We could look for waste products of life, or we could look for molecular building blocks of life, planetary scientist Mike Malaska tells Inverse.
When we look for biosignatures, it’s not only the presence of the molecule that matters, Morgan Cable, a planetary scientist, tells Inverse.
The Mars we know is a cold and dry world pummeled by radiation. Any life would have moved to the subsurface, planetary scientist Amy Williams tells Inverse.
In 2018, NASA’s Curiosity rover found fragments of complex organic molecules in 3-billion-year-old rock. These molecules tell us that if life once existed on Mars, we can detect it.
On Earth, we call these spots hydrothermal vents — or fissures in the ocean floor — and they are thriving ecosystems teeming with life which feed on the chemicals produced in the reaction between the hydrogen gas and the rock. But that doesn't mean the same is true for Enceladus, Cable says.
A biosignature in the atmosphere of an exoplanet has to pass a lot of tests. Firstly, the biosignature must be in the form of a gas, Clara Sousa-Silva, an astrobiologist and planetary atmospheres expert, tells Inverse.