Earthlike Planets and Aliens

NASA launched the Kepler space telescope Friday, a probe that promises to determine if other worlds like Earth exist, and,if so, to give an idea how common they are.

(A Delta II rocket roars toward space Friday evening at Cape Canaveral carrying NASA’s Kepler spacecraft. Image credit: NASA/Jack Pfaller.)

Monitoring the same patch of the Milky Way for 3 1/2 years, Kepler will measure minuscule changes in the light of 100,000 stars. A periodic dimming and brightening could signal the passage of a planet in front of one.

Kepler won’t return “Hubble-like pictures,” said Patrick Wiggins, NASA solar system ambassador to Utah. Don’t expect “real pretty pictures of the sky. And the other thing not to expect is any kind of discoveries immediately,” he said. If a planet is in a star’s “Goldilocks zone,” where it’s neither too cold nor hot for life, it could complete an orbit in one year, crossing the star’s face again at that time. To confirm the measurements, scientists may want to wait for two or three orbits.

“That is going to take time,” Wiggins thinks.

As NASA put it in a Feb. 20 press release, Kepler is “the first mission with the ability to find planets like Earth — rocky planets that orbit sun-like stars in a warm zone where liquid water could be maintained on the surface.”

Of the 300 or so exoplanets seen so far from ground-based telescopes, none fits the criterion. The reason, Wiggins said, is that today’s technology is not sensitive enough to find small planets that distant from the star while peering through our atmosphere.

“We need to be above the atmosphere, but we also need to be in a place where we can stare unblinkingly at a given spot in the sky for literally years on end.”

— Do Earthlike planets exist in the temperate zones of other stars? “My gut feeling is that they’re out there, but that is just a gut feeling,” he said.

— Does intelligent life exist on any of these planets? “I’m going to quote from (actress) Jodie Foster in the movie Contact,” he said, “and I agree with what she says. ‘If it turns out that we are alone, it’s a terrible waste of space.’ … My gut feeling is the universe is teeming with life.”

A negative result in the planet search also would be hugely important to our understanding of our place in the universe.

And this is where the kind blog-reader comes in. I am curious to know your take on the two questions that Wiggins answered. And while you’re at it, feel free to give an opinion about whether this probe’s search for other worlds is worth the money, about $600 million.

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