Topic

Biosignatures

NASA’s Perseverance rover on reddish Martian bedrock beside the arrowhead-shaped rock called Cheyava Falls, with a rocky hill behind under a hazy sky.

LifeAnalysis

The leopard spots of Cheyava Falls

A rock in an ancient Martian river valley carries chemical patterns that, on Earth, are usually made by microbes. NASA calls it a potential biosignature. The sample that could settle it may never come home.

CosmosLens EditorsNovember 8, 20264 min read

Illustration of a blue ocean-covered planet with a thick hazy atmosphere, lit from one side by a distant red star.

PlanetsAnalysis

How to read the sky of a world you will never see

Astronomers can now measure the gases around a planet 124 light-years away. The rise and fall of the claims about K2-18b show what that technique can do, and how easily it can be over-read.

CosmosLens EditorsNovember 8, 20264 min read