One of Slashdot's most-visited stories of all time was the 2016 story asking: Can Cow Backpacks Reduce Global Methane Emissions? "Enteric fermentation," or livestock's digestive process, accounts for 22 percent of all U.S. methane emissions, and the manure they produce makes up eight percent more, according to the U.S. Environmental Protection Agency... Methane, like carbon, is a greenhouse gas, but methane's global warming impact per molecule is 25 times greater than carbon's, according to the EPA.
Cow methane still "heats the Earth more than every flight across the world combined," the Washington Post added today, reporting on a new $30 million genetic engineering experiment undertaken by the Innovative Genomics Institute and the University of California at Davis.

Its mission: to transform a cow's gut so it no longer releases methane. Using tools that snip and transfer DNA, researchers plan to genetically engineer microbes in the cow stomach to eliminate those emissions. If they succeed, they could wipe out the world's largest human-made source of methane and help change the trajectory of planetary warming... The average cow produces around 220 pounds of methane per year, or around half the emissions of an average car; cows are currently responsible for around 4 percent of global warming, according to the Food and Agriculture Organization...

Scientists envision a kind of probiotic pill, given to the cow at birth, that can transform its microbiome permanently...

The current project doesn't target only a particular cow species — it takes aim at the microbiome itself, offering a solution that could apply to all of them. Brad Ringeisen, executive director at the genomics institute, cut his teeth running biotechnology at the U.S. defense research agency DARPA, which helped pioneer transformative innovations including the internet, miniaturized GPS, stealth aircraft and the computer mouse. "I'm taking the DARPA mentality here," he said. "Let's solve it for all cows, not just a fraction of the cows." ...]

"There's no reason a cow has to produce methane," Ringeisen said. So what if scientists could just ... turn it off?
"I personally think this is the one that can make the biggest impact in the world," Ringeisen said. "Say you could wave a magic wand and eliminate all those emissions."

The article says that currently the scientists are feeding red-seaweed oil to a cow to measure the changes, to prepare for their final goal: "replicate those changes with gene editing." (They're using machine learning to reassemble the hundreds of pieces of each miccroorganism's DNA, so they can understand which changes they need to make with their early-intervention probiotic.) Such a probiotic could also improve a farm's productivity. Cows can lose up to 12 percent of their energy through burping up methane; other ruminants, like sheep and goats, also lose energy in this way. "If there is a way to redirect that hydrogen and convert it into milk, meat, wool — it would be much more accepted by farmers," said Ermias Kebreab [a professor of animal science at UC-Davis].

Early treatments will be tested on the cows at Davis, with researchers tracking their burps to evaluate the drop-off in methane emissions. There is still a long way to go. While scientists have proved that they can gene-edit microbes, researchers have so far only shown that they can edit a small fraction of the microbes in the cow gut — or the human gut, for that matter. Institute researchers are developing microbial gene-editing tools, even as they are mapping the species of the microbiome. They are building the plane while flying it.

The teams have received enough funding for seven years of research. The project started last year, and they hope to have a trial treatment ready for testing in cows in the next two years.

Boeing "will return its Starliner capsule from the International Space Station without the NASA astronauts," reports CNBC. Though they've been on the space station since early June, the plan is to have them stay "for about six more months before flying home in February on SpaceX's Crew-9 vehicle.

"The test flight was originally intended to last about nine days." The decision to bring Starliner back from the ISS empty marks a dramatic about-face for NASA and Boeing, as the organizations were previously adamant that the capsule was the primary choice for returning the crew. But Starliner's crew flight test, which had been seen as the final major milestone in the spacecraft's development, faced problems — most notably with its propulsion system.

"Boeing has worked very hard with NASA to get the necessary data to make this decision," NASA Administrator Bill Nelson said during a press conference with top NASA officials at Johnson Space Center in Houston on Saturday. "We want to further understand the root causes and understand the design improvements so that the Boeing Starliner will serve as an important part of our assured crew access to the ISS."

He reiterated that test flights are "neither safe, nor routine," and that the decision was the "result of a commitment to safety." NASA will now conduct another phase of its Flight Readiness Review to determine when to bring the empty Starliner home. Boeing officials had been adamant in press briefings that Starliner was safe for the astronauts to fly home in the event of an emergency, despite delaying the return multiple times. NASA said there was a "technical disagreement" between the agency and the aerospace company, and said it evaluated risk differently than Boeing for returning its crew.

