Dartmouth researchers propose that dark matter originated from massless, light-like particles in the early universe that rapidly condensed into massive particles through a spin-based interaction. Phys.Org reports: [T]he study authors write that their theory is distinct because it can be tested using existing observational data. The extremely low-energy particles they suggest make up dark matter would have a unique signature on the cosmic microwave background, or CMB, the leftover radiation from the Big Bang that fills all of the universe. "Dark matter started its life as near-massless relativistic particles, almost like light," says Robert Caldwell, a professor of physics and astronomy and the paper's senior author. "That's totally antithetical to what dark matter is thought to be -- it is cold lumps that give galaxies their mass," Caldwell says. "Our theory tries to explain how it went from being light to being lumps." Hot, fast-moving particles dominated the cosmos after the burst of energy known as the Big Bang that scientists believe triggered the universe's expansion 13.7 billion years ago. These particles were similar to photons, the massless particles that are the basic energy, or quanta, of light. It was in this chaos that extremely large numbers of these particles bonded to each other, according to Caldwell and Guanming Liang, the study's first author and a Dartmouth senior. They theorize that these massless particles were pulled together by the opposing directions of their spin, like the attraction between the north and south poles of magnets. As the particles cooled, Caldwell and Liang say, an imbalance in the particles' spins caused their energy to plummet, like steam rapidly cooling into water. The outcome was the cold, heavy particles that scientists think constitute dark matter. The findings have been published in the journal Physical Review Letters.

Read more of this story at Slashdot.

18 years ago Slashdot covered the creation of Spaceport America. Today Space.com hails it as "the first purpose-built commercial spaceport in the world." But engineer/executive director Scott McLaughlin has plans to grow even more. Already home to an array of commercial space industry tenants, such as Virgin Galactic, SpinLaunch, Up Aerospace, and Prismatic, Spaceport America is a "rocket-friendly environment of 6,000 square miles of restricted airspace, low population density, a 12,000-foot by 200-foot runway, vertical launch complexes, and about 340 days of sunshine and low humidity," the organization boasts on its website... Space.com: What changes do you see that make Spaceport America even more viable today? McLaughlin: I think opening ourselves up to doing different kinds of work. We're more like a civilian test range now. We've got high-altitude UAVs [Unmanned Aerial Vehicles]. We're willing to do engine production. We believe we're about to sign a data center, one that's able to provide services to our customers who want low-latency, artificial intelligence, or high-powered computing. You'll be able to rent some virtual machines and do your own thing and have it be instantaneous at the spaceport. So I think being more broadminded about what we can do at the spaceport is helping generate customers and revenue... Our goal is to see Virgin Galactic fly in a year or so, hopefully flying twice a week, and that will have a big impact on the spaceport... [W]e're trying to be open-minded as we're partnered with White Sands Missile Range to use that airspace. We're even looking at things like an electromagnetic pulse facility. It's a customer that I can't identify yet... We are working on a "reentry" license too. We recently discussed this with specialists and we think we have a site relatively close to the spaceport that's flat and free of mesquite bushes and such, so we can do capsule return and other types of return. And of course we have the runway. So I'd think we'd be the only spaceport that does vertical and horizontal launch and reentry.... We're never going to have the throughput that the Cape in Florida has. But we'll be a good alternative especially if you're going to do a small to medium-sized launch, and you need to do it quickly, and perhaps do it more securely than you would if you were to fly over water. That's why the Department of Defense is showing interest in the inland spaceport.

Read more of this story at Slashdot.

