Amateur astronomer and YouTuber Alberto Caballero, one of the founders of The Exoplanets Channel, has found a small amount of evidence for a source of the notorious Wow! signal. Phys.Org reports: Back in 1977, astronomers working with the Big Ear Radio Telescope -- at the time, situated in Delaware, Ohio -- recorded a unique signal from somewhere in space. It was so strong and unusual that one of the workers on the team, Jerry Ehman, famously scrawled the word Wow! on the printout. Despite years of work and many man hours, no one has ever been able to trace the source of the signal or explain the strong, unique signal, which lasted for all of 72 seconds. Since that time, many people have suggested the only explanation for such a strong and unique signal is extraterrestrial intelligent life.

In this new effort, Caballero reasoned that if the source was some other life form, it would likely be living on an exoplanet -- and if that were the case, it would stand to reason that such a life form might be living on a planet similar to Earth -- one circling its own sun-like star. Pursuing this logic, Caballero began searching the publicly available Gaia database for just such a star. The Gaia database has been assembled by a team working at the Gaia observatory run by the European Space Agency. Launched back in 2013, the project has worked steadily on assembling the best map of the night sky ever created. To date, the team has mapped approximately 1.3 billion stars. In studying his search results, Caballero found what appears to fit the bill -- a star (2MASS 19281982-2640123) that is very nearly a mirror image of the sun -- and is located in the part of the sky where the Wow! signal originated. He notes that there are other possible candidates in the area but suggests his candidate might provide the best launching point for a new research effort by astronomers who have the tools to look for exoplanets. Caballero shared his findings via arXiv.

Ars Technica glimpsed a possible future at the Johns Hopkins University Applied Physics Laboratory: a solar simulator "that can shine with the intensity of 20 Suns..."

"They think it could be the key to interstellar exploration." "It's really easy for someone to dismiss the idea and say, 'On the back of an envelope, it looks great, but if you actually build it, you're never going to get those theoretical numbers,'" says Benkoski, a materials scientist at the Applied Physics Laboratory and the leader of the team working on a solar thermal propulsion system. "What this is showing is that solar thermal propulsion is not just a fantasy. It could actually work."

In 2019, NASA tapped the Applied Physics Laboratory to study concepts for a dedicated interstellar mission. At the end of next year, the team will submit its research to the National Academies of Sciences, Engineering, and Medicine's Heliophysics decadal survey, which determines Sun-related science priorities for the next 10 years... In mid-November, [APL's] Interstellar Probe researchers met online for a weeklong conference to share updates as the study enters its final year. At the conference, teams from APL and NASA shared the results of their work on solar thermal propulsion, which they believe is the fastest way to get a probe into interstellar space.

The idea is to power a rocket engine with heat from the Sun, rather than combustion. According to Benkoski's calculations, this engine would be around three times more efficient than the best conventional chemical engines available today. "From a physics standpoint, it's hard for me to imagine anything that's going to beat solar thermal propulsion in terms of efficiency," says Benkoski. "But can you keep it from exploding...?" If the interstellar probe makes a close pass by the Sun and pushes hydrogen into its shield's vasculature, the hydrogen will expand and explode from a nozzle at the end of the pipe. The heat shield will generate thrust. It's simple in theory but incredibly hard in practice.

A solar thermal rocket is only effective if it can pull off an Oberth maneuver, an orbital-mechanics hack that turns the Sun into a giant slingshot. The Sun's gravity acts like a force multiplier that dramatically increases the craft's speed if a spacecraft fires its engines as it loops around the star... The big takeaway from his research, says Dean Cheikh, a materials technologist at NASAâ(TM)s Jet Propulsion Laboratory, is there's a lot of testing that needs to be done on heat shield materials before a solar thermal rocket is sent around the Sun. But it's not a deal-breaker. "Additive manufacturing is a key component of this, and we couldn't do that 20 years ago. Now I can 3D-print metal in the lab."

Thelasko shares a report from Forbes: In a major milestone, the New Zealand-based launch company Rocket Lab has successfully recovered an orbital-class rocket after parachuting it back to Earth from near-space -- only the second company in history ever to do so. Yesterday, Thursday, November 20 at 9.20 P.M. Eastern Time, the company's two-stage Electron rocket lifted off from the company's launch site on the Mahia Peninsula on New Zealand's North Island.

