Can ETs Detect Voyager?

[Airbrush]

Is there anything about Voyager that an intelligent ET could detect, that would make it stand out against other objects in space? Is there something about it that if ETs had the technology that they could scan space and notice something unusual about Voyager?

[mathematic]

It looks like it was designed, not a random rock.

[Enthalpy]

From distance, ET could pick its radiowave emissions.

Human technology can but receive them from Earth with huge antennas and because the transmitting antenna is well directed, but others may have better receivers.

It depends from what distance. Far probes are half a light-day from Earth, but 5 light-years from the next star. Square that to estimate the received power.

[Moontanman]

From distance, ET could pick its radiowave emissions.

Human technology can but receive them from Earth with huge antennas and because the transmitting antenna is well directed, but others may have better receivers.

It depends from what distance. Far probes are half a light-day from Earth, but 5 light-years from the next star. Square that to estimate the received power.

 

The interstellar medium limits the distance radio signals can be detected, some estimates limit normal radio signal detection to less than a half light year, Voyager's signals are very weak and probably couldn't be detected very far, Signals from Earth to Voyager would be detectable further out depending on the signal strength...

[Airbrush]

Maybe ETs have advanced methods for scanning space for any objects with unnatural shapes.

Edited July 18, 2013 by Airbrush

[Enthalpy]

Radioastronomy works at huge distances, including at frequencies around Voyager's transmission, so the medium is not a limit. But the power received is certainly one.

[EdEarl]

Radioastronomy works at huge distances, including at frequencies around Voyager's transmission, so the medium is not a limit. But the power received is certainly one.

Antenna size increases sensitivity. The square kilometer array will be about 1M sq m and be nearly 50 times as sensitive as any other radio instrument. Who knows how large an array ET has.

[benevolenthellion]

Can they? Theoretically yes. Will they? The odd of another intelligent life form looking in out specific dot of the universe is extremely slim.

Though given enough time anything that can physically happen eventually will happen

[John Cuthber]

It's perfectly possible, though extremely unlikely that a member of some distant civilisation will be say "It's one small step for (a) splodgian, but one giant leap for splogdekind. What the f*** is that?" as voyager crashed into their moon.

They will detect it if they see it.

[Delbert]

I'd have thought that Voyager's signal will become gibberish at a distance when its strength becomes less than one photon per wavelength. And before that the receiving equipment will have to be ultra sensitive.

 

And as for this communicating with ET business, I understand light takes 100,000 years to traverse the Milky Way, and we've only been transmitting for 80 years? So if our galaxy filled an A4 sheet a circle representing said transmissions I calculate would be the diameter of a full stop!! And if we were to receive something that could be said to be ET it seems they would need to be a very local or a stable civilization to still be around!

[EdEarl]

Voyager transmits via a directional antenna pointed at Earth, and its power will fail within a few years. Thus, it is unlikely its signal will be received by anyone except us.

[Moontanman]

There are limits to receiving "leaking signals" most estimates of how far away a signal is detected assumes a powerful signal specifically intended to be detected from a great distance, not signals accidentally "leaking" from an earth like planet....

https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence

Another problem is the vastness of space. Despite piggybacking on the world's most sensitive radio telescope, Charles Stuart Bowyer said, the instrument could not detect random radio noise emanating from a civilization like ours, which has been leaking radio and TV signals for less than 100 years. ForSERENDIP and most other SETI projects to detect a signal from an extraterrestrial civilization, the civilization would have to be beaming a powerful signal directly at us. It also means that Earth civilisation will only be detectable within a distance of 100 light years.^%5B62%5D

Edited July 20, 2013 by Moontanman

[Enthalpy]

Detecting a transmitter is much easier than receiving properly the data. It can be done by integrating over much time the cross-correlation of signals from two receivers.

 

Imagine that we barely receive 100 bit/s from a distant probe through 40m antennas. Integrating the correlation over 10,000s (...not obvious, needs to compensate movements etc, but usual in radioastronomy) and you detect signals 1,000 times fainter, which improves the range by 30.

 

In the favourable direction, banal human technology would detect said probe not at 15 light-hours but 21 light-days. Then, 0.5km² antennas multiply the range by 20, or 1 light-year with current human possibilities.

 

Any hint to the technology they have, at 5 light-years? Though, Voyager wouldn't be the strongest transmitter of Mankind.

[Airbrush]

An ET civilization that is perhaps 1,000,000 years more advanced than we are, would probably be interested in ANY other intelligence, since intelligence is probably very scarce. They will have technology that is so far advanced that we cannot even start to imagine HOW they know things. Like explaining what Kepler does to a Neanderthal. But what ETs detect will probably be limited by how far LIGHT itself from Voyager has traveled.

[dimreepr]

That’s quite some ask, Airbrush, humanity as in Homo sapiens, thus far is 200,000 years old and given the world we inhabit is very stable and presents few disastrous scenario’s, relatively. It also supposes the exponential curve that represents the development of our current technology isn’t near its zenith, which I think maybe the case, certainly in terms of twenty percent.

Edited July 26, 2013 by dimreepr