Today I read an interesting article by Scientific American about seeing the skies of different planets, and extrasolar planetary discovery.  As it turns out, the skies of different planets (outside our solar system) are very hard to observe because all we can see is the glare from the star it orbits. 

The article begins with a brief history of our understanding and observations of extrasolar planets, and then gets into what scientists are doing today.  Because planets are so small few extrasolar ones have ever been directly observed.  How we normally detect them is by looking at minute changes in the star’s orbit.  Now though, using more modern telescopes, we have been able to detect planets just twice as massive as earth, and what is more, even look at their atmospheres.  Instead of only being able to use the star’s wobble to observe new planets we have also been looking at the apparent brightness of the star change as the planet passes in between it and Earth.  By looking at the light that shines through we can get an estimate as to what the atmosphere is made of and the planet’s density.

Though this new research had lead to the discovery of numerous potential Earth like planets it still brings up many questions.  One issue plaguing scientists currently is that on some planets, like Jupiter and Saturn temperature is not decreased with altitude, rather it increases.  Because there is no easy ways of telling which temperature gradient an extrasolar planet has it is impossible to know much more about its atmosphere, and perhaps, habitability for life. 

For now we will have to wait, but when the James Webb Space Telescope is lauched and new large sized ground telescopes become operational sometime at the end of this decade we will be able to see the planets much more directly.

I really find this article intriguing because of the sense of exploration that it captures.  Though directly imaging extrasolar planets is fantasy right now, it will be possible in the future, and I can’t wait for that to happen.

The article: http://www.nature.com/scientificamerican/journal/v309/n1/full/scientificamerican0713-40.html