There are at least 300 million potentially habitable planets in our galaxy, NASA finds

Photos: Weird and wonderful planets beyond our solar system
This illustration shows the metaphorical measuring of the density of each of the seven planets in the nearby TRAPPIST-1 system. New measurements have revealed the most precise densities yet for these planets and they're very similar -- which means they also likely have similar compositions.
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Photos: Weird and wonderful planets beyond our solar system
This artist's illustration shows the view from the furthest planet in the TOI-178 system.
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Photos: Weird and wonderful planets beyond our solar system