Your crazy uncle who believes he was visited by aliens might not be so insane after all. At a panel discussion this week, NASA scientists said it would be "improbable" to think humans are alone. We can't say that with 100-percent certainty, mind you. But there's still so much out there we have yet to see or explore, so the probability of us being the only ones is getting lower all the time.

In fact, NASA believes they can prove alien life exists within the next 20 years.

"Do we believe there is life beyond Earth?" asked NASA Administrator Charles Bolden. "I would venture to say that most of my colleagues here today say it is improbable that in the limitless vastness of the universe we humans stand alone."

Now, just because NASA is open to the possibility, that doesn't mean extraterrestrial life is like what we dream of in Hollywood movies. Researchers have most aggressively searched for life on Mars over the past couple years, finding clear evidence that the Martian planet may have one day supported microbial life. That's not exactly the same thing as the benevolent alien we saw in Steven Spielberg's E.T.

Elsewhere, NASA has spotted a number of super-Earths, suggesting there are many potentially-habitable candidates out there. NASA's Kepler Space Telescope has provided a ton of data suggesting every star in our galaxy has at least one planet circling it, so there's a lot of places to look for life. Meanwhile, the agency has plans to launch the James Webb Space Telescope in 2018, which will be used to study these billions of planets to see if they can support life. Or, even better, if they already harbor life.

According to Sara Seager, a planetary scientist at MIT, the conditions would have to be absolutely perfect for NASA to know with any certainty if a planet does harbor life.

"With the James Webb, we have the first capability of finding life on other planets, but we have to get lucky; we have to beat the odds," Seager said.

Beyond James Webb, though, Seager said that future developments in technology could make it easier for NASA to spot Earth-like planets. With current technology, it's difficult for researchers to spot planets of Earth's size because the light they emit is so faint compared to their host star. Gliese 832-c, for example, that so-called super-Earth NASA talked about recently, is 16 light-years away, so it's not exactly easy to see. It's not as simple as looking at our nearest neighbor, Venus, which, according to Universe Today, can be as close as 38 million km away.

"We believe we are very close in terms of science and technology to finding another Earth, and signs of life on another world," Seager said.