Suppose aliens have been trying to contact us/whoever

[Perspicuo]

Suppose aliens were trying to contact us or whoever might be around. Where could we find their messages that we haven't tried before? Some form of radiation? Some other for of anomaly?

What if there are messages not from the present but from the past? Suppose they knew a cosmic catastrophe could wipe them out, and thought they might leave something for "posterity"? How to go about looking for such possible evidence?

 

[Tom Sawyer]

Aliens have a tendency to make their messages look like floating rocks in space, which makes it difficult to distinguish them from asteroids and the like. It's just one more reason that aliens are assholes and we're better off not bothering with them.

 

[bilby]

Given the speed of light and the size of the Galaxy, any message is necessarily from the past.

Given that we would be pretty much undetectable to a civilisation with identical technology to ours from only a couple of light-years away, it isn't really surprising that we haven't detected anyone else.

Only a signal that is specifically designed to be detected at great distances, and which is very long-lived, has any chance of being picked up. It would require a massive amount of investment for us to generate such a signal, so we haven't done it. Why would we expect anyone else to have done it?

 

[skepticalbip]

Suppose aliens were trying to contact us or whoever might be around. Where could we find their messages that we haven't tried before? Some form of radiation? Some other for of anomaly?

What if there are messages not from the present but from the past? Suppose they knew a cosmic catastrophe could wipe them out, and thought they might leave something for "posterity"? How to go about looking for such possible evidence?

They did leave us a message. It is the (and in the) "Black Knight Satellite" that is in polar orbit and was first spotted in 1954, well before we could put things in polar orbit.



You just need to patrol the conspiracy theory sites to find all sorts of "proof" that "they" have been and are here but the government is keeping them from us.

 

[Eldarion Lathria]

Are they legal aliens or illegal aliens. If they're legal, they're legal and have documentation. If they're illegal, division six of the Immigration and Naturalization Service will take care of them. BTW, in Atlantis, space aliens are required to show passports, or show an orange card if they're resident aliens. Otherwise they're deported to Syed's residence.

Eldarion Lathria

 

[Perspicuo]

Given the speed of light and the size of the Galaxy, any message is necessarily from the past.

Har har. All messages are from the past.

But it's not the same thing to say, "I'm out here! How are you?!", than to say, "We're goners, to anyone who may see this, we leave you this."

Given that we would be pretty much undetectable to a civilisation with identical technology to ours from only a couple of light-years away, it isn't really surprising that we haven't detected anyone else.

Only a signal that is specifically designed to be detected at great distances, and which is very long-lived, has any chance of being picked up. It would require a massive amount of investment for us to generate such a signal, so we haven't done it. Why would we expect anyone else to have done it?

There was the famous Wow! signal, for instance. That we caught. What about something that hasn't caught our eye or it hasn't occurred to us to read? That is the question.

 

[skepticalbip]

There was the famous Wow! signal, for instance. That we caught. What about something that hasn't caught our eye or it hasn't occurred to us to read? That is the question.

Any sort of signal using anything in the EM spectrum would require them to continuously send it, perhaps for thousands or millions of years waiting for anything to possibly evolve that could detect it. We have done it once for less than three minutes in 1974. It was a very, very narrow beam aimed at a star cluster 21,000 LY away. IF anyone is there, are listening, have their antenna aimed toward Earth for the particular three minutes the signal gets there, and can figure out that it was a signal rather than random noise, and replies then we may get an answer in 42,000 years - if anyone is still listening here on Earth and happens to have their antennas aimed at that star cluster at the time.

Arthur Clarke suggested a personal visit to do their thing then leave a monolith buried on the Moon to signal them when we found it.

 

[Perspicuo]

If found this on the web:

7 signals from space that could turn out to be aliens
http://www.blastr.com/2014-8-5/7-signals-space-could-turn-out-be-aliens

 

[ryan]

Here are some of my thoughts about why we have not received any signals from other parts of the universe:

- Like a zoo, someone or something might be "protecting" us or hiding us from what is really out there. Likewise, maybe we are not ready to know what is out there like a child is not ready to explore the world alone. Could dark matter be civilizations cloaked by a concerned neighbor?

