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Christopher Crockett
Sunrise at Srah Srang, Cambodia

What is sidereal time?

Explanation of sidereal time, or star time. New Year’s celebrations on Mercury. How Venus spins backwards and is the slowest rotating planet in the solar system.

The Doppler effect

What is a redshift?

Subtle changes in the color of starlight let astronomers find planets, measure the speeds of galaxies, and track the expansion of the universe.

Dawn spacecraft reveals landscapes of Vesta

New findings from NASA’s Dawn spacecraft reveal enormous impact craters and diverse mineralogy on the asteroid Vesta.

New planet found in distant solar system by its tug on another world

Using the same technique that led to Neptune’s discovery in 1846, astronomers have found a previously hidden planet by observing its pull on a neighboring world.

Artists impression of the HD 10180 planetary system with two planets passing in front of the star.

Record-breaking nine planets orbiting a nearby star

HD 10180 might host a nine-planet solar system. Though slightly larger and brighter than our sun, this star might comfort human visitors with its familiar yellow glow.

Images from the Hubble Space Telescope of the six galaxies discovered to be recycling gas. Credit: NASA/STScI

Six galaxies caught in act of capturing star ingredients

The discovery is an important step to understanding how galaxies grow and sustain themselves over timescales as long as the age of the universe.

A supernova in M95

Currently supernova SN 2012aw is shining with the light of 500 million suns and will most likely get much brighter.

Citizen scientists uncover a galaxy of bubbles

Since December 2010, over 35,000 volunteers have used the crowdsourcing power of Zooniverse to uncover thousands of giant gas bubbles in our Milky Way galaxy.