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Should SETI Be Looking For Lasers Instead?
colonist writes "Frank Drake, creator of SETI's famous equation, says the detection of extraterrestrial radio signals won't work, because Earth's own radio signal will only be around for 100 years. More and more of Earth's communications use cable and satellites, with no radio-frequency leakage to space. Instead, we should be looking for intentional signals in the form of high-powered lasers that could 'outshine the sun by a factor of 10,000'. Meanwhile, Paul Davies writes that we should be conducting SETI in our DNA. In turns out that an alien message designed to last millenia should be 'inside a large number of self-replicating, self-repairing microscopic machines programmed to multiply and adapt to changing conditions', otherwise known as living cells. Are we the message?"
Are we the message?
I guess that's akin to leaving a flaming bag of poo on the doorstep.
We dump pretty enormous amounts of energy at RADAR wavelengths, 24/7, across the night sky. That'll stop approximately when we have no fear of hostile aircraft showing up at our borders.
You know, never.
--Dan
And exactly since when do satellite uplink transmissions stop at the satellite? The uplink is a radio wave, albeit a directed one. It might still be possible to pick up an alien uplink signal.
viruses and non-eukaryotes have to be too efficient with their DNA. Anything not needed will get discarded
___
It's the end of my comment as I know it and I feel fine.
"When all you have is a hammer, everything starts to look like a nail"
Next thing you know, we will look for SETI in the burn pattern of a tortilla...or maybe in the reflection from a store window...
Is anyone getting my point here?
"For centuries, mankind has searched for evidence of God, in the skies, in the stars, in animals and in himself." Now do a search and replace s/God/aliens/ and ask if this is really any more a sensible statement. Not to mention, if we do find aliens, are we their peers, or are they our gods?
Final thought of the day...from what I can understand, our solar system is rather young compared to other galaxies out there. And apparently there are hundreds of planets capable of supporting life (our life, that's not even counting life that forms in some environment we consider hostile). Well if that's the case, and life/evolution is as easy as the theories make it sound (all it takes is heat and time)...then why isn't the universe like something out of Star TRek with hundreds of alien species flittering about, dropping in to violate the prime directive, establish moonbases, and so forth? Think about it.
- JoeShmoe
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-- I wonder which will go down in history as the bigger failure: the War on Drugs or the War on Filesharing
A diffuse source contradicts with LASER, but yes, it's possible. But in order for it to be detected over ambient light it would have to be something huge and noticeable like a pulsar - I'd hate to see their electricity bill, these aliens of yours ;)
Sorry buddy. There are a couple of dozen, possibly even hundreds of stars within 25 light years. Alpha Centuari is something like 4.1 lightyears away. So, sun excepted, it takes a hair over 4 years for light from the nearest star to reach us.
Second. What does the difficulty of getting to Saturn have to do with making sense of radio signals?
I think we're really looking in all the wrong places. We're putting human assumptions on alien life.
We assume they would be using radio communication, or that they'd bother with a high-power laser. What if their communication is completely different. Like, something we haven't even considered to be a possibility yet, even in SciFi.. In a transmission media we don't even realize, we may be receiving communications from them, but we simply don't have the equipment to hear it.. We can't even decipher what any other creature on this planet is trying to communicate, why should we even be so egotistical to thing that not only would we know how to receive their communication, but have the vaugest idea of what they're saying.
I thought the idea of SETI was that we'd pick up an omni-directional broadcast, with some alien saying "here we are, can anyone hear me" A laser would be directional. It would have to be intended for Earth, and would need to be tracking many years ahead of where we are. We aren't broadcasting the same signal, why would they? There could be many planets near by with the same idea of listening, but if no one's talking, there's no communcation.
Maybe pulsars aren't just some celestial event, maybe they're beacons, and when we're ready to go to them, we'll find more information. But for now (and the next hundred+ years), we won't be going anywhere near them. Like, we haven't even managed to get a person to the next planet yet. There isn't enough "push" to develop to the next level. Imagine if every country spent their military budget on developing space travel. we'd alerady have a flag on Pluto, along with a bunch of empty beer cans from tourists.
But no, we waste our resources blowing each other up, or making sure we're on the virge of it every day. Remember the cold war? Ya, 40 years of "I'm going to kill you all", just for it to fall apart, and both sides realize that those people we were so scared of for so long aren't really that bad.
