Penn State expert determined to find life on Earth-like planets

June 17, 2011

Thanks to popular Hollywood films like "E.T.," "Avatar" and "Super 8," life on other planets seems highly conceivable to people who have considered the idea that we are not alone in the universe. Jim Kasting, distinguished professor of geosciences in Penn State's College of Earth and Mineral Sciences and an expert in atmospheric evolution, is one person who considers it a lot.

As a kid growing up near the space program in Huntsville, Ala., reading as much science fiction as he could get his hands on, Kasting had space exploration on his mind all the time. It influenced who he is today as well as the research he's most interested in conducting. By studying early Earth's atmosphere and the origins of oxygen in it, Kasting has become one of the foremost experts on planetary habitable zones. In his book, "How to Find a ," Kasting explains how his research with NASA may be able to detect worlds outside of our solar system that are suitable for sustaining life.

As a doctoral student studying in the late 1970s, Kasting read several papers written by American astrophysicist Michael Hart concerning atmospheric evolution. His work piqued Kasting's interest toward proving that, despite Hart's beliefs, there are in the universe besides Earth. After completing his doctoral degree at the University of Michigan, Kasting served as a research scientist at NASA's Ames Research Center before joining Penn State. After conducting extensive research on the subject, he feels confident saying there are other planets in the universe able to host -- and he hopes to live to see the day when this is a proven fact.

"I'm very much an optimist," Kasting said. "I think there is somewhere else that has a rocky surface with an atmosphere similar to ours and with on the surface. There are almost certainly other Earth-like planets on which life may arise."

In early 2010, NASA announced that the Kepler spacecraft, designed to discover Earth-like planets within the Milky Way galaxy, found several rocky planets within their star's habitable zone. All of these planets are too far away -- hundreds to thousands of light years -- to determine whether they are actually habitable.

So, how do Kasting and other researchers hope to prove that planets around other stars are capable of hosting life? There are several ways, according to Kasting. The first task is to identify rocky planets within the habitable zones of nearby stars. One option called the Space Interferometry Mission, or SIM Lite, could have done this. SIM Lite was a space telescope designed to hunt for Earth-sized planets, but NASA canceled the project in late 2010 after more than $500 million of work because the 2010 Astronomy and Astrophysics Decadal Survey didn't consider it a high priority. Kasting said the telescope would have been able to measure side-to-side wiggle in a planet's parent star, like our Sun, to determine the motion of a planet orbiting it.

Another option, but one that Kasting said is even more ambitious and expensive, is the Terrestrial Planet Finder (TPF). Several "flavors" of this telescope use different techniques to look for planets. One uses an internal coronagraph to block the light of a solar system's parent star, to see smaller, dimmer planets. Alternatively, one could fly an occulting disk, or "starshade," in front of the telescope to block the star's light while retaining light from its planets. Another technique uses an infrared astronomical interferometer to measure the heat energy emitted from the planets in a solar system, while blocking out the star's heat energy.

Right now, NASA has canceled the TPF mission indefinitely. However, the 2010 Decadal Survey recommended this mission for further study, so it may reappear in the future. Furthermore, since Japan and some of Europe are interested in similar technology and research, Kasting hopes the U.S. can collaborate with both to conduct international space missions.

"What hurt our funding is the previous administration's interest in putting men back on the moon and trying to send them to Mars," Kasting said. "Also, right now a lot of astronomers are more interested in researching the Big Bang and dark energy as well as gravitational waves. We need to convince more of them to be interested in planets and the search for extraterrestrial life."

Since astronomers' interests are varied, it's hard to secure the several billion dollars needed to build one of these big space telescopes. Kasting hopes to collaborate with other countries to acquire the funding needed to launch any of the telescopes. He also hopes other researchers can share the same equipment to conduct their own studies, saving money and ensuring many different astronomical investigations can be pursued using these instruments. If any of these efforts succeed, Kasting may finally help humankind learn whether extraterrestrial life exists.

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1.5 / 5 (4) Jun 17, 2011
It is certainly a great ideal to search for life on other planets. With such a search all the technologies and techniques by-products that drop out of it will be usefull in other areas as well. I wish the researcher the best with his intentions, ill-conceived or not.
1 / 5 (5) Jun 18, 2011
I think there is somewhere else that has a rocky surface with an atmosphere similar to ours and with liquid water on the surface. There are almost certainly other Earth-like planets on which life may arise."

I agree with Kasting.

If he is serious about finding them, he must first seriously study how this planet formed.

The answer in not in popular, lock-step consensus science textbooks and journals.

I suggest that he start with this paper in press and then back-track through references to earlier papers on this subject: "Neutron Repulsion", The APEIRON Journal, in press, 19 pages (2011)

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
1 / 5 (4) Jun 18, 2011
The first planetary system beyond ours was discovered in 1992: Three rocky, Earth-like planets orbiting a pulsar ["A planetary system around the millisecond pulsar PSR1257 + 12". Nature 355, 145147 (1992)].


Evidence that the solar system formed directly out of supernova debris was first reported 20 years earlier ["Xenon in carbonaceous chondrites", Nature 240, 99-101 (1972)].

The 1992 discovery was confirmed in 1994 ["Confirmation of Earth Mass Planets Orbiting the Millisecond Pulsar PSR B1257+12", Science 264 (1994) 538542].

Good luck, Kasting!
not rated yet Jun 20, 2011
The only way to declare a planet a strong candidate for hosting life as we know it, is to analyse its atmosphere spectrally for evidence of oxygen in the same approximate ratio as earth's. To do that, we'll need more powerfull light-collection systems. It occurs to me that photons which have left their star and passed through the atmosphere of that star's plant, then been captured by our telescopes are among the most valuable artifacts I can trhink of, yet very little effort is made to sort them from among other photons from these stars, or to preserve them in a manner which they would be useful to analysts. We should develop an international "photon databank" in which such photons are sorted from background noise, and the useful individuals have their raw data placed into separate records by planet so they can be compared to present and future captures.
not rated yet Jun 21, 2011
How about a much cheaper mission. Put a coronagraph in a (not-quite) geosynch orbit so it can be used in combination with telescopes on Earth. This would be a snowflake shaped device that could be extremely thin, plus a package to keep it oriented and in the proper position for observing particular stars. It would need to be about the size of the aperture of the telescope it would be used with.

Even though it could only be used to observe stars near the celestial equator and maybe just on star a day, it would allow images of everything close in to the star. (In fact thinking about it, you might need several observations per star to sort out galactic and intergalactic objects in the field of view.)

The next step would be to put a similar satellite out near L2, or perhaps free-flying in solar orbit. In any case you would want the satellite to use ion propulsion for both station keeping and relocation.

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