Should SETI Be Looking For Lasers Instead? 694
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?"
Optical SETI (Score:5, Interesting)
Optical (ie: laser detection) SETI has been up and running for a while now (see Optical SETI overview [seti.org] for example). Drake ought to declare an interest though, since he's one of the investigators on the project.
It's a reasonable argument, but it's far harder to set up optical "listening" posts than radio ones. It cost me about 1000 uk pounds (WHY is the pound symbol banned from
The counter argument of course is that to detect laser light, the remote civilisation have to be pointing their laser at us, whereas with radio it doesn't matter since it's not a directed beam. Against that you have to offset the time-period over which transmissions of either kind could be made...
The chances of getting a radio contact may be a few orders of magnitude lower than getting an optical contact, but since the chances of me setting up an optical SETI station are precisely 0, the chances of getting 'the' signal with radio is infinitely greater than with optics, at least for me
Simon
Re:Optical SETI (Score:5, Interesting)
Re:Optical SETI (Score:5, Insightful)
Re:Optical SETI (Score:5, Informative)
Not necessarilly. A LASER does 3 things:
1. Produces a narrow beam of light
2. Produces monochromatic light
3. Produces coherent light
Monochromatic light is produced by gas-discharge tubes (e.g. sodium lights, etc) - nothing special here.
You can produce a narrow beam of light using a point lightsource and mirrors/lenses.
Now, the special bit - your normal light bulbs produce incoherent light - you get lots of photons emitted but their waves aren't synchronised, so they interfere destructively with eachother. By contrast the light you get off a LASER is coherent - all the waves are synchronised, so they interfere constructively, making the light appear brighter.
So if you want to create a omnidirectional optical light beacon, rather than using a normal light bulb and ending up with the photons randomly interfering with eachother destructively, it makes more sense if you can synchronise the wave fronts so they expand away from your light source in neat coherent spheres.
(I have no idea if the technology exists to do this ATM - it seems like a rather complex problem)
Re:Optical SETI (Score:5, Interesting)
Actually, condition 3 is the only one that is necessarily true of all lasers. There are solid-state lasers with very wide bandwidths, thereby violating condition 2, and it is easy to expand or diffuse a laser beam, thereby violating condition 1.
To be honest, there is little point in creating an omnidirectional laser source, at least for SETI purposes, because that only degrades the signal-to-noise ratio. However, if you want to do so, it's pretty trivial: shine the laser beam into a high numerical-aperture microscope objective, and the wavefronts that emerge beyond the focal point will be an excellent approximation of ideal spherical waves.
Re:Optical SETI (Score:4, Interesting)
Hmm, not actually sure if this is correct. This is going back a bit but I think:
Laser stands for Light Amplification by the Stimulated Emission of Radiation.
A LASER doesn't produce light because of waves contructively interfering. The light is amplified by the absorbtion and emission of photons at specific wavelengths.
There are two types of photon emission, spontaneous and stimulated.
Spontaneous emission occurs when an electron in an atom "jumps" from a higher quantised state to a lower one giving up energy. This energy is emitted as a photon. This is what happens in street lights, electrons fall back to a lower energy level and that corresponds exactly to the wavelength of the orange light we see. The photon can be emitted in any direction.
Stimulated emission occurs when an atom absorbs a photon causing an electron to move to a "higher" state but in this case the electron can immediately jump back to it's lower state. This causes two photons to be emitted in exactly the same direction as the original photon was travelling.
Essentially a LASER works by putting mirrors round a cavity and multiplying the photons by bouncing them back off the mirrors and into the emitting atoms thereby causing a "chain reaction" to take place where two become four etc.
The reason that you get monochromatic light (normally) is that the wavelength of the photons produced is exactly related to the energy levels in the atom producing them. The reason you get coherent light is because the photons are travelling in the same direction.
IWAPIU (I was a physicist in Uni) and built a Nitrogen LASER for my final year project. That was a good 8 years ago now though.
Re:Optical SETI (Score:5, Insightful)
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.
Re:Optical SETI (Score:3, Insightful)
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 th
Re:Optical SETI (Score:3, Insightful)
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 g
Re:Optical SETI (Score:5, Informative)
Um, yes. Just take a look at your closest lightbulb. There's your omnidirectional light source right there. One might actually consider variable stars as messages from outer space...
