What happens when an astronaut in orbit says

  

A day earlier, he had quite literally felt on top of the world by becoming the first Chinese-born person to fly into space. But now, orbiting Earth on board the Space Shuttle, all of his hopes and dreams, everything he had worked on for the better part of a decade as an American scientist at NASA's Jet Propulsion Laboratory, had come crashing down around him.

Wang was the principal investigator of an experiment called the Drop Dynamics Module, which aimed to uncover the fundamental physical behavior of liquid drops in microgravity. He had largely built the experiment, and he then effectively won a lottery ticket when NASA selected him to fly on the 17th flight of the Space Shuttle program, the STS-51-B mission. Wang, along with six other crew members, launched aboard Space Shuttle Challenger in April 1985.

On the second day of the mission, Wang floated over to his experiment and sought to activate the Drop Dynamics Module. But it didn't work. He asked the NASA flight controllers on the ground if he could take some time to try to troubleshoot the problem and maybe fix the experiment. But on any Shuttle mission, time is precious. Every crew member has a detailed timeline, with a long list of tasks during waking hours. The flight controllers were reluctant.

After initially being told no, Wang pressed a bit further. "Listen, I know my system very well," he said. "Give me a shot." Still, the flight controllers demurred. Wang grew desperate. So he said something that chilled the nerves of those in Houston watching over the safety of the crew and the Shuttle mission.

"Hey, if you guys don't give me a chance to repair my instrument, I'm not going back," Wang said.

Exactly what happened after that may never be known. But thanks to new reporting, we may finally have some answers. And though this is an old story, it still reverberates today, four decades on, with lasting consequences into the era of commercial spaceflight as more and more people fly into orbit.

Space Shuttle missions fulfilled various tasks in the vehicle's early years, such as deploying satellites, but one of its primary functions was conducting research in microgravity. Working with the European Space Agency, NASA developed and flew a pressurized module called Spacelab on some missions for this purpose.

The STS-51-B mission was the second time this Spacelab module flew, and it carried 15 different experiments ranging from astrophysics to the behavior of fluids in microgravity. Due to the nature of these specialized science experiments, NASA had started to fly "payload specialists" who were not designated to operate the Shuttle but rather complete the experiments on board.

With this mission, flying on board Challenger, the two highest priority experiments concerned materials science and fluid mechanics. Accordingly, the two payload specialists—Lodewijk van den Berg, a Dutch-born American chemical engineer, and Taylor Gun-Jin Wang, a Chinese-born American physicist—were chosen because of their expertise in these areas.

Wang was born in Shanghai in 1940 but moved to the United States in 1963 to study at the University of California, Los Angeles. He later earned a doctorate in low-temperature superfluid physics from UCLA and joined NASA's Jet Propulsion Laboratory in 1972. He became a US citizen three years later. His research involved the behavior of droplets and other sphere-like objects in zero gravity, and he eventually flew on NASA's zero-g flights. He developed the "Drop Dynamics Module" experiment to take this work to the next level in space.

Space Shuttle Challenger launched for its weeklong mission on April 29, 1985. Because there was so much research to conduct inside Spacelab, the crew was broken into two groups, each operating a 12-hour shift. Wang was on the "Gold" team, led by the mission's commander, Robert Overmyer, who was making his second and final flight. Mission specialists Don Lind and William Thornton joined him on the Gold team. Challenger's pilot, Fred Gregory, led the "Silver" team along with mission specialist Norm Thagard and van den Berg.

Wang went to operate the Drop Dynamics Module on the second day, when the experiment failed. He later described his feelings at this moment for a Smithsonian book published in 2002 titled Space Shuttle, which featured lots of photos and snippets of interviews with astronauts from the first 20 years of the Shuttle program. Although Wang's remarks in this book comprise only a few hundred words, they are by far his most extended public remarks on the incident."When I turned on my own instrument, it didn't work," Wang said. "You can imagine my panic. I had spent five years preparing for this one experiment. Not only that, I was the first person of Chinese descent to fly on the Shuttle, and the Chinese community had taken a great deal of interest. You have to understand the Asian culture. You don't just represent yourself; you represent your family. The first thing you learn as a kid is to bring no shame to the family. So when I realized that my experiment had failed, I could imagine my father telling me, 'What's the matter with you? Can't you even do an experiment right?' I was really in a very desperate situation."

It was at this point that Wang became severely depressed and started to haggle with flight controllers on the ground, making his comment about "not going back."

So what happened after that?

Unfortunately, since this mission flew four decades ago, a majority of the crew members have passed. The commander and leader of the Gold team, Overmyer, died in 1996. The other members of the Gold team, Thornton and Lind, died in 2021 and 2022, respectively. Only Wang, 83, remains alive. Ars tried to reach Wang in multiple ways to describe the incident, but all were unsuccessful.

Gregory, 83, did speak with Ars about it. After piloting the Shuttle in 1985, Gregory became the first African-American to command a spaceflight in 1989. Later, Gregory served as the deputy administrator and briefly administrator of NASA. He wanted me to know that Wang had been a "fantastic" person and a good crew member.

As a member of the Silver team, Gregory said he was asleep when Wang tried and failed to operate his experiment. However, he does have one distinct memory from the flight 39 years ago.

“I remember waking up at the beginning of a shift and seeing duct tape on the hatch," Gregory told Ars. "I did not know what the origin of it was, and I didn’t pay any attention to it. I may have, but I don’t recall asking Overmyer about it.”

