What is a Potential Biosignature?

NASA program scientist Lindsay Hays explains what defines potential signs of ancient life on other worlds and why they require future study. NASA’s Perseverance Mars rover is searching for these signs, collecting samples for future return to Earth, and helping pave the way for human exploration.

Learn more about Perseverance: science.nasa.gov/mars2020

For details on each of the samples see: science.nasa.gov/mission/mars-2020-perseverance/mars-rock-samples/

What is a Potential Biosignature?

A potential biosignature is a substance or structure that might have a biological origin but requires more data or further study before reaching a conclusion about the absence or presence of life.

As the name indicates, a biosignature is a sign of life.

Oftentimes, when we think about biosignatures, we think about signs of past life, usually preserved in the rock record, sometimes preserved in atmospheric gasses or anything like that. But in general, what it is, is it's an indication not necessarily of a particular living thing at this moment, but a sign that there was life in an environment or in a place sometime in the past,

Sometimes when we think about potential biosignatures, we're also talking about something that's different than how we think of life on our planet.

When we're thinking about life on other planets, that can be different enough from life on our planet that we have to eliminate more possibilities. We have to think more deeply about the chemistry, about the geological processes on those other planets, as a way to make sure that something that we see is truly an indication of life somewhere else.