01Size11 kmDist5.30 billion kmTemp100 K (-173 °C)
Halley's Comet
An icy visitor that returns every human lifetime.
CometCosmos
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NASA / CXC / M. Markevitch — Bullet Cluster (1E 0657-56)
Picture this
Dark matter has no shape and no edges that we can see — only its gravity is visible, shaping the rotation of every galaxy ever measured.
Galaxies spin too fast for the matter we can see to hold them together — they should be flying apart. Something invisible is providing the extra gravity. We can map it through gravitational lensing, and it appears to outweigh ordinary matter five to one. We just don't know what it is.
Did you know?
Right now, dark matter particles are streaming through your body by the billions every second. They don't interact with the atoms in you — they only feel gravity — so you never notice.
Last updated 2026-07-05
An icy visitor that returns every human lifetime.
A city-sized star with the mass of a sun.
The dwarf planet that taught the Solar System has an outer layer we'd missed.