NASA's Kepler Mission Coming in 2006

Anonymous Coward writes "NASA Kepler mission should discover 50 terrestrial planets if most of those found are about Earth's size, 185 planets if most are 30 percent larger than Earth and 640 if most are 2.2 times Earth's size. To highlight the difficulty of detecting an Earth-sized planet orbiting a distant star, Borucki, Kepler's principal investigator, points out it would take 10,000 Earths to cover the Sun's disk. But in a 1000x1000 pixel jpeg, that is 100 pixels (large) and there are about 120 million 'astronomical' photocells or rods in the human eye (good pixel density)."

Comments

Resolution Irrelevant

[mgarraha]

in a 1000x1000 jpeg

Not even HST can resolve the nearest stars into disks. Instead of resolution, the Kepler project relies on sensitivity to changes in brightness. It continuously monitors a 10-degree region of sky, watching for any of the stars to dip slightly in brightness. If the dip happens regularly, then they conclude that a planet passed in front of the star, and they determine the size of the planet from the change in brightness. I suppose they would exclude stars known to fluctuate for other reasons.