NASA: Mission Accomplished, Kepler – Now Look Harder Still 28
cylonlover writes "It's been more than three and a half years since the Kepler Space Telescope began its mission as humanity's watcher for Earth-like planets outside of the Solar System. In that time, Kepler has done exactly what was asked of it: provide the data to help identify more than 2,300 exoplanet candidates in other star systems. And so NASA has announced the 'successful completion' of Kepler's prime mission. There's one nagging detail, though: we are yet to find a truly Earth-like planet. It's time to alter the parameters of the search, which is why NASA has announced Kepler will now begin an extended mission that could last as long as four years."
Re:Subtlety (Score:5, Interesting)
Well - sort of. The aim of the kepler primary mission was to detect earth-like planets, in earth-like orbits, around sun-like stars. Unfortunately, as one of the scientists working on the project pointed out, an early discovery was the sun wasn't a sun-like star.
The sun turns out to flicker rather less than most stars in the sun-like population. This does unfortunate things when you're trying to pick the tiny, tiny signals of planets crossing the stars disks, as the noise swamps the signal. It means that it can't be picked up in the primary mission length, and you need longer integration periods - hence the extended mission. It's not to get more data than was intended, but to get back to the baseline that was assumed, before we realised that stars twinkle rather more than we thought.
(It will have the side-effect of picking up some planets in non-earthlike orbits that couldn't have been seen too - very tiny and very long orbit ones.)
Frankly, I'm more interested in why the sun doesn't flicker as much as other stars of similar luminosity. Is it because we're not between light years worth of planetoid crossing the light path? Does space itself flicker?
Re:Subtlety (Score:5, Interesting)
Current thoughts seem to be simply that the sun just happens to be one of the stars that flickers less.
Most'sun-like' stars flicker more.
Before Kepler, it wasn't really possible to measure stars brightness variation other than the sun to the levels required.
Flickering was probably a bad word to choose.
Flickering of stars as observed by the eye (or ground-based telescopes) is utterly dominated by atmospheric effects.
The phenomena Kepler is observing is brightness variations of the star on the level of seconds to hours.
As I understand it, the brightness variations between the popularion of near and far similar stars in the kepler field of view is similar.
It's unlikely to be any effect of space.