TrES-2b, the blackest planet ever discovered in the Milky Way galaxy, is only three million miles away from the star it orbits, which makes its atmosphere burn at 980 degrees Celsius (1,800 degrees Fahrenheit). But still, the blacker than coal planet mysteriously reflects only one percent of the starlight that strikes it, a new study revealed.
The black gas giant, discovered by astronomers using NASA's Kepler space telescope, is located at a region, 750 light-years away from Earth. According to astronomers, the planet surprisingly absorbs almost 100 percent of the light that comes from its star.
"If we could see it up close it would look like a near-black ball of gas, with a slight glowing red tinge to it-a true exotic amongst exoplanets," said David Kippling, the lead author of the report and an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
According to astronomers, TrES-2b's darkness might be due to a large quantity of gaseous sodium and titanium oxide. But none of these materials can clarify the reason of its darkness, which is more extreme compared to any other astronomical objects in our own solar system.
"It's not clear what is responsible for making this planet so extraordinarily dark," said Princeton University professor David Spiegel, co-author of the report. "However, it's not completely pitch black. It's so hot that it emits a faint red glow, much like a burning ember or the coils on an electric stove."
"More likely there is something exotic there that we have not thought of before," Kippling said. "It's this mystery that I find so exciting about this discovery."
The Kepler telescope, orbiting Earth, spotted the dark alien world with the help of its light sensors called photometers. Kepler is a NASA spacecraft, designed to discover Earth-like planets orbiting other stars. It was launched in March, 2009 with a lifetime of at least 3.5 years.
TrES-2b is the size of Jupiter. But unlike Jupiter, which has clouds striping it with white and red that reflects more than one third of the sunlight reaching it, TrES-2b doesn't have such reflective clouds.
However, the research team studied the brightness of the TrES-2 system as the planet orbited its star and detected a subtle dimming and brightening due to the planet's changing phase.
Like the moon, the planet is believed to be tidally locked and hence, no side of the planet faces the star. Also, the planet shows changing phases as it orbits its star similar to earth's moon, which varied the total brightness of the star by around 6.5 parts per million.
Astronomers even doubt that the discovery of TrES-2b may lead to a whole new set of exoplanets. They believe that apart from the black planet, similar worlds orbiting other stars would be there, yet to be discovered.