U.S. Markets open in 3 hrs 54 mins
20 / 36

Distant planets

An artist's impression shows a Jupiter-sized planet passing in front of its parent star. Such events are called transits. When the planet transits the star, the star's apparent brightness drops by a few percent for a short period. Through this technique, astronomers can use the Hubble Space Telescope to search for planets across the galaxy by measuring periodic changes in a star's luminosity. The first class of exoplanets found by this technique are the so-called "hot Jupiters," which are so close to their stars they complete an orbit within days, or even hours. REUTERS/NASA/ESA/G. Bacon/Handout

Dazzling distant galaxies

An artistic sampling of some far-away worlds.