- Maybe life can go many more ways that we thought. Maybe humans are a very rare type of evolution. After all it took at least 1 billion years for life to evolve into humans; that's a considerable fraction of the age of the universe.

- Once a civilization becomes technologically advanced enough to produce signals, they may soon seize to exist. This could mean that we tend to extinct ourselves with technology. So there may only be 100 - 1000 light year periods of signals from civilizations that would show up once in a very long while.

 

[Kharakov]

I think the most likely "alien" contact would be through observation of a unique emission spectra from some form of synthesized material in a galaxy's halo or interstellar medium.

The material would have to be something easily synthesized from the elements available in the interstellar medium or galactic halo and available energy from starlight, yet was not something that could form via normal processes in the medium.



What if it's just some sort of primitive interstellar life form or its waste products?

Perhaps the interstellar medium is too inhospitable for primitive life, which would be a sign that any large scale changes of interstellar emission spectra are a sign of intelligent life capable of building self replicating technology that could transform the interstellar medium.

Better yet, the production of some product that changes emission spectra in a coordinated manner, so that the whole galaxy changes emission spectra according to some plan.

Say that there are periodic fluctuations in emission spectra of a distant galaxy, with no identifiable source of the fluctuating spectra except something in the halo or interstellar medium of the galaxy. If the time gaps between the fluctuations are specific to something like the number of 0s and 1s in the binary expansion of e (maybe repeat the first 1,000 decimal places of e, than fluctuate according to the 1st thousand decimal places of Pi, then the first thousand decimal places of the binary expansion of ln(2), then e again...), one would know that the fluctuations were intentional.

At the current level of information I've been handed, this appears to be the only method of communicating the existence of intelligence long range.

If humanity survives, and is able to turn outwards and create machines that can do this, in a few million years our galaxy could be signalling the existence of intelligent life to other galaxies. Not to mention, if we found something seeding the interstellar medium with machines that coordinate and change emission spectra, we'll know what they're for. Although to tell you the truth, I'd think that the machines that do this would also be part of a galactic communications network, to make it easier to transmit information across the galaxy to remote areas.

The strength of the galactic starlight would determine the rate at which the machines could alter their emission spectra, combined with the portion of energy allotted to communication transmission.


At any rate, any extra-galactic alien signal would be something that can be detected for a long period of time, and would probably have to rely on technology that can alter emission spectra of whole galaxies in a coordinated manner.

 

[Trodon]

AM radio broadcasts and shortwave radio broadcasts bounce off of the ionosphere, and come back to earth.

FM radio broadcasts and television broadcasts get through the ionosphere and get into outer space.

Radio telescopes look like huge satellite antennas, and work on the same principle. Since 1960 astronomers have been scanning the skies for radio transmissions from alien civilizations. These radio telescopes are sensitive enough to discover the kind of FM and television transmissions we have been sending into space from several hundred light years away. They have not found anything yet. I am confident they will eventually, and I am somewhat puzzled that they have not found anything yet.

I will define "intelligent life form" as a species that would be able to send radio transmissions into outer space. All an intelligent life form needs is a good brain and the ability to manipulate objects.

Once evolution begins on a planet an intelligent life form is likely to develop eventually. My nickname here is Trodon. Trodon lived 65 million years ago when the asteroid killed all the dinosaurs. He was about our size. He had a brain nearly as large as a chimpanzee. He had binocular vision, two fingers, and a thumb, so he could pick things up and examine them. He was evolving into the direction of an intelligent life form, but he never got the chance.

The existence of radio waves was not hypothesized until the 1860's. Radio waves were only discovered about twenty years later. It was not until the 1920's that many people owned radios and listened to broadcasts.

It is conceivable to me that a more advanced means of communication exists. Perhaps there is an instantaneous method of communicating throughout the universe.

An advanced civilization may consider our radio broadcasts to be as primitive as exchanging letters written on paper with quill pens. Nevertheless, they might still send radio broadcasts for less advanced species like us. Perhaps they have detected our broadcasts, and are sending some back.