Nonetheless, NASA officials repeatedly expressed support for Boeing, and Nelson said he was "100% certain" that Starliner would be able to launch with a crew again someday.
NASA posted on X.com that they'd reached the decision "after extensive review by experts across the agency.

And CNBC adds that "Ken Bowersox, NASA associate administrator, said NASA officials were unanimous in their decision to choose SpaceX to bring the crew home."

NASA's 2022 DART mission "successfully demonstrated how a fast-moving spacecraft could change an asteroid's trajectory by crashing into it," remembers Gizmodo, "potentially providing a way to defend Earth — though the asteroid in this test was never a real threat."

But a followup study suggests debris from that 525-foot (160-meter) asteroid "could actually strike back," they add, "though we're not in any danger." The [DART] team posits that the collision produced a field of rocky ejecta that could reach Earth within 10 years... [Various aerospace scientists] studied data collected by the Light Italian CubeSat for Imaging of Asteroids, or LICIACube, which observed DART's impact of Dimorphos up close. Then, they fed LICIACube's data into supercomputers at NASA's Navigation and Ancillary Information Facility to simulate how the debris from the asteroid — basically dust and rock — may have disseminated into space. The simulations tracked about 3 million particles kicked up by the impact, some of which are large enough to produce meteors that could be spotted on Earth. Particles from the impact could get to Mars in seven to 13 years, and the fastest particles could make it to our own world in just seven years.

"This detailed data will aid in the identification of DART-created meteors, enabling researchers to accurately analyze and interpret impact-related phenomena," the team wrote in the paper.
"However, these faster particles are expected to be too small to produce visible meteors, based on early observations," said Dr. Eloy Peña-Asensio, who lead the research team, in an interview with Universe Today. (He's a Research Fellow with the Deep-space Astrodynamics Research and Technology group at Milan's Polytechnic Institute.) The team's simulations indicated it could take up to 30 years before any of the ejecta is observed on Earth, in a new (and human-created) meteor shower called the Dimorphids.

So while they won't pose any risk, "If these ejected Dimorphos fragments reach Earth... their small size and high speed will cause them to disintegrate in the atmosphere, creating a beautiful luminous streak in the sky."

Over the next 50 years, people will push further into wildlife habitats across more than half the land on Earth, scientists have found, threatening biodiversity and increasing the chance of future pandemics. From a report: Humans have already transformed or occupied between 70% and 75% of the world's land. Research published in Science Advances on Wednesday found the overlap between human and wildlife populations is expected to increase across 57% of the Earth's land by 2070, driven by human population growth.

[...] As humans and animals share increasingly crowded landscapes, the bigger overlap could result in higher potential for disease transmission, biodiversity loss, animals being killed by people and wildlife eating livestock and crops, the researchers said. Biodiversity loss is the leading driver of infectious disease outbreaks. About 75% of emerging diseases in humans are zoonotic, meaning they can be passed from animals to humans, and many diseases concerning global health authorities -- including Covid-19, mpox, avian flu and swine flu -- likely originated in wildlife.

NASA astronauts Butch Wilmore and Suni Williams are facing challenges returning to Earth due to compatibility issues between their Boeing-designed spacesuits and SpaceX's Dragon spacecraft. Inc. Magazine reports: The space suits in question are the "intra-vehicular activity" outfits now worn by astronauts. They're simpler than the bulky extra-vehicular space suits used on space walks, and are designed to keep astronauts safe in the capsule in the very unlikely case there's a problem that causes the capsule's atmosphere to be lost. The problem is simple: Should Butch and Suni need to fly back aboard SpaceX's vehicle, their suits won't fit in Dragon's seats. [...]

Boeing and SpaceX suits evolved under totally different design sensibilities. If Boeing and NASA deem Starliner unsafe for humans to fly home in, Butch and Suni must head earthward aboard a SpaceX Dragon, but their suits won't be able to plug into Dragon's systems. Like trying to plug an essentially outdated USB A socket into an iPhone's charge port, the suit connectors have different shapes, styles, and functions. The suits themselves have different systems that integrate with their own capsules for purposes like air leak checks during pre-flight testing.