I grew up knowing the Soviet Union was the evil Red Army, who had so many weapons pointed at us because they hate us so much. Now, thanks to the fall of the Soviet Union, and the rise of the Internet, I now frequently talk to a Russian, and really, he's a nice guy. I've seen some beautiful pictures around where he lives, where not too long ago I would have believed was a frozen wasteland.
If only all of our governments would give up on this nonsense and cooperate in things, or better yet, ditch the whole "This is ours, you can't play with it" mentality, we'd make a lot more progress.
[rant mode off]
Serious? Seriousness is well above my pay grade.
The question "Are we alone?" is one of the most important philosophical questions; keep in mind that what we call "science" today was once called "pysical science". Philosophy was the profession of scientists centuries ago, and should be part of the toolkit of scientists today.
From a observational standpoint, you have the (yet unproven) theory: There is life outside Earth. In order to try to prove this theory (disproving it is much harder =), you gather data and analyze it. That's generally considered part of science. If for example, Mars missions finds self-replicating life, that can provide an answer to the simpler proposition. The harder one -- intelligent life -- would still need to be shown in some other manner. (Unless we found self-replicating intelligent life on Mars, of course.)
As for the "who cares, I'll be dead by then!" narrow-focused people, keep in mind that the tools and networks being developed for SETI -- massively parallel data set computations -- have usages for other areas of "science" that you would probably consider to be science -- protein folding, for example.
Uh...the flu virus is one of the most successful life-forms on the planet. It works by switching back and forth from infecting humans and infecting poultry. I don't think you can criticise its efficiency.
That's not to say there isn't some other cool shit at A51 we won't be seeing at airshows for a few decades of course. :)
UNIX? They're not even circumcised! Savages!
Let's see, you are comparing our solar system to other galaxies? You must realize that the scale of a solar system in relation to the scale of a galaxy is unbelieveably small, right? Ie., there are a (suitably big number) of solar systems in our galaxy alone.
Think of it this way, when you look at a picture of a galaxy, and you see the fuzzy white haze, that haze is (to quote Dr. Sagan) billions and billions of stars.
Now step back, and look at a Hubble Deep Field photo. What do you see? A (suitably large number) of galaxies each of which contains a (suitably large number) of stars/solar systems.
If you really consider the scale of the universe and the scale of time that the universe has been around, it seems pretty obvious that there is a lot of life out there.
The reason we don't have the Star Trek thing going on is that wonderful little thing called "c". That, and I guess they are all trying to learn English...
A house divided against itself cannot stand.
Detecting a simple content-free transmission would be a great start as you at least have somewhere to focus your investigation.
After that it's probably just a matter of looking hard enough.
Boffoonery - downloadable Comedy Benefit for Bletchley Park
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It's bizarre. The universe could be teeming with life, or it could be utterly, completely barren save for us, and both alternatives would look pretty much the same to us.
Communication modes: Our communications are getting more focused, more noiselike (anyone remember what 300 bps sounded like compared to 56K compressed?), less tangible. Maybe the signal came 500 years ago. We couldn't have heard it. Couldn't have. At least the Professor on Gilligan's Island had a radio - coconuts wouldn't have worked. You can't hear radio without a radio (or finely-tuned braces). Who knows what the next physics breakthrough in modes of communication will be? Something quantum? Gravity-related? When it arrives, and if it's better, we'll switch over to it wholesale, and guaranteed we don't have receivers for it at present. Who knows what aliens would be sending their messages with?
Lucky in the life lottery: Perhaps it's easy for life to take hold on a planet, but maybe we're lucky to have had relatively complex creatures survive the multiple catastrophes. Folks sometimes theorize that Jupiter has protected us from some major calamities just by being big and in a further orbit, acting as dustbuster. Maybe life was seeded here from elsewhere. Wouldn't even have to be an organism - just a decayed crappy chunk of RNA-esque material would do for initial seeding purposes, and it would only have to happen once - one intact chunk out of millions of rocks. It took a heck of a long time to evolve multicellular organisms - the number just boggles the mind. Perhaps it's just that hard to evolve anything past single-cell organisms.
Planets: There seem to be a significant number of planets around. The program Celestia keeps a semi-current list of the detected planets and systems (so you can have fun visiting). Some of them, though, seem like there are gas giants way too big, or way too close to the sun, or are in a funny configuration. That's likely not conducive to life.
