Astronomy

Beaverlab claims that this inexpensive AI-powered telescope will let you capture the cosmos in stunning 4K — we put it to the test.

Week in images: 04-08 November 2024

Discover our week through the lens

A 3D map of our cosmic neighborhood has revealed hot and cold regions as well as an "escape tunnel" from our local bubble.

The Martian new year arrives with the Red Planet’s vernal equinox. Explaining why requires a deep dive into celestial mechanics and Earth’s calendrical history

Saturn gets close to the moon tonight, and some skywatchers in Florida, Central America and South America will see the ringed planet briefly disappear behind our lunar companion.

A mysterious electromagnetic mechanism may be more important than the firing of neurons in our brain to explain our awareness

Focusing on size in health care might be doing more harm than good.

The Moai statues of Easter Island have some of the best views of the night sky on Earth.

Dangerous radiation reaches Mars at levels we aren't exposed to on Earth, which makes the Red Planet a particularly dangerous place to be during pregnancy

Dangerous radiation reaches Mars at levels we aren't exposed to on Earth, which makes the Red Planet a particularly dangerous place to be during pregnancy

This compilation of images, captured by the Copernicus Sentinel-2 mission, showcases the characteristic hues of autumn in different European countries.

ESA’s Hera mission has completed the first critical manoeuvre on its journey to the Didymos binary asteroid system since launch on 7 October.

Big,

Russia launched 53 small satellites into orbit on Monday (Nov. 4), including two for Iran. The 51 Russian payloads were a single-launch record for the country.

Mars’ ancient climate is one of our Solar System’s most perplexing mysteries. The planet was once wet and warm; now it’s dry and cold. Whatever befell the planet, it didn’t happen all at once.

New research shows that on ancient cold Mars, sheets of frozen carbon dioxide allowed rivers to flow and a sea the size of the Mediterranean to exist.

Mars’ climatic change from warm and wet to cold and dry wasn’t abrupt. There was no catastrophic impact or other triggering event. Throughout its gradual shift, there were different climatic episodes.

The planet’s surface is characterized by features that indicate water’s presence. River channels, impact craters, and basins that were once paleolakes illustrate Mars’ complex climatic history. Mars is much different from Earth, but they both follow the same set of natural rules.

In Earth’s frigid climates, rivers can flow underneath thick, protective ice sheets. New research shows that a similar thing happened on Mars. The research is published in JGR Planets and is titled “Massive Ice Sheet Basal Melting Triggered by Atmospheric Collapse on Mars, Leading to Formation of an Overtopped, Ice-Covered Argyre Basin Paleolake Fed by 1,000-km Rivers.” The lead author is Peter Buhler, a Research Scientist at the Planetary Science Institute.

The research examines a period about 3.6 billion years ago when Mars was likely transitioning from the Noachian Period to the Hesperian Period. At that time, most of the surface water was frozen into large ice sheets in Mars’ southern region, according to the research. The planet’s CO2 atmosphere suffered periodic collapses, and sublimated out of the atmosphere. Those collapses formed a layer of CO2 650 meters (0.4 miles) thick that created a massive ice cap over the South Pole. It insulated the 2.5-mile-thick (4 km) layer of frozen water that made up the ice sheets.

This simple schematic from the research shows how the proposed model works. When the CO2 atmosphere collapses and sublimates, it forms an insulating layer over the frozen water in Mars’ southern polar regions. The meltwater is released and flows across the surface, insulated by a layer of frozen water. Image Credit: Buhler, 2024.

Buhler modelled how the CO2 cap acted as a thermal blanket and showed that it released massive amounts of meltwater from the frozen pole. This water flowed down rivers, with the top layers freezing and insulating the liquid water underneath.

“You now have the cap on top, a saturated water table underneath and permafrost on the sides,” Buhler said. “The only way left for the water to go is through the interface between the ice sheet and the rock underneath it. That’s why on Earth you see rivers come out from underneath glaciers instead of just draining into the ground.”

According to Buhler’s work, enough water was liberated to fill the Argyre Basin.

