Halley's Comet: Facts about history's most famous comet

Martian meteorite’s organic materials origin not biological, formed by geochemical interactions between water and rock

NASA's Perseverance rover is clogged up with pebbles

Two new studies using data from NASA’s retired Spitzer Space Telescope shed light on giant exoplanets and brown dwarfs, objects that aren’t quite stars but aren’t quite planets either.