There were three flight directors during Challenger's time in orbit, each working an eight-hour shift. Only one of them, Bill Reeves, is still alive. In email correspondence, Reeves told me that he was not on console during the time that Wang grew deeply despondent.

"Overmyer told me about this after the flight in a personal conversation," Reeves said. "All he said was how upset Wang was. Bob said he sat up most of the night trying to console Wang."

Simulation suggests dying stars' cocoons as potential source of gravitational waves.

So far, gravitational waves have only been detected from binary systems - the mergers of either two black holes, two neutron stars or one of each. However, a team of researchers from Northwestern University has proposed a new, previously unexplored realm - the turbulent cocoons of debris surrounding dying massive stars. For the first time ever, scientists have leveraged simulations to demonstrate that these cocoons possess the capacity to emit gravitational waves and the frequency range of these waves should fall within the detectable range of the Laser Interferometer Gravitational-Wave Observatory (LIGO). When massive stars collapse into black holes, they often generate powerful outflows, known as jets, which consist of particles travelling at near-light speeds. Ore Gottlieb, a CIERA Fellow at Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and the lead author of this study, and his collaborators used state-of-the-art simulations to trace this entire process - from the star's collapse to the moment the jet escapes, with the initial aim of investigating whether the accretion disk around a black hole could emit detectable gravitational waves.
However, the data yielded an unexpected revelation.
"When I calculated the gravitational waves from the vicinity of the black hole, I found another source disrupting my calculations — the cocoon. I tried to ignore it. But I found it was impossible to ignore. Then I realized the cocoon was an interesting gravitational wave source," Gottlieb said.
According to the researchers, as the jets collided with the collapsing layers of the dying star, a turbulent region, described as a "cocoon," began to form around the jet. This region is chaotic, where hot gases and debris intermingle and expand in various directions. When the energetic bubble accelerates away from the jet, it causes disturbances in space-time, resulting in the creation of gravitational waves.
If cocoons do generate gravitational waves, then LIGO should be able to detect them in its upcoming runs, Gottlieb said. Traditionally, researchers have focused their search for single-source gravitational waves on phenomena like gamma-ray bursts or supernovae, but doubts remain about LIGO's ability to detect such events.
Gottlieb calls on the scientific community to shift their attention towards cocoons, which possess both asymmetry and high energy, making them an intriguing candidate for gravitational wave emission. By studying them, scientists could learn more about what happens in the innermost part of stars.

On International Space Station, astronauts ring in New Year 2023 ahead of 2nd Christmas.

A new year is rising in space.
The seven Expedition 68 crew members celebrated the arrival of 2023 on the International Space Station in holiday style, including Santa hats, streamers and an adapted Orthodox Christmas tree ahead of the Russian celebration Jan. 6.
"Just like back home, we have a tradition here to put up a New Year tree and decorate the interior of the space station to celebrate the New Year. Today, we will show you how to do it under zero-gravity conditions," Russian cosmonaut
Sergey Prokopyev said in a video message. Beside Prokopyev, Russian cosmonauts Dmitry Petelin and Anna Kikina put up tiny ornaments and performed somersaults, all underneath a colored banner festooned with the words "New Year" in Cyrillic. Holiday cheer also spread to the U.S. side of the orbiting complex.In a NASA video uploaded last week, Japanese astronaut Koichi Wakata pledged to take an image of the first orbital sunrise of 2023 in one of the nearby modules in the ISS Kibo module, also provided by Japan.
The U.S. astronauts have been quiet on social media during the holiday season, but in the meantime, NASA uploaded a few photos on Flickr (opens in new tab) of the crew floating around the space station with Santa hats, stockings and holiday sweaters. It will be a busy early 2023 for the Expedition 68 crew after Russia determines what to do with a Soyuz spacecraft that suddenly started leaking coolant on Dec. 15. There is no immediate danger to the space station crew, but it is unclear whether the Soyuz, called MS-22, can bear Prokopyev, Petelin and Rubio back to Earth as planned.
Russia has pledged its "final decision" in January on whether to send up a rescue Soyuz (which would arrive no earlier than February) or to bring the three affected crew members home in Soyuz MS-22, according to reports.
NASA has also reached out to SpaceX to see whether it would be possible to bring the trio home in a Crew Dragon spacecraft, if no other backup is available. Dragon Endeavour is docked to the space station right now, but is nominally full as it is scheduled to bring Mann, Cassada, Wakata and Kikina back to Earth.
The cause of the Soyuz leak has not yet been determined, but follow-up scans of the spacecraft revealed a hole in the radiator that might be from a micrometeoroid, or a piece of space debris too small to track. The three Soyuz MS-22 crew members might be without a lifeboat in the meantime, in case of emergency on the ISS.

Antarctica 'doomsday' glacier losing ice at fastest rate in 5,500 years: Study

The Thwaites Glacier, nicknamed the "doomsday" glacier, is losing ice at a rate not seen in more than 5,500 years, according to a new study, raising concerns about the Florida-sized glacier's future and the rise of the global sea level.
The glacier has become a focal point on the long list of natural features threatened by a warming climate, thus the nickname it was given when it was announced in January 2020 that warm water was present underneath the 74,000-square-mile glacier located in West Antarctica.

