How Scientists Would Prove Extraterrestrial Life

This is an unraveled version of a twitter thread upon request for clearer visibility and in the event the website implodes. It was written May 26, 2023.

how we'd prove we found life on Mars:

we'd need to first rule out contaminants. you may have heard of some organisms that can survive space (extremophiles!), but it's also thought bacteria could hitch a ride on spacecraft!

therefore NASA has V E R Y strict rules (even Officers!) about how one may visit and behave on alien surfaces. In fact, it has a name: Planetary Protection [here's a book about it!]

for example-- Perseverance has five "witness tubes." These tubes carry materials to capture contaminants, such as gases accidentally released from the rover, its propulsion system, or other accidental matter.

these tubes are opened to "witness" the environment samples were taken, and come back to earth to let scientists know if the area has been contaminated.

in other words-- we HAVE to be sure we haven't simply rediscovered OURSELVES on Mars! Rovers like Perseverance have very well-defined, meticulously documented deposit sites so scientists can keep track of where we've been!

This "analysis" I keep talking about is on the *microscopic* level and smaller. We're not just looking for bacteria, but the very *elements* in the soil. We need to know the soil's history as much as its present. Call it interplanetary archaeology!

shudder to imagine how many particles are shed by small collisions with this craft alone. It will become increasingly difficult to prove extraterrestrial life conclusively if private companies are not held to scientific standards.