So if an emergency situation presents itself and astronauts have to come back to Earth before proper plans are finalized, Butch and Suni will have to return inside the cargo section of a Dragon space capsule "unsuited," according to NASA leadership who spoke on the matter in a press conference last week. Other plans include flying up suitable Dragon-connecting space suits for the two astronauts on a later mission, should Starliner be deemed incapable of bringing them back.

Indian influencers It's the largest country on earth — home to 1.4 billion people. But "The Indian government has plans to classify social media creators as 'digital news broadcasters,'" according to the nonprofit site RestofWorld.org.

While there's "no clarity" on the government's next move, the proposed legislation would require social media creators "to register with the government, set up a content evaluation committee that checks all content before it is published, and appoint complaint handlers — all at their own expense. Any failures in compliance could lead to criminal charges, including jail term." On July 26, the Hindustan Times reported that the government plans to tweak the proposed Broadcasting Services (Regulation) Bill, which aims to combine all regulations for broadcasters under one law. As per a new version of the bill, which has been reviewed by Rest of World, the government defines "digital news broadcaster" as "any person who broadcasts news and current affairs programs through an online paper, news portal, website, social media intermediary, or other similar medium as part of a systematic business, professional or commercial activity."

Creators and digital rights activists believe the potential legislation will tighten the government's grip over online content and threaten the last bastion of press freedom for independent journalists in the country. Over 785 Indian creators have sent a letter to the government seeking more transparency in the process of drafting the bill. Creators have also stormed social media with hashtags like #KillTheBill, and made videos to educate their followers about the proposal.
One YouTube creator told the site that if the government requires them to appoint a "grievance redressal officer," they might simply film themselves, responding to grievances — to "make content out of it".

Ars Technica's John Timmer reports: [T]he International Astronomical Union has a resolution that calls for a "Lunar Celestial Reference System" and "Lunar Coordinate Time" to handle things there. On Monday, two researchers at the National institute of Standards and Technology, Neil Ashby and Bijunath Patla, did the math to show how this might work. [...] Ashby and Patla worked on developing a system where anything can be calculated in reference to the center of mass of the Earth/Moon system. Or, as they put it in the paper, their mathematical system "enables us to compare clock rates on the Moon and cislunar Lagrange points with respect to clocks on Earth by using a metric appropriate for a locally freely falling frame such as the center of mass of the Earth-Moon system in the Sun's gravitational field." What does this look like? Well, a lot of deriving equations. The paper's body has 55 of them, and there are another 67 in the appendices. So, a lot of the paper ends up looking like this.

Things get complicated because there are so many factors to consider. There are tidal effects from the Sun and other planets. Anything on the surface of the Earth or Moon is moving due to rotation; other objects are moving while in orbit. The gravitational influence on time will depend on where an object is located. So, there's a lot to keep track of. Ashby and Patla don't have to take everything into account in all circumstances. Some of these factors are so small they'll only be detectable with an extremely high-precision clock. Others tend to cancel each other out. Still, using their system, they're able to calculate that an object near the surface of the Moon will pick up an extra 56 microseconds every day, which is a problem in situations where we may be relying on measuring time with nanosecond precision. And the researchers say that their approach, while focused on the Earth/Moon system, is still generalizable. Which means that it should be possible to modify it and create a frame of reference that would work on both Earth and anywhere else in the Solar System. Which, given the pace at which we've sent things beyond low-Earth orbit, is probably a healthy amount of future-proofing. The findings have been published in the Astronomical Journal. A National Institute of Standards and Technology (NIST) press release announcing the work can be found here.

An anonymous reader quotes a report from Ars Technica: SpaceX will fly the first-ever human spaceflight over the Earth's poles, possibly before the end of this year, the company announced Monday. The private Crew Dragon mission will be led by a Chinese-born cryptocurrency entrepreneur named Chun Wang, and he will be joined by a polar explorer, a roboticist, and a filmmaker whom he has befriended in recent years. The "Fram2" mission, named after the Norwegian research ship Fram, will launch into a polar corridor from SpaceX's launch facilities in Florida and fly directly over the north and south poles. The three-to-five day mission is being timed to fly over Antarctica near the summer solstice in the Southern Hemisphere, to afford maximum lighting.

