Alien astronomers might be looking in our direction from distant planets. What would they see?
We've been searching the heavens for some time now. But despite decades of listening for tell-tale radio signals and hunting for signs that other worlds might be even vaguely habitable, it's been slim pickings so far. While astronomers have identified a few possible candidates for where life might conceivably exist elsewhere in the Universe, along with the odd mysterious signal, there is yet to be any concrete evidence of alien life out there.
But what if there was? And what if they were looking back, trying to find us? Would they know there is life on Earth?
That's a question scientists have had to grapple with in recent years, as we continue to inadvertently broadcast our presence out into the galaxy. "Hold the mirror up to yourself in space, and what would they see of us?" says Jacqueline Faherty, an astrophysicist at the American Museum of Natural History in the US. "We're looking. That means other worlds might be looking too."
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In April, Isaacson calculated whether some of these transmissions, up to 20 kilowatts, might reach other stars as they wash over the remote spacecraft and continue their journey into space. He found four nearby stars and any accompanying planets would have already received the transmissions, with more than 1,000 stars likely to hear the signals by the year 2300. "The signal would definitely show up as artificial," says Isaacson. By 2031, the closest of the stars would have had enough time to receive the signals and send their own message back, perhaps an interesting target for future study.
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... meanwhile out in the cosmos stands a lonely planet sized billboard: EARTH Next 10 Light Years, Stop by for some Famous BBQ or the People Hut for some Take Out.
We've been searching the heavens for some time now. But despite decades of listening for tell-tale radio signals and hunting for signs that other worlds might be even vaguely habitable, it's been slim pickings so far. While astronomers have identified a few possible candidates for where life might conceivably exist elsewhere in the Universe, along with the odd mysterious signal, there is yet to be any concrete evidence of alien life out there.
But what if there was? And what if they were looking back, trying to find us? Would they know there is life on Earth?
That's a question scientists have had to grapple with in recent years, as we continue to inadvertently broadcast our presence out into the galaxy. "Hold the mirror up to yourself in space, and what would they see of us?" says Jacqueline Faherty, an astrophysicist at the American Museum of Natural History in the US. "We're looking. That means other worlds might be looking too."
.....
In April, Isaacson calculated whether some of these transmissions, up to 20 kilowatts, might reach other stars as they wash over the remote spacecraft and continue their journey into space. He found four nearby stars and any accompanying planets would have already received the transmissions, with more than 1,000 stars likely to hear the signals by the year 2300. "The signal would definitely show up as artificial," says Isaacson. By 2031, the closest of the stars would have had enough time to receive the signals and send their own message back, perhaps an interesting target for future study.
Why aliens might already know that humans exist
Alien astronomers might be looking in our direction from distant planets. What would they see?
... meanwhile out in the cosmos stands a lonely planet sized billboard: EARTH Next 10 Light Years, Stop by for some Famous BBQ or the People Hut for some Take Out.
