Alpha Cephei, or Alderamin, is a fast-spinning star

Olbers' paradox asks why is space dark if the universe is filled with stars. The answer has to do with traveling light and red-shifting colors. The post Olbers’ paradox asks ‘Why is the night sky dark?’ first appeared on EarthSky.

On October 24, 1946 — 80 years ago — a movie camera on board a V-2 rocket captured the 1st-ever photo of Earth from space. The post 1st photo of Earth from space, 80 years ago first appeared on EarthSky.

[…] in the southern sky. After viewing it, swing around to the north and view the north star (Polaris) at that […]

Why does anything exist? A new theory suggests a forgotten particle might have shifted the balance between matter and antimatter. The post Why does anything exist? New theory emerges first appeared on EarthSky.

NASA’s Lucy mission is now less than a year from reaching the Trojan asteroids near Jupiter. And it has already made some exciting discoveries along the way. The post Lucy mission to Trojan asteroids: 5 years of discoveries first appeared…

Cassiopeia and Perseus are neighbors in the autumn sky. Use Cassiopeia's distinctive W or M shape to locate the dimmer Perseus on autumn and winter evenings. The post Cassiopeia and Perseus on October evenings first appeared on EarthSky.

Astronomers in the U.K. have found that the true colors of white dwarf stars can vary greatly. They even found the 1st known green star. The post Surprising colors of white dwarf stars revealed for 1st time first appeared on EarthSky.

The Euclid space telescope made an accidental comet discovery as it searched the universe for evidence of dark matter and dark energy. The post Euclid was mapping the universe. Then it found a comet first appeared on EarthSky.