KEPLER MISSION WILL TAKE A GALACTIC CENSUS OF EARTH-LIKE WORLDS
The Kepler mission will be the first serious search for habitable planets in our galaxy.
Taking a break from politics this weekend (at least on this blog) because I’ve had a hankerin’ to do some gee-whiz, wowie-zowie, omigod, eye-popping, knock you out of your sox, space blogging.
There’s a lot going on at NASA besides trying to keep the dinosaur Shuttle fleet in one piece. (I pray every time they launch that Edsel that humans will not pay with their lives for the bureaucratic bungling that has us using this antique rather than modernizing years ago.) It is a consequence of a lazy media and their even lazier audience that the truly stunning scientific accomplishments that NASA is generally responsible for (in partnership with the EU, the Russians, and others on occasion) are barely reported and commented on.
NASA may be an agency in search of a grand vision but when it comes to cutting edge science, they do alright. The Mars rovers, orbiters, and the most recent laboratory lander, the Phoenix, that discovered what almost certainly is water ice at the north pole, are radically changing our view of the “dead” red planet (recent discoveries of plumes of methane suggest the possibility of life).
The agency’s New Horizon’s mission to Pluto and the Kuyper Belt is chugging along about a third of the way to crossing the orbit of Uranus. Launched 3 years ago, the spacecraft is the fastest man made object in the solar system traveling at more than 43,000 MPH. Even at that speed, it won’t reach Pluto until July of 2015.
The Hubbell Space Telescope is still amazing scientists with its discoveries. And for pure, geeky, kewlness, the pictures that are beamed to earth from Hubbell can’t be beat. Hubbell’s successor - The James Webb Space Telescope - will, if it works properly, probably have the capability to see earth-like planets in enough detail that we will be able to discern whether any intelligent life exists there.
But the launch of Webb is four years off. In the meantime, the most sophisticated effort in history to find earth like planets will be undertaken on March 6 of this year when NASA launches the Kepler Spacecraft into orbit.
A different kind of telescope, Kepler will be equipped with a gigantic photometer and will peer at one, small section of the sky continuously, comprising about 100,000 stars. It’s job will be to catch earth-like planets crossing in front of its star - “transiting” is the scientific term - and then determining the shape of its orbit.
The goal is to discover those planets in the “Goldilocks Zone” or habital zone, where water can exist in liquid form and planetary temperatures would at least give life a chance to arise. It’s called the “Goldilocks Zone” because the orbit would place the planet in a zone not too cold and not too hot but “just right.” This is a narrow zone indeed if you think about it. Of our two closest planetary neighbors, Venus is probably too close to the sun for life to have arisen (other factors like a runaway greenhouse effect also doomed life there) and Mars may be at the outer edge of the habital zone, having seen liquid water early in its formation as well as the possibility mentioned previously that some form of microbial life still exists there.
Here’s a brief overview of the mission from the Kepler website:
The scientific objective of the Kepler Mission is to explore the structure and diversity of planetary systems. This is achieved by surveying a large sample of stars to:
- Determine the percentage of terrestrial and larger planets there are in or near the habitable zone of a wide variety of stars;
- Determine the distribution of sizes and shapes of the orbits of these planets;
- Estimate how many planets there are in multiple-star systems;
- Determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets;
- Identify additional members of each discovered planetary system using other techniques; and
- Determine the properties of those stars that harbor planetary systems.
Using supercooled charge coupled devices (CCD’s), the sensitive photometer will be able to determine a small body transiting a distant star by measuring light before and during the transit. It is described as akin to measuring the light blocked by a moth as it transits a searchlight. The telescope will have its eye fixed on one, relatively small section of the sky and study such transits for 100,000 stars over a 5 year period.
There are a couple of drawbacks to this method of detecting earth-like planets. First, Kepler will only be able to see planets orbiting within the plane of the star. In our solar system, Neptune orbits outide of the plane of the sun which means its transits are very, very rare. An earth like planet orbiting closer to the star but not in its plane would have more transits but probably not enough to be detected during the 5 year life span of Kepler. (Scientists believe they have to see at least 3 or 4 transits in that period that will show the exact same drop off in starlight due to the object’s transit in order to be able to have a “robust” confidence in the data.)
Secondly, there is a possibility (some astronomers believe a probability) that Kepler won’t discover many of these earth like planets at all, that there are just too few of them. NASA says that this will also be valuable knowledge and I agree. But with cost overruns pushing Kepler’s price tag toward $500 million, the Republican in me questions whether earth-based observations could eventually achieve the same results for about 1/10 the cost.
