NASA researchers, using a powerful telescope located in Chile, found a simple carbon-based molecule called cyclopropenylidene or C3H2
October 29, 2020 Share on FacebookShare Share on TwitterTweet Share on WhatsAppShare
Infrared images of Saturn's moon Titan representing some of the clearest global views of the icy surface (NASA)
Last year, a NASA scientist said that Titan, Saturn's largest moon that is home to seas and hydrocarbon rains, may be home to a “strange methane-based alien life.” It was the planetary researcher Amanda Hendrix, one of the leaders of NASA's new program of exploration of ocean worlds (Roadmaps to Oceans World Group), who explained that objects like Titan “represent the best possibility, in our solar system, of finding life. .
Today, new scientific research seems to agree with Hendrix, as colleagues of his at the US Space Agency have identified a molecule in Titan's atmosphere that has never been detected in any other atmosphere: cyclopropenylidene or C3H2.
Using the ALMA radio telescope, NASA scientists found the complex molecule (NASA)
Scientists claim that this simple carbon-based molecule may be a precursor to more complex compounds that could form or fuel possible life on Titan. The researchers found C3H2 using the ALMA (Atacama Large Millimeter / submillimeter Array) radio telescope observatory located in Chile . There, they detected C3H2, which is made up of carbon and hydrogen, while examining a spectrum of unique light signatures collected by the telescope. These revealed the chemical composition of Titan's atmosphere by the energy its molecules emitted or absorbed.
“When I realized I was looking at cyclopropenylidene, my first thought was, well, this is really unexpected, ” said Dr. Conor Nixon, a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who led the search for ALMA. Although scientists have found C3H2 in different parts of the galaxy, finding it in Titan's atmosphere came as a surprise. This is because cyclopropenylidene can easily react with other molecules with which it comes into contact and form different species. So far, astronomers have found C3H2 only in clouds of gas and dust floating between star systems; in other words, regions that are too cold and diffuse to facilitate many chemical reactions.
Titan, the largest moon of Saturn, is a bigger bet for NASA in order to find life (NASA)
A treasure trove of new molecules
But dense atmospheres like that of Titan are classified as hives of chemical activity. That's one of the main reasons scientists are interested in this moon, which is the destination for NASA's upcoming Dragonfly mission , a kind of robotic dragonfly that could fly from one place to another on the surface of Titan. using “quadcopter” technology similar to that used by drones here on Earth. Dragonfly may detect signs of Titan's life: biomolecules, for example, or variations in hydrogen that indicate that microbes are using this gas as a source of energy. Nixon's team was able to identify small amounts of C3H2 on Titan probably because they were looking at the upper layers of the moon's atmosphere, where there are fewer other gases that C3H2 interacts with. Scientists still don't know why cyclopropenylidene would appear in Titan's atmosphere but not in another atmosphere.
” Titan is unique in our solar system. It has proven to be a treasure trove of new molecules, ”Nixon said of the largest of Saturn's 81 moons. It is an intriguing world that, in a way, is the most Earth-like we've ever encountered. Unlike any other moon in the solar system (there are more than 200), Titan has a dense atmosphere that is four times as dense as Earth's, plus clouds, rain, lakes and rivers, and even an underground ocean of water. salty. Titan's atmosphere is made up mostly of nitrogen, like Earth's, with a hint of methane. When methane and nitrogen molecules break apart under the sun's glare, the atoms that compose them set off a complex web of organic chemistry that has captivated scientists and brought this moon to the top of the list of most important targets. on NASA's search for life in the solar system present or past.
“ We are trying to find out if Titan is habitable. So we want to know what compounds from the atmosphere reach the surface and then if that material can pass through the ice crust to the ocean, because we believe that the ocean is where the habitable conditions are, ”said Rosaly Lopes, senior scientific researcher and Titan expert at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.
Artist's conception of what Titan's methane lakes would look like – REUTERS / NASA / JPL-Caltech / USGS
An analysis of the chemical composition of nine impact craters on Saturn's moon Titan supports that there is a recipe with ingredients for life, albeit different from what works on Earth. A study published in early October by Astronomy and Astrophysics, which used advanced imaging technology to investigate Titan, has revealed that when impact craters form on Saturn's largest moon, relatively recent “water ice” of the icy crust of Titan.
On Titan, atmospheric processes bury the ice under a layer of organic material similar to sand. In the dry equatorial regions of Titan, the sand piles up; but at higher and more humid latitudes, surface streams erode the sand. It's difficult to assess what's under Titan's hazy atmosphere, but it was made possible by an ESA visible and infrared mapping spectrometer, which collected slightly longer wavelength visible and infrared light during NASA's Cassini mission.
Saturn's moon is home to numerous small lakes, dry lake beds, and disappearing lakes – NASA / JPL-CALTECH / ASI / USGS
The main results are consistent with an existing Titan surface evolution scenario, in which the impact crater process produces a mixture of organic material and water ice, which is then “cleaned up” by river erosion in the latitude plains. socks. “It is wild. There is no other place like Titan in the solar system. There is more sand on Titan per area than anywhere else. Titan has weather. It is no different than Earth in that sense. It's just that the ingredients are wrong. It has methane rain and streams running through the surface and moving organic sand. It's still very active, just like it is here on Earth, ”said Catherine Neish, a planetary geologist at the Institute for Earth and Space Exploration at Western Ontario University, lead author of the new research.
In his view, the new findings could prove beneficial in discovering ancient ecosystems frozen at the bottom of impact craters and in preparing data analysis and monitoring techniques for the next mission to Titan Dragonfly, a NASA helicopter drone. “I think that more and more, we are seeing a false equivalence between life and Mars. The recent discoveries about Venus and all the new things that we are learning about it once it is an ocean world is another game changer, ”Neish said. “Finally, people say, ' In our search for life in the universe, we really need to focus on a lot more places , and not just Mars .' And that includes NASA sending the Dragonfly mission to Titan. “
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