Science

Hubble offers a closer look at Comet ISON

Jupiter's water linked to comet impact

Hubble spots a hidden globular cluster

Black holes measure the expansion of our universe

A massive star factory in an early universe

NASA's Hubble space telescope snaps a horsehead of a different color

The growing threat of space debris

NASA's Kepler discovers three super-Earth-size planets in "habitable zone"

Stellar blazar is a high-energy astrophysics mystery