The Argyre Basin is one of the largest impact basins on the planet, measuring roughly 1800 km (1100 mi) in diameter. This massive impact basin was formed billions of years ago by a comet or asteroid striking Mars. It drops about 5.2 km (3.2 mi) below the surrounding plains, making it the second deepest basin on Mars. Scientists have long thought that the basin once held water—as much as the Mediterranean Sea—and Buhler’s work shows how it may have filled.

“Eskers are evidence that at some point there was subglacial melt on Mars, and that’s a big mystery,” Buhler said. Eskers are long stratified ridges of sand and gravel deposited by meltwater streams that flow under glaciers. They’re common on Earth, where glaciers once covered the surface. Mars’ eskers support the idea that the same thing happened on that planet.

These are eskers in western Sweden. They were created by water flowing under a glacier. When the glacier retreated, they were left as evidence. The same likely happened on Mars. Image Credit: By Hanna Lokrantz – https://www.flickr.com/photos/geologicalsurveyofsweden/6853882122/in/album-72157625612122901/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=42848874

The subglacial rivers would have flowed underneath the ice, where they were insulated from the cold. When they exited the glacier, they would have oozed along until a thick enough ice cap formed to insulate them. Buhler says that the ice would’ve grown until it was hundreds of meters thick, and the water flowing under the ice caps would’ve been several feet deep. The water would’ve carved out river channels thousands of miles long, and there are several of those that go from the polar cap to the Argyre Basin.

This figure shows the polar cap, the Argyre Crater, and the long sinuous channels that carried meltwater from the cap to the basin. Image Credit: Buhler 2024.

“People have been trying to discover processes that could make that happen, but nothing really worked,” Buhler said. “The current best hypothesis is that there was some unspecified global warming event, but that was an unsatisfying answer to me, because we don’t know what would have caused that warming. This model explains eskers without invoking climatic warming.”

Argyre Basin is massive and voluminous, and proposed explanations for how it was filled with water were left wanting. It has approximately the same volume as the Mediterranean Sea. Buhler’s model shows that it took about ten thousand years for the basin to fill, and after it filled, the water emptied into plains about 8,000 km (5,000 miles) away.

This process happened repeatedly over a one-hundred-million-year era, with each event separated by millions of years.

“This is the first model that produces enough water to overtop Argyre, consistent with decades-old geologic observations,” Buhler said. “It’s also likely that the meltwater, once downstream, sublimated back into the atmosphere before being returned to the south polar cap, perpetuating a pole-to-equator hydrologic cycle that may have played an important role in Mars’ enigmatic pulse of late-stage hydrologic activity. What’s more, it does not require late-stage warming to explain it.”

Buhler’s work is supported by other research. “Previous literature supports the presence of a ~0.6 bar (atmospheric) CO2 inventory, as utilized in the model, near the Noachian-Hesperian boundary,” he writes in his research. The history of Mars’ atmospheric pressure is backed up by cosmochemistry, mineralogy, atmosphere and meteorite trapped-gas isotopic ratios, geomorphology, and extrapolations of modern-day atmospheric escape.

“Thus, there is strong evidence that Mars had a sufficiently large mobile CO2 reservoir to drive the atmospheric-collapse-driven melting scenario described in this manuscript, with collapse occurring at a time commensurate with Valley Network formation during Mars’ intense, Late Noachian/Early Hesperian terminal pulse of intense fluvial activity,” Buhler writes.

That period of Mars’ history stands out as its own distinct phase of geological activity, whereas changes were more gradual in the earlier Noachian Period. The Late Noachian/Early Hesperian saw intense valley network formation. Many of these valleys are deeply carved into the landscape, often cutting through older geological features. That suggests that the water flow was powerful and erosive. This fluvial activity also created large deposits of sediment, like the ones NASA’s Perseverance Rover is exploring in Jezero Crater.

Jezero Crater on Mars. Scientists think that the sediments in the crater may be one km deep. Image Credit: NASA/JPL-Caltech/ASU

Buhler’s research is partly based on modern-day observations of Mars’ atmospheric CO2 and its cycles. Much of it is actually frozen and bound to the regolith. Mars’ rotational tilt shifts over a 100,000-year timeline. When it’s closer to straight up and down, the Sun hits the equator, and CO2 is released from the regolith into the atmosphere. It eventually reaches the poles, where it’s frozen into the caps.

