SUNSET: 
Planet Hunters are Losing Count
The latest 500 planet candidates from the Kepler mission are just part of the story. But Terra II remains elusive.
A Planet Orbiting Two Suns
NASA's Kepler mission has found an exoplanet that orbits a close pair of stars. This Tatooine-like world should have a lot to tell about planet formation in binary star systems.
50 New Worlds and a Big, Pleasant Earth?
The HARPS planet-hunting spectrograph of the European Southern Observatory has just produced 50 more worlds — one of which may be not too hot, and not too cold by Earth-creatures' standards.
A Planet Made of Diamond
Astronomers have discovered a truly weird planet-like object: a former star core apparently make of a superdense form of diamond, orbiting a pulsar with
The Darkest Exoplanet Yet
Think you know all the kinds of alien worlds? Think again. Two astronomers have just added another weirdo to the list: an exoplanet darker than powdered charcoal.
Kepler's Dilemma: Not Enough Time
NASA's planet-hunter has already identified more than 1,200 exoplanet candidates. But project managers now quietly acknowledge that the spacecraft will have serious difficulty spotting habitable, Earth-size worlds by the mission's end next year.
Kepler's Exoplanets: A Progress Report
The Kepler exoplanet-hunting mission got top press-conference billing at the American Astronomical Society convention in Boston. But some reporters left wanting more.
Do Planets Outnumber Stars?
Just-released observations suggest that the Milky Way could teem with hundreds of billions of free-floating planets.
The Hottest, Densest Super-Earth Yet
Two research teams combine forces to study the wildest exoplanet yet identified.
Kepler Finds Planets in Tight Dance
It can get pretty crowded in the solar systems discovered by NASA's Kepler observatory. In one case, four candidate worlds are locked in a tight orbital dance.
Kepler's Outrageous Six-planet System
NASA's Kepler space telescope has found1,200 likely new planets, including the most bizarre planetary system yet.
Kepler's Dense, Rock-and-Iron Planet
With just 1.4 times Earth's diameter but 4.6 times Earth's mass, Kepler-10b has the average density of iron.
Are You Smarter Than a Computer?
If you think you can spot evidence for an extrasolar planet in this light curve, then a new "citizen-science" effort wants your help.
Carbon is King on a Hot Jupiter
Infrared observations of the close-orbiting exoplanet WASP-12b show that its atmosphere is surprisingly rich in carbon-bearing gases yet contains very little water vapor.
A Steamy Super-Earth?
For the first time, astronomers have detected the atmosphere of an exoplanet that is not a gas giant.
Planet from Another Galaxy
Astronomers have found a planet orbiting a very ancient, high-velocity, former red giant star that came from beyond the Milky Way.
How Many Earths?
A team of planet-hunting astronomers argue, based on discovery statistics, that Earth-mass worlds should be orbiting a quarter of stars like the Sun.
Our "New, Improved" Solar System
Recent computer models suggest a radical yet robust concept: in order to get the Sun's planets and asteroids arranged as they are today, Jupiter must have once been much closer to the Sun.
Watching a Planet's Death Spiral?
The exoplanet OGLE-TR-113b is already too close to its host star for comfort — and new observations suggest it's being gradually drawn inward to its doom.
"Potentially Habitable" Planet Found
Not too hot, not too cold, Gliese 581g orbits in the liquid-water temperature zone of a dim red-dwarf star just 20 light-years away.
