Alien crystals ‘unlike anything found on Earth’ may line the shorelines of Saturn’s moon Titan, NASA says
- Rings of material left behind around evaporating lakes had been seen on Titan
- Researchers recreated this moon’s freezing cold conditions in their laboratory
- Novel minerals including crystals made of solid acetylene and butane formed
- On Earth these compounds are gases that are used for welding and for fuel
Exotic crystals — entirely unlike anything found naturally on Earth — might encrust the shorelines of lakes on Saturn’s frozen moon, Titan.
NASA researchers recreated the chilly conditions of Titan’s surface in the laboratory and found they could form strange new mineral compounds.
These included so-called co-crystals made up of solid acetylene and butane, which are used as liquid fuels on Earth.
It is possible that these crystals may make up the ring-like deposits spotted around evaporating lakes on Titan by the famed kamikaze Cassini–Huygens mission.
Exotic crystals — entirely unlike anything found naturally on Earth — might encrust the shorelines of lakes on Saturn’s frozen moon, Titan (pictured, is an artist’s impression)
Titan is the only place on Earth where liquid lakes are known to exist as vast bodies of hydrocarbons survive on the moon’s surface.
Data gathered by the Cassini–Huygens mission in 2004/5 revealed that lakes in the moon’s drier equatorial regions were encircled by deposits of mystery materials left behind as the liquids evaporated, much like soap scum around a bath.
‘We don’t know yet if we have these bathtub rings,’ said Dr Morgan Cable, planetary scientist of the NASA Jet Propulsion Laboratory in California.
‘It’s hard to see through Titan’s hazy atmosphere.’
To find out what these materials might be made of, Dr Cable of the NASA researchers set about recreating Titan’s alien environment in the laboratory.
It is believed that the atmosphere of Titan is a chilly -291.1°F (-179.5°C), so the researchers first filled a custom-built cold chamber, or cryostat, with liquid nitrogen.
Warming the cryostat slightly caused the liquid nitrogen to turn into gas, in the same way it would on Titan.
Finally, they added to the gas other chemical compounds that are expected to appear on the Saturnian moon — including ethane, methane and other carbon-containing molecules.
The first solids to form out of their cold hydrocarbon soup were crystals of benzene which behaved surprisingly as it incorporated ethane molecules inside itself.
This formed what scientists call a ‘co-crystal’ of the two components and they went on to find that these bizarre mergers also happened for various other chemicals.,
Researchers detected that similar co-crystals composed of acetylene and butane had also formed.
Although the cold environment of Titan allows these compounds to form solid crystals, on Earth they exist as gases and are commonly used as fuel for welding and cooking.
It is thought these acetylene–butane co-crystals are likely to be more common than their benzene counterparts, Dr Cable said.
Recreating the chilly conditions of Titan’s surface in the laboratory, NASA researchers found that they could form strange new mineral compounds
A similar process occurs on the Earth, where salts can form concentric crusts around the shores of lakes and seas — such as around the edges of the Dead Sea — Dr Cable explained
Researchers think that in Titan’s cold climate, acetylene-butane co-crystals might form around lakes on the moon as the liquid evaporates, causing crystals to form at their edges.
A similar process occurs on the Earth, where salts can form crusts around the shores of lakes and seas, Dr Cable explained.
The crystals may even provide a source of energy for any potential life that could exist on the moon, the researchers suggest.
It will take a spacecraft actually visiting Titan’s shorelines to confirm whether these crystals actually exist on the distant moon, however.
The full findings of the study were presented on June 24 during the 2019 Astrobiology Science Conference held in Seattle, Washington.
TITAN AND EARTH: SIMILARITIES
Titan and Earth share many similar features.
Just as the surface of oceans on Earth lie at what we call ‘sea level,’ Titan’s seas also lie at an average elevation.
It is currently the only other world we know of in our solar system that has stable liquid on its surface.
Smaller lakes on Titan appear at elevations several hundred feet higher than Titan’s sea level. This is similar to lakes found on Earth at high elevation.
For example, the Earth’s highest lake navigable by large ships, Lake Titicaca, is over 12,000 feet [3,700 meters] above sea level.
Titan’s liquid bodies appear to be connected under the surface by something akin to an aquifer system on Earth.
Hydrocarbons seem to be flowing underneath Titan’s surface similar to the way water flows through underground porous rock or gravel on Earth.
This means nearby lakes communicate with each other and share a common liquid level.
Aside from Earth, Titan is the only place in the solar system known to have rivers, rainfall and seas – and possibly even waterfalls.
Of course, in the case of Titan these are liquid methane rather than water on Earth.
Regular Earth-water, H2O, would be frozen solid on Titan where the surface temperature is -180°C (-292°F).
With its thick atmosphere and organic-rich chemistry, Titan resembles a frozen version of Earth several billion years ago, before life began pumping oxygen into our atmosphere.
Because Titan is smaller than Earth, its gravity does not hold onto its gaseous envelope as tightly, so the atmosphere extends 370 miles (595km) into space.
With Titan’s low gravity and dense atmosphere, methane raindrops could grow twice as large as Earth’s raindrops.