![Have astronomers discovered an alien megastructure? Have astronomers discovered an alien megastructure?](https://i.ytimg.com/vi/j5UHULLK1sY/hqdefault.jpg)
Astronomers have spotted an object in space that blocks a surprising amount of sunlight, leading to speculation it could be a massive structure built by aliens. CBS News science contributor Michio Kaku spoke to CBSN about the enormous discovery. Source
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