This image from NASA's Kepler mission shows the telescope's full field of view -- an expansive star-rich patch of sky in the constellations Cygnus and Lyra.

An animation of an imagined Earth-sized exoplanet.

For the first time since exoplanets, or planets around stars other than the sun, were discovered almost 20 years ago, X-ray observations have detected an exoplanet passing in front of its parent st...

Orbiting planets cause stars to wobble in space, changing the color of the light astronomers observe.

This image from the NACO system on ESO’s Very Large Telescope shows a candidate protoplanet in the disc of gas and dust around the young star HD100546.

Like ancient explorers who looked to the stars to guide them to new worlds, astronomers today use stars to discover worlds many light years beyond our solar system. By studying stars and their uniq...

Up-close picture of Kepler CCD hardware.

Artistic rendering of a planet's transmission spectrum

This artists impression shows the free-floating planet CFBDSIR J214947.2-040308.9. This is the closest such object to the Solar System.

This image from NASA's Kepler spacecraft shows the telescope's field of view taken in a new demonstration mode in late October. A new mission concept, dubbed K2, would continue Kepler's search for ...

Five years ago today, on March 6, 2009, NASA's Kepler Space Telescope rocketed into the night skies above Cape Canaveral Air Force Station in Florida to find planets around other stars, called exop...

The artistic impression shows NASA's planet-hunting Kepler spacecraft operating in a new mission profile called K2.

The flower you see in this picture isn’t NASA’s attempt to celebrate the coming of spring. It’s actually the latest design in a cutting-edge effort to take pictures of planets orbiting stars far fr...

A detailed explanation into the workings of the coronagraph and how it can help directly image exoplanets.

The first planet to have its clouds mapped showed us what weather looked like on a planet outside our solar system.

Scientists using NASA’s Hubble Space Telescope have found evidence that a planet orbiting a distant star may have lost its atmosphere but gained a second one through volcanic activity. 

Kepler does not directly observe the image of a planet. Rather it observes the effect the planet has on its parent star. If the orbit of the planet is aligned along Kepler's line of sight to the st...

This sculpture by Angela Palmer is created from the data gathered to date by the Kepler telescope. It literally reproduces in three dimensions the chunk of sky the Kepler telescope has been trained...

This episode of "Hubble at 25" uncovers Hubble's Key role in the study of planets beyond our solar system.

Transit data are rich with information. By measuring the depth of the dip in brightness and knowing the size of the star, scientists can determine the size or radius of the planet. The orbital peri...

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have taken the first ever image of the snow line in an infant planetary system.

When a planet passes directly between a star and its observer, it dims the star's light by a measurable amount. Light curves get complicated when more planets are transiting a star. The combined li...

The Kepler space telescope will remain for decades in orbit around the Sun, weaving in and out of Earth’s orbital path.

Planets having atmospheres rich in helium may be common in our galaxy, according to a new theory based on data from NASA's Spitzer Space Telescope. These planets would be around the mass of Neptune...

NASA's Kepler mission revealed that there are more planets than stars in our galaxy. It opened our eyes to diverse worlds – some entirely unlike planets found in our solar system.