Named 'Return to Sender', the mission lofted 30 satellites into a sun-synchronous orbit 500 kilometers above the surface of Earth -- the most satellites ever flown on an Electron rocket. Of the satellites launched, 24 were small communications satellites called "SpaceBees" from the California-based company Swarm Technologies. The others included a space junk removal test, a maritime observation satellite, and an earthquake investigation satellite -- while a small gnome also made its way to space for charity. The launch was especially notable, however, for Rocket Lab's recovery efforts. Shortly after the launch, the first stage of the rocket descended back to Earth under parachute, falling into the ocean where it was then recovered by a waiting ship several hours later. Rocket Lab's plan is to catch its smaller rockets with a helicopter as they fall from space under a parachute. At some point, possibly next year, the first helicopter recovery will be attempted.

"First, the company says it wants to perform a few more splashdown tests in the ocean like this one, to check everything is nominal," reports Forbes. "If all goes well, however, SpaceX quite soon might not be the only private company that's able to launch, recover, and re-launch its own rockets."

Amanda Jane Hughes, Lecturer, Department of Mechanical, Materials and Aerospace Engineering at University of Liverpool Stefania, and Soldini Lecturer in Aerospace Engineering at University of Liverpool, write: A space-based solar power station could orbit to face the Sun 24 hours a day. The Earth's atmosphere also absorbs and reflects some of the Sun's light, so solar cells above the atmosphere will receive more sunlight and produce more energy. But one of the key challenges to overcome is how to assemble, launch and deploy such large structures. A single solar power station may have to be as much as 10 kilometres squared in area -- equivalent to 1,400 football pitches. Using lightweight materials will also be critical, as the biggest expense will be the cost of launching the station into space on a rocket. One proposed solution is to develop a swarm of thousands of smaller satellites that will come together and configure to form a single, large solar generator. In 2017, researchers at the California Institute of Technology outlined designs for a modular power station, consisting of thousands of ultralight solar cell tiles. They also demonstrated a prototype tile weighing just 280 grams per square metre, similar to the weight of card.

Recently, developments in manufacturing, such as 3D printing, are also being looked at for this application. At the University of Liverpool, we are exploring new manufacturing techniques for printing ultralight solar cells on to solar sails. A solar sail is a foldable, lightweight and highly reflective membrane capable of harnessing the effect of the Sun's radiation pressure to propel a spacecraft forward without fuel. We are exploring how to embed solar cells on solar sail structures to create large, fuel-free solar power stations. These methods would enable us to construct the power stations in space. Indeed, it could one day be possible to manufacture and deploy units in space from the International Space Station or the future lunar gateway station that will orbit the Moon. Such devices could in fact help provide power on the Moon. The possibilities don't end there. While we are currently reliant on materials from Earth to build power stations, scientists are also considering using resources from space for manufacturing, such as materials found on the Moon.

Researchers with NASA's New Horizons say they've finally been able to determine if space is truly black. The group has posted their work online, and it will soon appear ini the Astrophysical Journal. NPR reports: New Horizons was originally designed to explore Pluto, but after whizzing past the dwarf planet in 2015, the intrepid spacecraft just kept going. It's now more than four billion miles from home -- nearly 50 times farther away from the Sun than the Earth is. That's important because it means the spacecraft is far from major sources of light contamination that make it impossible to detect any tiny light signal from the universe itself. Around Earth and the inner solar system, for example, space is filled with dust particles that get lit up by the Sun, creating a diffuse glow over the entire sky. But that dust isn't a problem out where New Horizons is. Plus, out there, the sunlight is much weaker.

To try to detect the faint glow of the universe, researchers went through images taken by the spacecraft's simple telescope and camera and looked for ones that were incredibly boring. Then they processed these images to remove all known sources of visible light. Once they'd subtracted out the light from stars, plus scattered light from the Milky Way and any stray light that might be a result of camera quirks, they were left with light coming in from beyond our own galaxy. They then went a step further still, subtracting out light that they could attribute to all the galaxies thought to be out there. And it turns out, once that was done, there was still plenty of unexplained light.

