Intriguing dark streaks on Mars may be caused by landslides after all - Space.com

Martian landslides might help explain mystery lines seen on the surface of the Red Planet, a new study finds.

For years, scientists analyzing the Martian surface have detected clusters of dark, narrow lines that seasonally appear on steep, sun-facing slopes in the warmer regions. Previous research has suggested that these enigmatic dark streaks, called recurring slope lineae (RSL), are signs that salty water regularly flows on the Red Planet during its warmest seasons.

Recent missions to Mars have revealed that the planet does possess huge underground pockets of ice. Prior work suggested that warmer temperatures during the Martian spring and summer could help generate salty brines capable, at least for a time, of staying liquid in the cold, thin air of the Red Planet.

Related: The search for water on Mars in pictures

However, geologists have discovered problems with the concept of brines causing RSL, explained study lead author Janice Bishop, a planetary scientist at the SETI (Search for Extraterrestrial Intelligence) Institute and NASA Ames Research Center, both of which are in California's Silicon Valley. For example, the angle of slopes where RSL occur and the features surrounding where they start "largely are inconsistent with a liquid flow process," she told Space.com.

Now Bishop and her colleagues suggest that chemical reactions could make the Martian surface vulnerable to landslides that might explain RSL.

"Although the surface of Mars today is dry and harsh and cold and dominated by wind and abrasion, underneath the surface, micro-scale interactions of salts with tiny ice and liquid water particles can be still occurring today," Bishop said.

The scientists focused on chemical reactions between sulfate minerals such as gypsum with chloride salts, of which table salt is one variety. "On Earth, interactions between gypsum and chloride salts have caused collapse of parts of caves, sinkholes in soft sediments near salty lakes and ponds, and uplift of roads," Bishop said.

The researchers speculated that similar interactions could happen on Mars, although the cold and dry conditions there would slow these reactions down. "I am super excited about the prospect of active chemistry below the surface on Mars, albeit at a slow rate," Bishop said.

In the new study, the scientists conducted lab experiments on mixtures of sulfates, chloride salts, tiny ice particles and volcanic ash similar to Martian soil. They froze and thawed such mixtures at the kinds of low temperatures found on the Red Planet.

The researchers found thin films of slushy water formed on the surfaces of the mineral grains. They suggested these films could expand and contract over time, leading to upheavals and contractions under the Martian surface. Wind and dust on these unstable surfaces could then set off landslides, producing the lines seen on the Red Planet, Bishop explained.

The scientists noted that in the future, surface missions on Mars to recent RSL sites could help test their model. They detailed their findings online today (Feb. 3) in the journal Science Advances.

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Live coverage: SpaceX poised for middle-of-the-night Starlink launch – Spaceflight Now - Spaceflight Now

Live coverage of the countdown and launch of a SpaceX Falcon 9 rocket from pad 39A at NASA’s Kennedy Space Center in Florida. The mission will launch SpaceX’s next batch of approximately 60 Starlink broadband satellites. Text updates will appear automatically below. Follow us on Twitter.

SpaceX’s live webcast will be available on this page beginning around 15 minutes before launch.

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NASA Mars Perseverance rover: What to expect on landing day - CNET

NASA will use a "sky crane" to gently lower Perseverance to the surface of Mars.

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When it comes to space happenings, few things are as thrilling as landing a vehicle on another planet. It's tense. It's exciting. It's high stakes. On Feb. 18, NASA's Perseverance rover will aim to stick the landing on Mars, kicking off a new era in red planet exploration. 

While NASA has a lot of experience with delivering machines to Mars (here's looking at you, Curiosity and InSight), that doesn't make it any easier this time. "Landing on Mars is hard," NASA said. "Only about 40% of the missions ever sent to Mars – by any space agency - have been successful."

It's going to be a wild ride. Here's what to expect on Perseverance's landing day.

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How to watch

NASA will provide live coverage of the landing. The NASA TV broadcast from mission control kicks off on Thursday, Feb. 18 at 11:15 a.m. PT. Touch down in the Jezero Crater on Mars is scheduled for around 12:30 p.m. PT. 

