Kepler Discovers First Earth-Sized Exoplanets

ananyo writes "NASA's Kepler telescope has reached one of its major mission milestones: finding an Earth-sized planet outside the Solar System. What's more, it has done it twice in the same star system. Whizzing around the star Kepler-20, about 290 parsecs (946 light-years) from Earth, is not only an Earth-sized planet, but also something just a touch smaller — a Venus."

Re:Remember the good ol' days

[gstoddart]

When stars used to be named after important scientists, and not machinery.

Ummm ... as much as Kepler is the name of the device, Johannes Kepler [wikipedia.org] laid out the mathematics of orbits. You know, Kepler's Laws [wikipedia.org].

Naming stars Kepler-20 (or whatever) is naming them after important scientists ... and since it's looking for things which orbit, it's quite apt.

Re:Note to all Science Fiction Writers

[Anonymous Coward]

The Kepler telescope only has a relatively narrow field of view compared with the entire sky. So most near by planets will not be called Kepler-nc.

Re:Zzzzzzz

[uigrad_2000]

We're quickly changing from "oh there's likely not many planets" to "the universe is full of them"

I wouldn't quite say that.

I don't really think that the estimates of how many planets there may be has increased. Instead, our technology has increased so that we can actually start finding the planets that we've always assumed were there.

The somewhat-dubious values that Drake used in 1961, according to Wikipedia, include:
fp = 0.5 (half of all stars formed will have planets)
ne = 2 (stars with planets will have 2 planets capable of developing life)

The value given for ne seems to be rather optimistic, but it's still too early to have reliable numbers. It will be a long time before we can take any arbitrary star, and see exactly how many planets it has.

Re:Margin of error?

[mbone]

Yes. These are transit measurements. They see the drop in light of the star, or not. If they see it, they can estimate how much the intensity changes, which gives them the ratio of the area of the star and the area of the planet. They can also time the duration of the transit, which, together with the period between transits and some information about the star, gives them the star's radius, and thus the planet's radius. If you can detect the transit at all, you should be able to get all of these things.

Re:Zzzzzzz

[Teancum]

The problem with this thinking is the presumption there is only two data points. There are currently at least 19 different planetary systems [wikipedia.org] with at least three or more planets which can be used for a comparison, and almost everybody involved with extrasolar planets knows this is just the beginning of discoveries. All told, there have been over 700 different planets [exoplanet.eu] which have been confirmed outside of our little old Solar System.

I would say that is enough to begin some statistical models and try to come up with some general trends based upon real data besides the single data point of the Sun and its planets. More significantly, this seems to indicate that planetary systems around stars are quite common to the point that stars without planets seem to be an exception... particularly if those stars are solitary stars rather than in systems of multiple stars.

Admittedly we are still mostly blind about what is "out there", but the Kepler survey seems to be providing some real statistical information about how common planetary systems might be, and since so many of the Kepler telescope candidates seem to be found in groups of multiple planets, it seems very likely that one common presumption of planetary formation being in a disc-like structure seems to be holding out very well. What the Kepler survey is really good at doing is identifying candidates which can then be studied with better telescopes now that we know some properties of these particular planetary systems, or even that they exist at all.

Re:Imagine what a 1.4M km telescope could see!

[Maritz]

Claudio Maccone's proposal to use the Sun as a giant gravitational lens (FOCAL [centauri-dreams.org]) is pretty astounding. All you gotta do is send your satellite out to about 550 AU (easy peasy eh?) - I think I recall reading that if you were to train it on a planet in the Alpha Centauri system you'd be able to resolve cars in the street assuming there are cars and streets there (bound to be). Not easy to steer though, you'd need to know well in advance what you were aiming it at. One nice thing is that the focal length goes to infinity, so even if you're shooting further out (say 1000AU +) you're still able to get a great picture.

Re:The Real Question

[waives]

Stop reading so much science fiction, and try some real science. There will never be FTL communication. ENTANGLEMENT DOES NOT WORK THAT WAY /Morbo