Alien Contact Unlikely For Another 1,500 Years, Says Study (msn.com)

An anonymous reader writes: Astronomers at Cornell University predict based off estimates that alien contact is unlikely for another 1,500 years. MSN reports: "According to the astronomers, signals from Earth would need to reach half of all the solar systems in the Milky Way in order to be picked up by an intelligent life form. Given that signals from TV and radio were first sent into space as a byproduct of broadcasting 80 years ago, it will take around 1,500 more years for aliens to receive, decode and respond to the signals." A co-author of the paper who will present it at the American Astronomical Society's meeting on June 16, Evan Solomonides, said, "We haven't heard from aliens yet, as space is a big place -- but that doesn't mean no one is out there. It's possible to hear any time at all, but it becomes likely we will have heard around 1,500 years from now. Until then, it is possible that we appear to be alone -- even if we are not. But if we stop listening or looking, we may miss the signals. So we should keep looking." Stephen Hawking and Russian entrepreneur Yuri Milner announced a $100 million research program in April to send robotic probes the size of postage stamps to nearby stars within a generation.

Comments

Twenty five thousand light years

[Geoffrey.landis]

The Solar System is 25,000 light years from the center of the galaxy. So, it takes 25,000 years for signals from Earth to reach half of the solar systems in the galaxy... and another 25,000 years for them to respond.

Re:Twenty five thousand light years

[Calydor]

No they're not.

Let's assume the aliens are advanced enough to pick up our TV signals and realize this isn't just background noise. At that point the time it will take them to figure out WHAT these signals are would probably be negligible; let's say ten or twenty years since the signals aren't encrypted in any way. 1500 year round trip minus those twenty years is 1480, which means some 740ish light years distant. That's on the optimistic end of the "1000 light years give or take a few hundred" spectrum.

Radio interference

[scorp1us]

How long until those signals are indistinguishable from background? It's not just that the signal is there, but that the SNR is low enough to stand out.