The four-person crew will fly, fittingly, aboard Crew Dragon Endurance, which is named after Ernest Shackleton's famous ship that was trapped in the Antarctic ice and eventually sunk there about a century ago. The spacecraft will be fitted with a cupola for both photography and filming. This will be SpaceX's third free-flying mission aboard Crew Dragon, following the Inspiration4 mission funded and commanded by US entrepreneur Jared Isaacman in 2021, and his forthcoming Polaris Dawn mission which may launch later this month. In an interview, Wang said he modeled the Fram2 mission's crew and public outreach programs on the template established by Isaacman.

sciencehabit shares a report from Science.org: For years, astronomers thought it was the Milky Way's destiny to collide with its near neighbor the Andromeda galaxy a few billion years from now. But a new simulation finds a 50% chance the impending crunch will end up a near-miss, at least for the next 10 billion years. It's been known that Andromeda is heading toward our home Galaxy since 1912, heading pretty much straight at the Milky Way at a speed of 110 kilometers per second. Such galaxy mergers, which can be seen in progress elsewhere in the universe, are spectacularly messy affairs. Although most stars survive unscathed, the galaxies' spiral structures are obliterated, sending streams of stars spinning off into space. After billions of years, the merged galaxies typically settle into a single elliptical galaxy: a giant featureless blob of stars. A study from 2008 suggested a Milky Way-Andromeda merger was inevitable within the next 5 billion years, and that in the process the Sun and Earth would get gravitationally grabbed by Andromeda for a time before ending up in the distant outer suburbs of the resulting elliptical, which the researchers dub "Milkomeda."

In the new simulation, researchers made use of the most recent and best estimates of the motion and mass of the four largest galaxies in the Local Group. They then plugged those into simulations developed by the Institute for Computational Cosmology at Durham University. First, they ran the simulation including just the Milky Way and Andromeda and found that they merged in slightly less than half of the cases -- lower odds than other recent estimates. When they included the effect of the Triangulum galaxy, the Local Group's third largest, the merger probability increased to about two-thirds. But with the inclusion of the Large Magellanic Cloud, a satellite galaxy of the Milky Way that is the fourth largest in the Local Group, those chances dropped back down to a coin flip. And if the cosmic smashup does happen, it won't be for about 8 billion years. "As it stands, proclamations of the impending demise of our Galaxy appear greatly exaggerated," the researchers write. Meanwhile, if the accelerating expansion of the universe continues unabated, all other galaxies will disappear beyond our cosmic event horizon, leaving Milkomeda as the sole occupant of the visible universe. The study is available as a preprint on arXiv.

"AT&T has been told to stop running ads that claim the carrier is already offering cellular coverage from space," reports Ars Technica: AT&T intends to offer Supplemental Coverage from Space (SCS) and has a deal with AST SpaceMobile, a Starlink competitor that plans a smartphone service from low-Earth-orbit satellites. But AST SpaceMobile's first batch of five satellites isn't scheduled to launch until September.

T-Mobile was annoyed by AT&T running an ad indicating that its satellite-to-cellular service was already available, and filed a challenge with the advertising industry's self-regulatory system run by BBB National Programs. The BBB National Advertising Division (NAD) ruled against AT&T last month and the carrier appealed to the National Advertising Review Board (NARB), which has now also ruled against AT&T...

AT&T, which is also famous for renaming its 4G service "5GE," reluctantly agreed to comply with the recommendation and released a new version of the satellite-calling commercial with more specific disclaimers.
The 30-second ad — titled "Epic Bad Golf Day" — featured Ben Stiller golfing chasing a badly-hit golf ball all the way into the desert (accompanied by the Pixies' song "Where is My Mind").

But according to the article, T-Mobile filed an official complaint with the advertising review board that "the use of humor does not shield an advertiser from its obligation to ensure that claims are truthful and non-misleading." The ad originally included small text that described the depicted satellite call as a "demonstration of evolving technology." The text was changed this week to say that "satellite calling is not currently available...."

The original version also had text that said, "the future of help is an AT&T satellite call away." The NARB concluded that this "statement can be interpreted reasonably as stating that 'future' technology has now arrived... In the updated version of the ad, AT&T changed the text to say that "the future of help will be an AT&T satellite call away."