In fact, the amount of light coming from mysterious sources was about equal to all the light coming in from the known galaxies, says Marc Postman, an astronomer with the Space Telescope Science Institute in Baltimore, Maryland. So maybe there are unrecognized galaxies out there, he says, "or some other source of light that we don't yet know what it is." [...] So where does the light come from? Perhaps, he says, there are far more small, faint dwarf galaxies and other faint regions on the outskirts of galaxies that instruments like the Hubble Space Telescope can't detect and so scientists just aren't aware of them. Or, maybe there's more dust out there interfering with the measurements than scientists expected. Or perhaps there's a more exotic explanation -- some unknown phenomenon out in the universe that creates visible light. It's even possible it's something associated with dark matter, a mysterious form of matter that exerts a gravitational pull on visible matter but has never been seen directly.

A group of astronomers from The University of Texas at Austin has revived an idea shelved by NASA to build a lunar liquid-mirror telescope on the moon to study the first stars in the universe. "The team, led by NASA Hubble Fellow Anna Schauer, will publish their results in an upcoming issue of The Astrophysical Journal," reports Phys.Org. From the report: These first stars formed about 13 billion years ago. They are unique, born out of a mix of hydrogen and helium gasses, and likely tens or 100 times larger than the Sun. New calculations by Schauer show that a previously proposed facility, a liquid mirror telescope that would operate from the surface of the Moon, could study these stars. Proposed in 2008 by a team led by Roger Angel of The University of Arizona, this facility was called the Lunar Liquid-Mirror Telescope (LLMT). NASA had done an analysis on this proposed facility a decade ago, but decided not to pursue the project. According to Niv Drory, a senior research scientist with UT Austin's McDonald Observatory, the supporting science on the earliest stars did not exist at that point. "This telescope is perfect for that problem," he said.

The proposed lunar liquid-mirror telescope, which Schauer has nicknamed the "Ultimately Large Telescope," would have a mirror 100 meters in diameter. It would operate autonomously from the lunar surface, receiving power from a solar power collection station on the Moon, and relaying data to satellite in lunar orbit. Rather than coated glass, the telescope's mirror would be made of liquid, as it's lighter, and thus cheaper, to transport to the Moon. The telescope's mirror would be a spinning vat of liquid, topped by a metallic -- and thus reflective -- liquid. (Previous liquid mirror telescopes have used mercury.) The vat would spin continuously, to keep the surface of the liquid in the correct paraboloid shape to work as a mirror. The telescope would be stationary, situated inside a crater at the Moon's north or south pole. To study the first stars, it would stare at the same patch of sky continuously, to collect as much light from them as possible. The team is proposing that the astronomical community revisit the shelved plan for a lunar liquid-mirror telescope, as a way to study these first stars in the universe.

An anonymous reader shares a report: Earthlings are lucky to live near a relatively stable Sun, which has enabled life on our planet to emerge and thrive over the past four billion years. While many worlds in our galaxy might contain the right ingredients to support life, though, a lot of them could be stuck with a more volatile star that prevents them from becoming -- or remaining -- habitable. To get a better grip on which types of star systems might be most likely to host aliens, a pair of scientists at New York University Abu Dhabi (NYUAD) Center for Space Science have observed space weather around nearly 500 stars, according to a study published on Sunday in the journal Monthly Notices of Royal Astronomical Society: Letters. The results suggest that planets subjected to occasional but intense flares are probably more hospitable to life than worlds that receive a constant flux of radiation and low-energy flares, which blows their protective atmospheres away. Planetary habitability "is one of the most important concepts in exoplanet science" and "is defined as the zone around a star in which a planet is able to sustain liquid water on its surface," said research scientist Dimitra Atri and graduate student Shane Carberry Mogan, both at NYUAD, in the study. "While this approach is useful to identify potentially hospitable planets around stars, it fails to take into account the damaging aspect of stellar activity on such planets," the pair added. "The main goal of this paper is to understand how stellar luminosity and flares can lead to atmospheric escape on [habitable zone] planets on long time-scales and how these losses impact planetary habitability."