Age of the universe: I'm guessing, according to an increasing number of observations of late (mostly from the Hubble), that the universe is a lot older than we've been theorizing over the past few decades. The older it is, the more likely extraterrestrial life becomes.
The Ultimate Find: If we found someone, something out there, it would be the greatest discovery... well, practically ever. At least, "are we alone?" is something we've been asking for so long, and actually having a definitive answer would be amazing.
I think the voyages to Mars and (soon) Titan will inspire a new generation. Gads, if we can be that surprised in our own solitary back-yard...
I don't know if we'll find anything out there. I remain hopeful, but I certainly don't have "faith" in anything being out there.
-- Ritchie
Binary geeks can count to 1,023 on their fingers
The idea here seems to be that at some point we'll just decide to abandon the whole RF spectrum because we have better mechanisms of comminucating. This is implausible to the point of silliness. We *will* have better mechanisms, but the RF specrum is still there, and still as usable as it ever was, and if no one is using it, why, it will be very cheap. So people *will* use it, of course.
Imagine, for instance, that UHF TV goes away, and non one wants the spectrum any more. Now you can build a local TV system for the cost of a transmitter (which you can get as cheap surplus). So lots of people will do that, so there will be lots of use of the UHF spectrum. It will just be by people doing more interesting thigns than it was before.
Suppose we picked up a signal from some ET and that there was no doubt, scientifically speaking, that it came from ETI. At least half the world doesn't believe in science, so if you're hoping that some of the more narrow-minded religions in the world are going to suddenly snap out of their narrow mindedness, I wouldn't count on it. Just look at the amount of scientific evidence they already manage to ignore or discount. Probably several new and conflicting religions would be founded by people claiming to have found some "divine" interpretation of the ET's message.
Maybe you're hoping the ETs could tell us something that would advance our technology. Given how many of us subscribe to irrational world views, it seems to me that would be damned irresponsible of them. Sort of like throwing gasoline on a fire.
My bet is the first communication detected from an ETI will be a question, something they want to know, or something they want to make sure we know before they say anything else. If our world was enlightened enough to support broadcasting to the stars, rather than just listening, I think we'd ask a question. Asking a question implies you've developed the patience to wait for a reply, which, for light-speed communication at least, is a lot of patience!
The concept that just because our use of radio is supposedly going to decline over the next 100 or so years any possible alien civilisation is already beyond radio, is pretty weak.
I have a few points to make. Firstly, it is not unwise to scan for other forms of communication. However, by the time the laser reaches us, their ancient radio technology would have reached us first. That is depending on their stage of development relative to our own of course.
;-D
Secondly, while it is true we have been moving away from radio signals by using more wired and directed technologies, we have since rekindled radio communications with the popularity of cell phones and wifi.
Also, having said this, I'd like to thank all the unsecure routers for making the echoes of the internet available to our alien friends. Now, our filth, knowledge, politics, and confusion will be available for anyone who can decipher our layers of protocols.
Lastly, I'd like to point out that we have no motivation to operate an expensive high powered resource eating laser for hundreds of years. Especially one pointed at random stardust with the hopes that someone will notice it millions of years from now. They're more likely to notice the past two hundred years of radio than we are likely to attempt to communicate via a laser. As a result, its safe the to assume the same about other civilizations out there, if there are any.
Yet another bogus attempt to inject some credence to that hoary ghost of ID. No, there is no "message" in our DNA other than the message of how to make and use cell parts.
This is the last friggin' retreat the ID'ers can have. The last bastion of that stupid concept of "irreducible complexity". Couldn't have your way with the eye? Couldn't make the flagellum work for you? Now, trying to encode some decipherable message in the DNA? Yeesh.
Been watching that Star Trek movie too many times.
More and more of Earth's communications use cable and satellites, with no radio-frequency leakage to space.
Why would there be no radio-frequency leakage to space using satellites? Some of the signal sent down to earth probably bounces back to space. More importantly, most of the radiation beamed up to satellites goes right into space! There's no way those beams are so narrow that they only hit the satellite's receiving antenna...
Meanwhile, Paul Davies writes that we should be conducting SETI in our DNA. In turns out that an alien message designed to last millenia should be 'inside a large number of self-replicating, self-repairing microscopic machines programmed to multiply and adapt to changing conditions', otherwise known as living cells. Are we the message?
