Xena Discovery

The 10th planet is so far away that the moon appears quite close to it. So close, in fact, that all of the telescopes that have looked at the planet up until now have completely missed it. The telescopes miss it because the earth's atmosphere blurs the view of the planet as the light makes its way to the ground. In the past few years a technique known as Adaptive Optics has allowed astronomers to measure and then partially correct for the blurring caused by the atmosphere. One limitation of Adaptive Optics has been that you must be looking at a very bright object to be able to measure the blurring, otherwise you can make no corrections.

The Keck Observatory has recently commissioned a new cutting-edge addition to its Adaptive Optics system. The new addition uses a laser beam launched from the side of the telescope to make an artificial star in the sky right next to the target. This laser star then allows Adaptive Optics to be used even when the target is not particularly bright. Just one year ago, observations such as these would have required the Hubble Space Telescope. Today they can be made from observatories on earth. The new system is so powerful that many many astronomers want to use it right away, which is why, even though we know that the 10th planet has a moon, we have not been able to obtain any new observations of it since the initial discovery.