This won't be like a rocket launch where we get to see every detail as it's happening. We will get NASA commentary and updates, views from mission control, and hopefully some images not too long after landing. It will be a must-watch event for space fans.    

Perseverance resonates

We've been to Mars before. So why all the hype? The red planet is our solar system neighbor. It's rocky like Earth. It has a long history of water. We can imagine ourselves perhaps living there some day. 

"The level of interest that people have in this planet is just extraordinary," Alice Gorman -- space archaeologist and associate professor at Flinders University in Australia -- told CNET. Gorman highlighted humanity's search for life beyond Earth and how Mars is a candidate for having hosting microbial life in its ancient past.

NASA Perseverance rover ready to explore the wilds of Mars

See all photos

There's also something special about a rover, a wheeled mechanical creature with a "head" and "eyes." "People feel towards the rovers because they're active and they move," said Gorman, likening it an almost parental sense of attachment. The outpouring of emotion over the demise of NASA's Opportunity rover proves how connected humans can get to a Mars explorer. Perseverance is set to become our new Martian sweetheart.

Seven minutes of terror

Mars arrivals are always harrowing. NASA calls the process EDL for "entry, descent and landing."

"During landing, the rover plunges through the thin Martian atmosphere, with the heat shield first, at a speed of over 12,000 mph (about 20,000 kph)," said NASA in a landing explainer. There's a reason NASA describes the landing process as "seven minutes of terror."

This NASA graphic shows the entire entry, descent and landing (EDL) sequence.

NASA/JPL-Caltech

Small thrusters will fire to keep the rover on track on the potentially bumpy ride through the atmosphere. The rover's protective heat shield helps to slow it down. At an altitude of around 7 miles (11 kilometers), a supersonic parachute will deploy and Perseverance will soon separate from its heat shield.

NASA gave a briefing on Jan. 27 with a detailed rundown on the entire EDL sequence, including the "sky crane" maneuver, which lowers the rover the final distance to the surface using a set of cables.

If all goes well, Perseverance will end up standing on the surface of Mars. "The really hard part is to soft land and not crash land, and then to deploy the moving parts," said Gorman. Perseverance is not alone on the trip. It also carries a helicopter named Ingenuity in its belly. Ingenuity will be unleashed later in the mission.

Now playing: Watch this: How NASA's Mars helicopter could change the future of...

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Experiencing the landing

The mission is equipped with cameras and microphones designed to capture the EDL process, so we can expect to both see and hear the excitement of the landing at some point. "It will be the raw sounds of the descent and coming onto the surface," said Gorman. "So that's a whole other level of sensory engagement."

It takes time to send data between Mars and Earth. For us back home, we can expect a first photo not too long after landing, but the full visual and audio experience may take a few days for NASA to share with the world. 

The agency released an arrival trailer in December that shows an animated, sped-up version of the process. You'll get the idea of just how wild it is to land a rover on another planet.

Gorman is excited about getting visuals of the rover's landing spot in Jezero Crater. It will be our first close-up look at the landscape in an area that had a history of water. Perseverance hopes to explore that history and look for evidence of life.

While the photos, sounds, helicopter and all-around science will be reasons to celebrate, there's the big lingering question the mission might answer: Was Mars home to microbial life? Said Gorman, "It would just be really great if we've got a bit of a closer handle on whether anything once lived on Mars." 

Perseverance is our next great hope in the search for signs of life beyond Earth. It all starts with sticking the landing.

Follow CNET's 2021 Space Calendar to stay up to date with all the latest space news this year. You can even add it to your own Google Calendar.    

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Spiders hoist big prey with silk 'pulleys' — and now scientists know how - Livescience.com

Tangle-web spiders are eight-legged engineers, crafting silk pulleys to snag oversized prey like lizards or even small mammals walking on the ground below. 

