Mercury, a planet known for its extreme heat and extreme conditions, is the last place we would expect to find glaciers.
However, planetary scientists have discovered possible evidence of glacier-like structures on the planet closest to the sun and smallest in our solar system.
The discovery could show that even the most volatile conditions in the inner solar system may sometimes mirror conditions found on Earth, where microbial life thrives.
Contrary to what we might assume, these glaciers are not ice, and instead, they are likely composed of salt.
Planetary Science Institute (PSI) scientists confirm that these salty glaciers may provide favorable conditions for some types of bacteria to thrive in harsh conditions similar to those we see on Earth.
“Certain salt compounds on Earth create habitable environments even in some of the extreme environments in which they exist, such as the arid Atacama Desert in Chile,” Alexis Rodriguez, lead author of the study, said in a statement. “This line of thinking leads us to consider the possibility of subsurface regions.” "Mercury may be more hospitable to life than on its harsh surface."
The new study adds to evidence suggesting that glaciers of various types may be more widespread in our solar system than previously thought.
The team's findings complement recent findings that Pluto contains nitrogen glaciers. Since Pluto is on the far side of the solar system, the two discoveries indicate that glaciation extends from the hottest regions of the solar system, near the sun, to its frigid outer limits.
Mercury's glaciers may have evolved from volatile rich layers, or VRLs, that were subjected to asteroid impacts. Volatile substances are compounds that evaporate quickly.
The planet closest to the sun in our solar system continues to shrink
“Our models strongly confirm that salt flow likely produced these glaciers, and that after emplacement, they retained volatiles for more than a billion years,” explained Brian Travis, co-author of this new study.
The team believes that Mercury's glaciers are arranged in a complex configuration with cavities forming small 'sublimation pits', with sublimation being the process by which a solid is instantly converted into a gas bypassing the liquid phase.
To better understand the factors that contribute to the creation of volatile-rich layers, the study team examined the Borealis Chaos, located in Mercury's north polar region.
According to the statement, this area is characterized by turbulent terrain that appears to have obliterated entire groups of craters that were previously there. Some of these craters date back more than 4 billion years.
Gravity-based research reveals older, cratered terrain beneath the collapsed layer.
Study of this region provides vital information regarding the geological processes and history that led to the formation of layers rich in volatile materials on Mercury.
“The juxtaposition of fragmented upper crust, which now forms the Borealis Chaos terrane, on top of this ancient surface exposed by gravity, suggests that volatile-rich layers were layered on top of an already hardened landscape,” Rodriguez said.
The study aims to reshape understanding of the geological history of Mercury. The team proposed a scenario where the placement of volatile-rich, salt-dominated layers might be significantly affected by underwater deposition on Mercury.
Water drainage resulting from "volcanic degassing" could create transient pools or shallow seas on Mercury. Due to the high pressure and temperature, the water is likely to be in a liquid state or a supercritical fluid state, an intermediate state between liquids and gases (such as dense, highly salty vapor).
This scenario may have allowed salt deposits to stabilize.
"This pioneering discovery of Mercury's glaciers expands our understanding of the environmental parameters that can support life, adding a vital dimension to our exploration of astrobiology that is also related to the potential habitability of Mercury-like exoplanets," Rodriguez noted.
The study was published in the Planetary Science Journal.
NASA announces an important discovery on an exoplanet!
Methane attracts scientific interest mainly because of its short duration in the planetary atmosphere. It cannot withstand starlight for a long time, especially in terrestrial atmosphere.
If the rocky planet contains a lot of methane, the source must be massive, making a biogenic source likely. On Earth, biological activity produces a huge amount of methane.
Methane is common in our solar system, although it is not necessarily abundant. As far as scientists can tell, it's all non-vital. A process called "serpentinization" could explain this.
Serpentinization is a natural, abiotic process that involves water, carbon dioxide and the mineral olivine, which is common on Earth and is the main component of our planet's upper mantle. It was also found on the Moon, Mars, and some asteroids.
The James Webb Space Telescope recently detected methane in the atmosphere of WASP-80b, a gas giant with a mass about half the size of Jupiter. It orbits a K-type main sequence star that is about 1.5 billion years old.
Since WASP-80b is a gas giant, discovering life there is unlikely, except in some science fiction scenarios. Olivine, the most well-known abiotic source of methane, is also ruled out since WASP-80b is not a rocky planet.
Now, the exoplanet can be compared to the methane-containing atmospheres of Uranus and Neptune in our solar system.
A new research paper published in the journal Nature presents a discovery entitled “Methane in the atmosphere of the warm exoplanet WASP-80b.”
The temperature of the WASP-80b is approximately 550°C.
The temperature of WASP-80b places it in "an interesting transition regime where equilibrium chemistry models predict there should be detectable CH4 and CO/CO2 properties in the planet's transmission and emission spectra," the paper's authors explain.
WASP-80b is very close to its red dwarf star, and its orbit takes only three days.
Astronomers used the James Webb Space Telescope to study the combined light from the star and the planet during transits and eclipses.
There have not been many detections of methane in exoplanetary atmospheres by telescopes such as Hubble and Spitzer. Since the James Webb Space Telescope discovered methane, this raises an important question.
So, if astronomers continue to detect methane in more exoplanet atmospheres, we may have to change our thinking about methane as a biosignature.
Researchers explain that finding exoplanets that contain methane in their atmosphere also helps understand our solar system.
“NASA has a history of sending spacecraft to the gas giants of our solar system to measure the amount of methane and other molecules in their atmospheres,” they wrote. “Now, by measuring the same gas in an exoplanet, we can begin to make a comparison and see if the predictions from "The solar system matches what we see outside it."
Researchers also say that measuring methane along with water helps determine how and where the planet formed.
The discovery of methane in exoplanets will help us build a better comprehensive understanding of exoplanetary atmospheres.
The James Webb Space Telescope is poised to play a major role in building our knowledge of methane and the atmosphere.
Nice finding!
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