01Size3,475 kmDist384,400 kmTemp250 K (-23 °C)
The Moon
Earth's only natural satellite — locked to us forever.
SatelliteCosmos
Loading…
Loading…
NASA / JPL-Caltech (PIA21085)
Neutron Star Mount Everest
Drawn to true scale.
Picture this
A neutron star is roughly the diameter of a city — yet packs more mass than the entire Sun into that space.
By weight
A single sugar cube of neutron-star matter would outweigh every human on Earth combined.
When a massive star collapses, its core can be crushed until protons and electrons fuse into pure neutrons. The result is roughly 20 km across but weighs more than the Sun. A spinning, magnetised neutron star is called a pulsar — its lighthouse beams sweep past Earth with the regularity of an atomic clock.
Glossary
Did you know?
A newly formed neutron star has a surface temperature near 600,000 K (about 600,000 °C — the two scales are essentially the same at stellar temperatures), more than 100 times hotter than the surface of the Sun. Most of that heat radiates as X-rays our eyes can't see.
Last updated 2026-05-17
You are here
Scale
A city-sized star with the mass of a sun.
Size
20 km
Tap a dot to preview it. Use the Open stop link to read its full page. Stops are arranged from smallest on the left to largest on the right.
Earth's only natural satellite — locked to us forever.
Our reference grain of sand.
The Solar System's largest planet — a failed star, almost.