At any rate, here are NASA’s expectations for Kepler:
Expected Results:
Based on the mission described above, including conservative assumptions about detection criteria, stellar variability, taking into account only orbits with 4 transits in 3.5 years, etc., and assuming that planets are common around other stars like our Sun, then we expect to detect:
From transits of terrestrial planets in one year orbits:
- About 50 planets if most are the same size as Earth (R~1.0 Re) and none larger,
- About 185 planets if most have a size of R~1.3 Re,
- About 640 planets if most have a size of R~2.2 Re,
- About 12% with two or more planets per system.
These numbers come out substantially higher, when one takes into consideration all orbits from a few days to more than one year.
From modulation of the reflected light from giant inner planets:
- About 870 planets with periods less than one week.
From transits of giant planets:
- About 135 inner-orbit planet detections,
- Densities for 35 inner-orbit planets, and
- About 30 outer-orbit planet detections.
Detection of the short-period giant planets should occur within the first several months of the mission.
The sample size of stars for this mission is large enough to capture the richness of the unexpected. Should no detection be made, a null result would still be very significant.
As you can see, there would still be valuable data gleaned from the mission even if they only discovered a handful of earth like planets. To date, extra-solar planets have overwhelmingly been of the “hot giant” class due to the methods employed to discover extra-solar planets using earth based observations. The debate over why this is so is fascinating. Are these Hot Giants failed stars? Since about half of the stars in our galaxy are binary star systems with two suns in close proximity to one another, that explanation makes sense. Or are our theories on how planets form wrong? The “accretion disc” theory has been with us for several decades but suppose there are alternate means by which the dust and gas surrounding a new star resolves itself?
The big question is can both short period Hot Giants and earth like planets exist in the same solar system? Kepler may help answer that.
Kepler is the next step in NASA’s efforts to discover extra-solar life and perhaps, intelligent neighbors who might also be searching the heavens for signs they are not alone. More likely, those planets Kepler will find, if they harbor intelligent life, feature civilizations far more advanced or far less advanced than ours. But the discovery that there are perhaps thousands of earth like planets in the habital zones of stars in our galaxy alone would almost certainly change the way we look at our universe. Even many skeptics would be forced to rethink their notions of life in the universe if Kepler meets expectations.
Enjoy these discoveries while you can. With trillion dollar deficits staring Congress in the face, the probability that NASA funds will be cut to the bone are about 95%. Congressmen find it easy to cut programs that don’t enrich cronies or buy them votes back home. Most of the pure scientific exploration represented by Kepler, New Horizons, the Mars probes, and the Webb telescope are easy pickings for the budget cutters.
The paltry amounts that will be saved pale in comparison to what we will be losing.
With trillion dollar deficits staring Congress in the face, the probability that NASA funds will be cut to the bone are about 95%. Congressmen find it easy to cut programs that don’t enrich cronies or buy them votes back home. Most of the pure scientific exploration represented by Kepler, New Horizons, the Mars probes, and the Webb telescope are easy pickings for the budget cutters.
And that’s too bad, because basic science is one of the few things deserving full governmental support. The media likes to credit the Omnibus Bill of 1993 for the boom and surplus of the nineties, but the actual credit goes to five decades of scientific research which led to the information economy; if we want long-term sustainable prosperity, we need to make these sorts of investments. The Republicans can regain some of their intellectual currency by advocating more spending on basic science instead of direct intervention in the economy. Not only do the projects themselves generate thousands of new jobs in the short term, but the work itself leads to hundreds of new industries and enterprises in the long term. This is something the great physicist and conservative Republican Robert Millikan advocated during the Great Depression, and we should revisit his position in the light of today’s crisis.
Bravo! Hurrah! Couldn’t have said it better.
The catch is, we don’t know how this basic scientific research will payoff in the end. The process of discovery and invention itself leads to unknown real world benefits. The knowledge that will accrue to us as a result of Kepler is tiny compared to the spin-offs in new technolgies and products.
Can’t put that on a graph, unfortunately. Which is why NASA budgets are so easy to cut.
ed.
Comment by RWA — 1/25/2009 @ 11:50 am
So, if the missions found life, and far superior beings who believed in God, would that convince you, Rick?
If so, then I say, fund the programs. Because, you know, if it saves just one life….then spending billions is worth it.
Said,facetiously. Happy Sunday.
Comment by sara in va — 1/25/2009 @ 2:45 pm
The Federal Government, in the form of NASA and NOAA, has a monopoly on space research. The current financial meltdown, caused by a simpering, mincing Congress more addicted to bribing constituents and receiving ‘donations’ to their respective ‘Political Action Committee(s)’ puts private enterprise endeavors in limbo.
