8 of the most compelling places we could discover alien life outside our solar system

NASA/Ames/JPL-Caltech

On May 10, NASA added 1,284 new planets to its running list of confirmed planets outside of our solar system, or exoplanets. That brings the total well above 3,000.

And those are just the ones we've detected. Scientists now believe that, on average, every star in the Milky Way has at least one planet orbiting it.

And there are more than 100 billion stars in our galaxy alone.

With numbers like those, its hard to believe that we're all alone.

Exploring these exoplanets is our best bet to locate distant neighbors in our lonely chunk of the universe.

Here are some of the most promising places we might find life beyond our solar system:

Scientists judge whether or not a planet is habitable based on factors such as its size, its rockiness and its distance from its host star. The rockier a planet is and the closer it is to the star's "Goldilock zone" which allows for liquid water, the more likely there is alien life roaming its terrain.

Based on this criteria, exoplanet Kepler-442b was actually found to be even more habitable than Earth. The near Earth-sized planet, discovered in 2015, is about 1,100 light years away. It orbits in the habitable zone of a star slightly cooler than our sun and, if it turns out to be a rocky planet, might only be about twice as massive as Earth.

Kepler-186f, discovered in 2014, is the first validated Earth-sized planet to be located in the Goldilocks zone of its star. The planet is only 10% larger than Earth and evidence suggests it has a rocky composition. The planet orbits a star about 500 light years away that is cooler and redder than the sun.