Kepler Mission Finds 752 Extrasolar Planet Candidates 103
An anonymous reader lets us know about the initial release of data from the Kepler spacecraft, launched in the spring of 2009, which has been hunting extrasolar planets. The instrument has found 752 candidates to examine in its first 43 days of operation. This is exciting news, because even if only half of the possibilities pan out as exoplanets (as the Kepler team expects) the results would still almost double the count of known planets. And some of the new ones could be Earth-sized, or not too much larger. Controversy has erupted however because NASA has decided to allow the Kepler team to withhold 400 of the best candidates for its own examination, releasing about 350 others to the worldwide community. The reasons for this are complicated and the New York Times does a good job of digging into the issue of proprietary vs. public data. Nature.com first reported two months ago on the decision to hold back some of the data.
Drake equation? (Score:4, Interesting)
I'm wondering if all this effort in discovering exoplanets is getting us any closer to a better estimate of the fp (fraction of stars that have planets) factor of the Drake Equation. Obviously, a complete survey of the sky isn't practical, and we know that some exoplanets are going to be undetectable, and it might also be skewed by the scientifically minded looking closer at stars likely to have planets rather than stars unlikely to have planets, but at the same time we have a lot more to go on than we once did.
Re:Drake equation? (Score:3, Interesting)
Well, from what I've understood it'll always be easier to see planets that are huge and either a short distance from star or in a very elliptical orbit, so they'll be overrepresented. Also those in plane with the star, but that goes for small and big planets alike. But when we get a little more data, we can probably get good estimates by taking say the closest 1000 ly of stars (the most distant detected is already at 21500 ly) where we can see both small and large planets, longer orbital times etc. to get a representative sample than trying to extrapolate from all the planets found.
Re:Earth to slashdotters (Score:5, Interesting)
NASA is indeed a scientific organization. I know a decent number of people who have/currently do work for NASA, due to my step father being an electrical engineer for Orbital (formerly Fairchild) (he helped design some of the tools used in the earlier Hubble Repair Missions. He no longer works there [he is, for all intents and purposes, retired at this point], but he worked for Fairchild/Orbital for a little over 20 years.) They are a dedicated, unbelievably intelligent group of people, who are amongst the most passionate people in the whole country.
The people in charge of their funding, those are the folks that are political. The people who actually work for NASA are just trying to utilize what little freedom they have been given.
Re:Drake equation? (Score:2, Interesting)
Kepler is designed in such a way to have a similar likelihood to see a large planet and a small planet. It is based on transit based system . ESA has a good article describing it http://www.esa.int/esaSC/SEMYZF9YFDD_index_0.html
but the chance of a large and a small planet passing in front of a sun is approximately the same and when that condition happen kepler has the sensitivity to pick up the difference for many of the close planets. So it should be able to determine fp with more accuracy
Re:Drake equation? (Score:3, Interesting)
well its not very sensitive data (Score:3, Interesting)
if china or al qaeda get information about where exoplanets are, its not like bin laden is going to go there to hide. there's little anyone can do about exoplanets right now except look at them, and it will be this way for generations to come
but if the scientific research were about nanotechnology or particle physics, meanwhile, i would expect everything to be censored, as it should be, even if funded with tax dollars
I worked with a woman who left astrophysics... (Score:1, Interesting)
research because of data access problems (well, and the pay). Senior researchers get
first crack at the data, then the next level gets access, finally grad students get
the detritus to pick over. The argument is that that was the reward for all the work
the senior researchers had to do to get the project funded and underway. Could
be true I guess.
Re:Data Archives (Score:3, Interesting)
Who payed for Kepler? This isn't Schrodinger's Cat. Information can most certainly be 'owned', traded, or sold. Got Spam? Exactly...
If these guys won't release the data due to concerns that they won't spot the next 'earth-like planet' and claim the 'credit', then there are probably thousands who would eagerly take that chance. At this point, it comes down to someone simply evaluating the data. The 'discovery' has already been made in a manner of speaking, so now it's turned into some sort of ugly 'wheres Waldo'.
Re:Candidates? (Score:3, Interesting)
The IAU definition of a planet that you speak of is about Solar System only. Why would you be annoyed about status of some rock anyway? (except for trying to maintain consistency of course, which the IAU tries to do)
Besides, there will be quite a mess with extrasolar systems too; what is a giant planet and what is a sub-brown dwarf? Or what about moons of gas giants that will turn out to be larger than Earth?
Re:Drake equation? (Score:3, Interesting)
It's approximately the same (in the given time of observations) only assuming comparable orbital periods, isn't it?
In our system that would overrepresent terrestrial planets. Who knows what is the norm... (most extrasolar planets being gas giants orbiting close to their star might be itself a selection bias)
Re:Candidates? (Score:3, Interesting)
Besides, there will be quite a mess with extrasolar systems too; what is a giant planet and what is a sub-brown dwarf? Or what about moons of gas giants that will turn out to be larger than Earth?
A sub-brown giant is a body with less than 13 Jupiter masses that doesn't orbit a start or stellar remnant. If it goes around the star and is below that size limit it is a planet. A moon the size of the earth is still a moon by definition, size alone doesn't determine what is or isn't a planet; if it orbits a planet it is a moon. An as yet unanswered question would be "What about two planet sized bodies that orbit around a common center of gravity?"
