Viewing a single comment thread. View all comments

nosmelc t1_j9tea12 wrote

An earth-like planet with a similar technological civilization would have to be no more than 122 light years away to detect our signals because we've only been using radio for that long. Most likely they'd have to be much closer or the signals would just be too weak to pick out from the background noise.

122 light years sounds like a long distance, but keep in mind that our Milky Way galaxy is over 100,000 light years across. Any other galaxy would be hopelessly too far away to ever receive a radio signal. The closest major galaxy is Andromeda at over 2.5 million light years away.

It's entirely possible there are several radio signals from other planets traveling from planets in our galaxy but they either haven't reached us yet or are too weak to pick up by the time they've crossed that vast distance.

13

tjmick1992 t1_j9terr4 wrote

Wait wait wait you mean we have smaller galaxies closer?

3

doctorgibson t1_j9tmv61 wrote

The milky way has a couple dwarf satellite galaxies close by, including the small and large Magellanic Clouds

3

tjmick1992 t1_j9vu8pp wrote

Why isn't this more common knowledge? Like holy fuck this literally blew my mind and made my day

1

doctorgibson t1_j9xjp4p wrote

I know right? It's really cool, there's tons of knowledge out there that people just don't know

1

jcargile242 t1_j9ttgay wrote

Or their signals reached Earth millennia before humans existed, or will reach Earth long after we’ve managed to exterminate ourselves. Time and space are unimaginably vast, and our place in both is infinitesimally small.

3

Union_Jack_1 t1_j9us4k8 wrote

It makes me laugh when people play this “where is everyone?” argument despite the evidence plainly stated in this thread about the massive distances, the time frame chances (before humans existed/could receive signals, etc).

There is an almost mathematical certainty of life in the universe beyond our own.

2

lukinhasb OP t1_j9tf3ay wrote

Is radiowave signal the most appropriate for this kind of communication? Suppose that we want to send a signal out there to be picked up, would it be radio?

Does radio lose power when it travels long distances?

2

mobyhead1 t1_j9tgbps wrote

Radio is the only kind we can send at our technology level. Any electromagnetic signal (this includes radio) we send decreases in power with the square of the distance.

5

nosmelc t1_j9th4j4 wrote

Yes radio does lose power when it travels long distances.

I think radio might be the most appropriate for this kind of communication because it should be the first method of communication that technological civilizations discover. That means everybody should be able to send and receive radio.

3

Heisenberg_Hat_ t1_j9tfvjg wrote

Neutrinos or gravity waves are some of the more exotic/advanced theoretical communication methods proposed.

2

solidcordon t1_j9tnxez wrote

Laser light would be more efficient but you would have to know where to point the laser.

Probably something that would need to be "negotiated" with radio communication first to convey specifics of wavelength though.

1

Italiancrazybread1 t1_j9twyy3 wrote

You can make a laser out of radio waves, there's nothing special about radio waves that prevent you from making a radio frequency laser.

3

solidcordon t1_j9ty7vm wrote

good point, well made.

RASER sounds pretty cool too.

1