Long-time Slashdot reader fahrbot-bot shared this report from the New York Times: A decade ago, a band of astronomers set out to investigate one of the oldest questions taunting philosophers, scientists, priests, astronomers, mystics and the rest of the human race: How many more Earths are out there, if any? How many far-flung planets exist that could harbor life as we know it?

Their tool was the Kepler spacecraft, which was launched in March 2009 on a three-and-a-half year mission to monitor 150,000 stars in a patch of sky in the Milky Way. It looked for tiny dips in starlight caused by an exoplanet passing in front of its home star. "It's not E.T., but it's E.T.'s home," said William Borucki when the mission was launched in March 2009. It was Dr. Borucki, an astronomer now retired from NASA's Ames Research Center, who dreamed up the project and spent two decades convincing NASA to do it. Before the spacecraft finally gave out in 2018, it had discovered more than 4,000 candidate worlds among those stars. So far, none have shown any sign of life or habitation. (Granted, they are very far away and hard to study.) Extrapolated, that figure suggests that there are billions of exoplanets in the Milky Way galaxy. But how many of those are potentially habitable?

After crunching Kepler's data for two years, a team of 44 astronomers led by Steve Bryson of NASA Ames has landed on what they say is the definitive answer, at least for now. Their paper has been accepted for publication in the Astronomical Journal... The team calculated that at least one-third, and perhaps as many as 90 percent, of stars similar in mass and brightness to our sun have rocks like Earth in their habitable zones, with the range reflecting the researchers' confidence in their various methods and assumptions. That is no small bonanza, however you look at it.

According to NASA estimates there are at least 100 billion stars in the Milky Way, of which about 4 billion are sunlike. If only 7 percent of those stars have habitable planets — a seriously conservative estimate — there could be as many as 300 million potentially habitable Earths out there in the whole Milky Way alone.

On average, the astronomers calculated, the nearest such planet should be about 20 light-years away, and there should be four of them within 30 light-years or so of the sun...
"The new result means that the galaxy is at least twice as fertile as estimated in one of the first analyses of Kepler data, in 2013."

"Joe Biden, the projected winner of the U.S. presidency, will move to restore dozens of environmental safeguards President Donald Trump abolished," reports the Washington Post, "and launch the boldest climate change plan of any president in history."

destinyland shares their report: While some of Biden's most sweeping programs will encounter stiff resistance from Senate Republicans and conservative attorneys general, the United States is poised to make a 180-degree turn on climate change and conservation policy. Biden's team already has plans on how it will restrict oil and gas drilling on public lands and waters; ratchet up federal mileage standards for cars and SUVs; block pipelines that transport fossil fuels across the country; provide federal incentives to develop renewable power; and mobilize other nations to make deeper cuts in their own carbon emissions... Biden has vowed to eliminate carbon emissions from the electric sector by 2035 and spend $2 trillion on investments ranging from weatherizing homes to developing a nationwide network of charging stations for electric vehicles.

That massive investment plan stands a chance only if his party wins two Senate runoff races in Georgia in January; otherwise, he would have to rely on a combination of executive actions and more-modest congressional deals to advance his agenda.

Still, a number of factors make it easier to enact more-ambitious climate policies than even four years ago. Roughly 10% of the globe has warmed by 2 degrees Celsius (3.6 degrees Fahrenheit), a temperature rise the world has pledged to avoid. The price of solar and wind power has dropped, the coal industry has shrunk, and Americans increasingly connect the disasters they're experiencing in real time — including more-intense wildfires, hurricanes and droughts — with global warming. Biden has made the argument that curbing carbon will produce high-paying jobs while protecting the planet...

Some of the new administration's rules could be challenged in federal court, which have a number of Trump appointees on the bench. But even some conservative activists said that Biden could enact enduring policies, whether by partnering with Congress or through regulation... The new administration may be able to broker compromises with key industries that have experienced regulatory whiplash in the past decade, including the auto industry and power sector, while offering tax breaks for renewable energy that remain popular with both parties. And Biden can rebuild diplomatic alliances that will spur foreign countries to pursue more-ambitious carbon reductions...