Slashdot reader sciencehabit shared this report from Science magazine: One of the classic tropes of science fiction is terraforming Mars: warming up our cold neighbor so it could support human civilization. The idea might not be so far-fetched, research published today in Science Advances suggests...

Samaneh Ansari [a Ph.D. student at Northwestern University and lead author on the new study] and her colleagues wanted to test the heat-trapping abilities of a substance Mars holds in abundance: dust. Martian dust is rich in iron and aluminum, which give it its characteristic red hue. But its microscopic size and roughly spherical shape are not conducive to absorbing radiation or reflecting it back to the surface. So the researchers brainstormed a different particle: using the iron and aluminum in the dust to manufacture 9-micrometer-long rods, about twice as big as a speck of martian dust and smaller than commercially available glitter. Ansari designed a simulation to test how these theoretical particles would interact with light. She found "unexpectedly huge effects" in how they absorbed infrared radiation from the surface and how they scattered that radiation back down to Mars — key factors that determine whether an aerosol particle creates a greenhouse effect.

Collaborators at the University of Chicago and the University of Central Florida then fed the particles into computer models of Mars's climate. They examined the effect of annually injecting 2 million tons of the rods 10 to 100 meters above the surface, where they would be lofted to higher altitudes by turbulent winds and settle out of the atmosphere 10 times more slowly than natural Mars dust. Mars could warm by about 10 degreesC within a matter of months, the team found, despite requiring 5000 times less material than other proposed greenhouse gas schemes...

Still, "Increasing the temperature of the planet is just one of the things that we would need to do in order to live on Mars without any assistance," says Juan Alday, a postdoctoral planetary science researcher at the Open University not involved with the work. For one, the amount of oxygen in Mars's atmosphere is only 0.1%, compared with 21% on Earth. The pressure on Mars is also 150 times lower than on Earth, which would cause human blood to boil. And Mars has no ozone layer, which means there is no protection from the Sun's harmful ultraviolet radiation. What's more, even once warmed, martian soils may still be too salty or toxic to grow crops. In other words, McInnes says, upping the temperature "isn't some kind of magic switch" that would make Mars habitable.

That isn't stopping Ansari and her colleagues from investigating the possibilities.

Longtime Slashdot reader schwit1 shares a report from Ars Technica: The upper stage from a Chinese rocket that launched a batch of Internet satellites Tuesday has broken apart in space, creating a debris field of at least 700 objects in one of the most heavily-trafficked zones in low-Earth orbit. US Space Command, which tracks objects in orbit with a network of radars and optical sensors, confirmed the rocket breakup Thursday. Space Command initially said the event created more than 300 pieces of trackable debris. The military's ground-based radars are capable of tracking objects larger than 10 centimeters (4 inches). Later Thursday, LeoLabs, a commercial space situational awareness company, said its radars detected at least 700 objects attributed to the Chinese rocket. The number of debris fragments could rise to more than 900, LeoLabs said. The culprit is the second stage of China's Long March 6A rocket, which lifted off Tuesday with the first batch of 18 satellites for a planned Chinese megaconstellation that could eventually number thousands of spacecraft. The Long March 6A's second stage apparently disintegrated after placing its payload of 18 satellites into a polar orbit.

Space Command said in a statement it has "observed no immediate threats" and "continues to conduct routine conjunction assessments to support the safety and sustainability of the space domain." According to LeoLabs, radar data indicated the rocket broke apart at an altitude of 503 miles (810 kilometers) at approximately 4:10 pm EDT (20:10 UTC) on Tuesday, around 13-and-a-half hours after it lifted off from northern China. At this altitude, it will take decades or centuries for the wispy effect of aerodynamic drag to pull the debris back into the atmosphere. As the objects drift lower, their orbits will cross paths with SpaceX's Starlink Internet satellites, the International Space Station and other crew spacecraft, and thousands more pieces of orbital debris, putting commercial and government satellites at risk of collision.

An anonymous reader quotes a report from Ars Technica: The past several years have been absolute scorchers, with 2023 being the warmest year ever recorded. And things did not slow down in 2024. As a result, we entered a stretch where every month set a new record as the warmest iteration of that month that we've ever recorded. Last month, that pattern stretched out for a full 12 months, as June of 2024 once again became the warmest June ever recorded. But, despite some exceptional temperatures in July, it fell just short of last July's monthly temperature record, bringing the streak to a close.

