Lawrence B. Crowell

Human activity on Earth might be detectable “out there.” Some SETI types arrgue that EM transmissions will travel out and be detectable. We will never know if Sagan’s Cosmic Connection exists or not unless we look. Even still we might facilitate it if we transmit information ourselves, or erect AC Clarke’s Sentinel or Monolith on moons in extra-solar systems so that maybe in the distant future ETI will find our announcement to the universe and what we know about it. Sagan’s cosmic connection might just amount to distant ETI’s sending bits of information here and there, receiving some in return and each ETI might end up as a rather transient actor in the web.

Lawrence B. Crowell

Maybe Tesla inadvertantly killed cows on ET’s home world and in a case of tit-for-tat are doing the same thing to us…or maybe they think that’s how our civilization communicates…with dead cows lol

Lawrence has an excellent point here which can be extended to point out that any civilization that has access and control of the levels of energy needed to conquer space would likely view the resources of Earth as miniscule…a speck of dust.

Another thing: Dead cows, Colorado, ET. Think about it.

windy on Jan 22nd, 2008 at 8:38 pm

-one of the less advanced cultures uses tech/contacts from the more advanced culture against its neigbours (this has historically been a major danger and could be still, but it’s one that humans would control themselves!)

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Before the Iraq invasion I thought about a Sci Fi story where Saddam got interstellar military technology from some ET. The USA starts its war and within a day the entire US military is destroyed and the Iraqi flag is flying over Capital hill.

Lawrence B. Crowell

I’d say that we might consider instead of “hiding this little light of mine,” that we let it shine. We might consider instead sending out powerful signals directed at G-class stars announcing ourselves and revealing what we have discovered. Maybe some ETI will get our signal 2000 years from now and be grateful for being able to compare their ideas about the universe with ours. As I have written a book about sending probes to other stars I think that something similar to AC Clarke’s monolith should be send along as well. The probe craft might set up a durable structure that contains information about ourselves and what we have learned. In particular this would be done if the probe explores a bio-active planet. Maybe millions of years in the future some ETI might evolve and they discover this thing and learn about us and our science.

The Fermi paradox does indicate that actual travel between stars is unlikely. Under the exceedingly small probability they come here they probably would be no threat. After all, if the Apollo astronauts were greated by a tribe of angry stone aged “fuzzy-wussies” they would have been in big trouble. So we can play the turtle and pull into our shell, or we can come out and be seen. If we get an ET message they might do much the same.

Lawrence B. Crowell

I’m with Julianne. History has not been kind to less technologically advanced cultures.

So we should stay on the reservation and preserve our traditional way of life, secure from the temptations?

It’s not just a bad thing that history hasn’t been kind to less technologically advanced cultures, since otherwise we’d be living like most of our ancestors did. The problem is that usually history hasn’t been kind to the people involved (which I’m sure what you had in mind). But the analogy might not be very accurate, if the dangers are not likely to be the same as from some of the actual historical contacts on Earth:

-they want land or slave labor: the implausibility of this was pointed out by Z and others.

-they seek to convert us to the one true religion: it might make interesting sf but…

-they want resources: again, why go the distance, unless it’s something that’s only found here, like biological resources (and we could share the genetic material)

-disease: actually we would be unlikely to catch diseases (as such) from ET’s because of the phylogenetic gulf. An invasive lifeform that competes with Earth life would be a more likely danger.

-one of the less advanced cultures uses tech/contacts from the more advanced culture against its neigbours (this has historically been a major danger and could be still, but it’s one that humans would control themselves!)

I think we have a long way to go before we can play with the galactic big boys, presuming there are any.

Why do you assume we are advancing faster than them? If you want to apply the historical analogy, there’s also the fact that the cultures that stayed isolated longest (like the Tasmanians) didn’t do any better at first contact, they did worse…

As for figuring out a WIFI TCP/IP signal, the ETs don’t need to do that to figure out that there exists a signal and that there is some sort of information content. Actually communicating with ET, or ET figuring out what we are transmitting (imagine how much porn they would get on those Wifi signals) would require some serious decryption work. With elliptic variety coding structures (Goppa) there is a wide range to work in, and this can be extended to more general algebraic or projective varieties. The Golay, hexacode to M_{24} might work and M_{24} code have 196560 roots or possible state configurations, but this might not be enough to get a Hamming measure on an ET code.

BTW, I have been working on quantum gravity as a quantum code system.

Of course to cap it off ETI might be more different from us than the brainiest octopi is from us. An ETI might know about electromagnetism, but their mathamatics might be da-da poetry to us, assuming we figure out where their math is encypted in the signal. Of course Sagan had them sending prime numbers in pulses, but if there sense of numbers is completely different than ours, they still might send information we would have a hard time decrypting.

Lawrence B. Crowell

This then has the effect that frequencies roughly below the plasma frequency are screened by the plasma just like static fields and the signal strengths will decay exponentially with the distance. Only signals of frequency higher than about the plasma frequency can propagate through the interstellar plasma.