Until now, scientists didn't know exactly how the arachnids were able to capture such hefty victims. For the first time, researchers analyzed the spiders' building techniques and silk construction for trapping and lifting heavy animals. 

Turns out, the spiders actively "tuned" their silk mechanisms once the prey was caught, attaching pre-stretched threads in pulleys to maximize their lifting power and elevate prey much heavier than the arachnids themselves, the researchers reported in a new study.

Related: 21 totally sweet spider superlatives

Spider silk is very good at dispersing energy; when an insect flies into a web, energy from its struggles gets absorbed and dissipated through the network of joined threads. The silk is also elastic, which enables it to store and amplify energy, much like the string on a bow that's pulled taut and then released to shoot an arrow. 

For the study, scientists questioned how tangle-web spiders might use the elastic in silk to do their heavy lifting, whenever their sticky trapping threads caught something too cumbersome for the spider to haul up from the ground.

There are more than 2,200 described species of tangle-web spiders (also called cobweb weavers) in the family Theridiidae. They live around the world and are known for their dense, irregularly-shaped webs, according to the biodiversity database Encyclopedia of Life (EOL). For the researchers' experiments, they worked with two tangle-web species — Steatoda paykulliana and Steatoda triangulosa — and tasked the spiders with lifting live orange-spotted roaches (Blaptica dubia). The spiders weighed 0.007 ounces (0.22 grams) at most, and the heaviest roaches weighed nearly three times that at 0.02 ounces (0.56 g).

Trapping threads of the web include small blobs of "glue" and are placed close to the ground in order to catch the prey. (Image credit: Copyright Emanuele Olivetti)

"The trap changes"

In the experiments, the scientists observed the spiders as they built their snares, dangling special fibers studded with sticky glue to both ensnare prey and signal to the spider when something was caught. If the unlucky victim is a small insect, that one thread may be enough to lift it up, said lead study author Gabriele Greco, a postdoctoral researcher with the Laboratory of Bio-inspired, Bionic, Nano, MetaMaterials Mechanics at the University of Trento in Italy.

But if the prey is too big for the spider to yank up using the power of its own legs, "this is when the trap changes," Greco told Live Science. "The spider is getting involved, too." 

No longer a passive observer, the spider then starts producing hypertension threads — silk fibers that the spider stretches as it anchors one end to the web and attaches the other to the trapped prey. When the threads relax, they release their stored energy to incrementally raise the animal's weight, and the spider does this over and over again until the prey is at the desired height, Greco explained. In the experiments, the spiders hefted the heavy roaches as high as 3 inches (8 centimeters) off the ground, and their fastest lifting speed was about 0.004 inches (0.01 cm) per second, the researchers reported.

The study authors also described four different types of silk that the spiders used to construct the web, each with a specific function. There were two types of supporting threads, each produced by a different gland; "trapping" threads, coated with sticky droplets; and finally, a cement-like silk joining the threads together. The spider then produced a fifth type of silk to bind and immobilize its prey, Greco said. 

"The spider is a perfect factory of silk, it produces multifunctional materials in less than milliseconds — at least five different materials" he added.

Another type of arachnid — the triangle weaver spider (Hyptiotes cavatus) — also takes advantage of silk's ability to store and release energy; it uses its silk to craft stretchy slingshots that launch the spider much farther than it could travel by jumping, Live Science reported in 2019.

But there is much the researchers still don't know about spider silk elasticity, such as how much the silk can relax and stretch again. Calculating this limit would help scientists understand just how far a spider could stretch the tension threads, which also have to withstand the struggles of a captured animal without snapping or going limp.

"These were just the first insights in this direction," Greco said.

The findings were published online Feb. 3 in the Journal of the Royal Society Interface.

Originally published on Live Science.

