Stars move slowly across the sky over very long periods. The closer a star is, the more easily we can see its movement. Stellar parallax is a shift in a star's apparent position due to Earth's orbit.

Following the Big Bang, the universe entered a period of darkness for approximately 100 million years, with its primordial composition dominated by hydrogen, helium, and trace lithium. The first stars ...

ESO’s VISTA telescope, at the Paranal Observatory in Chile, has captured a striking new image of the Helix Nebula. This picture, taken in infrared light, reveals strands of cold nebular gas that are ...