Big takeaway here: more Earth-like planets. (Score:2, Interesting)
Most of the previously-discovered exoplanets are Jupiter-sized, and many are in close and/or eccentric orbits which would seem to preclude Earth-like planets. BUT this MIGHT have been due to sampling bias from the methods we'd been using. So this mission was really important to determine if big, disruptive planets in close orbits were the rule (thus making Earth-analogs less common) or an exception that was just easy to detect.
What this mission seems to show so far is that - at least for very close orbiting planets - rocky worlds are much more common than gas giants. This is a very, very good sign, because if the 1/R^2 relation holds at orbits around 1 AU, there will be about as many systems with Earth-sized planets in the habitable zone as there are systems with larger (2+ Earth-radius) planets. Combining what we learn here from what we've learned before, it seems that *when* big planets are in closer orbits than they are in our solar system, they tend to have disruptive orbits, *but* these are not the common case.
The big question will be where the 1/R^2 relation between planetary radius and frequency shown in this study breaks down. In our solar system, there are two Earth-sized bodies, a number of bodies between 1/4 and 1/2 Earth radius (especially if you count moons), and many, many smaller bodies. But the smallest body in a planetary orbit is only about 1/3 Earth size. Again, this could be error due to very small sample size but there is probably a minimum mass/radius to achieve a stable, clear orbit; I'm still guessing it's considerably smaller than Earth, however, and so our chances of finding Earth analogues in habitable orbits is hopefully quite good.
three regular eclipses to verify (Score:3, Interesting)
It would take 2-3 years to verify an Earth-like planet, so 700 already is amazing.
Re:Drake equation? (Score:3, Interesting)
yes but that's the thing about kepler,
it's aim is to discover h-congruous planets. kepler doesn't detect the planet, it detects the planet's transit across it's sun. it can find earth-sized planets in this way. they can estimate the size based on change in apparent magnitude.
also, based on the frequency of transit (kepler makes long-term observations of candidate planets) it can estimate the distance from the star, and based on the type / size of the star, it can figure out if the planet is in the "habitable zone" for C-based life, as we understand it anyway.
Re:Drake equation? (Score:3, Interesting)
The answer seems to be that either one or more of the assumptions we are making about values in the Drake equation is wildly out of touch with reality or there is another factor to the equation that we are overlooking.
*****
Several of the typical assumptions in the Drake equation *are* off by a couple of orders of magnitude. My astronomy class back in the early 90s decided to figure out a more reasonable number and only concentrate on planets that could support any form of life (only variable we were really looking for was liquid water) The estimate came out to something like 1/50 stars. I felt it was closer to 1/20 myself if you added moons and so on.
But that's a big difference compared to "Hi, how are you?" Almost all of it would be microbes and simple plants and so on.
We plugged that back into the equation and added in the fact that we would be looking for a slice of 200 years, tops, for radio waves(the assumption was that they would figure out FTL/point-to-point communication * by then), and then a 25% chance that they didn't blow themselves up/have a disaster/etc before they got there, we came up with 4 or 5 in our galaxy. Anything more advanced would not be using means to communicate that we can detect or will avoid us if they are ever aware of us, that is. Given the raw materials in the outer solar system (Ort cloud, Kupier Belt, etc) it's likely that most civilizations also wouldn't leave their solar system for many thousands of years except to maybe send a probe to check something out. And only if it's close by. (if you scaled the galaxy to the size of your living room wall, you'd hardly see 50-100LY as a movement at all, which is as far as most conventional/slower than light exploration is likely to happen)
*Note - this was more than a decade before theories about quantum entanglement and micro-wormholes became well-known, but we felt it was reasonable that any advanced civilization would have a super-sized version of the internet even if they couldn't ever physically travel faster than light.
We could find alien life pretty soon (Score:3, Interesting)
I hope more people share my opinion that finding and characterizing exoplanets is THE most exciting scientific field of our time. My elderly astronomy professor at Stockholm University said three years ago that he hoped to live to see the day when they discover alien life the first time.
His explained that all the evidence is out there - all we need is better instruments. With Kepler we can now find many more planets. If some of them turn out to be of roughly the same size as Earth and in the habitable zone, the next thing to do would be analyzing the atmospheric spectrum of the planet. Presence of free oxygen in such a spectrum would be a VERY strong indication of life. Oxygen is highly reactive and if not for the constant re-supplying of free oxygen by plants, the percentage of free oxygen in the atmosphere would be next to nothing.
Best thing of all is that the upcoming James Webb Space Telescope will be able to measure spectra from exoplanets (maybe just jovian planets though, not sure on the details so someone please enlighten me). This means that with extreme luck, the first discovery of alien life could come as soon as 2014 (not that I actually believe that, but just so you get a sense of the timescale.) Extra-terrestrial life has for a long time had a reputation of being a subject for philosophers and conspiracy theorists, but this isn't sci-fi or some far-flung ideas that will never work - this is real science and we're doing it now.
The next few decades could very well turn out to be the most exciting years ever in the history of astronomy. I just wish more people could realize how cool this really is.