How Do Stars Influence the Search for Life? We Asked a NASA Expert

How do stars influence the search for life? When astronomers search for life on other worlds, they look for atmospheric molecules called biosignatures, or gases that could indicate biological activity. But starlight can dramatically alter a planet’s atmosphere through photochemistry, sometimes creating or destroying these signals. A NASA scientist explains why understanding a planet’s star is essential when searching for life beyond our solar system.

What is said in the film

How Do Stars Influence the Search for Life? We Asked a NASA Scientist. Just like children are influenced by their parents, planets are also influenced by their parent stars, and this has an impact on the search for life elsewhere in the universe. In the search for life on other worlds, we're going to be searching for molecules in planetary atmospheres called biosignatures. Biosignatures are remotely observable signs of life that we can see with our telescopes.

Some examples of biosignatures in Earth's atmosphere are gases like oxygen and methane that are produced by life on our planet. But in the search for life and these biosignatures on other worlds, we have to remember that stars have a major role to play, because starlight can actually change the composition of planetary atmospheres through a process called photochemistry. Photochemistry can enhance the observability of biosignatures, can actually destroy biosignatures, preventing us from seeing them at all. And photochemistry can even generate the production of false biosignatures. These are things that could fool us into thinking that a non-living planet is alive.

And so when we're trying to interpret potential signs of life on planets outside of our solar system, we'll need to carefully measure the light from every star that these potentially habitable worlds are orbiting to understand whether these potential biosignatures we might see could be truly from life. Astronomers have a saying, “Know thy star, know thy planet,” and this definitely applies in the search for life too. We Asked a NASA Expert. NASA. A NASA 360 Production.

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