There are alien worlds light years from Earth that share more than a few similarities with our own planet.
Over the past 20 years, astronomers have found thousands of exoplanets orbiting stars other than our Sun. And of those thousands, a dozen or so are considered to be similar to our own — and have potentially habitable conditions.
We aren't packing our bags and headed towards those planets just yet, but scientists want to get to know those alien Earths better. To get a sense of what we might find, here is a who's who list of six alien planets that are most like Earth.