NASA’s James Webb Space Telescope will begin searching for methane to detect life in space.
Researchers have found that under certain conditions, methane could be a promising sign of life if found in the atmosphere of a rocky exoplanet – even more so than oxygen.
One of these conditions is that, in addition to methane, atmospheric carbon dioxide must also be present on the exoplanet.
In addition, the exoplanet cannot be water-rich and its planetary atmosphere must contain more methane than carbon monoxide.
A team of researchers from the University of California, Santa Cruz (UCSC), with support from NASA, presented the results in the journal Proceedings of the National Academy of Sciences.
Methane is one of the few biosignatures detected by the James Webb Space Telescope (JWST), which was deployed last Christmas Day.
“Oxygen is often cited as one of the best biosignatures, but with JWST it will likely be difficult to detect,” said Maggie Thompson, a doctoral student in astronomy and astrophysics at UCSC and lead author of the new study.
JWST can identify chemicals like water and methane based on the infrared wavelengths they emit.
Methane emits near-infrared wavelengths (1-3 um), which is the level best for the space telescope to pick up.
However, finding methane on an exoplanet does not necessarily mean that there is life there.
This is because many non-biological sources can release the chemical, such as volcanoes, hydrothermal vents, and comet or asteroid impacts.
“One molecule isn’t going to give you the answer — you have to consider the whole context of the planet,” Thompson said.
“Methane is one piece of the puzzle, but to determine if there is life on a planet, one must consider its geochemistry, how it interacts with its star, and the many processes that can affect a planet’s atmosphere on geological timescales,” continued she continued .
Fortunately, Nasa’s $10 billion space instrument may also be able to reveal whether a methane source on an exoplanet is biological or non-biological.
“This study focuses on the most obvious false positives for methane as a biosignature,” said co-author Joshua Krissansen-Totton, an astrobiologist at UCSC.
“The atmospheres of rocky exoplanets are likely to surprise us, and we have to be careful about our interpretations,” he added.
JWST reached its cosmic parking spot at the Earth-Sun Lagrange point 2 (L2) nearly two months ago and is scheduled to become operational this summer.
Once operational, the telescope will scan the night sky for faint infrared light, some of which may be emitted by first-generation stars and galaxies.
The data should help researchers in the coming years to better understand the beginnings of our universe.
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https://www.the-sun.com/tech/5002453/alien-life-nasa-key-sign-space/ How to spot ALIEN life – Nasa reveals the key sign it’s now looking for in space