Europe's Copernicus system was first to announce that July of 2024 was ever so slightly cooler than July of 2023, missing out on setting a new record by just 0.04 degrees C. So far, none of the other major climate trackers, such as Berkeley Earth or NASA GISS, have come out with data for July. These each have slightly different approaches to tracking temperatures, and, with a margin that small, it's possible we'll see one of them register last month as warmer or statistically indistinguishable. According to the Copernicus system, July 2024 was 0.68 degrees above the average temperature for July from 1991 to 2020. It also included the warmest day ever recorded.

In terms of anomalies, July 2024 also represents the first time in a year that a month was less than 1.5 degrees C above preindustrial temperatures (defined as the average from 1850-1900).

An anonymous reader quotes a report originally published by Business Insider: A Chinese state-backed company has launched its first 18 satellites in its bid to build a vast orbital network aimed at rivaling Starlink, according to local media. The launch on Monday by Shanghai Spacecom Satellite Technology involved 18 satellites and one rocket, per The China Securities Journal, which is run by state news agency Xinhua. According to the outlet, the rocket lifted off from the Taiyuan satellite and missile launch center in Shanxi province.

These satellites mark the first step in the company's effort to create a 15,000-strong network of Low Earth Orbit satellites, which the firm has dubbed the "Thousand Sails Constellation." The company said it plans to reach that final tally by 2030, per The China Securities Journal. Domestic media has widely called the project the Chinese version of Starlink, which runs about 6,000 satellites. Elon Musk has said that he plans to eventually host a network of 42,000 satellites.

The Thousand Sails Constellation, also known as the G60 project, is one of three planned major satellite networks in the country. Each is expected to field 10,000 or more satellites. Most are anticipated to orbit between 200 and 1,200 miles above the Earth's surface, which is also where Starlink satellites are generally found. The three constellations, along with dozens of ambitious space projects from other Chinese firms, have been fueled by a recent push from the central government to loop the private sector into its science and technology goals.

An anonymous reader quotes a report from the New York Times: For weeks, NASA has downplayed problems experienced by Starliner, a Boeing spacecraft that took two astronauts to the International Space Station in June. But on Wednesday, NASA officials admitted that the problems with the spacecraft were more serious than first thought and that the astronauts may not travel home on the Boeing vehicle, after all. The agency is exploring a backup option for the astronauts, Suni Wiliams and Butch Wilmore, to hitch a ride back to Earth on a vehicle built by Boeing's competitor SpaceX instead. Their stay in orbit, which was to be as short as eight days, may extend into next year. "We could take either path," Ken Bowersox, NASA's associate administrator for the space operations mission directorate, said during a news conference on Wednesday. "And reasonable people could pick either path."

NASA and Boeing officials had maintained that the crew that launched with Starliner on its first crewed test flight was not stranded in space. Ms. Williams and Mr. Wilmore have spent two months aboard the orbital outpost while engineers continue to analyze data about the faulty performance of several of the Starliner's thrusters when it approached for docking. Under the contingency plan, a SpaceX Crew Dragon capsule would travel to the space station with two astronauts instead of its planned crew of four. Ms. Williams and Mr. Wilmore would then join as full-time members of the space station crew for a half-year stay, returning on the Crew Dragon around next February. "In the last few weeks, we have decided to make sure we have that capability there, as our community, I would say, got more and more uncomfortable," said Steve Stich, the manager of the commercial crew program at NASA. NASA officials said no decision had been made yet.

Ocean temperatures in the Great Barrier Reef are now the hottest in at least 400 years and are an "existential threat" to the planet's unique natural wonder , according to new scientific research. From a report: Scientists analysed long-lived corals in and around the reef that keep a record of temperature hidden in their skeleton and matched them to modern observations. The research, published in the journal Nature, used climate models to find the extreme temperatures of recent decades could not have happened without the extra greenhouse gases in the atmosphere caused mostly by burning fossil fuels.

The "existential threat" to the reef from the climate crisis was "now realised," the scientists wrote, and without ambitious and rapid cuts to greenhouse gas emissions "we will likely be witness to the demise of one of the Earth's natural wonders." The research comes two weeks after the World Heritage committee decided not to place the reef, which covers an area larger than Italy, on its list of sites "in danger," saying it would consider the question again in 2026.

