Question

What challenges do planet hunters face in trying to find new planets?

Answer 1

in **our ** solar system?

Answer 2

Exo-solar planets are very far away. In order to determine if an star system contains planets, an astronomer must take photos of that star over a long period of time: weeks, months or years in order to detect the signature wobble of a star with a massive object or objects in orbit. The light from a star in a well focused image, even with the best telescope, will only register as a few pixels in an image. For ground observers, viewing conditions (the turbulence of the atmosphere) greatly affect the quality of these images. The astronomer must detect periodic changes in the brightness of this star in order to determine if there are interesting orbital dynamics. Most of the time, "stars" with these dynamics are actually binary star systems: two stars orbiting each other. If the brightness changes with the right dynamics, it could be marked as a possible exo-solar planetary system. Exo-solar planetary systems usually have much more subtle dynamics, as the planets have much smaller masses compared to their star, and are therefore more difficult to detect than binary star systems.