February 5, 2011 by Istvan

I’ve seen a good bit of traffic lately in the media and in blogs regarding the recent data from the Kepler mission.  My general reaction to Kepler previously has been rather ho-hum.  I mean, getting more exoplanet data is good, but Kepler hasn’t excited me much until now, because the starfield it’s examining is entirely made up of quite distant targets, hundreds of light-years away or more.

I’m interested in seeing humanity locate some exoplanets rather closer than hundreds or thousands of light-years away.  We humans are short-sighted as a rule. Nearby stars with planets that we might reach with near-current technologies, in the time of our grandchildren, could inspire many more people than just scientists.  Kepler isn’t finding those targets, so we must continue to await results from other research groups, such as the two at least continuing to study the Alpha Centauri system.

However, the latest Kepler results are stunning.  I’m still not excited about the six planetary detections around a single star (Kepler-11) that have been so much in the news.  Those are all small baked worlds closer to their sun than Mercury is to ours.  What is impressive to me is the sheer number of detections in the broad target starfield.

Keep in mind Kepler isn’t finding everything.  Kepler can only spot transiting planets, planets which happen to cross in front of the disc of their star as seen from the angle from which we’re viewing it.  Kepler also hasn’t been looking all that long, so it can only spot the planets that have transited at least several times, while it has been watching.  This means it’s only detecting, for now, some of the hot worlds closely hugging their parent stars, such as those six baked balls around target Kepler-11.

So what?

“What” is that Kepler has already found easily more than a thousand planet candidates.  This is with what one might call “a good first try”.

We’ve only started finding exoplanets in the last decade or so.  Our efforts thus far have been slow and halting, done by choosing specific targets and examining them closely. What we’re able to spot is still subject largely to chance and circumstance.  Kepler is the first serious effort at getting a proper statistical sample.  Kepler helps us build a real picture of just how many planets are truly out there around other stars.

In the last century, many of us, scientists and laymen alike, have simply assumed, somewhat hopefully, that our solar system is “normal”, that planets are not unusual, that there must be many, many out there.  But we did not know.

The other exoplanet surveys continue to turn up more and more candidates, becoming increasingly convincing to us that indeed there are many planets around other suns.  But perhaps we’ve been accidentally cherry-picking so far, targeting just the right stars.  Kepler’s scattergun approach to surveying a distant starfield tells us unequivocally:  planets are literally common as dirt.

If we want to find some interesting ones, perhaps some habitable ones, perhaps some already with life, perhaps some near enough that our grandkids could send a robot there, well then, knowing for sure that an awful lot of planets really are out there seems like a pretty awesome thing, in all senses of the word.