Glossary

Biosignature

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.

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Cosmology · Exoplanets · Astrobiology

The First Exoplanet Whose Surface We Have Actually Seen

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...

June 2, 202614 min read

Cosmology · Astrobiology · Origin of Life

Every Living Thing on Earth Descended From One Cell. We Now Know Roughly Where It Lived.

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...

May 29, 202615 min read

Cosmology · Astrobiology · Asteroids

The Asteroid Sample That Brought Back Almost Every Ingredient for Life

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...

May 23, 202616 min read

Cosmology · Exoplanets · Astrobiology

Seven Earth-Sized Worlds Around One Star, and What James Webb Just Found Out About Them

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...

May 20, 202617 min read

Cosmology · Astrobiology · Icy Moons

The Deepest Place on Earth Tells Us What to Look For on Europa

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...

May 10, 202616 min read

Cosmology · Astrobiology · SETI

Where Is Everybody?, and Why the Most Famous Question in Astronomy Just Got Quietly Demolished by Math

Enrico Fermi reportedly asked the question over lunch at Los Alamos in 1950. For seventy-five years it has been one of the most cited puzzles in scien...

May 9, 202615 min read