When Mars is tilted, the poles are warmed, and the CO2 sublimates and is released into the atmosphere again. It eventually reaches the now-cooler regolith, which absorbs it. “The atmosphere is mostly just along for the ride,” Buhler said. “It acts as a conduit for the real action, which is the exchange between the regolith and the southern polar ice cap, even today.”

Buhler is still working with his model and intends to continue testing it more rigorously. If it successfully withstands more testing, our understanding of Mars will take a big leap forward.

The post Flowing Martian Water was Protected by Sheets of Carbon Dioxide appeared first on Universe Today.

Earth observation technology is set to play a larger role in how agencies respond to natural disasters and weather events.

Space debris, which consists of pieces of spent rocket stages, satellites, and other objects launched into orbit since 1957 – is a growing concern. According to the ESA Space Debris Office, there are roughly 40,500 objects in LEO larger than 10 cm (3.9 inches) in diameter, an additional 1.1 million objects measuring 1 and 10 cm (0.39 to 3.9 inches) in diameter, and 130 million objects 1 mm to 1 cm (0.039 to 0.39 inches). The situation is projected to worsen as commercial space companies continue to deploy “mega-constellations” of satellites for research, telecommunications, and broadband internet services.

To address this situation, researchers from the University of Kyoto have developed the world’s first wooden satellite. Except for its electronic components, this small satellite (LingoSat) is manufactured from magnolia wood. According to a statement issued on Tuesday, November 5th, by the University of Kyoto’s Human Spaceology Center, the wooden satellite was successfully launched into orbit atop a SpaceX Falcon 9 rocket from NASA’s Kennedy Space Center in Florida. This satellite, the first in a planned series, is designed to mitigate space debris and prevent what is known as “Kessler Syndrome.”

In 1978, NASA scientists Donald J. Kessler and Burton G. Cour-Palais proposed a scenario in which the density of objects in Low Earth Orbit (LEO) would become high enough that collisions between objects would cause a cascade effect. This would lead to a vicious cycle in which collisions caused debris, which would make further collisions more likely, leading to more collisions and more debris (and so on). For decades, astronomers and space agencies have feared that we are approaching this point or will be shortly.

Animation of Kyoto University’s prototype wooden satellite in space. Credit: Kyoto University

By manufacturing satellites out of wood, the University of Kyoto scientists expect they will burn up when they re-enter Earth’s atmosphere at the end of their service. This will prevent potentially harmful metal particles from being generated when a retired satellite returns to Earth. The small satellite measures just 10 cm (4 in) on a side and weighs only 900 grams, making it one of the lightest satellites ever sent to space. Its name comes from the Latin word for wood (“lingo”) and CubeSat, a class of small satellites with a form factor of 10 cm cubes.

Before launch, the science team installed LingoSat in a special container prepared by the Japan Aerospace Exploration Agency (JAXA). According to a spokesperson for Sumitomo Forestry, LignoSat’s co-developer, the satellite will “arrive at the ISS soon and will be released to outer space about a month later.”

Once the satellite reaches the ISS, it will dock via the Kibo Japanese Experiment Module (JEM) before deployment. It will then spend the next six months in space, and data will be sent from the satellite to researchers who will monitor it for signs of strain. Ultimately, the goal is to determine if wooden satellites can withstand the extreme temperature changes and conditions in space. A second satellite, LingoSat 2, is a double-unit CubeSat currently scheduled for launch in 2026.

Further Reading: The Guardian

The post Japan Launches the First Wooden Satellite to Space appeared first on Universe Today.

Rafael made landfall in Cuba Wednesday (Nov. 6), and NOAA's GOES satellites have been monitoring the storm every step of the way.

A new species of tardigrades with thousands of genes that become more active when exposed to radiation could help in devising better protection for astronauts on long missions.

Intuitive Machines' lunar terrain vehicle (LTV) is not your grandfather's moon buggy. The company's Moon RACER, or Reusable Autonomous Crewed Exploration Rover, just made its public debut.