If I remember correctly, the plasma frequency of the interstellar medium is about 1 MHz…

The short version is “Even a 3000 meter diameter radio telescope could not detect the “I Love Lucy” TV show (re-runs) at a distance of 0.01 Light-Years!” But, it does turn out that radars have higher power and relatively narrow bandwidth, and might be detectable at a few light years.

Thanks for an informative reply. I was being a little flip with the “watching I Love Lucy” comment, and you’re right, I completely neglected how hard it is to figure out what a signal’s actual message is. It’s funny, we seem to think that there’s some “natural” relationship between radio waves and sounds/images, when in fact its the result of decades of engineering. And, as other people have pointed out, the more advanced your technology, the more your signals resemble static.

Still, I think we can sweep that problem under the table, at least at a first cut for two reasons: First, determining that signal is from a technological source is (I think) a much easier problem than actually decoding it, and second, once you think you’ve got a technological signal, pretty much every curious mind on your planet is going to be working on decoding it. That being said, I defy anyone to figure out how to pull a video stream out of a compressed TCP WiFi signal…let alone figuring out things like that RGB encoding is based on quirks of human eyes, MP3 on our hearing, etc…

So, to give a better defined problem, what would you need to distinguish our broadcasts from natural signals? As a start, you’d need enough resolution to seperate the Earth from the Sun–the back of my envelope says that get a resolution of 1 light-minute, using a 100Mhz signal, you need an antenna of 1923KM/light year. Not infeasable with interferemotry just a little better than ours.

For most signals we emit now, I assume that if you got a broadband recording and did a standard bunch of FFT’s on it, they’d pop right out. That is, it’s not too hard to realize you’re seeing a narrow band, complexly modulated signal–are those assumptions correct? Also, I since a radio antenna’s aren’t omnidirectinal, they’d have a pretty distinctive modulation over a 24-hour period. (Assuming that ET can figure out how long our day is).

The big unknowns for me are what kind of S/N ratio you’d need to figure out you’ve got a technological signal, and what the sources of noise are. I guestimate we’re putting out a few GW ERP of RF (http://www2.sims.berkeley.edu/research/projects/how-much-info/broadcast.html#fun) Any idea how what natural emissions there are in the various broadcast bands?

And, sort of related, does anyone know if the power grid leaks significant amounts of 50/60Hz radiation? Hard to detect something that low, but even a fraction of a percent leakage would probably be brighter than the intentional broadcasts.

Lawrence B. Crowell

I agree with you on your point.

What I was implying with the “evolution” comment is that as our technology progresses and our communications become more digitized, compressed and encrypted, the ability for ET to watch our TV becomes even less likely.

A few years back, npr did a very successful april fools joke that highlighted some of the issues with the rapid changes in technology. Its worth a read, and good for a chuckle.

Shellac, the Sound of the Future
An April Fool’s Day Treat from All Things Considered
http://www.npr.org/templates/story/story.php?storyId=1216161

As for Craig’s comments, this might be the case if there is some unforeseen breakthrough in our understanding of things. A look back at the 20th century reveals that its fortunes were built largely on one thing, petroleum. This black gold was the refined energy source that took us from the coal/steam age into the age of internal combustion engines, which is what founded the American 20th century rise to ascendency. We are going to be facing some very serious problems on this front. Of course there is nuclear energy, but fission power plants have not exactly materialized the way people thought in the 1950s. Fusion? Well that frankly is a long way off, and the D-T process being most intensively worked on sends 80% of its energy in a neutron. The energy in a neutron is not easily harnessed. Petroleum represented the last major improvement in refined energy, but what we may be facing in the future may be a step backwards in some ways.

Sending people into interstellar space will require energy, and lots and lots of it. This is not even to mention exotic ideas of warp drives, wormholes, Kraznynov tubes and related things. Progress in “speed” took off expnentially from the early 20th century, from 100 mph to 30,000 mph by the 70s. Yet in the last 30-40 years that progress has largely stopped. If you extrapolate previous growth we would already be sending craft or travelling at 1000km/sec or so. The same thing is observed with life span improvements. Life spans went from the mid-40s in the early 19th century to the mid-50s by 1900 to now in the upper 70s. But most of that 20th century gain was made before 1970. Life spans have improved from the low 70’s to the high 70’s over the last 30-40 years. The progress is hitting a ceiling.

In effect we may have plucked the low hanging fruit. We also appear to be going in other directions as well. Usually instead of working hard to get the high hanging fruit, we go off and pick the low fruit on another tree. Instead of travelling off into outer space we seem to be going into virtual reality, and the cell-phone is a clear indication of how our information technology is becoming rapidly integrated into us. People are wearing head pieces these days like Lt. Uhruh on StarTrek. Before long it will be glasses or contact lenses which raster scan retinas with virtual reality overlays, then implants, brain-cyber connections and so forth. By 2050 human brains directly cyber-connected may be the dominant nodes on the internet.

Sure enough things will change in the future, but I think it will be very different from the future of the past, and even what we can maybe foresee of the future is at best a murky idea of things.

Lawrence B. Crowell

“Even if ET had a huge reciever…”

should be

“Even if ET had a huge antenna…”