In the interests of mentioning something real that actually exists, take a look at 802.11 over IR [wi-fiplanet.com]
Lasers are used for point-to-point links because there is usually an intended recipient. All of the energy goes to that single, intended direction. However, there shouldn't be anything to stop creating ambient monocromatic light source..
Re:Optical SETI (Score:5, Informative)
Re:Optical SETI (Score:4, Funny)
Sure, radioactive sludge thrown in space is a sure sign of intelligence.
Re:Optical SETI (Score:3, Informative)
basically an energy issue... (Score:3, Informative)
photon energy is proportional to frequency
So for a given amount of energy you can get either more photons at a lower frequency or fewer photons at a higher frequency.
Since visible light is in the THz range (10^12) and radio waves are in the say MHz range (10^6), that's a factor a million less photons emitted per unit of energy.
Since we are essentially detect
Re:Optical SETI (Score:5, Informative)
If laser light travels, it loses this coherency, so the laser light gets more and more diffuse (the coherency gets slowly down, so the diffuse part increases). Optically this means that the light beam diameter gets wider and wider with the distance from the source. If the starting laser beam is very strongly bundled and has a very small diameter (thus a high energy density), this widening effect gets stronger. Less strong bundled lasers with lower energy density don't widen that much, so most long distance laser experiments (like measuring the distance to the Moon by shooting a laser beam there and take the time until the reflection can be measured) use quite large diameters, which you wouldn't call "laser" at all, because they don't spur the needle fine light
Re:Optical SETI (Score:5, Informative)
(OT) This is the first time I have ever seen... (Score:5, Funny)
Truly we live in amazing times.
Re:Optical SETI (Score:5, Funny)
Re:Optical SETI (Score:5, Informative)
I believe the answer would be because Slashdot only supports the lower 128 bits/characters of ASCII because the upper or extended 128 bits/characters are not standardized. Or rather, there are too many standards - hundreds of them - used by different people and countries to represent various different characters. Perhaps Slashdot should support the most common of them, ISO-8859-1 (Latin-1), in which the code for the UK pound symbol is 163... but Unicode will probably be supported before that happens. In short, Slashdot sucks a bit.
As an AC showed in reply to this thread, you can display the UK pound symbol using its HTML equivalent '£' - producing £.
Re:Optical SETI (Score:4, Funny)
Quantum SETI (Score:5, Interesting)
Anyone know about beam splitting entangled pairs etc. Many moons ago, Einstein, Podolski, and Rosen carried out there unusual experiment whereby the they observed what is now known as quantun weirdness. A photon in an entangled state could be split using a sophisticated 50:50 beam splitter. Each split photon could travel off in opposite directions and appear to be twins, in the sense that any change in behaviour of one would instantly (exactly synchronized regardless of distance!!!) be felt by the other, its twin.
Evidence that this was no fluke is gathering thanks to continuing experiments, yet it is still not in stone.
My reasoning is that if this phenomenan is genuine, it could be one way extraterrestrials would chose to contact us. Why not. They send a conventional optical signal, only this time encased in a surrounding cylindar of light, thus allowing for the entangled photons charateristic properties to be influenced only by this cylinder of light. Allot can till go wrong so conceivably, the 'ET's' would send a large stream of such light cylinders- the centre of which is a stream of entangled photons. That way any measurement of the entangled photon would cause an immediate change to its twin (The twin photon - of entangled pair)would presumably be archived on the alien world bouncing back and forth in a cavity (not unlike the cavities we use today - only presumably far more advanced.) So, once change is observed, an immeditae alarm bell is triggered. The ET's can know instantly someone/something has comeinto contact with their signal. Just like Earth SETI, the ET SETI would categorise all their findings and have mant false positives. They would probably already have chartered the area of space to which they send a signal. They may know the only objects (meteorites, stars, planets, commets...) that are likely influences over the transmitted light signal. Hence, if we Earthlings intercept the light in a very manufactured manner (i.e fire a encoded light signal of our own into theres, they are likely to get some unusual data back at there end - instantly.
Anyway, lets face you can't have an interest in SETI without being imaginative.
All Im tring to say is.
