NASA: Mission Accomplished, Kepler – Now Look Harder Still

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."

Comments

Subtlety

[Anonymous Coward]

So, this is how they tell us that in fact they did found earthlike planets, but they had to sign NDAs with the aliens.

Re:Subtlety

[wierd_w]

More like:

OK, we discovered that planet formation is radically more common than we previously thought. When we designed the parameters of Kepler's mission, we wanted to detect large bodies because they would be easier to detect, and they would give us a statistical sampling we could use to determine how frequent planetary systems are.

We know that now. We aren't so interested in big jupiter size gas giants. They don't get the funding dollars we are looking for. So, now that kepler's initial mission objective is met, we will call it a success, and start a new mission, with tighter controls, looking exclusively for small, rocky planets in the systems we know to have really big gas giants in them.

Re:Subtlety

[queazocotal]

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.)

Re:Subtlety

[__aaltlg1547]

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

[queazocotal]

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.

Re:First

[wonkey_monkey]

We can find a desert planet, and send all the racists there.

And let them get all the spice? I don't think so!

Impossible without a flyby

[aNonnyMouseCowered]

The best that Kepler and allied planet-finding projects can do is whittle down the list of exoplanets to a candidate list of Earth-like planets. Spectral analysis might give a hint to the chemical composiition of a planet's atmosphere, but other factors might transform that planet into something worse than our worst climate-change nightmares. What we're probably looking for are planets that are easier to terraform, rather than life itself, which would be invisible to any direct imaging technique here on earth. Ironically, the SETI project probably stands a greater chance of confirming the presence of life on an extra-solar planet. Then again, that extraterrestrial transmission might come from the intelligent machines of a long extinct God-like species.

Re:Impossible without a flyby

[mbone]

Kepler is not looking at particularly close stars, so it not likely to find any real flyby candidates, even for the century star ship time frame. The recent find at Alpha Centauri is much more encouraging in that regard.

Re:Impossible without a flyby

[Teancum]

The one major accomplishment of the Kepler observatory is that the understanding of the frequency of planets in other stellar systems and where they will likely be found has been nailed down very well. Back when we had a data set with a sample size of one (aka just our own solar system) it was very hard to try and determine just how many stars had planetary systems of their own. it was even hypothesized that multiple star systems (by far the more common type in the universe) simply didn't even have planets. That notion has now been thrown completely out the window as stellar systems with planets are now seen as extremely common.

The fun part has yet to happen though, as planets that may be found in the "habitable zone" are just barely starting to be identified. So far most of the planets that have been identified are planets that have very short orbital periods (some as short as just a few days). Instead, as Kepler can continue its mission it will be possible to identify planets that are much,much further away and their orbital periods are on the order of years instead of weeks.

When the time comes, I expect that probes to other stars (I think it will happen eventually... even if it is centuries away from happening) will be traveling to planets that will already be well identified in terms of basic characteristics... to have at least the degree of understanding of those planets like we do a great many asteroids at the moment.

This is how it is done.

[mbone]

NASA doesn't like to commit to really long missions. Get it up there, get good results, and they will then commit to extensions. (See, for example, the "3 month mission" of the MER rover Opportunity.)

Re:This is how it is done.

[Immerman]

I believe the key phrase is "attainable goals". Shoot for the stuff you're fairly certain you can accomplish on your grant application - then all the really interesting stuff comes as the "added bonus". Especially good if the "easy" stuff is interesting in it's own right. It certainly looks much better under congressional review than "yeah... so we though we could accomplish X, but it turns out to be a lot harder than we expected..."