The bright one, currently known as S/2002 N5, is 15 miles across and takes 9 years to orbit Neptune. The fainter one, S/2021 ...

A neutron star’s density is mind-boggling. These stars are composed almost entirely of neutrons packed together in a tiny radius. Just a teaspoonful of this material would weigh over a trillion ...

The Planet Parade of 2025 is a truly extraordinary celestial event that has stargazers excited. From January 21 to mid-February, six planets will align in the sky: Venus, Mars, Jupiter, Saturn, Uranus ...