Earth-Like Planets: 2012 featured a ton of exoplanet discoveries, but the sighting of HD 40307g was without a doubt the most unexpected and exciting.  The planet, bigger than earth but not so large as to be a gas giant, seems to orbit in its sun’s “goldilocks zone” (not too hot and not too cold), making it potentially capable of hosting liquid water, considered a prerequisite for life as we know it.

Even better, it’s just 42 light-years away: distant by human standards, but fairly close by compared many of the astronomical objects, making future projects to observe the planet much more feasible.

A composite image of self-portraits taken by Curiosity on Mars. Image via NASA/JPL-Caltech/MSSS

Read more: http://blogs.smithsonianmag.com/science/2012/12/mythical-particles-goldilocks-planets-and-more-top-5-suprising-scientific-milestones-of-2012/#ixzz2eI2KeWu0 
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