The search for planets that could support intelligent life reached a frenzy recently when NASA announced that it has located seven new planets that exist in a habitable zone – i.e. the right distance from a star to support life. Although they are light years away, these planets could potentially be the home of living things — even intelligent life. This got us thinking about just how many planets there could be out there in the vastness of space that could support life? Most scientists and astronomers agree that the chances of humans being the only intelligent life in the uiverse is so slim it is not really worth considering any longer. Conventional wisdom states that there is life out there somewhere; we just have to locate it — which is like finding a needle in a haystack, but a million times harder. Here is a list of 10 faraway planets that scientists think could have life on them.

10. Gliese 163c

Astronomers are divided over planet Gliese 163c, which is so large that its sheer mass puts the planet in the so called “gray zone” in terms of supporting life. Gliese 163c is roughly seven times the mass of Earth, which could make it either a very large rocky planet or a dwarf gas giant. Astronomers aren’t sure at this point. Gliese 163c whirls around its dim parent star every 26 days, at a distance of 50 light years away from Earth. Its parent star is in the constellation Dorado. Time and further study will tell us if Gliese 163c is capable of supporting life or not. But one thing is known at this point, Gliese 163c is one of the largest planets with the potential to support life that has been discovered to date. Scientists have been blown away by this planet’s scope and mass. It’s huge!

Via wikipedia.org

9. Gliese 581g

Another planet with a name that is more technical than sexy is Gliese 581g. This planet is much closer to Earth (although still impossible to travel to, like all the planets on this list) at about 20 light years away – if it actually exists. Astronomers are divided as to whether this planet is real or not – with a slight majority agreeing that it is, in fact, real. First discovered in 2010, there has been difficulty in getting Gliese 581g confirmed as a real planet. Shadows and sun spots have made identification tough for astronomers. Still, the University of Puerto Rico at Arecibo fully backs the existence of Gliese 581, and even goes so far as to declare that this planet is the top candidate for alien life near our home world. This rocky world is about 20 light years away from Earth’s sun, and is two to three times as large as Earth. It orbits its parent star about every 30 days in the constellation Libra. Truly, this would be an exciting option for life (if the planet can officially be proven to be real).

Via cosmoquest.org

8. Gliese 667Cc

One planet that scientists seem to agree definitely exists is Gliese 667Cc, another so called “Super Earth.” Like the previously mentioned Gliese 581g, the similarly named Gliese 667Cc is also close to Earth by interplanetary standards – about 22 light-years away in the constellation Scorpius, to be exact. This super planet is at least 4.5 times larger than Earth, and takes 28 days to make an orbit around its parent star: GJ 667C. This parent star is actually part of a triple-star system that has long intrigued astronomers. The star is an M-class dwarf, that is about a third of the mass of Earth’s sun, meaning it is less powerful but still powerful enough to potentially support life. The planet’s true size and density are unknown, and there is a possibility that this is a gas planet, hostile to life as we know it. And powerful magnetic fluxes also could mean periodic drop-offs in the amount of energy reaching the planet. Still, there’s hope.

Via Wikiwand

7. Kepler-22b

What makes Kepler-22b interesting is not the planet itself, but the star it orbits. Kepler-22b is larger than Earth, yet it circles a star that is quite close in size and temperature to our own sun. Specifically, Kepler-22b is 2.4 times Earth’s size and, assuming its greenhouse gas effect is similar to Earth’s, the planet has an estimated surface temperature of 22 degrees Celsius. This would make it ideal for supporting life, as long as it has a rocky surface and water on it. However, this planet is very far from Earth at 600 light years away (for reference, it takes about 37,200 years to travel a single light year at current speeds) in the constellation Cygnus. Still, despite the distance, this planet has astronomers excited given that the star it orbits is so similar to our own sun and that the surface temperature could be just right to comfortably support life. Stars, and a planet’s distance to them, are the biggest factors in terms of supporting life or not.