Biden's advisers have said that they plan to elevate climate change as a priority in departments that have not always treated it as one, including the Transportation, State and Treasury departments. It will influence key appointments, affecting everything from overseas banking and military bases to domestic roads and farms.... Biden's pledge to achieve a carbon-free U.S. power sector within 15 years would mean the closing or revamping of nearly every coal- and gas-fired power plant around the country, and the construction of an unprecedented number of new wind turbines and solar farms. On top of that, engineers still need to devise a better way of storing energy when the sun is not shining or the wind is not blowing.

"If I were advising Biden on energy, my first three priorities would be storage, storage and storage," said Sen. Angus King, I-Maine, who worked in the alternative energy businesses before running for office.

Here's a good sign for alien hunters: More than 300 million worlds with similar conditions to Earth are scattered throughout the Milky Way galaxy. A new analysis [PDF] concludes that roughly half of the galaxy's sunlike stars host rocky worlds in habitable zones where liquid water could pool or flow over the planets' surfaces. From a report: "This is the science result we've all been waiting for," says Natalie Batalha, an astronomer with the University of California, Santa Cruz, who worked on the new study. The finding, which has been accepted for publication in the Astronomical Journal, pins down a crucial number in the Drake Equation. Devised by my father Frank Drake in 1961, the equation sets up a framework for calculating the number of detectable civilizations in the Milky Way. Now the first few variables in the formula -- including the rate of sunlike star formation, the fraction of those stars with planets, and the number of habitable worlds per stellar system -- are known. The number of sunlike stars with worlds similar to Earth "could have been one in a thousand, or one in a million -- nobody really knew," says Seth Shostak, an astronomer at the Search for Extraterrestrial Intelligence (SETI) Institute who was not involved with the new study.

Astronomers estimated the number of these planets using data from NASA's planet-hunting Kepler spacecraft. For nine years, Kepler stared at the stars and watched for the brief twinkles produced when orbiting planets blot out a portion of their star's light. By the end of its mission in 2018, Kepler had spotted some 2,800 exoplanets -- many of them nothing like the worlds orbiting our sun. But Kepler's primary goal was always to determine how common planets like Earth are. The calculation required help from the European Space Agency's Gaia spacecraft, which monitors stars across the galaxy. With Gaia's observations in hand, scientists were finally able to determine that the Milky Way is populated by hundreds of millions of Earth-size planets orbiting sunlike stars -- and that the nearest one is probably within 20 light-years of the solar system.

Most clocks are handled automatically by computers, points out Tora (Slashdot reader #65,882). So in lieu of daylight saving time, "what about shifting time each month, rather than twice a year?"

On Medium developer Brandon Gillespie offers the details of "Universal Solar Time." The clock is adjusted up by 10 minutes every month for the first six months, and then down by 10 minutes in the same manner, and can be offset by your timezone. The computerized systems can handle the time shift the same on the 1st...just like they currently do twice a year.

The benefit of such an automated system is the day cycle stays perceptibly the same — the sun is up roughly at the same period each day for any given month. While there are many challenges to such a system, such as what to do with all of the analog clocks, the advantages of a system like this should give all of the positive benefits of Daylight Savings, without the negative impact on a person's day.

"Its that time of year again," writes long-time Slashdot reader rufey: Millions of people around the world will be adjusting (or have already adjusted) their clocks... Over the years it is apparent that most people who have spoken about the twice-yearly clock change oppose it.

So I ask, why are we still changing clocks in the year 2020?
Long-time Slashdot reader thegreatbob believes the answer is: inertia. Personally, I am less opposed, and much more indifferent to its continued existence. One thing (arguably good) that it does do is provide distinct, specific temporal reference points that the gradual changing of seasons does not, by forcing people to take some sort of irregular action.

Do I think this in any way helps cancel out the harm caused by upsetting the sleep cycles of a huge portion of the population? Absolutely not.
But Slashdot reader Anonymouse Cowtard argues they're grateful for the time change — because "I was sick of the sun waking me at 5 a.m."

Since it is that time of year again, share your own thoughts in the comments.

And why do we keep setting our clocks back an hour?