According to a recent study, SpaceX's new Starlink direct-to-cell (DTC) satellites are nearly five times brighter than traditional Starlinks due to their lower orbit. While these satellites offer the promise of widespread connectivity, their increased brightness poses challenges for astronomical observations, prompting SpaceX to consider applying brightness mitigation techniques. Space.com reports: The higher luminosity of these DTCs compared to regular Starlinks is partly because they circle Earth at just 217 miles (350 kilometers) above the surface, which is lower than traditional Starlink internet satellites, whose altitude is 340 miles (550 kilometers), the study reported. [...] At the time the study was conducted, SpaceX had not yet applied its routine brightness mitigation techniques to the DTCs, such as adjusting their chassis and solar panels to reduce the portion of spacecraft illuminated by the sun, study lead author Anthony Mallama of the IAU Centre for the Protection of Dark and Quiet Skies from Satellite Constellation Interference (IAU-CPS) told Space.com.

SpaceX began applying brightness mitigation techniques to regular Starlinks in 2020, after astronomers voiced serious concerns about the satellites' trails streaking across telescope images, rendering them unusable. Prior to launch, the company now applies a mirror-like dielectric surface to the underside of each Starlink chassis, to help reflect sunlight into space rather than scattering it toward Earth. Post launch, the company adjusts spacecraft chassis and solar panels to further reduce luminosity. Together, these techniques are very effective, reducing Starlink satellites' brightness by a factor of 10, Mallama said. If SpaceX applies these brightness mitigation techniques to the DTCs, which are nearly the same size as the regular Starlinks, the DTCs would still be 2.6 times brighter than their traditional counterparts, Mallama and his colleagues reported in the recent study, which was reviewed internally by IAU-CPS and posted to the preprint server arXiv last month.

However, while DTCs are brighter objects, they move at a faster apparent rate and spend more time in Earth's shadow than regular Starlinks, which would offset some of their negative impact on astronomy observations, the study noted. "I see it as a tradeoff in parameters rather than an absolute better/worse kind of situation," John Barentine, a principal consultant at Arizona-based Dark Sky Consulting who was not involved with the new study, told Space.com.

Scientists studying lunar samples brought back by the Apollo missions have determined that the moon's thin atmosphere is produced largely by meteorite impacts. "Our findings provide a clearer picture of how the moon's surface and atmosphere interact over long timescales, [and] enhance our understanding of space weathering processes," said Dr Nicole Nie, the co-author of the new study based at MIT's department of Earth, atmospheric, and planetary sciences. The Guardian reports: Writing in the journal Science Advances, Nie and her colleagues describe how the lunar atmosphere must be constantly replenished because its atoms are continuously being lost to space, primarily because of the moon's weak gravity, or trapped on the lunar surface. Ultraviolet photons from the sun can rerelease the latter, but the researchers say replenishment of the atmosphere is thought to rely on atoms being released from within lunar minerals -- either via vaporisation by meteorite impacts, or by solar wind sputtering, a process in which charged particles from the sun hit the moon and eject atoms. But which of the two factors dominates had been unclear, with data from Nasa's lunar atmosphere and dust environment explorer, launched in 2013, suggesting both were at play.

Nie and colleagues unpicked the conundrum by studying the different forms, or isotopes, of potassium and rubidium in 10 samples of lunar soil from the Apollo missions. The team say meteorite impacts and solar wind sputtering both favor the release of lighter forms of the elements, but that the actual proportion of heavy to light isotopes that end up in the lunar atmosphere and soil would differ depending on the process. "After measuring the isotopic compositions of lunar soils, we built a mathematical model taking into account various space weathering processes, and solve for the contribution of each of them by matching the measured isotopic compositions," said Nie. The results suggest about 70% of the moon's atmosphere is down to impact vaporization and 30% to solar wind sputtering.

A professor in the University of Chicago's department of geophysical sciences "believes that by intentionally releasing sulfur dioxide into the stratosphere, it would be possible to lower temperatures worldwide," reports the New York Times.

