CNN reported today that the Kepler telescope has already made a remarkable discovery. A planet with an atmosphere and surface temperatures near 4000F spinning around its sun in 2.2 days with one side always facing towards its star. Now that has to be one heck of a big planet because what I find incredible about the claim is that any planet is capable of sustaining any type of atmosphere that close to a star.
Here is where I have a problem with the science: the corona of a star based on observations of our own sun have been shown to be several millions of degrees higher than the surface temperature (~6000K/10000F). Ignoring the effects of coronal mass ejections for a moment – such radiation on the outside of the planet and a core temperature of 1000F+ from the surface should provide sufficient energy for atmospheric molecules to vaporize off into space , be picked up by the solar winds, and blown off. In short – the planet shouldn’t have an atmosphere that close to the sun’s corona.
What then are we looking at? Most likely the culprit is superheated gas trapped in the magnetosphere of the planet providing the illusion of an atmosphere where none should exist. However even there we have a bit of a problem.
See – for the planet to have a rotation period equal to it orbital period – this would suggest that any internal metallic core had long since stopped spinning. This is in part what accounts for planetary magnetic fields. So if we can infer from the rotation of the planet that its magnetic field is weak then there shouldn’t be a residual atmosphere due to interaction with solar wind.
The other other two mechanisms I can think of that may be responsible for the presence of an atmosphere would be venting of carbon dioxide and methane from within the planet’s core as the planet cooks like being in a microwave oven. The issue with this theory is that for a planet to get this close to its star it is likely that any such residual gas may have leached from the planet surface millions of years ago.
The second mechanism is a combination of gravity and thermal currents that may cause molecules to bind more tightly to the surface of the planet. If so then it may be possible to get a much more accurate read on the size / mass of the planet simply by figuring out at what point the pull of gravity counteracts the vacuum of space considering the amount of heating that needs to occur to heat the planet’s surface temperature to 4000F.
Of course there is another possibility – the one which I found myself drawn to immediately upon reading the article. The science could just be out and out wrong. Personally I hope this isn’t the case as I would like to think that we can identify earth sized planets in other star systems that our children can one day visit. I’m just more than a little disappointed however that those people who purport to be on the cutting edge of this science who just out and out assume that what they are looking at represents an atmosphere without critiquing the possibility that what they are doing is inherently at the cutting edge.
It wouldn’t be the first time that humanity’s exploration of science has shot off on a tangent. Let’s hope that other communications about Kepler will be a bit more considered.