NASA's Mars 2020 Perseverance rover mission has logged a lot of flight miles since being lofted skyward on July 30 -- 146.3 million miles (235.4 million kilometers) to be exact. Turns out that is exactly the same distance it has to go before the spacecraft hits the Red Planet's atmosphere like a 11,900 mph (19,000 kph) freight train on Feb. 18, 2021. From a report: "At 1:40 p.m. Pacific Time today, our spacecraft will have just as many miles in its metaphorical rearview mirror as it will out its metaphorical windshield," said Julie Kangas, a navigator working on the Perseverance rover mission at NASA's Jet Propulsion Laboratory in Southern California. "While I don't think there will be cake, especially since most of us are working from home, it's still a pretty neat milestone. Next stop, Jezero Crater." The Sun's gravitational influence plays a significant role in shaping not just spacecraft trajectories to Mars (as well as to everywhere else in the solar system), but also the relative movement of the two planets. So Perseverance's route to the Red Planet follows a curved trajectory rather than an arrow-straight path.

"Although we're halfway into the distance we need to travel to Mars, the rover is not halfway between the two worlds," Kangas explained. "In straight-line distance, Earth is 26.6 million miles [42.7 million kilometers] behind Perseverance and Mars is 17.9 million miles [28.8 million kilometers] in front." At the current distance, it takes 2 minutes, 22 seconds for a transmission to travel from mission controllers at JPL via the Deep Space Network to the spacecraft. By time of landing, Perseverance will have covered 292.5 million miles (470.8 million kilometers), and Mars will be about 130 million miles (209 million kilometers) away from Earth; at that point, a transmission will take about 11.5 minutes to reach the spacecraft.

Windows Central reports: Microsoft is preparing a major OS update for Windows 10 in 2021 that sources say will bring with it a significant design refresh to the Windows UI. I'm told that Microsoft is planning to update many top-level user interfaces such as the Start menu, Action Center, and even File Explorer, with refreshed modern designs, better animations, and new features. This UI project is codenamed "Sun Valley" internally and is expected to ship as part of the Windows 10 "Cobalt" release scheduled for the holiday 2021 season. Internal documentation describes the project as "reinvigorating" and modernizing the Windows desktop experience to keep up with customer expectation in a world driven by other modern and lightweight platforms.

Windows 10 has remained much the same these last few years, with little to no changes in its design or feature set. Many other platforms on the market have gone through entire redesigns or UI refreshes in the last five years, and while Windows 10 has gone through minor design iterations with the introduction of Fluent Design, we've not seen a significant refresh or rethinking of its UI. The Sun Valley project appears to be spearheaded by the Windows Devices and Experiences team, lead by Chief Product Officer Panos Panay, who took charge of said division back in February. Microsoft announced in May that the company would be "reinvesting" in Windows 10 in the 2021 timeframe, and my sources say that Sun Valley is the result of that reinvestment.

Using NASA's Chandra X-ray Observatory, astronomers have discovered that "gravitational redshift" exists in two stars orbiting each other in our galaxy about 29,000 light years (200,000 trillion miles) away from Earth. Gravitational redshifts, where light is shifted to redder colors because of gravity, "have tangible impacts on modern life, as scientists and engineers must take them into account to enable accurate positions for GPS," reports Phys.Org. From the report: The intriguing system known as 4U 1916-053 contains two stars in a remarkably close orbit. One is the core of a star that has had its outer layers stripped away, leaving a star that is much denser than the Sun. The other is a neutron star, an even denser object created when a massive star collapses in a supernova explosion. The neutron star (grey) is shown in this artist's impression at the center of a disk of hot gas pulled away from its companion (white star on left). These two compact stars are only about 215,000 miles apart, roughly the distance between the Earth and the Moon. While the Moon orbits our planet once a month, the dense companion star in 4U 1916-053 whips around the neutron star and completes a full orbit in only 50 minutes.

In the new work on 4U 1916-053, the team analyzed X-ray spectra -- that is, the amounts of X-rays at different wavelengths -- from Chandra. They found the characteristic signature of the absorption of X-ray light by iron and silicon in the spectra. In three separate observations with Chandra, the data show a sharp drop in the detected amount of X-rays close to the wavelengths where the iron or silicon atoms are expected to absorb the X-rays. One of the spectra showing absorption by iron -- the dips on the left and right -- is included in the main graphic. An additional graphic shows a spectrum with absorption by silicon. In both spectra the data are shown in grey and a computer model in red.