Via NASA

6. HD 40307g

There have been so many “Super Earths” discovered by researchers in the past ten years, that it has led scientists to conclude that our own planet is quite small in the cosmic scheme of things. Most planets that are similar to our own are much, much larger. Case in point is HD 40307g, which orbits comfortably inside the habitable zone of its parent star. It lies about 42 light years away from Earth in the constellation Pictor. This is a relatively close distance to us by the standards of the known universe. In fact, HD 40307g is so close by to Earth that future telescopes may be able to peer at its surface (yes, telescopes are becoming that powerful). HD 40307g orbits its parent star about 56 million miles (90 million kilometers) away, which is just over half of the Earth to Sun distance of 93 million miles (150 million kilometers.) Could we one day even reach this planet that has the potential to support life? Not currently, but if we are to reach one far off planet, this could be the one, say scientists.

Via phl.upr.edu

5. HD 85512b

HD 85512b is a planet that was discovered in 2011, along with a total of 50 planets that were discovered by the High Accuracy Radial Velocity Planet Searcher telescope, or HARPS, in Chile. This planet is another big one, at about 3.6 times the size of Earth. It resides about 35 light years from us in the constellation Vela (the Sail). Researchers are currently debating whether there is water on this planet’s surface. Conventional thinking is that there is water, which, of course, is the foundation for supporting any and all life. The probability of water on this planet is based on a mathematical calculation, so water has never been visually confirmed on this planet. Still, given its size, placement within a habitable zone of a star, and proximity to Earth, HD 85512b was once considered to be one of the best candidates for habitability in our galaxy.

Via daniel-irimia.com

4. Tau Ceti e

Finally a planet without a series of numbers in its name! The planet Tau Ceti e, which kinda sounds like something out of Star Trek, was first detected in December 2012 and is super close to us at just 11.9 light years from Earth. As is the case with most of the planets on this list, Tau Ceti e is another Super Earth in that it is 4.3 times bigger than our own planet. And, depending on its atmosphere, Tau Ceti e could be a temperate planet suitable for life or a scorching world similar to Venus where life is impossible. As is often the case in these matters, astronomers remain divided on this planet. Although its proximity to Earth would make Tau Ceti e really cool if we were to discover intelligent life on it. While physically reaching the planet would still be difficult (and impossible with current technology), communicating with it might be plausible given its relative closeness to Earth.

3. Gliese 581d

One of the potentially life supporting planets that astronomers are most excited about is Gliese 581d, which at just 20 light years away from our sun, is considered to be in Earth’s backyard. How much life this planet could support, and what form it would take, remains a mystery. Some scientists and researchers have a theory that Gliese 581d might have a thick, carbon dioxide atmosphere that would be poisonous to life as we know it. Others suppose that the planet could have an atmosphere very similar to our own. At about seven times larger than Earth, Gliese 581d is one of the biggest of the Super Earths. It also orbits a red dwarf star, and has a sister planet called Gliese 581g that could also be potentially habitable.

Via Seeker.com

2. Tau Ceti f

Like the aforementioned and similarly named Tau Ceti e, neighboring Tau Ceti f is a Super Earth that orbits close to the outer edge of a habitable zone. Scientists have noted that Tau Ceti f traps significant amounts of heat within its atmosphere. How hot the planet is will ultimately determine if it can support life. But its rocky surface and the high likelihood that there is water on the planet makes it a top candidate for potentially supporting life. Orbiting a star in the constellation Cetus that is spectrally similar to the Sun makes Tau Ceti f a likely planet for hosting life. It takes Tau Ceti f 642 days to orbit its star once, and the planet has a mass 6.6 times bigger than Earth. Like its sister planet, Tau Ceti f is fairly close to Earth. Close enough to potentially communicate with if the need arose.

1. Kepler-186f

Not a very sexy name, but Kepler-186f has the distinction of being the first ever Earth-sized exoplanet (meaning it likely has a rocky surface) ever found in a host star’s habitable zone. This alien world, which lies 490 light years from Earth and would take more than 18 million years to reach at the current top speed of a space shuttle, is just 10 percent bigger than Earth itself. And the likelihood of water and a rocky terrain on the surface make the potential for life very high indeed. The only issue, of course, is the massive distance to this planet and the length of time it would take to reach it. Fun fact: Kepler-186f orbits its star once every 130 days and receives one-third the energy that Earth does from the sun, placing it near the outer edge of a habitable zone. If a planet is too close to a star, it is too hot for life. If it orbits too far from a star, it is freezing and lifeless. If a person could stand on the surface of Kepler-186f, the brightness of its star at high noon would appear as bright as our own sun is about one hour before sunset on Earth.

Drawing by NASA Ames/SETI Institute/JPL-CalTech