The new dangers facing the glacier were highlighted in a peer-reviewed study published on Thursday in the journal Nature Geoscience.
Researchers came to their conclusion by analyzing prehistoric seashells and penguin bones on arctic beaches through radiocarbon dating. These fossils, which were more than 5,000 years old, were around when Earth was much warmer than present day, even with today's rising global temperatures. Through this process, researchers could figure out when these beaches arose and the local sea level around them. 

The results showed the glacier had begun to lose ice at a steady pace in that time frame roughly 5,000 years ago, with a local sea level rising rate of 0.14 inches per year. However, in the past 30 years, that rate has increased to 1.57 inches per year, a pace not seen in 5,500 years.
"These currently elevated rates of ice melting may signal that those vital arteries from the heart of the (West Antarctic Ice Sheet) have been ruptured, leading to accelerating flow into the ocean that is potentially disastrous for future global sea level in a warming world," Dylan Rood, co-author and faculty of engineering at Imperial College London, said in a statement.
The glacier already is contributing to sea level rise, as ice draining from it into the Amundsen Sea already accounts for about 4% of global sea-level rise, according to the International Thwaites Glacier Collaboration.
The loss of ice comes a few months after another group of researchers said the eastern ice shelf holding the "doomsday" glacier in place has cracks that could result in its collapse in the next three to five years, exposing it to ocean water and leading to eventual cliff breakoffs.
Collapse: Ice shelf collapses in East Antarctica for first time in human history. It's the size of New York City.
'Not a good sign': The temperature was 70 degrees above average near South Pole, a troubling record
The eventual demise of the glacier could result in global sea levels rising up to a foot in the next century, scientists with the American Geophysical Union said in December, threatening numerous coastal cities around the world.
Researchers aren't giving up hope; they said they will be drilling through the glacier to collect rock underneath it, which could determine if the accelerated melting could be reversed or not

NASA telescope spots highest-energy light ever detected from Jupiter

The planet's auroras are known to produce low-energy X-ray light. A new study finally reveals higher-frequency X-rays and explains why they eluded another mission 30 years ago.

Scientists have been studying Jupiter up close since the 1970s, but the gas giant is still full of mysteries. New observations by NASA's NuSTAR space observatory have revealed the highest-energy light ever detected from Jupiter. The light, in the form of X-rays that NuSTAR can detect, is also the highest-energy light ever detected from a solar system planet other than Earth. A paper in the journal Nature Astronomy reports the finding and solves a decades-old mystery: Why the Ulysses mission saw no X-rays when it flew past Jupiter in 1992.

X-rays are a form of light, but with much higher energies and shorter wavelengths than the visible light human eyes can see. NASA's Chandra X-ray Observatory and the ESA (European Space Agency) XMM-Newton observatory have both studied low-energy X-rays from Jupiter's auroras—light shows near the planet's north and south poles that are produced when volcanoes on Jupiter's moon Io shower the planet with ions (atoms stripped of their electrons). Jupiter's powerful magnetic field accelerates these particles and funnels them toward the planet's poles, where they collide with its atmosphere and release energy in the form of light.

Electrons from Io are also accelerated by the planet's magnetic field, according to observations by NASA's Juno spacecraft, which arrived at Jupiter in 2016. Researchers suspected that those particles should produce even higher-energy X-rays than what Chandra and XMM-Newton observed, and NuSTAR (short for Nuclear Spectroscopic Telescope Array) is the first observatory to confirm that hypothesis.

"It's quite challenging for planets to generate X-rays in the range that NuSTAR detects," said Kaya Mori, an astrophysicist at Columbia University and lead author of the new study. "But Jupiter has an enormous magnetic field, and it's spinning very quickly. Those two characteristics mean that the planet's magnetosphere acts like a giant particle accelerator, and that's what makes these higher-energy emissions possible."

Researchers faced multiple hurdles to make the NuSTAR detection: For example, the higher-energy emissions are significantly fainter than the lower-energy ones. But none of the challenges could explain the nondetection by Ulysses, a joint mission between NASA and ESA that was capable of sensing higher-energy X-rays than NuSTAR. The Ulysses spacecraft launched in 1990 and, after multiple mission extensions, operated until 2009.

The solution to that puzzle, according to the new study, lies in the mechanism that produces the high-energy X-rays. The light comes from the energetic electrons that Juno can detect with its Jovian Auroral Distributions Experiment (JADE) and Jupiter Energetic-particle Detector Instrument (JEDI), but there are multiple mechanisms that can cause particles to produce light. Without a direct observation of the light that the particles emit, it's almost impossible to know which mechanism is responsible.

In this case, the culprit is something called bremsstrahlung emission. When the fast-moving electrons encounter charged atoms in Jupiter's atmosphere, they are attracted to the atoms like magnets. This causes the electrons to rapidly decelerate and lose energy in the form of high-energy X-rays. It's like how a fast-moving car would transfer energy to its braking system to slow down; in fact, bremsstrahlung means "braking radiation" in German. (The ions that produce the lower-energy X-rays emit light through a process called atomic line emission.)

Each light-emission mechanism produces a slightly different light profile. Using established studies of bremsstrahlung light profiles, the researchers showed that the X-rays should get significantly fainter at higher energies, including in Ulysses' detection range.

"If you did a simple extrapolation of the NuSTAR data, it would show you that Ulysses should have been able to detect X-rays at Jupiter," said Shifra Mandel, a Ph.D. student in astrophysics at Columbia University and a co-author of the new study. "But we built a model that includes bremsstrahlung emission, and that model not only matches the NuSTAR observations, it shows us that at even higher energies, the X-rays would have been too faint for Ulysses to detect."

