May 02, 2013
Image of the Day: Sunset on Osiris (Exo-Planet HD209458b)
The amazing image above of a sunset on exo-planet HD209458b 150 light years away, was reconstructed by Frederic Pont of the University of Exeter using data from a camera onboard the Hubble Space Telescope.
Pont used his knowledge of how the color of light changes based on
chemicals it encounters, and computer modeling, to create an actual
image of what a sunset on the actual planet would look like.
The large exo planet in question, exoplanet HD209458b, nicknamed Osiris,
circles its star rather closely. At certain points, when the planet
passes between us and its star, the light from that star passes through
Osiris’s atmosphere before reaching us, which allowed Pont to determine
the chemical composition of the atmosphere and deduce what colors would
appear to the naked human eye.
The light from Osiris’s star is white, like our own sun, but when it
passes through the sodium in Osirisi’s atmosphere, red light in it is
absorbed, leaving the starlight to appear blue. But as the sun sets, the
blue light is scattered in the same way as it is here on Earth (Rayleigh scattering)
causing a gradual change to green, and then to a dim dark green. And
finally, due to diffraction, the bottom of the image becomes slightly
The Daily Galaxy via Hubble/ESA and Frederic Pon
Image of the Day: Sunset on Osiris (Exo-Planet HD209458b).
Thanks to: http://2012indyinfo.com