Kepler researcher Tom Barclay found one of the first Goldilocks.
"Did you yell, go 'Eureka!'?" asked Petersen.
"To some extent, it was relief - 'Finally we've done it!'" replied Barclay.
It helps to have a telescope in outer space, and the use of a $100 million supercomputer to crunch the numbers. But still, that hint of dimming so many light years away is beyond miniscule.
"This is much less than, say, a flashlight on the moon," said Barclay. Yet that difference can be detected. "It's astounding. It's absolutely astounding what we can do."
And that little bit of light may also help find signs of an atmosphere -- and that means a chance to find life.
That's where NASA'S Tori Hoehler comes in -- studying the simple types of life he imagines we might expect to find on planets light years away.
At his greenhouse he showed Petersen his "window back in time."
"We had a microbial planet for probably more than two billion years," Hoehler said. "And if you wanted to put a picture in your head of what that might look like, this is it."
As for what kind of life that may be out there, he says look to Earth and its extremes. Hoehler says organisms have been found in the hot springs of Yellowstone, which reach a pH close to battery acid. "Remarkable capabilities of these sorts of organisms," he said.
The planet hunters started their search with one major question: Are there any Earth-type planets out there?
Now that that's been answered, the burning question everyone wants answered is: Are we alone?
When asked if she has any doubts that there is life in the universe besides us, Batalha replied, "I myself think that life is too creative. Here on Earth, we find life under every rock we lift, right? So I tend to be of the camp that believes that life is going to be prolific."
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