However, the wavelengths of these characteristic signatures of iron and silicon were shifted to longer, or redder wavelengths compared to the laboratory values found here on Earth (shown with the blue, vertical line for each absorption signature). The researchers found that the shift of the absorption features was the same in each of the three Chandra observations, and that it was too large to be explained by motion away from us. Instead they concluded it was caused by gravitational redshift. The article goes on to explain how gravitational redshifts connect with Einstein's General Theory Relativity: "As predicted by Einstein's theory, clocks under the force of gravity run at a slower rate than clocks viewed from a distant region experiencing weaker gravity. This means that clocks on Earth observed from orbiting satellites run at a slower rate. To have the high precision needed for GPS, this effect needs to be taken into account or there will be small differences in time that would add up quickly, calculating inaccurate positions..."

The findings have been published in the Astrophysical Journal.

As Voyager 2 moves farther and farther from the Sun, the density of space is increasing. "It's not the first time this density increase has been detected," notes SciencAlert. "Voyager 1, which entered interstellar space in 2012, detected a similar density gradient at a separate location." From the report: Voyager 2's new data show that not only was Voyager 1's detection legit, but that the increase in density may be a large-scale feature of the very local interstellar medium (VLIM). The Solar System's edge can be defined by a few different boundaries, but the one crossed by the Voyager probes is known as the heliopause, and it's defined by the solar wind.
[...]
One theory is that the interstellar magnetic field lines become stronger as they drape over the heliopause. This could generate an electromagnetic ion cyclotron instability that depletes the plasma from the draping region. Voyager 2 did detect a stronger magnetic field than expected when it crossed the heliopause. Another theory is that material blown by the interstellar wind should slow as it reaches the heliopause, causing a sort of traffic jam. This has possibly been detected by outer Solar System probe New Horizons, which in 2018 picked up the faint ultraviolet glow resulting from a buildup of neutral hydrogen at the heliopause. It's also possible that both explanations play a role. Future measurements taken by both Voyager probes as they continue their journey out into interstellar space could help figure it out. But that might be a long bet to take. The findings have been published in The Astrophysical Journal Letters.

"Astrobiologists have identified 24 exoplanets that aren't just potentially habitable, they're potentially superhabitable, exhibiting an array of conditions more suitable to life than what's seen on Earth..." reports Gizmodo: For exoplanets to be superhabitable, they should be older, larger, heavier, warmer, and wetter compared to Earth, and ideally located around stars with longer lifespans than our own. So yeah, not only is Earth inferior, so too is our Sun, according to the new research...

As the new study points out, planets marginally older than Earth have a greater chance of being more habitable. When planets get old, "exhaustion of internally generated heat may result in eventual cooling, with consequences for global temperatures and atmospheric composition," write the authors. Earth is 4.5 billion years old, but planets between the ages of 5 billion and 8 billion years are likely to be more habitable, simply from a probabilistic standpoint...

To be clear, many of the criteria, such as atmospheric oxygen, plate tectonics, geomagnetism, and natural satellites, are currently beyond our ability to detect. What's more, only two of these planets, Kepler 1126 b and Kepler-69c, are scientifically validated planets, the remainder being on the list of unconfirmed Kepler Objects of Interest. Consequently, some of these "exoplanets" might not even be planets at all...

There are other limitations to consider as well. The authors are naturally biased towards Earth-like conditions, given that our planet provides the only known example of habitability. Life may proliferate under conditions not yet understood, and it's important to keep that in mind... We also don't know about the potential knock-off effects of these conditions. They sound good on paper, but the reality could be vastly different, as these environmental characteristics could collectively result in conditions wholly unsuitable for life.
"What's useful here is the criteria for planets that may not look exactly like Earth, but could be even more awesome locations for life," writes CNET.

"This could help us direct the resources of next-generation space telescopes like NASA's much-delayed James Webb."

Long-time Slashdot reader fahrbot-bot quotes Quanta magazine: It was an old idea of Stephen Hawking's: Unseen "primordial" black holes might be the hidden dark matter. It fell out of favor for decades, but a new series of studies has shown how the theory can work...