1) If I were a highly advanced ET, I would use Quantum entaglement (if it is indeed feasible) to transmit photons of light.
2)I believe we should start sending entangled photons of light, encased in our own manufactured cylinders of background light, out into space.
3)I hope SETI read this.
Re:Quantum SETI (Score:3, Informative)
EPR were just freaked because it seemed to them that a signal that
Re:Quantum SETI (Score:3, Interesting)
So, having said that, history is filled with theories that are very accurate within their intended scope, but fail when applied to a different or expande
Re:Quantum SETI (Score:3, Informative)
Re:Quantum entanglement does not allow FTL comms (Score:4, Interesting)
"Confirmation?" asks the observer, "I haven't sent you anything yet!" After all the light has not yet reached the observer, so how could he have sent the communication?
You're assuming there's such a thing as absolute time, which Special Relatively disproved.
So there is no such thing as T time. There is O(T) - Observer time. And R(T) - caR time. Let T0 be the time when the car flashes its headlights, and T1 be the time when the light from this flash reaches the observer.
So the car flashes it's headlights at R(T0). The observer sees the flash at O(T1). The observer then immediately sends an instantaneous message to the car, which is recieved at R(T1).
To both parties, at the time T1, the light ray from the headlights has reached the observer. The difference is that (R(T1) - R(T0)) > (O(T1) - O(T0)).
Your thought experiment assumes that there is a "universal time". So that one minute for the car is the same as one minute for the observer. This is incorrect.
And the race is on... (Score:3, Funny)
as /. users rush to see who can excel the other at sophistry. The rules are simple.
Message from aliens in our DNA finally found! (Score:5, Funny)
FIRST POST!
Re:Message from aliens in our DNA finally found! (Score:4, Funny)
Re:Message from aliens in our DNA finally found! (Score:3, Funny)
1> Leave primordial goo on new planet.
2> Let simmer for a couple of billion years.
3> Harvest.
4> Cook and add A1 Bleeagnarg Sauce and server.
Health Note: Not all humans are guarenteed to be fat free. Pasty white ones should be tossed for lack of sun light unless your from Olga Snerga Prime, then prep with Oooogla Sauce instead.
Manufacturers Note: Any resemblance between intelligent life is purely coincidental.
They always did put the cooking directions on most foods.
What a horrible message. (Score:5, Insightful)
I guess that's akin to leaving a flaming bag of poo on the doorstep.
Ever seen Casshern? (Score:3, Interesting)
That's almost exactly what the movie suggests: that we are a message and we can pass the same message onward. Won't say too much lest I ruin the movie for yall though, as much as I realize it has but a small chance of ever making it to the states. (wonders about the prospects of Cutie Honey in the same vein.)
My guess on the message... (Score:5, Funny)
Are we the message? (Score:5, Interesting)
Re:Are we the message? (Score:2, Funny)
Yes (Score:3, Funny)
Kjella
Re:Are we the message? (Score:3, Funny)
Re:Are we the message? (Score:4, Interesting)
A comment on the intro bit... Searching for an easily controlled and powerful phenomenon, like electromagnetic radiation, is a smart tactic at least for starters. As the tech gets more sophisticated in terms of control and detectability (LASERs), the challenge is greater.
But who is this Paul Davies guy, and whose ass did he pull the SETI-in-DNA idea from? SETI has always been on the edge of SciFi-fringedom, but the jump from that to finding encoded messages in DNA leaves no shred of credibility. Here's why:
"The Bible Code". What the Bible Code showed us is that given a sufficiently large text, you can pretty much find anything you want. Your birthday, apocolyptic predictions, SETI-in-DNA ideas, etc. By changing the search algorithm (ignoring punctuation and vowels is the equivalent method used in the Bible Code for searching Hebrew IIRC) you artificially expand the chances of finding a self-confirming data sequence.
This isn't science -- it's a parlor trick.
message of means? (Score:5, Funny)
Re:message of means? (Score:5, Informative)
Maybe we should consider the possibility that we are part of a device to perform some calculation to find the answer to a certain big question.
Actually, in my opinion, Kurt Vonnegut is the real master of "perhaps humanity only exists for a very stupid reason" stories.
