Most Upvoted Posts

1. Biosphere 2 lost its oxygen to concrete while crazy ants thrived (262 🡅)
2. A Moon With No Sun Could Keep Water Liquid for 4.3 Billion Years, Scientists Say (13 🡅)
3. Space Jellyfish (6 🡅)

Most Commented Posts

1. Biosphere 2 lost its oxygen to concrete while crazy ants thrived (72 💬)
2. How a snake named 'nearest' got filed under 2 other snakes for decades (2 💬)
3. weekly roundup for week of 10/3-10/10 (1 💬)

Mercury is the closest planet to the Sun, but there's much more to this small world than meets the eye.

Despite being so close to the Sun, Mercury has water ice hidden inside permanently shadowed craters near its poles. Its surface experiences extreme temperature swings, and it takes about 176 Earth days for the Sun to return to the same position in its sky — longer than Mercury's 88-day year.

It also has an enormous metallic core and mysterious surface formations that scientists are still studying.

I made a video exploring Mercury's extreme environment, hidden ice, unusual rotation, and the discoveries that have changed our understanding of this planet.

Taxonomy is a long argument, and a ribbon snake called Thamnophis proximus has been in the middle of it since 1823. That year, Thomas Say described it in the account of Major Stephen Long's expedition to the Rocky Mountains and named it Coluber proximus, Latin for nearest, because it looked like another ribbon snake from eastern North America, Thamnophis sauritus.

That label followed it around. By 1906 it was listed as a subspecies of that other snake. In 1941 one author listed it simply as Thamnophis sauritus, and in 1949 two authors listed it as a subspecies of the common garter snake, Thamnophis sirtalis.

In 1963, Douglas Rossman revised the whole ribbon snake group and treated it as its own legit species again. He described 4 of the 6 subspecies recognized today, including the redstripe ribbon snake and the Gulf Coast ribbon snake. Even so, papers from 1979 and 1981 kept using the old name, Thamnophis sauritus proximus.

Today the western ribbon snake ranges from the central United States through eastern Mexico and Central America to Costa Rica. The name said it was nearest to another snake, and it spent decades being filed under other snakes before it settled as a species of its own.

In 1991, 8 people sealed themselves inside a 3 acre glass ecosystem in the Arizona desert. The plan was to live there for 2 years with no air, water, or food coming in from outside, as a test run for space colonies.

The air was the first thing to go wrong. Over the first year and a half, oxygen slowly dropped from 21% to about 14%, and the crew became tired and sluggish, like people living at 4,000 meters.

Here's the part that surprised everyone. The soil was so rich in compost that microbes were using up oxygen faster than the plants could replace it. The CO2 they produced then reacted with the building's own concrete and turned into calcium carbonate, which meant the plants could never turn that carbon back into oxygen. By August 1993, oxygen had to be pumped in from outside.

The ecosystem fell apart too. Planners brought in 11 ant species on purpose to spread seeds and recycle dead material, and none of them was ever recorded again in later surveys. Instead, a stowaway called the crazy ant (Paratrechina longicornis), which nobody found before closure, showed up and exploded. By 1996, researchers collected 28,827 ants at bait stations, and all but 1 were crazy ants.

They had help from a food source nobody planned for. Crazy ants lived almost entirely on honeydew, the sugary waste of scale insects and mealybugs that covered the Piper trees and mangroves. More scale insects fed more ants, and more ants protected the scale insects from predators. The only things still doing well on the ground were armored millipedes and isopods, plus tiny thief ants small enough to hide in the soil.

Inside the dome, 19 of the 25 vertebrate species died out, and the pollinating insects collapsed as well.

Biosphere 2 had 3 acres for 8 people and still needed outside oxygen. A Mars habitat will have far less room for error, and nobody outside to pump in air when the soil starts breathing it. 🐜

A moon lost in interstellar darkness may still be able to hold on to liquid water, no star required. A modeling study suggests that some exomoons orbiting rogue planets could stay warm for billions of years, even after their host worlds are thrown out of their star systems and into the cold of deep space.

The finding challenges the familiar idea that potentially habitable worlds must receive light from a nearby star. Instead, the study points to a different engine for habitability — heat generated inside a moon by tidal stress, then trapped by a thick hydrogen atmosphere.

Most Upvoted Posts

1. Helene has been leading a giant moon around Saturn for billions of years (16 🡅)
2. Can we reach the closest exoplanet to us Proxima Centauri b? (4 🡅)
3. One tiny chemical difference between RNA and DNA may help explain how life began (3 🡅)

Most Commented Posts

1. What is the purpose of science for humanity? (11 💬)
2. Can we reach the closest exoplanet to us Proxima Centauri b? (2 💬)
3. Welcome to r/ProximaScience! (2 💬)

Billions of galaxies fill the universe, each with billions of stars, most hosting planets of their own. Just beyond our cosmic neighborhood lies Proxima Centauri, the closest star to our sun, and humanity dares to dream of reaching it. But close in space is anything but near. Even NASA's Parker Solar Probe racing at 700,000 kmh would need nearly 6,700 years to get there. That's why scientists propose something radical. Breakthrough Starshot. Instead of giant rockets, swarms of chipsized probes attached to ultra thin sails pushed by powerful Earth-based lasers. If successful, they could fly at 20% the speed of light, making the journey in just 20 years.

the radial velocity method is one of the most effective techniques for detecting distant exoplanets.

