed to a mass several times that of Earth. Although astronomers have never found any primordial black holes, observations do rule out several mass ranges. For example, any primordial black hole smaller than 10¹² kg would have already evaporated thanks to Hawking radiation. Anything larger than 10²⁰ kg would gravitationally lens stars in the Milky Way. Since we haven’t detected these lensing effects, they must at the very least be exceedingly rare. If they exist at all.

Some theoretical models argue that primordial black holes could be the source of dark matter. If that’s the case, observational limits constrain their masses to the 10¹³ – 10¹⁹ kg range, which is similar to the mass range for asteroids. Therefore, the study focuses on this range and looks at two effects: tidal forces and shock waves.

Tidal forces occur because the closer you get to a mass, the stronger its gravity. This means a black hole exerts a force differential on you as it gets near. So the question is whether this force differential is strong enough to tear flesh. Asteroid-mass black holes are less than a micrometer across, so even the tidal forces would cover a tiny area. If one passed through your midsection or one of your limbs, there might be some local damage, but nothing fatal. It would be similar to a needle passing through you.

But if the black hole passed through your head, that would be a different story. Tidal forces could tear apart brain cells, which would be much more serious. Since brain cells are delicate, even a force differential of 10 – 100 nanonewtons might kill you. But that would take a black hole at the highest end of our mass range.

Shockwaves would be much more dangerous. In this case, as a black hole entered your body, it would create a density wave that would ripple through you. These shockwaves would physically damage cells and transfer heat energy that would do further damage. To create a shockwave of energy similar to that of a 22-caliber bullet, the black hole would only need a mass of 1.4 x 10¹⁴ kg, which is well within the range of possible primordial black holes.

So yes, a primordial black hole could kill you.

While that makes for a great story, it would never happen in real life. Even if asteroid-mass primordial black holes exist, the number of them out there compared to the vastness of space means that the odds of it happening to anyone in their lifetime are less than one in 10 trillion.

Reference: Niven, Larry. “The Hole Man.” Analog Science Fiction/Science Fact (1974): 93-104.

Reference: Robert J. Scherrer. “Gravitational Effects of a Small Primordial Black Hole Passing Through the Human Body.” arXiv preprint arXiv:2502.09734
(2025)

The post What Would Happen if a Tiny Black Hole Passed Through Your Body? appeared first on Universe Today.