Astronomers may not detect extraterrestrial broadcasts for another century. Astronomers may detect some minutes after I post this comment. I am confident it will happen. I hope I am still alive when it does happen.

 

[bilby]

AM radio broadcasts and shortwave radio broadcasts bounce off of the ionosphere, and come back to earth.

FM radio broadcasts and television broadcasts get through the ionosphere and get into outer space.

Radio telescopes look like huge satellite antennas, and work on the same principle. Since 1960 astronomers have been scanning the skies for radio transmissions from alien civilizations. These radio telescopes are sensitive enough to discover the kind of FM and television transmissions we have been sending into space from several hundred light years away. They have not found anything yet. I am confident they will eventually, and I am somewhat puzzled that they have not found anything yet.

I will define "intelligent life form" as a species that would be able to send radio transmissions into outer space. All an intelligent life form needs is a good brain and the ability to manipulate objects.

Once evolution begins on a planet an intelligent life form is likely to develop eventually. My nickname here is Trodon. Trodon lived 65 million years ago when the asteroid killed all the dinosaurs. He was about our size. He had a brain nearly as large as a chimpanzee. He had binocular vision, two fingers, and a thumb, so he could pick things up and examine them. He was evolving into the direction of an intelligent life form, but he never got the chance.

The existence of radio waves was not hypothesized until the 1860's. Radio waves were only discovered about twenty years later. It was not until the 1920's that many people owned radios and listened to broadcasts.

It is conceivable to me that a more advanced means of communication exists. Perhaps there is an instantaneous method of communicating throughout the universe.

An advanced civilization may consider our radio broadcasts to be as primitive as exchanging letters written on paper with quill pens. Nevertheless, they might still send radio broadcasts for less advanced species like us. Perhaps they have detected our broadcasts, and are sending some back.

Astronomers may not detect extraterrestrial broadcasts for another century. Astronomers may detect some minutes after I post this comment. I am confident it will happen. I hope I am still alive when it does happen.

I don't think FM radio or TV are powerful enough to be detected over relevant distances. However Randal Monroe has looked at this, and he suggests that while incidental TV and radio broadcasts might not do the job, Cold War radar could - but only for a short time frame of less than half a century.

Only deliberate broadcasts to space are reasonably detectable at the range of hundreds of light years; and even then, the window of opportunity to detect them is minuscule.

 

[skepticalbip]

We can be thankful that the signal strength of our TV broadcasts would be so far below the noise level as to be undetectable even as close as Alpha Centauri. If they saw our TV programming then they would have to conclude that there is no intelligent life in the Sol system so not worth the time sending a signal this way.

 

[Underseer]

In case something happens to the link in the future: "Sometimes I think the surest sign intelligent life exists elsewhere in the universe is that none of it has tried to contact us." --Bill Watterson, Calvin and Hobbes

 

[rousseau]

The best evidence we have of life on other planets is life on our planet. The best description of what alien life is likely to be like can be found in our own textbooks.

 

[Perspicuo]

Humans discovered/will discover near-immortality populating the universe back in time over and over and in successive planets in order to escape the death of the universe (and other cataclysms such as supernovæ or the Andromeda-Milkyway collision) and the end of the capacity for sustaining life of the planets they come to inhabit. The universe if full of humans hiding from detection of 21st century Terrans.

 

[fromderinside]

Humans discovered/will discover near-immortality populating the universe back in time over and over and in successive planets in order to escape the death of the universe (and other cataclysms such as supernovæ or the Andromeda-Milkyway collision) and the end of the capacity for sustaining life of the planets they come to inhabit. The universe if full of humans hiding from detection of 21st century Terrans.

So much for any multiverse theory eh, Perspicuo​.*

*^{_{limiting options just sucks.}}

 

[Perspicuo]

When I conceived it I thought it would be awesome to write a novel with that premise. But, alas, I am no writer.

I could mail it to Stephen King. I'd love it to start off as a supernatural thriller turning out to be future humans all over the universe. The final page could be a secondary character visiting Hadean Earth, before life... the very final line would be him sneezing over a puddle of ooze after unsuccessfully looking for the first signs of abiogenesis...