The conclusions of the paper relied on simultaneous observations of Jupiter by NuSTAR, Juno, and XMM-Newton.

New chapters

On Earth, scientists have detected X-rays in Earth's auroras with even higher energies than what NuSTAR saw at Jupiter. But those emissions are extremely faint—much fainter than Jupiter's—and can only be spotted by small satellites or high-altitude balloons that get extremely close to the locations in the atmosphere that generate those X-rays. Similarly, observing these emissions in Jupiter's atmosphere would require an X-ray instrument close to the planet with greater sensitivity than those carried by Ulysses in the 1990s.

"The discovery of these emissions does not close the case; it's opening a new chapter," said William Dunn, a researcher at the University College London and a co-author of the paper. "We still have so many questions about these emissions and their sources. We know that rotating magnetic fields can accelerate particles, but we don't fully understand how they reach such high speeds at Jupiter. What fundamental processes naturally produce such energetic particles?"

Scientists also hope that studying Jupiter's X-ray emissions can help them understand even more extreme objects in our universe. NuSTAR typically studies objects outside our solar system, such as exploding stars and disks of hot gas accelerated by the gravity of massive black holes.

The new study is the first example of scientists being able to compare NuSTAR observations with data taken at the source of the X-rays (by Juno). This enabled researchers to directly test their ideas about what creates these high-energy X-rays. Jupiter also shares a number of physical similarities with other magnetic objects in the universe—magnetars, neutron stars, and white dwarfs—but researchers don't fully understand how particles are accelerated in these objects' magnetospheres and emit high-energy radiation. By studying Jupiter, researchers may unveil details of distant sources we cannot yet visit.

More about the missions

NuSTAR launched on June 13, 2012. A Small Explorer mission led by Caltech and managed by JPL for NASA's Science Mission Directorate in Washington, it was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The telescope optics were built by Columbia University; NASA's Goddard Space Flight Center in Greenbelt, Maryland, and DTU. The spacecraft was built by Orbital Sciences Corp. in Dulles, Virginia. NuSTAR's mission operations center is at the University of California, Berkeley, and the official data archive is at NASA's High Energy Astrophysics Science Archive Research Center. ASI provides the mission's ground station and a mirror data archive. Caltech manages JPL for NASA

.Comet Leonard puts on a final, spectacular display

Comet Leonard is falling out of view, but not without putting on one last show.
Discovered just a year ago, the comet, formally known as Comet C/2021 A1, made its closest approach to Earth on Dec. 12, marking the climax of a month full of prime observing opportunities. As the comet has continued on its journey through the inner solar system, however, something has changed: its tail has taken on the appearance of twisted streamers, even as the core of the comet became brighter.
"Somehow it decided to return to life and unleash a couple of outbursts that reversed the fading trend," Quanzhi Ye, an astronomer at the University of Maryland who specializes in comets, told Space.com.

Comets are notoriously unpredictable, and in that regard, Comet Leonard is no anomaly. The comet, which was first spotted in January 2021, caught scientists' eyes for two key reasons: It was making a rare journey from the frigid outer zone of the solar system and its path would carry it remarkably close to the sun, as well as to Earth.
Skywatchers hoped that the pair of close approaches would make Comet Leonard a spectacular addition to the year's observing opportunities. But during the run-up to the comet's Earth flyby in December, Comet Leonard stopped brightening as fast as expected.
Observers expect a comet to brighten both as it approaches Earth due to the decreasing distance and as it approaches the sun due to the warming temperatures causing the comet to shed more material. But for Comet Leonard, this trend didn't quite hold. It appeared to brighten, but only because of its lessening distance. In terms of the comet's intrinsic properties, it actually faded.
But as it continued approaching the sun, Comet Leonard changed again and skywatchers were hypnotized by a dramatic, twisted tail.
The new spectacle is the result of the solar wind, a stream of charged plasma particles that constantly flows off the sun and across the solar system. Comets sport two tails, one made of dust and one of ions. And because ions are charged particles, a comet's ion tail is particularly susceptible to being shaped by the solar wind, as well as the magnetic field located in interplanetary space.
"What we see here are all sorts of visual effects caused by the influences from the solar wind," Ye said. "Most of the fascinating effects that we see in the pictures are from the ion tail."
Coincidentally, astronomers already had their eyes on Comet Leonard's ion tail. The strange fading episode in December made scientists wonder whether the comet might be falling apart, an event that would be first indicated by the disappearance of the ion tail.
But that hasn't happened. "Right now the comet seems to be doing well, and it is mostly the solar wind that is doing its thing," Ye said.
Comet Leonard made its closest approach to the sun on Monday (Jan. 3), when it came within about 56 million miles (90 million kilometers) of the sun. (Earth orbits about 93 million miles, or 150 million km, from the sun.)
Now, the comet is speeding outward across the solar system. By early next year, it will be about as far from the sun as Jupiter, which was about its distance when astronomers first spotted it. And while Comet Leonard has sped past the sun before this year, it never will again; its trajectory is due to carry it beyond the solar system into interstellar space.

Comet Leonard has been a great target for amateur astronomers, although it is becoming trickier to see for northern observers. It is currently appearing very low in the southwest sky just before sunset for skywatchers farther south than about Washington D.C. By mid-January, Comet Leonard will be exclusively overhead during daylight hours for all of the mainland United States.
If you're looking for gear to observe objects like Comet Leonard, check out our guides for the best binoculars deals and the best telescope deals. For night-sky imaging gear, check our best cameras for astrophotography and best lenses for astrophotography guides.

