A biosignature is a substance or pattern that could indicate the presence of life, such as certain combinations of gases in a planet's atmosphere that would be hard to sustain without biology. Oxygen alongside methane is a classic example. Detecting a biosignature on an exoplanet would be suggestive rather than conclusive, since non-living chemistry can mimic many signals, which is why the field stresses caution and independent confirmation.
Cosmology · Exoplanets · Astrobiology
In 2025, a team announced a gas in a distant world's air that, on Earth, is made almost only by living things. Then the scrutiny began, and it became ...
Cosmology · Exoplanets · Astrobiology
For the first time, the James Webb Space Telescope has read the bare rock of a world 48.5 light-years away. LHS 3844 b is a dark, hot, airless slab of...
Cosmology · Astrobiology · Origin of Life
Three billion years ago, perhaps four, a single cell at the bottom of an ocean was the ancestor of every plant, animal, fungus, and microbe ever to ex...
Cosmology · Astrobiology · Asteroids
Fifteen of the twenty amino acids life uses. All five DNA and RNA bases. Ribose. Glucose. And a polymer never seen anywhere else in space. NASA opened...
Cosmology · Exoplanets · Astrobiology
TRAPPIST-1 has seven Earth-sized planets at 40 light-years from Earth. Three sit in the habitable zone. JWST has spent two years probing their atmosph...
Cosmology · Astrobiology · Icy Moons
At 10,935 meters down, in pitch darkness and pressure that would crush a submarine, life persists. Tube worms grow two meters long around hydrothermal...