This was a Star Trek: TNG episode. I distinctly remember Romulans, Klingons, the Federation (and perhaps a couple other species) all fighting over some secret weapon they had discovered in human DNA when it turned out to be a holographic image of a common ancestral species that had seeded the planets. It was probably the second season.
I've always thought that a Dyson Sphere with "holes" in appropriate places might serve a dual purpose. The first is, of course, a place to live, collect the star's energy, etc...
Secondly, as the sphere rotates around the star the "holes" (notches, spaces, gaps, whatever) would -- from the outside -- appear to be blinking lights. Spaced at prime-number width intervals it'd serve as a nearly eternal beacon for other intelligent life. No maintenance, no machinery, and a broad-spectrum beacon as well.
Get off my lawn.
All photons in laser light have the same wavelength, and do not scatter, so they travel in the same direction over long distance.
Light such as white light consists of light of different wavelengths that scatter in an omni directional pattern. Only part of the light reaches your eye, and the further away you go from the sources, the more gets scattered before it reaches you.
So, you can't diffuse laser light and still have it visible over long distances, which means if your looking for it you can expect a point source and you have to be looking directly at it.
A good SETI tool? I don't think so, but there is no harm in trying, because it definitely a possibility!
of cours ethen all you need is enough material to produce a dyson sphere.
Given the relative size of stars to planets... the Boston MOS has a great display where they show the sun and the planets to scale.
They have a portion of a sphere which, if memory serves is stickin gout of the wall. It is about 1/3rd of a sphere...and looks like it has a solid 2/3 of a meter radius. Thats the sun.
The earth is around the size of a golf ball at this scale.
So I am thinking you need to not just mine but just destroy and completely use all of the mass in several thousand planets just to have enough raw material to produce the sphere.
Other than those purely logistical issues, sure, sounds like a great idea.
-Steve
"I opened my eyes, and everything went dark again"
Correct me if I'm wrong, but doesn't the Dyson sphere suffer from the same problem as the Ringworld? Because it is a solid, it won't remain in "orbit", but will degenerate, with one edge sliding into the sun, in spite of rotation?
Not to the same degree. Ringworld is actively unstable, meaning that if it gets off-center, the star's gravity will pull it further off-center. A Dyson sphere is neutral, meaning that the star's gravity has no net effect on it. If it gets off-center, it can be stabilized in that position -- with an unusual gravity gradient on the surface!
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
Yes, a ringworld is stable along the axis of rotation. However, I did the math for stability in the plane of rotation, and it is unstable.
For a ringworld, mass per angular unit increases linearly with offcenter-ness, but gravity falls off as the inverse square, so the further off-center the star is, the more it pulls the ring offcenter.
For a Dyson sphere, gravity falls off as the inverse square of distance, but mass per angular unit increases as the square of distance, so the net result is no change in gravitational attraction.
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
The easiest artificial signal to differentiate from natural noise are signals with frequency spikes. FM and AM radio have good frequency spikes. VSB modulation which is used in television broadcasts has a decent spike. These are pretty easy to detect as manmade.
These days the trend of RF technology is moving from spiked spectrum to spread spectrum modulations that looks more and more like noise.
For example lets take TV from an alien perspective. There is a move from VSB picture and FM voice to spread spectrum transmissions. With FM and VSB the cells on same frequency must be pretty far away from each other not to interfere with each other. And to get a good picture the transmision must be high over the noise floor. The alien observer would see some strong spikes on his spectrum analyser moving along the frequency as earth turns (dobbler). Now with spread spectrum the signal is spread evenly over the spectrum so no spikes. And because spread spectrum signals don't interfere with each other so easily the cells on same frequency will be closer together. So the alien observer would see more transmitters sending evenly spread transmission over another and another and another,each with a slight changing frequency shift to each other because of dobbler. Impossible to differentiate from noise.
So new technology is changing earth from spiked hedgehodge to fluffy ball, looking just like a natural noise source.
In future the detection bubble may thicken because of microwave power transmission. If there will be solarpower spacefarms, there will be new spikes with enough oomph to an alien observer.
"Sure, radioactive sludge thrown in space is a sure sign of intelligence."
Becouse we wouldn't want to put radioactive materials in space right?? Ha ha thats funny becouse putting stuff that is radiocative in space would be dumb becouse there isn't anything radioactive in space....its like pure and perfect and entierly free of evil radioactivity which is of course only produced by us evil dumb humans who shouldn't be producing such evil dumb things that are radioactive.
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