A schoolbus sized asteroid hits with a energy = 100kton explosion, about 6 Hiroshima bombs. Now NASA has a Planetary Defense Office to track potential asteroid impacts.
White dwarfs are the remains of dead stars. They cool in a predictable manner, giving astronomers a way to determine how long ago they died.
There are about 100 times as many stars in the observable universe as insects living on earth.
Active Galactic Nuclei can produce a jet that accelerates matter to 0.99995 times the speed of light.
Pulsars are rapidly rotating neutron stars that emit a lighthouse-like beam that we can detect when pointed at us, appearing to “pulse”. Some pulses are so short (ms) that we can use them as clocks, like one clock at the European Parliament.
Astronomers have discovered over 2,000 planets in the Milky Way since 1988. This means there could be up to 40 billion potentially habitable Earth-sized planets in the Galaxy.
Our sun is a middle aged star (4.5 billion years old). When it runs out of hydrogen fuel, the sun will double in size, engulfing Mercury, Venus, and maybe Earth. Don’t worry. We’ve got 5 billion years before that!