With the Herschel/Planck telescopes now on their way — the successful launch took place at 1312 UTC from the European Space Agency’s launch pad at Kourou, and the two spacecraft are now on separate trajectories — we can take a breather to reflect on what a busy time it’s been of late for space telescopes. The ongoing Hubble repairs are a fascinating story in and of themselves, but we’ve also got Kepler to think about as its hunt for Earth-like planets around other stars now gets underway.
Shaking out the instrumentation has taken some time, but the Kepler operations team slowed the pace of communications about a week ago to eighteen hours per day, a number that will drop to six as science observations now proceed. For the balance of the mission, according to JPL project manager Jim Fanson, communications will occur only twice per week as Kepler sends home precious data.
“Now the fun begins,” said William Borucki, Kepler science principal investigator at NASA’s Ames Research Center, Moffett Field, Calif. “We are all really excited to start sorting through the data and discovering the planets.”
Expect the first discoveries to be gas giants close to their stars, easiest to spot and confirm using Kepler’s transit methods. Then things get even more interesting. This is a mission that should be able to find terrestrial worlds in the ultimate sense; i.e., planets that not only approximate ours in size but are also roughly at the distance required for liquid water to exist at the surface. We still call that distance the ‘habitable zone’ even though it’s becoming clear, as witness the case around Jupiter, that tidal forces can provide immense energies that could extend a different kind of habitable zone much farther from its star. And then there’s Enceladus…
Given my own predilection for small, red stars and the chances for life around them, I’ll be fascinated to see what we learn about the number of potentially life-bearing planets around M-dwarfs. Remember that these account for something like 70 percent of the stars in our galaxy. Kepler’s take on this after completion of its three and a half-year mission should give us some sense whether such planets are commonplace, or whether we’re more likely to find life around G- and K-class stars more similar to our own Sun.
As to Kepler itself, having read Alan Boss’ book The Crowded Universe (Basic Books, 2009) recently, I’m still amazed that the mission ever got into space. The agonizing politics of funding top-end science have put the brakes on such powerful options as the Space Interferometry Mission (now shrunken to SIM Lite) and the Terrestrial Planet Finder. How Kepler made its way through the maze of review panels and budget cuts to get on the launch pad makes for absorbing reading, but not nearly as absorbing as what we may find in its final report.
Regarding the funding of future exoplanet missions, we need to keep our fingers crossed that Kepler finds enough of them to warrant investment in the near-to-mid-term future.
I read somewhere that if all 100,000 of Kepler’s targets have Earth-like planets in orbit around them, we should be able to detect about 500 of them (i.e. the ones that transit their suns in relation to Earth), and that astronomers are hoping for about 50 Earth-like planet detections during the mission (i.e. a 10% rate), and around 1200 total (mostly hot-Jupiters and other large planets).
It would certainly be a blow if Kepler detected far fewer planets than anticipated as the cost per exoplanet observation would sky-rocket, but I prefer to be more optimistic than that.
If Kepler finds few to none Earth-like planets, it is likely that future space based planet search missions will be canceled.
kurt9’s assessment is bleak, but I’m afraid it’s on target, based on what I read in the Boss book. On the other hand, Boss is convinced we’re going to find terrestrial worlds all over the place.
Hi everyone,
Correct me if I am wrong, but as for Kepler and M dwarf stars, is it true that the mission was recently reprogrammed to look at more of these small stars than was originally planned since these stars are now considered better candidates for hosting habitable planets than they were, say, ten years ago?
Also, shouldn’t a large super-earth or even an earth-sized planet orbiting an M dwarf stick out like a sore thumb to Kepler given that such planets would obscure a much greater fraction of M stars’ surface area than in the case of a larger G type star?
I’ve followed the Kepler mission almost since it was first proposed, so it’s a great satisfaction that it’s now collecting science data.
As for NASA’s budget, look at it this way: if we cut it to zero we could spend an extra month or two in Iraq.
My recollection regarding SIM is that it was financially strangled during the time when the Bush Administration was maneuvering to shift NASA’s budgetary priorities towards manned Moon & Mars missions (’04-’06). It seems to me that SIM had been rechristened “SIM Planetquest” in a gambit to ATTRACT funding. Its latest reincarnation as “SIM LITE” still lacks any funding whatsoever, and has now become vastly overshadowed by ESA’s unflagging commitment and steady momentum with GAIA — still on schedule for launch in December, 2011.
I am not too concerned about future “planet search missions” as such. I look most forward to the creation of general observatories (whether in space or on earth) having cutting-edge capabilities (in terms of astrometry, spectrography, and photometry) and directed to perform synoptic surveys that produce enormous datasets released to the public domain. Whatever the results of Kepler may be, it will impose no constraints upon projects such as Pan-STARRS, LSST, GAIA, etc., which, while not designed to find planets per se, have enormous planet-finding potential in the hands of intrepid data-miners.
I was just wondering, the length of the Kepler mission is 3.5 years. However, I thought a full 4 years would be necessary to, with a high degree of confidence, detect an Earth analogue at ~ 1 A. U. around a solar type star? Is this true, and if so, wouldn’t one of the mission’s primary goals be thwarted?