What is life? It sounds like a dumb question, but if we want to find aliens, we really need to be sure of the answer. If we say life needs to eat, reproduce, and grow, all of that can influence what it might look like from far away.

Professor Lisa Kaltenegger was part of a team of researchers that published a paper in 2024 suggesting that life on other planets might be purple rather than the “little green men” imagined by Hollywood. The idea applies specifically to what color dots we should be on the lookout for when searching for planets that might have life; not blue like our own watery world, not worlds of forest green, but instead purple ones.

We spoke to Kaltenegger about how on Earth you begin looking for life on other planets, and what we’ve learned so far about what it might look like.

This talk originally appeared at CURIOUS Live, May 2024: https://www.iflscience.com/atomic-bom...

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Prof Lisa Kaltenegger: https://astro.cornell.edu/lisa-kalten...