Did Mars Ever Look Like Earth? NASA Scientist Answers

 

Mars is quite similar to Earth, as per a NASA scientist. Astrobiologoist Dr. Becky McCauley Rench said that the Red Planet wasn't as dry always, as we see it today. As per NASA's own website, “Mars, like Earth, has seasons, polar ice caps, volcanoes, canyons, and weather.” Signs of ancient floods have also been detected on Mars. Besides, there is evidence of liquid salty water as well, especially on some Martian hillsides, making our celestial neighbour similar to our own home planet. The question was straightforward and simple: Did Mars ever look like Earth? "Yes, we think it did. Ancient Mars may have been wetter and warmer — similar to our home planet," Rench answered.

Explaining further, Rench added that whenever the solar system was formed 4 billion years ago, Mars and Earth were made "of the same stuff" and so they looked very similar. "Today, whenever we look at Mars, we see a very dry planet as compared to earth which is, you know, our Blue Marble," she added.  

Shining light on what makes her believe that Mars once looked like earth, Rench said that we see evidence of past streams and maybe Mars had a shallow northern ocean as well. "However, they diverged and we have two different planets today," she added.

"As the Earth progressed with the development of life, on Mars the geologic activity subsided, it lost that water and became a much drier place. That's why it's so fascinating to study Mars. It helps us understand more about its past and future as well as understanding Earth and planetary evolution in our solar system and beyond," she said.
"So did Mars ever look like Earth? Yes, it did, a very, very long time ago," Rench concluded.NASA says on its SpacePlace section that Mars, a cold desert world, is half the size of the earth. It's  referred to as the Red planet because of rusty iron in the ground. "There are signs of ancient floods on Mars, but now water mostly exists in icy dirt and thin clouds," added the space agency. 

Scientists have been wanting to understand if there was life on the Red Planet in the past. Missions are currently underway to figure out if Mars could support life now, or in the future.

Brace yourselves, humanity: The "Cow of Comets" approache.

 

The largest comet ever observed will graze within our cosmic pasture come 2031.

The majesty of space is often difficult to put into words, but every so often professional stargazers are able to reverently meditate upon the heavens before properly articulating the cosmic grandeur on display far above humanity’s humble heads. Late last month, the universe gifted just one such occasion to us: A big “cow comet” is farting its way towards us real fast, y’all.

The largest comet ever observed by humanity is currently on track to pass through our solar system between Uranus and Saturn in less than ten years’ time. At an estimated 60 to 100 miles wide, Bernardinelli-Bernstein (named after its discoverers) is the “nearly spherical cow of comets,” dwarfing its celestial comparisons like Hale-Bopp, which only measures a measly 37 miles across.
“It’s pristine,” University of Pennsylvania astronomer Pedro Bernardinelli explains of their beloved bovine comet. “Not a lot has happened to this object since its formation in the early days of the solar system, and so we can think of it as a window into the past.”

According to astronomers, Bernardinelli-Bernstein (BB, as it has been affectionately nicknamed) is a remnant of our solar system’s creation from billions of years back, and will provide an illuminating look at our cosmic neighborhood’s formative era.
Due to BB generally hanging out in deep space most of the time, its chemical composition is likely to be largely unchanged from its earliest years, namely a mix of nitrogen and carbon dioxide. Observations about that composition will be able to reveal just where, exactly, BB first got its start in the solar system.

Although BB’s watchers are hopeful that a space agency might fund a probe’s voyage to the comet’s surface (as NASA is currently doing for asteroids near Jupiter), they aren’t holding their breath.
In all likelihood we’ll only be able to gawk at the big cow comet from telescopes here on Earth, but that alone should at least provide a host of new information on how all this mess first got started.  

We Finally Know Why Icy Plumes Flare Ahead of Deadly Supercell Storms.

 

Something strange often happens just before a severe thunderstorm produces a tornado, high winds, or hailstones: A plume of ice and water known as an Above-Anvil Cirrus Plume (AACP) billows up above the top of the storm clouds and head downwind, acting as a sort of early warning system for extreme weather events.

For the first time, scientists think they've figured out what causes these cloudy plumes. What are known as hydraulic jumps – also seen when a waterfall crashes into the still water below creating a foamy cloud – are created as air rises above and then falls back into the thunderstorm clouds.
The researchers behind the new study say that their findings could give advance warnings to people on the ground about the risk of tornadoes, high winds, and hailstorms, particularly in places where existing Doppler radar system technology isn't working or isn't available to use.
"If there's going to be a terrible hurricane, we can see it from space," says atmospheric scientist Morgan O'Neill from Stanford University and the study's lead author. "We can't see tornadoes because they're hidden below thunderstorm tops. We need to understand the tops better."
O'Neill and her colleagues ran detailed simulations of supercell thunderstorms, the type of storms most likely to spawn tornadoes. In these fierce supercells, super-strong rotating updrafts push moist air higher than it would normally go in Earth's atmosphere, through the top of the lower troposphere into the stratosphere.

The rising shoots of air – the AACPs – soon drop back to the troposphere, but the modeling showed a downslope windstorm at the border of the troposphere and the stratosphere, with wind speeds of up to 240 miles per hour (386 kilometers per hour) possible.

