Will Kepler Reveal Alien Planet Discovery?

As astronomers search through their telescopes for a carbon copy of the Earth, NASA is getting ready to release a trove of new data on hundreds of planets that might be capable of supporting life.

Few scientists expect something so bold. But the latest data on exoplanets - which orbit stars besides our sun - is said to include approximately 400 prospects. The information was part of a the latest data dump sent back by the Kepler space probe, which so far has surveyed some 156,000 stars since it launched into orbit in 2009. On Wednesday, NASA will host a press conference to talk about new information gleaned from Kepler as well as the discovery of any more possible alien planets.

Earlier this month NASA announced the discovery of the first Earth-size exoplanet. That hardly will be the last.

"Honestly, Kepler's so good that it's hard to beat it. It gets the numbers. Kepler's going to find thousands," said Geoff Marcy, an astronomer at the University of California, Berkeley, and a Kepler co-investigator, in an interview with LiveScience.com. "I bet by 2020, there'll be 10,000 planets, and by 2030 there might be another 20,000 or 30,000 more planets."

But it's also likely to be a journey punctuated by disagreement and discord. In fact, last week other astronomers challenged the exoplanet discovery announcement. That was followed by word from Philip Gregory of the University of British Columbia, who also cast doubt on the finding in the Monthly Notices of the Royal Astronomical Society

Chalk it up to the natural process of vetting a scientific hypothesis - albeit in a very public way. But the controversy hasn't shaken Marcy's conviction that the discovery of Earth-like planets is only a matter of time.

We know they're out there for sure. I mean, there's too many stars. But there's two parts to the question. What do you mean by "Earth-like?" And then, how common are they? Basically, we know what we want for Earth-like, so we shouldn't beat around the bush: We would love to know whether there are planets suitable for life as we know it.

A short checklist of must-have attributes would include water and stable temperatures - but that's just for starters.

"You probably want a moon to stabilize the spin axis," according to Marcy. "You probably want a Jupiter to sweep up the debris. You probably want a stable ocean for a long enough time that it can serve as the solvent for biochemistry."

The intriguing question is how many planets out there - if any - indeed fit that description.