He's not the only one promoting the idea. "Harvard University has a solar geoengineering program that has received grants from Microsoft co-founder Bill Gates, the Alfred P. Sloan Foundation and the William and Flora Hewlett Foundation. It's being studied by the Environmental Defense Fund along with the World Climate Research Program.... But many scientists and environmentalists fear that it could result in unpredictable calamities." Because it would be used in the stratosphere and not limited to a particular area, solar geoengineering could affect the whole world, possibly scrambling natural systems, like creating rain in one arid region while drying out the monsoon season elsewhere. Opponents worry it would distract from the urgent work of transitioning away from fossil fuels. They object to intentionally releasing sulfur dioxide, a pollutant that would eventually move from the stratosphere to ground level, where it can irritate the skin, eyes, nose and throat and can cause respiratory problems. And they fear that once begun, a solar geoengineering program would be difficult to stop...

Keith, a professor in the University of Chicago's department of geophysical sciences, countered that the risks posed by solar geoengineering are well understood, not as severe as portrayed by critics and dwarfed by the potential benefits. If the technique slowed the warming of the planet by even just 1 degree Celsius, or 1.8 degrees Fahrenheit, over the next century, Keith said, it could help prevent millions of heat-related deaths each decade...

Opponents of solar geoengineering cite several main risks. They say it could create a "moral hazard," mistakenly giving people the impression that it is not necessary to rapidly reduce fossil fuel emissions. The second main concern has to do with unintended consequences. "This is a really dangerous path to go down," said Beatrice Rindevall, the chair of the Swedish Society for Nature Conservation, which opposed the experiment. "It could shock the climate system, could alter hydrological cycles and could exacerbate extreme weather and climate instability." And once solar geoengineering began to cool the planet, stopping the effort abruptly could result in a sudden rise in temperatures, a phenomenon known as "termination shock." The planet could experience "potentially massive temperature rise in an unprepared world over a matter of five to 10 years, hitting the Earth's climate with something that it probably hasn't seen since the dinosaur-killing impactor," Pierrehumbert said. On top of all this, there are fears about rogue actors using solar geoengineering and concerns that the technology could be weaponized. Not to mention the fact that sulfur dioxide can harm human health.

Keith is adamant that those fears are overblown. And while there would be some additional air pollution, he claims the risk is negligible compared to the benefits.
The opposition is making it hard to even conduct tests, according to the article — like when Keith "wanted to release a few pounds of mineral dust at an altitude of roughly 20 kilometers and track how the dust behaved as it floated across the sky."

The experiment was called off after opposition from numerous groups — including Greta Thunberg and an organization representing Indigenous people who felt the experiment was disrespecting nature.

The planet Mercury could have "a layer of diamonds," reports CNN, citing new research suggesting that about 310 miles (500 kilometers) below the surface...could be a layer of diamonds 11 miles (18 kilometers) thick.

And the study's co-author believes lava might carry some of those diamonds up to the surface: The diamonds might have formed soon after Mercury itself coalesced into a planet about 4.5 billion years ago from a swirling cloud of dust and gas, in the crucible of a high-pressure, high-temperature environment. At this time, the fledgling planet is believed to have had a crust of graphite, floating over a deep magma ocean.

A team of researchers recreated that searing environment in an experiment, with a machine called an anvil press that's normally used to study how materials behave under extreme pressure but also for the production of synthetic diamonds. "It's a huge press, which enables us to subject tiny samples at the same high pressure and high temperature that we would expect deep inside the mantle of Mercury, at the boundary between the mantle and the core," said Bernard Charlier, head of the department of geology at the University of Liège in Belgium and a coauthor of a study reporting the findings.

The team inserted a synthetic mixture of elements — including silicon, titanium, magnesium and aluminum — inside a graphite capsule, mimicking the theorized composition of Mercury's interior in its early days. The researchers then subjected the capsule to pressures almost 70,000 times greater than those found on Earth's surface and temperatures up to 2,000 degrees Celsius (3,630 degrees Fahrenheit), replicating the conditions likely found near Mercury's core billions of years ago.

After the sample melted, the scientists looked at changes in the chemistry and minerals under an electron microscope and noted that the graphite had turned into diamond crystals.
The researchers believe this mechanism "can not only give us more insight into the secrets hidden below Mercury's surface, but on planetary evolution and the internal structure of exoplanets with similar characteristics."