|This artist's rendition released NASA October 30, 2013 shows Kepler-78b orbiting its parent star. (AFP/NASA)|
The space scientists are baffled after finding the first ever Earth-sized planet, which has the same density as our home world, and violates all known planetary formation theories by its existence.
The discovery of Kepler-78b was made by two separate groups of astronomers in the US and Switzerland, who were analyzing data from NASA’s Kepler Space Telescope. The new planet orbits a sun-like Kepler-78 star in the Cygnus or Swan constellation some 400 light years away from Earth.
The scientists say that Kepler-78b is unique as it’s the first known Earth-sized planet, which has a density similar to Earth. Despite being twice as heavy, it’s just 20 per cent larger than Earth and is believed to be composed of the same rock and iron as our home world. But this is where the similarities end as the astronomers stressed that life is impossible on Kepler-78b, which Andrew W. Howard from the University of Hawaii described “as one of the most hellish” places ever discovered.
The planet is a lava world where the surface temperatures exceed 1000 Celcius, “well above the temperature where rock melts,” Howard told the New York Times. Such extreme conditions are caused by Kepler-78b’s super tight orbit, which overturns the existing knowledge on planetary formation.
The planet circles around its star in just eight and a half hours at a distance of less than a million miles (around 1.6 million kilometers). By contrast, Earth is 93 million miles (around 150 million kilometers) away from the sun, completing a full circle around it in 365 days. According to current theories, Kepler-78b couldn't have formed so close to its star as its orbit would’ve been inside the sun when the system was taking shape.
“It couldn't have formed in place because you can't form a planet inside a star. It couldn't have formed further out and migrated inward, because it would have migrated all the way into the star. This planet is an enigma,” Dimitar Sasselov, a member of Dr. Pepe’s team, told the Harvard-Smithsonian Center for Astrophysics (CfA) website.
Another CfA astronomer, David Latham, acknowledged that modern science doesn’t “know how it formed or how it got to where it is today,” calling Kepler-78b “a complete mystery.”
However, Latham stressed that the newly discovered planet “isn’t going to last forever.”
In three billion years, the gravitational tides will draw Kepler-78b close to the sun and it’ll eventually be ripped part. Kepler-78b is one of more than 150 planets, which NASA’s Kepler Space Telescope spotted by registering dimming of the starlight when a planet passes in front of it. The spacecraft was launched in 2009, but went out of order this May, with the US Space Agency saying that it won’t be making attempts to resume its operations.
But the amount of data on exoplanets (planets outside the Solar system), which Kepler managed to collect, will take several years for the astronomers to analyze.