Their very blackness makes it hard to estimate how many black holes inhabit the cosmos and how big they are. So it was a genuine surprise when the first gravitational waves thrummed through detectors at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in September 2015. Previously, the largest star-size black holes had topped out at around 20 times the mass of the sun. These new ones were about 30 solar masses each — not inconceivable, but odd. Moreover, once LIGO turned on and immediately started hearing these sorts of objects merge with each other, astrophysicists realized that there must be more black holes lurking out there than they had thought. Maybe a lot more.

The discovery of these strange specimens breathed new life into an old idea — one that had, in recent years, been relegated to the fringe. We know that dying stars can make black holes. But perhaps black holes were also born during the Big Bang itself. A hidden population of such "primordial" black holes could conceivably constitute dark matter, a hidden thumb on the cosmic scale...

Following a flurry of recent papers, the primordial black hole idea appears to have come back to life. In one of the latest, published last week in the Journal of Cosmology and Astroparticle Physics, Karsten Jedamzik, a cosmologist at the University of Montpellier, showed how a large population of primordial black holes could result in collisions that perfectly match what LIGO observes. "If his results are correct — and it seems to be a careful calculation he's done — that would put the last nail in the coffin of our own calculation," said Ali-Haïmoud, who has continued to play with the primordial black hole idea in subsequent papers too. "It would mean that in fact they could be all the dark matter."

"It's exciting," said Christian Byrnes, a cosmologist at the University of Sussex who helped inspire some of Jedamzik's arguments. "He's gone further than anyone has gone before...." And with every subsequent observing run, LIGO has increased its sensitivity, allowing it to eventually either find such small black holes or set strict limits on how many can exist. "This is not one of these stories like string theory, where in a decade or three decades we might still be discussing if it's correct," Byrnes said.

An anonymous reader quotes Teslarati: On August 19th this year, astronomers using the Panoramic Survey Telescope and Rapid Response System observatory in Hawaii spotted an object destined to enter Earth orbit this fall. Designated as object 2020 SO, the item is now believed to be a rocket booster from NASA's Surveyor 2 mission which crash landed on the Moon in 1966 during the Apollo-era of the Cold War's space race.

"I suspect this newly discovered object 2020 SO to be an old rocket booster because it is following an orbit about the Sun that is extremely similar to Earth's, nearly circular, in the same plane, and only slightly farther away the Sun at its farthest point," Dr. Paul Chodas, the director of NASA's Center for Near Earth Object Studies, explained in comments to CNN.

"That's precisely the kind of orbit that a rocket stage separated from a lunar mission would follow, once it passes by the Moon and escapes into orbit about the Sun. It's unlikely that an asteroid could have evolved into an orbit like this, but not impossible," he said. This specific type of event has only happened once before, namely in 2002 with a Saturn V upper stage from Apollo 12, according to Dr. Chodas.

The supermassive black hole at the center of the M87 galaxy has a shadow crescent that moves, like a dancer in the dark. From a report: Over a year ago, scientists unleashed something incredible on the world: the first photo of a black hole ever taken. By putting together radio astronomy observations made with dishes across four continents, the collaboration known as the Event Horizon Telescope managed to peer 53 million light-years away and look at a supermassive black hole, which is 6.5 million times the mass of the sun and sits at the center of the galaxy Messier 87 (M87). The fiery historic image showed off a bright crescent of ultra-hot gas and debris orbiting the black hole's event horizon, the pitch-black central point-of-no-return that traps anything that goes over, even light. The EHT team had just made one of the most impressive achievements in the history of astronomy, but this was only the beginning. On Wednesday, members of the EHT collaboration published new findings in the Astrophysical Journal about M87's supermassive black hole (known as M87*), revealing two new major insights.

First, the shadow diameter of the event horizon doesn't change over time, which is exactly what Einstein's theory of general relativity predicts for a supermassive black hole of M87*'s size. However, the second insight is that the bright crescent adorning this shadow is far from stable: it wobbles. There's so much turbulent matter surrounding M87* that it makes sense the crescent would bug out and get fidgety. But the fact that we can watch it over time means we now have an established method for studying the physics of one of the most extreme kinds of environment in the entire universe.