I don't understand how a planet can absorb light and not reflect it. :shrug: Is it the atmosphere or the planet itself? It may be hard to imagine a planet blacker than coal, but that's what astronomers say they've discovered in our home galaxy with NASA's Kepler space telescope. Orbiting only about three million miles out from its star, the Jupiter-size gas giant planet, dubbed TrES-2b, is heated to 1,800 degrees Fahrenheit (980 degrees Celsius). Yet the apparently inky world appears to reflect almost none of the starlight that shines on it, according to a new study. "Being less reflective than coal or even the blackest acrylic paint—this makes it by far the darkest planet ever discovered," lead study author David Kipping said. "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," added Kipping, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.... Please Register or Log in to view the hidden image!
Two reasons that this planet is quite not as black as it is painted; first of all it is hot, glowing at a temperature of 1200 Kelvin, so it won't look black, but cherry red. Secondly this planet is very close to its star, so the light reflecting off it will be bright, even if only 1% is reflected.
On the sun, sun spots look dark, but that is only an illusion created due to brighter surrounding areas. Those sun spots are in reality bright enough to blind any humans dumb enough to look at them for a length time. That planet it close enough to it's star that a similar effect will take place.
This is very true. But if you were between this planet and its sun, looking towards the planet, all you would see is the relatively bright reflected sunlight that comes from the surface. Even though its albedo is quite low, it will be quite a bright object in these circumstances. Perhaps the best graphic representation of a planet like this can be found here http://www.universetoday.com/wp-content/uploads/2008/10/2005-0703core-full.jpg note that the sunlit side is quite bright compared to the darker side, but that is quite bright in its own right.
Sense we have never had a close up view, it's really hard to say for sure. But I do like the graphic representation. But there's a whole new generation of VLT's scheduled to come online this decade, plus the new Web Space Telescope. I can hardly contain myself for waiting.Please Register or Log in to view the hidden image!
TrES-2b rotates around a star with the original name: GSC 03549-02811. This star is a G0V class (that's pretty bright our own sun is also a G2V type star). So let's asume it has the exact same brightness, the planet rotates at 0.035 AU or roughly 10 times closer then mercury does to our sun. Who allready recieves 14 times the solar energy that earth does. So ebarucum is right and this dark planet reflects even 1% the solar energy it's still brighter then earth
It can absorb it and then re-radiate it later (at a different wavelength, usually infrared unless the thing is really hot. See http://en.wikipedia.org/wiki/Black_body). This is different to reflection. Since this is a gas giant it is the composition of the atmosphere that is responsible for this. On the earth the atmosphere is still very important in this process (i.e. big white clouds reflect much more sunlight than no clouds) but the ground cover is important too (big white areas of snow reflect much more sunlight than forest canopies). Of course the details are complex.
What I like about this story is that the exoplanet was discovered by the Trans-Atlantic Exoplanet Survey which uses three 10cm (4-inch) telescopes. You don’t need huge expensive astronomy infrastructure to do amazing astronomy research!
fk, I am so humbled right now that I think I just lost a testicle... oh wait... I don't have those... but you get the point.
According to NASA’s Astronomy Picture of the Day, the reasons for TrES-2b's darkness remain unknown and are an active topic of research. http://apod.nasa.gov/apod/ap110822.html
