How would Earth send messages to a starship—or a distant civilization?

February 14, 2014 by Elizabeth Howell, Universe Today
USS Enterprise NCC-1701-D, a starship of the Star Trek: The Next Generation era. Credit: Memory-Alpha.Org/Paramount Pictures/CBS Studios

I have a new exercise routine where I watch Star Trek: The Next Generation most mornings of the week while doing my thing. Besides serving as awesome distraction, the episodes do get me thinking about how humans would talk to extraterrestrials. It likely wouldn't be as easy as the show portrays to zoom across space to conduct diplomatic negotiations at the planet "Parliament", for example, so interstellar communication would be a problem.

Luckily for non-engineers such as me, there are folks out there (on Earth, at least) that are examining the problem of talking between stars. David Messerschmitt, of the University of California at Berkeley, is one of those people. A new paper by him on Arxiv examines the issue. Note this is a preprint site and not a peer-reviewed journal, but all the same it provides an intriguing addition to how to communicate outside of Earth.

Messerschmitt explains that humans already communicate with probes that are a fair distance from Earth (say, Voyager 1 in ) at radio frequencies, and there is some usage now of laser/optical communications (namely between the Earth and the moon).

Across greater distances, however, you lose information, the gets in the way, and stars shift due to relative motion. Besides all that, at first you wouldn't know how the other civilization designs its systems and you could therefore send a message that wouldn't be picked up.

This sequence of images, showing a region where fewer stars are forming near the constellation of Perseus, illustrates how the structure and distribution of the interstellar medium can be distilled from the images obtained with Planck. Credit: ESA / HFI and LFI Consortia

He further explains that starships and civilizations would have different communications requirements. Starship communication would be two-way and based on a similar design, so success comes by having high "uplink and downlink transmit times". The more information, the better it would be for scientific observations and keeping down errors.

Civilization-to-civilization chats, however, would present headaches. As with all diplomatic negotiations, crafting suitable messages would take time. Then we'd have to send the message out repeatedly to make sure it is heard (which actually means that reliability is not as big of a problem.) Then the ISM would have to be contended with (something that pulsar astronomers and astrophysicists are already working on, he said).

In either case—talking to starships or other civilizations—one can assume there'd be a lot of energy involved, he added. "Starships are likely to be much closer than the nearest civilizations, but the cost of either a large transmit antenna or transmit energy is likely to be considerably greater for the starship than for a terrestrial-based transmitter," he said, suggesting that a solution would be to minimize the energy delivered to the receiver. Other civilizations may have found more efficient ways to overcome this problem, he added.

You can read more details of the research on Arxiv, where Messerschmitt talks about Gaussian noise, channel coding and other parameters to keep in mind during communication.

Explore further: Self-replicating alien probes could already be here

More information: "Design for minimum energy in starship and interstellar communication." David G. Messerschmitt. arXiv:1402.1215 [astro-ph.IM]

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5 / 5 (1) Feb 14, 2014
I think the first step is finding out where life exists and where it doesn't.
3 / 5 (2) Feb 14, 2014
It seems to me energy would be the least of your problems. If we became able to go to the stars, the light speed speed limit would cause any communication to be impossible.

I wonder if quantum entanglement will eventually solve this problem.
not rated yet Feb 14, 2014
Isn't ,"sub-space" transmission the way it's done?
not rated yet Feb 14, 2014
Communication wouldn't be impossible, assuming that the respective civilizations are stable. Conversations would be very difficult, if not impossible, except for VERY long-lived species. For stable civilizations communication may be closer to an interstellar bulletin board than a phone system. Round trip message times would be in the hundreds of years, but they would learn from, and about, each other.
1 / 5 (1) Feb 14, 2014
I think JamesG nails it. Use quantum entanglement.....we are already doing just that. We are being ambiguous or saying nothing about the speed of transmission. It is probably classified, but Schrodinger's cat is probably dead as mutton. By simply pandering to popular dogma, our military can hide this in plain sight and no one for fear of his career will say a thing.....just like the fairy tail emperor with his 'new clothes'.
5 / 5 (1) Feb 14, 2014
All of our entanglement successes to date involve first entangling, then moving the entangled particles apart for potential exploitation.

So saying 'use quantum entanglement' for communication across light years begs the question, how? If we have to physically move entangled particles apart before we can use them, we'd not only need an awful lot of time to pull it off, but knowledge of where it would do some good. We'd have to know both that a civilization was there and that it could decode and encode using entanglement, and would care to bother. And that doesn't even consider the difficulty of keeping particles entangled for centuries.

That's *infinitely* more challenging than just spraying out photons and seeking to detect them.

The rest of Osiris1's comment is pretty obviously paranoid-schizophrenic. Pandering... dogma... military hiding in plain sight... take it to a therapist, not
3.7 / 5 (3) Feb 15, 2014
Sometimes it's better to stay quiet, especially if you don't know your neighbors.
1 / 5 (2) Feb 15, 2014
Why to send messages for distant civilizations? The less advanced civilization will not catch them, the more advanced civilization wouldn't need them. It's just another nonsense, generated with lobby of people without more useful job.
5 / 5 (1) Feb 18, 2014
As previous comments suggest, there may be no practical reason to contemplate this right now, aside from just having fun. But it is a fun thing to think through. If you believe, as I do, that we aren't the only intelligence in the Universe, then some civilization out there might already have found a way to do it. If so, then maybe there is a practical reason. If we figure out how to listen, then maybe there's someone already trying to talk to us?

Anyway, there's another technical barrier for starship communication, if for example we send probes to nearby stars. When you have ships traveling at significant portions of the speed of light, you'll need to adjust your frequency to account for doppler effects. This isn't too hard to do, but it makes your sending/receiving antennea more complicated. Different frequencies require different antenna designs, so you might even need multiple dishes for different speed ranges. You would definitely want a plan in place ahead of time.
3.7 / 5 (3) Feb 20, 2014
I think JamesG nails it. Use quantum entanglement.....we are already doing just that.
No we're not.

"Superluminal communication is the hypothetical process by which one might send information at faster-than-light (FTL) speeds. The scientific consensus is that faster-than-light communication is not possible and to date superluminal communication has not been achieved in any experiment.

"In standard quantum mechanics, it is generally accepted that the no cloning theorem prevents superluminal communication via quantum entanglement alone, leading to the no-communication theorem."

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