This frenetic turbulence produces hydraulic jumps, the scientists suggest, and those jumps are capable of injecting large amounts of water vapor into the stratosphere very quickly.

These jumps are also created by winds rushing down mountains and rocks, but they've never been seen before this high up in the atmosphere since the storm clouds are effectively acting as physical barriers.

"Dry air descending from the stratosphere and moist air rising from the troposphere join in this very narrow, crazy-fast jet," says O'Neill. "The jet becomes unstable and the whole thing mixes and explodes in turbulence."

"These speeds at the storm top have never been observed or hypothesized before."

With NASA research aircraft now equipped with devices that allow them to map the winds at the top of thunderstorms in high-resolution 3D, the next step will be gathering real-world data to help corroborate what these models have shown.
About 75 percent of thunderstorms with these plumes produce large hail or tornadoes, so the research is likely to be useful in improving meteorological models in the future. Hurricane Ida recently left a trail of death and destruction across the northeastern United States, and a better understanding of these storms can save lives and property. 

The study is also important in the broader picture of climate change, as these hydraulic jumps push large volumes of water into the typically very dry stratosphere. Over time, that's going to have a long-term impact.
"In a warming climate that produces stronger and more intense convection, climate scientists are interested in how much water is injected into the stratosphere by thunderstorms because of the aggregate effect this has on stratospheric ozone," says atmospheric scientist Leigh Orf from the University of Wisconsin-Madison.
"In our simulations that exhibit plumes, water reaches deep into the stratosphere where it possibly could have more of a long-term climate impact."

Comets visit our solar system more frequently than thought

 

Comets from other star systems, such as 2019 Borisov, visit the sun's neighborhood more frequently than scientists had thought, a new study suggests.

The study, based on data gathered as Borisov zipped by Earth at a distance of about 185 million miles (300 million kilometers) in late 2019, suggests that the comet repository in the far outer solar system known as the Oort Cloud might be full of objects that were born around other stars. In fact, the authors of the study suggest that the Oort Cloud might contain more interstellar material than domestic stuff. 

Named after famous Dutch astronomer Jan Oort, who first proved its existence in the 1950s, the Oort Cloud is a spherical shell of small objects — asteroids, comets and fragments — far beyond the orbit of Neptune. The cloud's inner edge is thought to begin about 2,000 astronomical units (AU) from the sun, and its outer edge lies about 200,000 AU away. (One AU is the average Earth-sun distance — about 93 million miles, or 150 million kilometers.)

No spacecraft has ever visited the Oort Cloud, and it will take 300 years for NASA's farflung Voyager 1 probe to even glimpse the cloud's closest portion. 

Astronomers have very limited tools to study this intriguing world, as objects in the Oort Cloud don't produce their own light. At the same time, these objects are too far away to reflect much of the sun's light. 

So how exactly did the scientists figure out that there must be so many interstellar objects in the Oort Cloud, and what did Borisov have to do with it?

Amir Siraj, a graduate student at Harvard University's Department of Astronomy and lead author of the study, told Space.com in an email that he could calculate the probability of foreign comets visiting the solar system simply based on the fact that the Borisov comet had been discovered. 

"Based on the distance that Borisov was detected at, we estimated the implied local abundance of interstellar comets, just like the abundance of 'Oumuamua-like objects was calibrated by the detection of 'Oumuamua," Siraj said. 

The mysterious 'Oumuamua, first spotted by astronomers in Hawaii in October 2017, was the first interstellar body ever detected within our own solar system. The object passed Earth at a distance of 15 million miles (24 million km), about one-sixth of the distance between our planet and the sun. An intense debate about 'Oumuamua's nature ensued, as it wasn't clear at first whether the object was a comet or an asteroid.

Even the detection of a single object can be used for statistical analysis, Siraj said. The so-called Poisson method, which the astronomers used, calculates the probability of an event happening in a fixed interval of time and space since the last event. 

Taking into consideration the gravitational force of the sun, Siraj and co-author Avi Loeb, an astronomer at Harvard, were able to estimate the probability of an interstellar comet making its way to Earth's vicinity. They found that the number of interstellar comets passing through the solar system increases with the distance from the sun. 

"We concluded that, in the outer reaches of the solar system, and even considering the large uncertainties associated with the abundance of Borisov-like objects, transitory interstellar comets should outnumber Oort Cloud objects (comets from our own solar system)," Siraj added.

So why have astronomers seen just one interstellar comet so far? The answer is technology. Telescopes have only recently gotten powerful enough to be able to spot those small but extremely fast-travelling bodies, let alone study them in detail. 

"Before the detection of the first interstellar comet, we had no idea how many interstellar objects there were in our solar system," said Siraj. "Theory on the formation of planetary systems suggests that there should be fewer visitors than permanent residents. Now we're finding that there could be substantially more visitors."

The astronomers hope that with the arrival of next-generation telescopes, such as the Vera C. Rubin Observatory, currently under construction in Chile, the study of extrasolar comets and asteroids will truly take off.

What color is the universe?

 

It is a bit tamer than you might imagine.

When you look up at the night sky, it's easy to think that the universe is a never-ending sea of blackness. But if you measured the visible light from all of the luminous celestial bodies out there, what would the average color of the universe be?
Let's get this out of the way first: It's not black.
"Black is not a color," Ivan Baldry, a professor at the Liverpool John Moores University Astrophysics Research Institute in the U.K., told Live Science. "Black is just the absence of detectable light." Instead, color is the result of visible light, which is created throughout the universe by stars and galaxies, he said. 

