Humans Are Ready to Find Alien Life...We finally have the tools we need. By Adam Frank
In the thousands of years that people have been arguing about whether life exists elsewhere in the universe, one thing has been constant: No one really has had a clue. But not anymore.
One form of evidence that astronomers are seeking on their great cosmic stakeout is “biosignatures”—features in a planet’s atmosphere that can come only from life.
- Thanks to spectacular advances in science, we’ve identified many stars that have planets in the habitable zone where life can form.
- We are learning which of those planets are Earthlike enough to be worth pointing our telescopes at.
- We have giant telescopes equipped with spectrographs that can analyze light from distant stars, and powerful computers to simulate far-flung worlds.
- If we want to find aliens, we don’t need them to announce their presence to the cosmos.
One form of evidence that astronomers are seeking on their great cosmic stakeout is “biosignatures”—features in a planet’s atmosphere that can come only from life.
Scientists have learned from studying our own planet’s history that Earth’s life has been a major player in our world’s evolution for billions of years.
- Life hijacked the Earth, transforming, among other things, the very air around us.
- Earth’s atmosphere has chemicals in it that would not exist on a lifeless world.
- These include oxygen, ozone, and dimethyl sulfide (a compound that gets released into the air by marine plankton). It stands to reason that the same thing would happen on an alien planet hosting alien life, and now we have a way to check
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