Seven Earth-sized planets orbit an alien star only 40 light-years away

A small, cool star in distant space plays host to something amazing. 
Scientists have discovered that at least seven Earth-sized worlds circle the star TRAPPIST-1, a ultracool dwarf star only about 40 light-years (235 trillion miles) from Earth. 
The planetary haul — which includes at least six rocky planets total, three of which were first discovered last year — is detailed in a new study published in the journal Nature on Wednesday. 
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