In 2002, Baldry and Karl Glazebrook, a distinguished professor at the Centre for Astrophysics and Supercomputing at the Swinburne University of Technology in Australia, co-led a study published in The Astrophysical Journal that measured the light coming from tens of thousands of galaxies and combined it into a singular spectrum that represented the entire universe.
In doing so, the pair and their colleagues were able to work out the average color of the universe.
The cosmic spectrum
Stars and galaxies emit waves of electromagnetic radiation, which is separated into different groups based on the length of the waves emitted. From shortest to longest wavelength, the groups include gamma-rays, X-rays, ultraviolet light, visible light, infrared radiation, microwaves and radio waves.
Visible light makes up a tiny portion of the electromagnetic spectrum in terms of the range of wavelengths, but it is the only part the naked eye can see. What we perceive as colors are actually just different wavelengths of visible light; reds and oranges have longer wavelengths, and blues and purples have shorter wavelengths. 

The visible spectrum of a star or a galaxy is a measure of the brightness and wavelengths of light that the star or galaxy emits, which, in turn, can be used to determine the average color of the star or galaxy, Baldry said.

In 2002, Australia's 2dF Galaxy Redshift Survey — which was the largest survey of galaxies ever carried out at the time — captured the visible spectra of more than 200,000 galaxies from across the observable universe. By combining the spectra of all these galaxies, Baldry and Glazebrook's team was able to create a visible light spectrum that accurately represented the entire universe, known as the cosmic spectrum.

The comic spectrum "represents the sum of all the energy in the universe emitted at different optical wavelengths of light," Baldry and Glazebrook wrote in a separate non-peer-reviewed in 2002 based on their discovery. The cosmic spectrum, in turn, allowed them to determine the average color of the universe.  

Color conversion 

The researchers used a color-matching computer program to convert the cosmic spectrum into a single color visible to humans, Baldry said.

Our eyes have three types of light-sensitive cones, each of which helps us perceive a different range of visible light wavelengths. This means that we have certain blind spots where we cannot properly register certain colors of wavelengths between these ranges, Baldry and Glazebrook wrote in their online paper. The colors we see also depend on what our reference for white light is as we are observing an object. For instance, the color of an object may appear different in a brightly lit room compared with the outdoors on an overcast day.

However, the CIE color spaces, created by the International Commission on Illumination in 1931, compensate for our visual limitations by attributing a color to different wavelength combinations as seen by a standardized human observer, which is what the team's computer models used.
The team determined that the average color of the universe is a beige shade not too far off from white. Although this is a rather boring finding, it is not a surprising one, considering that white light is the result of combining all the different wavelengths of visible light and the cosmic spectrum includes such a wide range of wavelengths.
The new color was eventually named "cosmic latte," based on the Italian word for milk, after a poll of the whole research team. Other suggestions included cappuccino cosmico, Big Bang beige and primordial clam chowder.

Unshifting the red
A key concept of the cosmic spectrum is that it represents the light of the universe "as originally envisaged," Balrdy and Glazebrook wrote in their online paper. This means that it represents the light as it was emitted throughout the universe, not just as it appears to us on Earth today.
Like all waves, light gets stretched over vast distances because of the Doppler effect. As light gets stretched, its wavelength increases and its color moves toward the red end of the spectrum, known by astronomers as redshift. This means that the light we see is not the same color it was when it was first emitted. 

"We removed the effect of redshift from the spectra of the galaxies," Baldry said. "So, it is the spectra of the galaxies when they emitted the light."

Cosmic latte is, therefore, the color you would see if you could look down on the universe from above and see all the light coming from every galaxy, star and gas clouds all at once, Baldry said.

NASA is training robots like humans to explore caves on Mars

 

When searching for signs of life on other planets, scientists say caves are a crucial place to look. But how can a team on Earth effectively explore intricate, dark, unfamiliar landscapes on another world?
NASA and Boston Dynamics have found an answer: Fully autonomous robots.
Caves are one of the most likely places to find signs of both current and past life on other planets because they are capable of protecting life from cosmic rays and extreme temperature fluctuations around our solar system. A NASA project called BRAILLE is now working on exploring Mars-like caves that already exist on Earth in order to hone key technologies for future missions. 

According to researchers, the project has enabled the first-ever fully autonomous robotic exploration of these types of caves, which are several hundred meters long and limit communication with the surface. As the robots explore, with no prior information about the environment, a team of researchers outside the cave simultaneously performs actions that scientists on Earth would be executing during a real Martian mission. 

The research, which project lead Ali Agha said could "fundamentally change how we think about future missions," is now in year three of four in its quest to journey to the moon, the red planet and beyond.
But researchers are interested in exploring caves for another reason beyond finding signs of life: caves provide obvious natural shelters for future astronauts exploring Mars or the moon.

"Future potential human exploration missions can benefit from robots in many different ways," Agha told CBS News. "Particularly, robots can be sent in precursor missions to provide more information about the destination before humans land on those destinations. In addition, robots can accompany astronauts during the missions to help with scouting certain terrains or with logistics and many tasks that can make astronauts' missions safer and more efficient."

So, how is designing a Mars robot different from designing an Earth robot? They are similar in a lot of ways, Agha said, especially when it comes to the AI robot brain, called NeBula, and its ability to process information and make decisions when they don't have contact with scientists on Earth. 