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Earth heats up due to pandemic’s cleaner air, study finds - WJW FOX 8 News Cleveland

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1. Earth heats up due to pandemic’s cleaner air, study finds  WJW FOX 8 News Cleveland
2. Study: Pandemic's Cleaner Air Added Heat to Warming Planet  U.S. News & World Report
3. COVID-19 Lockdowns Caused Cleaner Air – And Warmed the Planet  SciTechDaily
4. COVID-19 lockdowns temporarily raised global temperatures  Phys.org
5. Nature Didn't Heal: Pandemic Induced Cleaner Air Added Head to Warming Planet, Finds Study  News18
6. View Full Coverage on Google News

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NASA Ready to Start Building Its Asteroid-Bound Psyche Spacecraft - Futurism

Psyche Out

NASA’s Psyche mission, an uncrewed expedition to an unusual asteroid of the same name, is entering the final stages of preparation.

After years of testing and development for the scientific instruments that will analyze the metallic asteroid, NASA is ready to send individual components to the Jet Propulsion Laboratory (JPL). There, engineers will begin to integrate and assemble the full spacecraft, according to a JPL press release.

“It’s really the final phase, when all of the puzzle pieces are coming together and we’re getting on the rocket. This is the most intense part of everything that happens on the ground,” Psyche principal investigator Lindy Elkins-Tanton said in the release.

Hitting Deadlines

If all continues to go well, the spacecraft will be ready well in advance of its planned launch in August 2022. NASA expects that final testing and assembly will last until spring 2022, when it will eventually be sent down to the Kennedy Space Center in Florida.

“The project has made tremendous progress, particularly given the world around us and COVID-19 and dealing with the constraints that imposes,” Psyche project manager Henry Stone said in the press release. “We’re in very good shape. We’re on track and have a plan to go forward to make launch.”

Poking Around

During its 21-month orbit around Psyche, NASA’s spacecraft will take images of the asteroid while also studying its surface and — if it finds one — its magnetic field.

The asteroid seems to have a much higher metal content than a typical space rock, prompting scientists to suspect that it’s really the exposed core of a planet that broke apart. Depending on what the mission finds, NASA’s spacecraft may reveal new information about how our planet formed as well.

READ MORE: NASA’s Psyche mission moves forward, passing key milestone [NASA Jet Propulsion Laboratory]

More on Psyche: NASA Hires SpaceX to Launch Mission to Giant Metal Asteroid

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Study: Pandemic's cleaner air added heat to warming planet - The Associated Press

Earth spiked a bit of a fever in 2020, partly because of cleaner air from the pandemic lockdown, a new study found.

For a short time, temperatures in some places in the eastern United States, Russia and China were as much as half to two-thirds of a degree (.3 to .37 degrees Celsius) warmer. That’s due to less soot and sulfate particles from car exhaust and burning coal, which normally cool the atmosphere temporarily by reflecting the sun’s heat, Tuesday’s study in the journal Geophysical Research Letters reported.

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Overall, the planet was about .05 degrees (.03 degrees Celsius) warmer for the year because the air had fewer cooling aerosols, which unlike carbon dioxide is pollution you can see, the study found.

“Cleaning up the air can actually warm the planet because that (soot and sulfate) pollution results in cooling” which climate scientists have long known, said study lead author Andrew Gettelman, an atmospheric scientist at the National Center for Atmospheric Research. His calculations come from comparing 2020 weather to computer models that simulated a 2020 without the pollution reductions from pandemic lockdowns.

This temporary warming effect from fewer particles was stronger in 2020 than the effect of reduced heat-trapping carbon dioxide emissions, Gettelman said. That’s because carbon stays in the atmosphere for more than a century with long-term effects, while aerosols remain in the air about a week.

Even without the reduction in cooling aerosols, global temperatures in 2020 already were flirting with breaking yearly heat record because of the burning of coal, oil and natural gas — and the aerosol effect may have been enough to help make this the hottest year in NASA’s measuring system, said top NASA climate scientist Gavin Schmidt, who wasn’t part of this study but said it confirms other research.

“Clean air warms the planet a tiny bit, but it kills a lot fewer people with air pollution,” Gettelman said.

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Follow Seth Borenstein on Twitter: @borenbears

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

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