Especially the sub-stories of his sf author character Kilgore Trout often have that theme - humanity exists only to train the hardiest microbes in the universe, because hyperintelligent rays of light want to help organic life travel the universe and only microbes could do that, etc.
In one of KV's books (spoilers for "Sirens of Titan"!), there is an intelligent alien who brings a message from his side of the universe to the only other intelligent species in the whole universe, millions of light years away. Half way, his ship breaks down, the alien manages to land on the moon we know as Titan. He needs a replacement part to fix his ship. His home planet sends the part, but this of course takes a long time; but the thing they can do faster than light is influence the thoughts of the monkeys that live on a planet nearby.
As the millennia pass by, the monkeys evolve under the influence of the far-away aliens, eventually building huge pyramids and the like in patterns that meant "almost there now" to the alien who was watching from some moon, eventually producing an extremely complex story line, including many wars, the stock market, the development of space travel, and fashion, that ends in a human going to Titan with a weirdly shaped piece of metal adorning his neck.
This is of course the replacement part for the alien, who can thus continue his travels. Humanity has served its purpose of producing the spare part, and is left to its own devices.
Eventually the alien reaches the other side of the universe, to deliver the message to the only other intelligent species in the universe. It said "Hello there".
I love Kurt Vonnegut. Adams must have read quite a few of his books.
Re:message of means? (Score:3)
If they outshine Sol by 10,000x... (Score:3, Funny)
Re:If they outshine Sol by 10,000x... (Score:2, Informative)
Re:If they outshine Sol by 10,000x... (Score:5, Funny)
We should decode viruses too (Score:2, Interesting)
Re:We should decode viruses too (Score:3, Insightful)
Re:We should decode viruses too (Score:2)
Some advanced viruses such as bacteriophages of the family Leviviridae, can reach almost 300 Kbp (kilobase pairs) which should be enough to store some additional data.
Re:We should decode viruses too (Score:2, Interesting)
We don't need to search there.
Quoted from the article: The cargo would be designed to infect, without harm, any DNA-based life it encountered.
There, they KNOW that we are a DNA-based life form, universally sprung from a watery solution, the salty sea. Like we all know, that harmless DNA can be engineered quite easily. That's why I don't understand that all the rocks from the moon (and mars) are in quarantine
are we the message ? (Score:5, Funny)
Re:are we the message ? (Score:2)
Regarding RF Leakage to Space (Score:5, Insightful)
You know, never.
--Dan
Re:Regarding RF Leakage to Space (Score:2)
Re:Regarding RF Leakage to Space (Score:5, Insightful)
A pretty good start really (Score:3, Insightful)
After that it's probably just a matter of looking hard enough.
Re:Regarding RF Leakage to Space (Score:3, Informative)
But if we did, we'd really have to pump the power up,
Satellites? (Score:5, Insightful)
Re:Satellites? (Score:5, Funny)
Fuck... if aliens are anything like us, the signal is going to have DRM all over it.. you know, to ward off space pirates.
We are the message. (Score:2, Funny)
Next thing you know, all those conspiracy nutters who say we are "Children of the Gods" will be being appointed to national agencies
Look, if someone knows something about space aliens, then OUT WITH IT!! Why the American people have put up with Area 51 for so long without any sort of culpability being required of their government, I do not know. Of the people and for the people, my ass.
Of the Grey Overlords, and For
Re:We are the message. (Score:3, Interesting)
Simple, regardless of whatever else has gone on there; they have developed some really cool technology that has kept our country safe and free.
The U2, SR-71, F-117A and B2 were all flown at Area 51 during tests. Who knows what other cool shit [abovetopsecret.com] is out there. Guess we'll find out in 40 years.
LK
Re:We are the message. (Score:3, Insightful)
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. :)
Zindell's Neverness & Requiem for Homo Sapiens (Score:3, Interesting)
Duh? (Score:2)
user reg bypass (Score:4, Informative)
An experiment (Score:2)
While using SETI on our genetic code might be helpful in identifying patterns and so forth, the notion that another creature would talk to us that way seems a little far fetched.
I for one... (Score:5, Funny)
This reminds me of a saying... (Score:5, Insightful)
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
.