If some smart engineers met up with equally smart and visionary financiers, a true revolution in space exploration/exploitation can occur. Zero-G silicon crystals, nanotube light switching computers or the odd hydrogen-3 power plant would certainly make money.
Get the Feds out of space exploration and put real risk takers in charge of their own corporations to take advantage of the science they can do.
You sound like Rand Simberg - blogger at Transterrestial Musings. There are already a lot of smart engineers who have hooked up with visionary financiers. And in about 15 years, those are the people who will taking humans into space.
Still be a role for NASA with these missions of exploration and discovery, I think. At least until the research and development infrastructure for the private sector can match what NASA can do.
ed.
Comment by SeniorD — 1/25/2009 @ 4:33 pm
Imteresting timing for your post; I just finished re-reading Shklovskii’s and Sagan’s book, “Intelligent Life in the Universe.” I’m sure Sagan would have loved to see this program.
Funding from the Federal government for science continues apace. It is the nature of that funding that is changing. It’s all about return on investment now. “When will it be ready,” “how many lives will this help,” and so on. This is becoming a bad precedent, as the funding agencies are constantly being pushed by Congress for the “right” kind of research. There aren’t many scientists on the Hill, but they like to pretend that they are.
Very good points - and reminiscent of the science advisor in Sagan’s “Contact” who cut basic research in favor of funding projects with a return on investment.
ed.
Comment by Allen — 1/25/2009 @ 4:53 pm
The problem is that you can’t direct invention. For example, there is the hope for biotech ‘garages’ producing anything from biofuels to novel medications. It might sound naive but it happens when enough people is convinced it can happen. My example always is Florence at the end of the Middle Ages. How many inhabitants were there? Perhaps 50,000. Now does that mean any place in the US has the same talent pool that Florence? Perhaps so but they don’t believe that themselves. The few that do actually migrate towards institutions like MIT because they think that is where it is ‘happening’. And so it does. True enough; whether today with government funding and or visionary financiers or back then the Medici, money is still needed. Hope we don’t forget the greatest strength of the United States especially in time of crisis, innovation and discovery.
Comment by funny man — 1/25/2009 @ 7:38 pm
The quest for earth-like planets poses interesting philosophical questions. First, if we find some, should we seed them with collections of earth life in a Star Trek “Genesis” project? After all, Earth may become inhospitable one day.
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Second, are we prepared to acknowledge that intelligent life is a unique miracle bestowed upon, and entrusted to, us? I wonder if the search for life elsewhere is really an attempt to evade this responsibility. The universe is a pretty big place, it’s not likely that the searching or the evading will end anytime soon.
Comment by Mark30339 — 1/26/2009 @ 10:18 am
If anyone is interested, here is the Hubble Heritage gallery of truly awesome images, one of my favorite bookmark visits…
http://heritage.stsci.edu/gallery/gallery.html
Comment by Chuck Tucson — 1/26/2009 @ 5:04 pm
Thanks for the kind words, Rick. However, I’d say that the fact that we don’t when the research will pay off is reason enough to fund it now, so that it pays off ASAP. Furthermore, the jobs it creates in the short term aren’t just in research itself; the doubling of funding for the NIH which Gingrich rammed through Congress helped fuel the construction boom by enacting the construction of new facilities. If we don’t want economic bubbles to pop, then we need this sort of continual investment, which guarantees that funding of current industries will be continuous and permanent, while opening the window for new ones.
Now you see why I keep asking you draft Fortner?
Comment by RWA — 1/27/2009 @ 5:51 pm
> The goal is to discover those planets in the “Goldilocks Zone” or habital zone, where water can exist in liquid form and planetary temperatures would at least give life a chance to arise. It’s called the “Goldilocks Zone” because the orbit would place the planet in a zone not too cold and not too hot but “just right.” This is a narrow zone indeed if you think about it. Of our two closest planetary neighbors, Venus is probably too close to the sun for life to have arisen (other factors like a runaway greenhouse effect also doomed life there) and Mars may be at the outer edge of the habital zone, having seen liquid water early in its formation …
Don’t get too dogmatic about this Goldilocks zone. A lot depends on the size of the planet. Make Mars 4 or 5 times more massive, it holds on to it’s atmosphere and there’d be liquid water on it’s surface today. Give Venus a big ass moon like Earth has, it strips off some of the extra atmosphere and maybe Venus ISN’T too close under those conditions.
Heck, Earth isn’t in the Goldilocks zone. The daylight temps on the moon are far too high for liquid water - therefore, anything at Earth’s distance is too close to the sun.
It’s the combination of distance and the planet’s atmosphere that you need to know. I don’t know if Kepler is fancy enough to tell us that.
Still, it’s worthwhile.
Comment by Arthur — 1/28/2009 @ 7:46 pm