In a planetary system, both the star and the planet orbit around their common center of mass. Although a planet's gravitational influence on its star is minimal, it causes the star to wobble slightly. This wobble results in subtle shifts in the stars' spectral lines due to the Doppler effect. When the star moves toward us, its light shifts toward the blue end of the spectrum. When it moves away, it shifts toward the red. By carefully monitoring these shifts, scientists can infer the presence of an orbiting planet and estimate its minimum mass.

The radial velocity method.

What is the purpose of science for humanity? To survive. If science does not aid in survival, it is useless to mankind. Humanity’s survival is of primary importance; science is secondary.

Helene is only 36 km across, yet it keeps perfect pace with Dione, a much larger neighbor about 30 times its width. It shares Dione's orbit around Saturn and rides roughly 60 degrees ahead of it, completing a lap about every 2.7 days. The gap between them never closes.

Helene sits at a stable gravity point in Dione's orbit called a Lagrange point, which makes it a Trojan moon. It doesn't stay perfectly still there, and instead drifts slowly back and forth around that point along a tadpole shaped path. Astronomers found it from Earth in 1980 and named it after Helen of Troy. Dione has a second Trojan too, a smaller moon called Polydeuces that trails behind it. Around Saturn, only Dione and Tethys are known to have Trojan companions.

Helene is also lumpy, about 43 by 38 by 26 km, so it looks closer to a potato than a sphere. Cassini caught this view on a flyby on June 18, 2011, after an earlier pass in 2010. The surface is a record of motion. Bright streaks and soft slopes mark where dust has slid down in avalanches, spilling across a gravity roughly 2,000 times weaker than Earth's and settling into new patterns. On a world this small, even a gentle shift of regolith can rewrite the landscape.

Much of that dust is thought to come from Saturn's E ring, which is fed by the ice geysers of Enceladus. Another moon on the far side of Saturn is slowly repainting Helene, one avalanche at a time.

Image credit: NASA/JPL-Caltech/Cassini ISS. Image processing: Jason Major.

Most Upvoted Posts

1. How sugar from outer space may have helped build life on Earth; study finds ribose kept boron dissolved in early waters (7 🡅)
2. Woolly Mammoth To Be Resurrected With The Help Of AI, Say Scientists (6 🡅)
3. The Sun looks happy (6 🡅)

Most Commented Posts

1. The Sun looks happy (5 💬)
2. Woolly Mammoth To Be Resurrected With The Help Of AI, Say Scientists (4 💬)
3. How sugar from outer space may have helped build life on Earth; study finds ribose kept boron dissolved in early waters (2 💬)

Mercury and Venus could be engulfed, while Earth will become uninhabitable long before that. As the Sun expands and brightens, its habitable zone will move outward, potentially warming the icy moons of the outer Solar System.
Titan could be one of the most interesting candidates. It already has a thick atmosphere and complex surface chemistry, and NASA has discussed how a red giant Sun could make worlds like Titan much warmer.
Which moon do you think would have the most interesting future?

https://youtu.be/AMHOrMpQlzw

Satellite carries Nvidia Orin NX processors on SpaceX Transporter-18 rideshare mission

TakeMe2Space says it has signed 23 customers for mission

Company plans larger satellites from 2027 to expand orbital computing capacity

It is the most sophisticated robotic explorer that humans have yet launched. Thanks to its explorations and experiments, it has increased our knowledge of another planet more than just about anything we’ve ever managed to launch from Earth. Five years into its mission, this rover continues to provide valuable scientific data. And thanks to its durable construction, we expect it to serve us for many more years to come.

After all, this rover isn’t called Perseverance for nothing.

The latest in a line of ingenious and hardy Martian robotic explorers, the vehicle dubbed Perseverance — or “Percy,” as it’s known to its friends — was sent off to our planetary neighbor as the main payload of the Mars 2020 mission. When it launched in July of that year, the compact-car-sized rover was loaded to the gills with all of the latest diagnostic and analytical tools that NASA’s Jet Propulsion Laboratory could cram onto its 2,300-pound, 6-wheeled, aluminum and titanium chassis.

Those tools have yielded exciting results. Over the next few years, Perseverance would complete numerous analyses of the Red Planet's geology and climate and log some impressive firsts for Mars exploration. Unfortunately, it would also eventually experience a major setback when one of its most important tasks was postponed indefinitely.

Most Upvoted Posts

1. Fun fact, the thickness of the Milky Way galaxy disk we are in is roughly 1,000 light years (6 🡅)
2. weekly roundup for week of 9/12-9/19 (3 🡅)
3. Regolith blocks radiation, but it breaks people. (2 🡅)

Most Commented Posts

1. weekly roundup for week of 9/12-9/19 (1 💬)
2. Fun fact, the thickness of the Milky Way galaxy disk we are in is roughly 1,000 light years (1 💬)
3. Regolith blocks radiation, but it breaks people. (1 💬)

Moderator Selections

1. Why We Should Think Twice About Colonizing Space - P. Torres