Re:This reminds me of a saying... (Score:5, Informative)
There are no aliens, and there never have been. Humanity is unique in the Universe.
There have been plenty of aliens, but civilizations only moderately more advanced than ours always blow themselves up in nuclear wars.
The lifespan of an alien civilization is only a few million years. They visited us ten million years ago, and will turn up again in ten million years time, but there is nobody around at the moment.
Aliens exist, but interstellar travel is impossible because of relativistic limits on the speed of light, or because living creatures cannot survive it.
Aliens exist, but are not interested in interstellar travel.
Aliens exist and have interstellar travel, but they are not interested in contacting us.
Aliens exist, but galactic law forbids any contact with us because we are too primitive, or violent.
Some aliens see it as their duty to eliminate all other forms of life that come to their attention.
Any technological civilization will develop radio and TV, attract their attention, and be eliminated11. They are on their way now.
They are here already (the preferred answer on the Internet s UFO pages).
It's a matter of scale (Score:3, Insightful)
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 lar
Re:This reminds me of a saying... (Score:4, Informative)
The author Iain M. Banks [iainbanks.net] has discussed this issue throughout his "Culture" series of books. He suggests that perhaps there are galazy spanning civilisations out there, but that they are evolved enough to leave us alone until we reach a level as a species where we can be considered for inclusion in the galactic community.
Why would they need to do anything as unsubtle as establishing moonbases when they could have invisible ships 30 kms long able to control every single tv screen on this planet from outside the orbit of Jupitor? :)
In fact, one of his short stories from the collection The State of the Art [iainbanks.net] is about what happens when the Culture use Earth as part of a control group. An excellent read.
Of course this is sci-fi but you get the drift. If anyone is interested I would go as far as saying that for thought provoking Sci-Fi, Iain M. Banks is the man to beat at the moment.
Here he is in an interview at scifi.com [scifi.com] talking about his writing. And here is the man with a few introductory notes [onetel.net.uk] on the Culture for the unitiated - I just picked this site from the top of google so I hope they don't mind me posting here :P
Caveat: Matter dispersion in the universe (Score:3, Interesting)
Maybe the universe isn't old enough. Seriously! Stuff like carbon, iron took multiple generations of stars (birth-to-supernova) to produce. Intelligent life that appeared approximately before the existence of Sol/Earth would have lived and died without the means to forge swords, much less spaceships. I believe our star
Re:This reminds me of a saying... (Score:3, Interesting)
From an SF writer's viewpoint, this doesn't led to very interesting stories, so most of them have assumed some solution to the FTL problem. A few, such as Ursula LeGuin, have written stories in an "Einsteinian" universe, but have added the gimmick that FLT communication turns out to be possible. This does le
So now we are looking for... (Score:4, Funny)
Because that would rock.
Are We the Message ... (Score:2)
Nice idea. But, IMHO, it is not the 'Magic Encrypted Formula' hardcoded into whatever finally rendering the even more magical 42. What about the hypotheses that the system that the instances based on that DNA create is covering (for sure alternati
The real alien DNA (Score:5, Interesting)
Re:The real alien DNA (Score:3, Interesting)
Or, could it be that they thought some sort of DNA-based lifeform was out there somewhere, whatever nucleotides it was using. They could then send out their own self-
SETI on DNA (Score:2, Funny)
That is to fool the lameness filter. It counts the capitals or something like this.
I had an idea like this a while back. (Score:3, Interesting)
I think we would probably be able to program organisms from scratch by that point, so what kind of organisms would you send to establish life on a distant planet? It would probably start off small, or virus like, but would need to be preprogrammed to evolve into something more complex. Since the evolution would be random, you really couldn't determine the outcome after billions of years.
Then it occurred to me that if we were going to go through all this trouble for a slight chance that these packets of life might just thrive and grow some brains, we would probably put some kind message in there. Then it occurred to me that we could possibly be the product of such a plan.
It is possible that the structure of the genetic code itself is an artificial creation of an advanced race. Maybe we should examine the fossil record to look for patterns in the earliest life on the planet. Maybe humans got an evolutionary speed pass to intelligence. Who knows? At any rate understanding the underlying structure of genetic programming would be necessary for understanding the rational behind choosing one structure over another. Just like programmers develop an understanding of the language they program in, perhaps we'll see some calculated order to it all.