There's 9,000 satellites circling the earth, the Guardian points out, with projections over over 60,000 by 2040. But "A new study shows that the emissions from expired satellites, as they fall to Earth and burn up, will be significant in future years, with implications for ozone hole recovery and climate." Most old satellites are disposed of by reducing their altitude and letting them burn up as they fall, releasing pollution into Earth's atmosphere such as aerosolised aluminium. To understand the impact of these growing emissions from expired satellites, researchers simulated the effects associated with an annual release of 10,000 tonnes of aluminium oxide by 2040 (the amount estimated to be released from disposal of 3,000 satellites a year, assuming a fleet of 60,000 satellites). The results, which are published in Journal of Geophysical Research Atmospheres, show that the re-entry material will accumulate at high latitudes and could result in temperature anomalies of up to 1.5C in the middle to upper atmosphere, reduction of wind speeds and ozone depletion, which could jeopardise ozone hole recovery. "At present, impacts on the middle and the upper atmosphere are small," the researchers write, "but have the potential to increase." They argue that "to shed light upon the potential climate impacts of increased satellite reentry," an "expanded effort, including observations and modeling is needed." Thanks to long-time Slashdot reader AmiMoJo for sharing the article.

Read more of this story at Slashdot.

Slashdot reader sciencehabit shares this excerpt from a new article in Science magazine: At first, astronomers knew of only one cosmic scenario that fit the bill for the violent formation of "jewelry shop" elements [gold and sliver]: the collision of two ultra-dense stellar corpses called neutron stars. Now, a second has stepped onto the scene. As they report this week in The Astrophysical Journal Letters, researchers have discovered signatures of this heavy element formation — called the r-process — in a giant flare first detected from a highly magnetic neutron star in 2004. The flare, which released more energy than our Sun does in a million years as it spewed electrically charged material, has remained shrouded in mystery since its discovery 20 years ago. Researchers quickly traced the outburst to a nearby magnetar, a special breed of neutron star whose magnetic fields are trillions times stronger than Earth's. But ten minutes after the massive flare, a second, fainter signal inexplicably came from the same star. More r-process sources may still be looming in the dark. The new study accounts for about 10% of the Milky Way's heavy elements, suggesting that astronomers will have to scour the cosmos for even more places where the r-process is hiding. One potential spot is a rare type of supernova that births rapidly rotating neutron stars, says says Anirudh Patel, the new study's lead author and an astronomer at Columbia University. He hopes that with more observations, astronomers will be able to sharpen that picture.... "It's humbling to realize that these were made in such extreme astrophysical environments."

Read more of this story at Slashdot.

