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Biosignatures, Wright said, are going to be “extremely challenging to detect — if they exist. So that’s two big ifs. It’s very possible that life is just so rare that there’s nothing within a kiloparsec for us to find.”

But technology, he explained, could have started the same distance away — a kiloparsec is 3,261 light-years in distance — and moved closer to Earth over eons.

A kiloparsec is 1,000 parsecs or 3,262 light-years.

“We don’t expect life to be easy within the inner kiloparsec of the Milky Way,” says Abraham Loeb from the Harvard–Smithsonian Center for Astrophysics.

Past models have ignored the innermost kiloparsec, Forgan says, because astronomers were not sure how to take into account the supermassive black hole.