DNA messages? Where have I seen this before? (Score:3, Informative)
Looking in the wrong places. (Score:5, Insightful)
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]
10,000 times outshine the sun? Yeah right. (Score:5, Informative)
The divergence of a laser beam is, assuming ideal optical components, mostly dependent on the diameter of the beam where it starts. You can take a big telescope and let the light pass through in the opposite direction, so let's say, a diameter of 4 meters. For visible light, that will generate a beam with a divergence of 1e-14 sr. So, to get to 2e29 W/sr, you need a laser with a power of no less than 2e15 watts. (Compare this to a mid-size electrical power plant at 1e9 watt...)
Yes, there exist lasers that can generate ultrashort pulses in the near-infrared, with such a high peak energy, say 100 femtoseconds (100 fs=1e-13 s) and 100 joules per pulse, so there you have our desired fluence.
Unfortunately, such lasers can only fire something like one shot per second. If you really want to appreciate the high peak power, you need a camera with a shutter time of 100 fs. Imagine looking at the sky with such an ultrafast camera. The chance that you actually manage to catch a flash from this laser is virtually zero, unless you have a way to know when the flash is going to come. Someone who is looking at a nearby star and expecting flashes is more likely to have an aperture time of 0,1 seconds or so in order to capture any photons at all. At 0,1 seconds aperture time, the laser is no longer 10,000 times more bright than the nearby star (that is, our sun), but rather 1e8 times weaker.
So, it is unlikely that this is going to word, assuming that someone is looking at us anyway.
Should SETI Be Shut Down Instead? (Score:3, Interesting)
Life. Don't talk to me about life. (Score:3, Insightful)
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
We won't stop using RF (Score:4, Insightful)
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.
Re:We won't stop using RF (Score:3, Insightful)
The odds of a million watt AM carrier surviving a trip light-years across space is pretty good.
Compare that to a signal from most personal communications devices, the likely long-lasting legac
Re:We won't stop using RF (Score:3, Insightful)
SETI@Home and other SETI searches skip right past sources like this, but guess what: ten years ago an astronomer named Walter Sullivan wrote up his observations of intense thermal microwave emissio
In our DNA, my ass (Score:3, Insightful)
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.
Re:In our DNA, my ass (Score:3, Insightful)
And what makes you so sure of this? I'm not suggesting there is a message coded in our DNA, but if there is a possibility, it should be explored. After all there are many parts of DNA which scientists have NO IDEA what they are for.
Your type of flat denial is what held science back for many years throughout human development.
Bible Codes (Score:3, Funny)
> Meanwhile, Paul Davies writes that we should be conducting SETI in our DNA.
Let's see, we're looking for an unspecified message in an unknown language spelled out in an unknown coding... Yeah, I bet you can 'find' any kind of message you want in there, just like the silly Bible Codes thing. The only surprise is that k00ks haven't already been making their claims.
pathetic humans (Score:4, Funny)
The sad truth is that my planet found your planet from the leaked signal of an '802.11b' device owned by Dave Stewart in Provo, Utah as he was attempting to download a copy of Blue Oyster Cult's Don't Fear The Reaper song. But soon no other intelligence will be able to find your planet due to the decline in the P2P that was a beacon in the long dark night of space. You see, it's the legal dickering of the RIAA that is more a threat to your society than high powered lasers... so sad.
No radio-frequency leakage? (Score:4, Insightful)
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...
Star Trek TNG Episode (Score:3, Insightful)
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.
Replicators (Score:3, Interesting)
If we were the message, it would have long ago mutated as to be undecipherable. The message was destroyed by SG-1 and the those gray aliens in last seasons Stargate. Seriously, DNA wouldn't be my choice, but a self replicating nanobot designed to reproduce with extreme fidelity would be more suitable for a message. Unfortunately, uncontrolled replication could have disastrous results.
For the record (Score:3, Informative)
Interesting.... (Score:3, Interesting)
How would we know if there was a message in our genomes? Presumably ET would make it easy for us to spot. Some sort of in-your-face pattern would be best, something that stood out from the random scatter of genetic letters.
