Jupiter-sized Alien Planet is Darkest Ever Seen, Astronomers Say

The planet in question, TrES-2b, was detected by NASA's Kepler spacecraft circumventing the yellow sun-like star GSC 03549-02811 about 750 light years away in the Draco constellation. Scientists said the newly discovered planet is "blacker than coal" and said the world -- a giant the size of Jupiter -- reflects less than one percent of the sunlight falling into it, making it the darkest planet or moon ever seen up to this point.

"It's darker than the blackest lump of coal, than dark acrylic paint you might paint with. It's bizarre how this huge planet became so absorbent of all the light that hits it," David Kipping, an astronomer at the Harvard-Smithsonian Center for Astrophysics and lead author of the study, told SPACE.com.

The research will be published in the journal Monthly Notices of the Royal Astronomical Society.

While Jupiter, which is also a gas planet, contains clouds that reflect more than a third of the sunlight reaching it, scientists say TrES-2b apparently lacks those clouds due to the intensity of the heat on the planet. The atmosphere of the super-heated world is thought to reach temperatures of some 2,192 degrees (1,200 degrees Celsius).

TrES-2b is so hot that scientists said it emits a faint red glow, similar to a burning ember.

Researchers believe the lack of reflective clouds doesn't completely explain why the planet is as dark as it is. Researchers propose that light-absorbing chemicals such as vaporized sodium and potassium or gaseous titanium oxide in the planet's atmosphere may explain why it so stealthily cloaked.  However, Kipping also acknowledged that it is likely that the planet may have an exotic chemistry that researchers on Earth have never seen before.

TrES-2b is one of about 1,200 candidate planets discovered by Kepler. Of those, 54 appear to reside in locations where temperatures would be right for liquid water, known as habitable zones.  Researchers predict that at least 500 million of the Milky Way's probable 50 billion planets are located in the habitable zone, indicating there is an enormously positive chance of someday discovering alien life.

To date, astronomers have identified more than 500 alien planets. The Kepler spacecraft, which launched in March 2009, is planned to run until at least November 2012.