Astronomers may have found the best candidate yet for the elusive Planet Nine: a mysterious object in infrared sky surveys taken 23 years apart that appears to be more massive than Neptune and about 700 times farther from the sun than Earth. Space.com reports: [A] team led by astronomer Terry Long Phan of the National Tsing Hua University in Taiwan has delved into the archives of two far-infrared all-sky surveys in search of Planet Nine -- and incredibly, they have found something that could possibly be Planet Nine. The Infrared Astronomy Satellite, IRAS, launched in 1983 and surveyed the universe for almost a year before being decommissioned. Then, in 2006, the Japanese Aerospace Exploration Agency (JAXA) launched AKARI, another infrared astronomy satellite that was active between 2006 and 2011. Phan's team were looking for objects that appeared in IRAS's database, then appeared to have moved by the time AKARI took a look. The amount of movement on the sky would be tiny -- about three arcminutes per year at a distance of approximately 700 astronomical units (AU). One arcminute is 1/60 of an angular degree. But there's an extra motion that Phan's team had to account for. As the Earth orbits the sun, our view of the position of very distant objects changes slightly in an effect called parallax. It is the same phenomenon as when you hold your index finger up to your face, close one eye and look at your finger, and then switch eyes -- your finger appears to move as a result of you looking at it from a slightly different position. Planet Nine would appear to move on the sky because of parallax as Earth moves around the sun. On any particular day, it might seem to be in one position, then six months later when Earth is on the other side of the sun, it would shift to another position, perhaps by 10 to 15 arcminutes -- then, six months after that, it would seem to shift back to its original position. To remove the effects of parallax, Phan's team searched for Planet Nine on the same date every year in the AKARI data, because on any given date it would appear in the same place, with zero parallax shift, every year. They then also scrutinized each candidate object that their search threw up on an hourly basis. If a candidate is a fast-moving, nearby object, then its motion would be detectable from hour to hour, and could therefore be ruled out. This careful search led Phan's team to a single object, a tiny dot in the infrared data. It appears in one position in IRAS's 1983 image, though it was not in that position when AKARI looked. However, there is an object seen by AKARI in a position 47.4 arcminutes away that isn't there in the IRAS imagery, and it is within the range that Planet Nine could have traveled in the intervening time. In other words, this object has moved a little further along its orbit around the sun in the 23 or more years between IRAS and AKARI. The knowledge of its motion in that intervening time is not sufficient to be able to extrapolate the object's full orbit, therefore it's not yet possible to say for certain whether this is Planet Nine. First, astronomers need to recover it in more up-to-date imagery. [...] Based on the candidate object's brightness in the IRAS and AKARI images, Phan estimates that the object, if it really is Planet Nine, must be more massive than Neptune. This came as a surprise, because he and his team were searching for a super-Earth-size body. Previous surveys by NASA's Wide-field Infrared Survey Explorer (WISE) have ruled out any Jupiter-size planets out to 256,000 AU, and any Saturn-size planets out to 10,000 AU, but a smaller Neptune or Uranus-size world could still have gone undetected. Phan told Space.com that he had searched for his candidate in the WISE data, "but no convincing counterpart was found because it has moved since the 2006 position," and without knowing its orbit more accurately, we can't say where it has moved to. "Once we know the position of the candidate, a longer exposure with the current large optical telescopes can detect it," Phan told Space.com. "However, the follow-up observations with optical telescopes still need to cover about three square degrees because Planet Nine would have moved from the position where AKARI detected it in 2006. This is doable with a camera that has a large field of view, such as the Dark Energy Camera, which has a field of view of three square degrees on the Blanco four-meter telescope [in Chile]."

Read more of this story at Slashdot.

An anonymous reader shares a report: In the nearly two months since former Google chief executive Eric Schmidt acquired Relativity Space, the billionaire has not said much publicly about his plans for the launch company. However, his intentions for Relativity now appear to be increasingly clear: He wants to have the capability to launch a significant amount of computing infrastructure into space. We know this because Schmidt appeared before the House Committee on Energy and Commerce during a hearing in April, speaking on the future of AI and US competitiveness. Among the topics raised then was the need for more electricity -- both renewable and non-renewable -- to power data centers that will facilitate the computing needs for AI development and applications. Schmidt noted that an average nuclear power plant in the United States generates 1 gigawatt of power. "People are planning 10 gigawatt data centers," Schmidt said. "Gives you a sense of how big this crisis is. Many people think that the energy demand for our industry will go from 3 percent to 99 percent of total generation. One of the estimates that I think is most likely is that data centers will require an additional 29 gigawatts of power by 2027, and 67 more gigawatts by 2030. These things are industrial at a scale that I have never seen in my life."

Read more of this story at Slashdot.

An invisible molecular cloud that could shed light on how stars and planets form has been detected surprisingly close to Earth. From a report: Named Eos after the Greek goddess of the dawn, the cloud of gas would appear huge in the night sky if visible to the naked eye. It measures roughly 40 moons in width and has a weight about 3,400 times the mass of the sun, researchers reported in a study published Monday in the journal Nature Astronomy. "In astronomy, seeing the previously unseen usually means peering deeper with ever more sensitive telescopes -- detecting those smaller planets ... those more distant galaxies," said study coauthor Thomas Haworth, an astrophysicist at Queen Mary University of London. "This thing was pretty much in our cosmic backyard, and we've just missed it," he added. Molecular clouds are composed of gas and dust from which hydrogen and carbon monoxide molecules can form. Dense clumps within these clouds can collapse to form young stars. The article clarifies that Eos is 300 light-years away, which to be sure, is closer than any of the molecular clouds that we've known about previously.

Read more of this story at Slashdot.