But when it comes to the robot body, that's where things get more complicated. Scientists need to consider temperature management, shielding the robots from radiation, as well as the severe power and energy constraints that come with trekking to a far-away world — all aspects not previously considered on Earth. 

Boston Dynamics' Spot robot has proven an extremely viable body for NeBula.

"SPOT is one of the most capable robots that we have and it is amazing to see how it successfully reacts to high-level decisions and commands coming from the robot brain and how it can maintain stability over rough and extreme terrains," Agha said. "In addition to our capable traditional wheeled rovers, the ability to "walk" is a huge asset when dealing with uneven terrains with no roads and no flat surfaces."

There are three main factors for the robot's success:

• It needs to be able to carry enough payload for its eyes, ears and brain to be able to traverse the challenging Martian or lunar terrain.
• It needs to carry a meaningful amount of science instruments.
• It must prove it can maintain a "reasonable" level of stability, speed and endurance on another world. 

"We have these multiple mobile robots that can carry different instruments, as opposed to one big robot that's going to have trouble traversing its terrain," said deputy project lead Benjamin Morrell, referring to past Martian rovers. 

"Boston Dynamics Spot robot is one of the few robots that satisfy these constraints simultaneously," Agha said. "So integrating our robot brain, NeBula, on Spot has been pushing the boundaries of what was possible in exploring unknown Mars-like environments."

The robots typically cannot communicate from inside the cave, so scientists eagerly await their return to the surface for data, which could include a 3D map of the cave's interior, information on science targets or general findings about the environment. 

Some of the robots are also equipped with arms to bring back small samples from the cave walls for analysis. Researchers hope that these robots will be able to autonomously carry out parts of future missions in space, after humans have built up a certain level of trust with them. 

"The next-generation robot bodies and mechanical locomotion capabilities would enable new types of missions over terrains that were otherwise inaccessible by traditional rovers," Agha said. "Also, due to the increased speed and traversal capabilities, future missions can target destinations that are traditionally considered to be too far from landable regions on Mars.

No hope for life in Venus clouds

The amount of water in the atmosphere of Venus is so low that even the most drought-tolerant of Earth's microbes wouldn't be able to survive there, a new study has found. The findings seem to wipe out the hope stirred by last year's discovery of molecules potentially created by living organisms in the scorched planet's atmosphere that were seen as an indication of the possible presence of life. 

The new study looked at measurements from probes that flew through the atmosphere of Venus and acquired data about temperature, humidity and pressure in the thick sulfuric acid clouds surrounding the planet. From these values, the scientists were able to calculate the so-called water activity, the water vapor pressure inside the individual molecules in the clouds, which is one of the limiting factors for the existence of life on Earth.

"When we looked at the effective concentration of water molecules in those clouds, we found that it was a hundred times too low for even the most resilient Earth organisms to survive." John Hallsworth, a microbiologist at Queen's University in Belfast, U.K., and lead author of the paper, said in a news conference on Thursday (June 24). "That's an unbridgeable distance."

The findings are likely a disappointment for the Venus research community, which was invigorated last September by the discovery of phosphine, a compound made of atoms of phosphorus and hydrogen that on Earth can be associated with living organisms, in Venus' atmosphere. At that time, researchers suggested the phosphines may be produced by microorganisms residing in those clouds. 

On Earth, Hallsworth said, microorganisms can survive and proliferate in droplets of water in the atmosphere when temperatures allow. However, the findings of the new study, based on data from several Venus probes, leave zero chance of anything living in the clouds of Venus, he said.

"Living systems including microorganisms are composed mainly of water and without being hydrated, they can't be active and are unable to proliferate," Hallsworth said. 

Studies on microorganisms living in extreme conditions on Earth found that life can exist at temperatures as cold as minus 40 degrees Fahrenheit (minus 40 degrees Celsius). For water activity, which is measured on the scale from 0 to 1, the lowest survivable value is 0.585. The water activity level found in the molecules in the Venusian clouds was merely 0.004. 

NASA Ames astrobiologist Chris McKay, one of the co-authors of the paper, said in the news conference that the findings of the study were conclusive and the new fleet of space missions currently being prepared for Venus will not change anything about the hope for life on Earth's closest neighbor. 

"Our conclusion is based directly on measurements," McKay said in the briefing. "It's not a model, it's not an assumption. The missions that NASA just selected to go to Venus will do the same measurements again —  temperature, pressure — and they are going to come to very much the same conclusions because Venus is not changing on that type of time scale."

However, the researchers looked at data from other planets too and found that the clouds of Jupiter do provide sufficient water activity to theoretically support life. Data collected by the Galileo probe at altitudes between 26 and 42 miles (42 and 68 kilometers) above the surface of the gas giant suggest the water activity value to sit at 0.585, just above the survivable threshold. Temperatures in this region are also just about survivable, at around minus 40 degrees F. 

"Jupiter looks much more optimistic," McKay said. "There is at least a layer in the clouds of Jupiter where the water requirements are met. It doesn't mean that there is life, it just means that with respect to water, it would be OK."

High levels of ultraviolet radiation or lack of nutrients could, however, prevent that potential life from thriving, the researchers said, and completely new measurements would be needed to find whether it actually could be there or not. 

Hallsworth added that the technique used to calculate the water activity could also help determine the habitability of exoplanets.

"What excites me the most is that we can go down to the scale of water molecules for these distant planets and pinpoint their potential habitability," Hallsworth said.