We’ve seen countless sunsets, we’ve seen earthrise from moon, and the Martian sunset. Now we feel qualified enough to take a trip outside our solar system and observe “sunsets” on exoplanets. This particular rendering shows the sunset on exoplanet HD 209458, also known as Osiris.
It is one of the few well studied exoplanets, and scientists have a fair idea of the constitution of the planet’s atmosphere and the prevailing conditions. Osiris is nearly 70% the size of Jupiter and revolves very close to its star which happens to be white like our sun.
As the star moves to the horizon of the planet, it gains the alien-world bluish tinge because sodium in Osiris’ atmosphere absorbs red and orange parts of the spectrum, while its atmosphere scatters blue light. The flattening towards the bottom is due to diffraction, something that happens on earth as well.
The image is the work of researcher Frédéric Pont, and while it is not real it is pretty accurate, given our knowledge of the planet’s atmosphere and prevailing conditions. Pont also made a similar image for exoplanet HD 189733 b, which doesn’t quite look as alien as that of Osiris. And lets face it, when we talk of alien worlds, we do expect weird wonders that would never happen on earth.