Astronomers have discovered a planet blacker than coal in our home galaxy, thanks to the NASA Kepler space telescope. The Jupiter-sized gas planet, dubbed TrES-2b, orbits about three million miles out from its star, yet still reflecting almost none of the light shining upon it.
According to lead study author and Harvard-Smithsonian Center for Astrophysics astronomer David Kipping, “being less reflective than coal or even the blackest acrylic paint – this makes it by far the darkest planet ever discovered.” He then added “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.”
Kepler was designed to find planets outside of our solar system, but a planet as far as TrES-2b, at 750 lightyears away, is not exactly a simply done photo-op. The Earth-orbiting spacecraft used light sensors that continuously monitor tens of thousands of stars to look for the regular dimming of stars, and large brightness dips often indicate that a planet is transitioning. In the case of this coal black planet, it was blocking small amounts of light from its star, leaving an alarming brightness.
When planets pass in front of their star, the shaded side faces Kepler. As the planet orbits behind the star, the other side becomes visible. The amount of starlight projected gradually increases until the planet passes behind the star, becoming invisible to Kepler.In the case of TrES-2b, there was only a very slight dimming and brightening difference. According to Kipping, “this represents the smallest photometric signal we have ever detected from an exoplanet.” Scientists compared it to a fruit fly passing in front of a car headlight.
The darkness of the planet remains a mystery, with some suggestions that it is composed of large amounts of gaseous sodium and titanium oxide. However, there may also be something exotic, that we have never heard of before.
Scientists are already coming up with nicknames for the planet – Erebus, for one – ancient Greece’s god of darkness.
Sounds like the next generation of naughty children will receive lumps of Erebus in their Christmas stockings.
Via Nat Geo