I would posit that an ET intelligence smart enough to create a pattern in our DNA would also be smart enough to make the evidence of their existence readily apparent to even those without the ability to decode DNA. I mean, if the point of sending a message is to communicate, why would you require such sophisticated techniques to understand it, with the attendant risk of misinterpretation?
Replace ET with God, and you've got a good paraphrase of the "intelligent design" argument for God's existence.
I think what irks me the most is the assumption that aliens are trying to contact us. When we think about communication, there are some interesting principles:
- The sender of a message fulfills some need in sending the message. Perhaps it is a call for help; perhaps "they" need some more friends.
- A message is always sent with a reasonable expectation that the recipient will be able to understand it.
- The sender usually wants some sort of response from the recipient, even if it is merely an acknowledgement.
This leaves us with some fundamental problems regarding ET's contacting us with "sophisticated" techniques:- An alien intelligence seeking to make contact with other civilizations would probably choose the most easily recognized form of communication, not one which required sophisticated technology or a considerable degree of intelligence to decode.
- What purpose would such a message serve? If they are more advanced technologically, why would they contact us - we don't have anything that they need? If less so, then we would be able to decode their messages with ease.
- If "they" are sending messages, then surely they must already know, or strongly suspect, our existence. If this is the case, then why don't they already know how to communicate with us?
It would seem to me that if aliens were trying to contact us, we would have known it by know. I suspect that if SETI discovers any "intelligent signals", we'll come to discover that they were not intended for us to decode. Perhaps some alien military communications, or ARIA (Alien Recording Industry Association) encrypted music broadcasts, etc...Just a rhetorical exercise here: Would God qualify as the sender of such a message?
With what we know now, only our Creator would possess the knowledge of our existence, the desire to communicate, and the means to do so. I wonder if this occurs to the SETI team, or if they are trying to find God in outer space...
No, no, no (Score:4, Funny)
If it hasn't already been mentioned... (Score:3, Interesting)
The Law of Accelerating Returns by Ray Kurzweil [kurzweilai.net]
It offers a very well reasoned argument as to 1) why the technological singularity must occur, and 2) why SETI is likely a failure. Actually, I would suggest reading Vernor Vinge's writings on the singularity, then read Kurzweil's work above.
One should then read the story (posted at k5?) called "The Metamorphisis of Prime Intellect".
Finally, read Albert-Laszlo Barabasi's book "Linked" (network theory), Kevin Kelly's "Out of Control" and Steven Johnson's "Emergence" (emergence theory), and Stephen Wolfram's "A New Kind of Science" (The Principle of Computational Equivalence).
There are many more references, both fictional and non-fictional (for entertainment purposes only, I also suggest the anime "Serial Experiments: Lain") - but these which I have listed detail a staggering breadth of information which, after you have digested it and left it to simmer in your mind, just might change your opinions and worldview in radical directions.
Lastly - a plea for help: Does anybody here know of any papers or references from reputable sources which discuss why the singularity can't occur, or is wrong in some manner? I have only read one side of the debate, and I would like to hear the other.
Re:Light takes 25 years from nearest star.. (Score:5, Insightful)
Second. What does the difficulty of getting to Saturn have to do with making sense of radio signals?
Re:Light takes 25 years from nearest star.. (Score:5, Informative)
Erm, are you SURE about that?
Ignoring the real nearest star, Sol, the next nearest star is Proxima Centauri [nasa.gov] which is 4.22 light-years away... i.e. its light only takes 4.22 years to get here, not the 25 you claim.
There are 25 known stars within 13 lightyears [nasa.gov]. Their light won't take 25 years to get to us either.
Seriously. You wanna check your random information before presenting it as a fact!
Re:A different mode of life. (Score:3, Interesting)
Easy. Study science for 4 years undergrad, then 3 years grad, distinguish yourself in the field and then call them and arrange a meeting. People who can't be bothered to do that are usually dillitants who think they're smarter than they really are. There are some brillant people out there who get great ideas outside of their field, but there are also hundreds of crackpots, weirdos and just misinformed people who seem to thin
Re:Question (Score:3, Insightful)
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
Re:What are we really hoping for? (Score:4, Interesting)
Unless the first ETs we encounter live in a different time dimension. What we consider couple of thousand years, might be a few minutes for them, who knows?