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)."

Area vs Volume

[ObviousGuy]

If someone can tell me the rate of change of pi^3 / 3, we'll all have a good laugh.

Re:Area vs Volume

[ObviousGuy]

Oh god. Shoot me now.

Rate of change of x...
x = r^3 / 3

Of course.

Human Eye?

[hackwrench]

Somehow the pixel density of the human eye just doesn't seem to fit with the rest of the article.

Re:Human Eye?

[tjgoodwin]

Indeed. The conjunction of the various articles linked to would seem to imply that we don't need the Kepler mission: if you just have a snack at night, and avoid drinking, smoking, and high altitudes you'll soon be spotting Earth-sized planets with your naked eye.

Re:Human Eye?

[Anonymous Coward]

I can always spot atleast one. I just have to look down.

Re:Human Eye?

[John Sullivan]

Drink enough and you'll be able to spot the other 49 too!

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.

Betelgeuse, Betelgeuse, Betelgeuse!

[isaac]

Actually, in 1998 the HST directly imaged Betelgeuse [nasa.gov], but then, it's a supergiant with a diameter greater than the orbit of Jupiter, and only 600 light-years distant.

-Isaac

Sorry, 1995

[isaac]

That image was actually made March 3, 1995.

-Isaac

What about sunspots?

[mcfiddish]

I'm sure they've thought of this, but how much does the visible light from a star dim when there's a big sunspot? I'm sure it's more than one part in ten thousand.

Re:What about sunspots?

[-douggy]

Actually a star gets brighter when there are sunspots on it! Yeah a bit weird a know but the darker spots are counter by brighter hotspots. Unfortunatly I cannot remember what these are caled but it is why there is a ~1-2% increase in light/heat radiation from the sun impacting the earth in sunspot maxima years.