Correct me if I'm wrong, but AFAIK, this project is tuned to listen in a frequency that lies in a "waterhole" type of area, where there is little cosmic noise. The idea is that it's most likely any communicating civilization would use such a "quiet" frequency, because signals are less likely to be disturbed by noise on their way.

But is it likely that advanced civilizations use radio signals at all? I don't know what else they'd use, but it seems to me that the drawbacks of radio signals are several:

- They are slow for the task
- They are fragile to noise
- They are bent by gravity

What do you think? As we are only starting on this path, are we likely only to catch those in the same situation as ours; those who "fumble" (ie. all others have moved on to a better way of communicating)? Do we have to invent a new technology before we discover that the universe is suddenly packed with inter-stellar communication?

I'm not the impatient type, and I don't mind that this project goes on for thousands of more years, but I think we should sit down and seriously consider if we can improve our chances to success by altering our technology. :)

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what would your alternatives be, radio waves travel at the speed of light which is the speed limit for the universe so nothing can go faster,
Can't comment on secomd point as don't know.
All electromagnetic waves are bent when they pass through any objects gravity well so you can't get round that, anyway you could say that the waves would be bent to us that would otherwise miss the earth completely,
Both of these are picked up in The general theory of relativity
So I think this is as good ( if not better ) way as any other of picking up the signal.

Babyface uk

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I'm a bit of a newbie to Seti, but I'm curious about this as well. I'm sure we'd like to detect any coherent, created em radiation, whatever it's source. Is that essentially the limit of the goal or, is there an expectation that some beings out there are sending signals to contact budding technological civilations like ours, e.g. the theme of "Contact."

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> radio waves travel at the speed of light which is the speed limit for the universe so nothing can go faster

I think I heard that kvarks may go faster that speed of light?
Didn't they just confirm that? (I'm not certain about this)
If so, do they have any mass? If not, can they avoid gravity?

I'm certainly no expert on Einstein's Relativity theory, but isn't the law about nothing going past the speed of light connected to objects with mass?

Well, I'm puzzled about this and it seems to me that we can't be satisfied with the technology we're currently using. Doesn't progress leap forward in most areas, and why shouldn't it when it comes to communication? :)

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Are kvarks scandinavian quarks?

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as I understand it, quarks ( kvarks ) have mass therefore cannot go faster than light as they would have infinate mass at that speed and therefore take infinate energy to get them to that speed,
To get anything faster than light ( for use as communications ) would require a fundimental rewriting of the laws of physics, unless you start going down the wormhole route or anything else thats going around atm which is so far beyond what we have right now its classed as thoery or in practice science fiction.
As for they type of signal we are looking for, any will do, we can worry about its meaning at a later date. ( and if one of my crunchers find it, the aliens are going to all be called Babyface's )

Babyface uk

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> Are kvarks scandinavian quarks?

Yes, probably! LOL
Perhaps only they can go faster - and not the english ones... ;)

I meant quarks, of course.

Can they be used for communication purposes...?

> ( and if one of my crunchers find it, the aliens are going to all be called Babyface's )

ROTFL! I wonder how they would take that...? (Maybe we should soon adopt the Prime Directives from Star Trek, to avoid offending them)

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AFAIK, there have been experimental proof of about half a dozen effects (not mass) that definitely exceed the speed of light, never can remember the bunch though.

Will have to read up on those again, it's been quite some time.

-- edit --

Found a few :

- Superluminar Tunneling
http://arxiv.org/PS_cache/physics/pdf/0204/0204043.pdf

- EPR-Effect/Paradox
http://www.stillmoving.ca/physics/faq/Quantum/bells_inequality.html
http://en.wikipedia.org/wiki/EPR_paradox

Note -
Since these fields of science are touching the boundary of mankinds knowledge, they remain not completely undisputed as of now (despite partly being verified in Experimental setups).

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As far as radio frequencies go, what about newer flavors like spread spectrum? If it is possible for us, with our presumed limited knowledge, to create variations on an existing theme, what about other "advanced" life forms? Could SETI even detect spread spectrum signals? What if "they" are using some other type of permutation or algorithm based on what we would call "normal" radio frequencies?

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<BR><B><I>Regards, UA

it's right that we may listen at the wrong frequency and the chances to find any signal is very low, but think about how long computers exist and how long they are as powerfull as today. We are just at the very beginning, 100 Years ago we didnt even think about such technology as today. Seti@Home is the first project and its the biggest "supercomputer" (if you see it as one Computer) in the world, but we really have to be patient and can only do our little piece and wait how this develops...

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At first:
quarks do have mass! Additionally a very high mass:
up quark: 1,5 - 4 MeV
down quark: 4 - 8 MeV
strange quark: 80 - 130 MeV
charm quark: 1,15 - 1,35 GeV
bottom quark: 4,1 - 4,4 GeV
top quark: 174,3 +- 5,1 GeV
for example: an electon has a mass of 0,511 MeV

Furthermore: you can't produce free quarks (f.e. one single quark) they are always bound together in hadrons. So you would have to communicate i.e. with protons and this would just be stupid.

Additionally: there are some effects that can travel with speed greater than the speed of light, unfortunately this effects can't carry any information. So Einsteins boarder that no information can travel with a greater speed than light is still right.

greets

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It is possible, but we have to start somewhere and this is as good a place as any. The other types of communication possibilities may require instruments we do not have yet.

So, though this has a very low probability of success we need to START. Later we can get smarter. Just as a side note, the Einstein@Home project's data may be another place that we could do something similar to the current SETI@Home.

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What's this can't travel faster that the speed of light nonsense? I do it all the time. Lets say you are on another planet in another solar system and I shine a light at you. If both our planets are stationary the light is traveling at 186,000 miles a second. If your planet is stationary but I'm rotating in a normal earth orbit, traveling to you, then the light is traveling 186,000 mile a second plus 67,000 miles and hour(for the speed around the sun). So as I go around the sun and travel away from the perspective of that very first leading wave or beam of light I'm traveling faster than the speed of light. Not only that I'm rotating around the earths axis at about a thousand miles an hour at the same time. That's faster than the speed of sound. It wasn't that long ago we were debating if a person could travel faster than the speed of sound and we were doing it all along while we were setting there figuring.

Back to the subject. I've noticed that on earth we can track lightning strikes with great precision and from great distances. What if we were to direct the same technology toward space. Would we be able to detect planets that have atmospheres that are much like our own?

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> What's this can't travel faster that the speed of light nonsense? I do it all
> the time. Lets say you are on another planet in another solar system and I
> shine a light at you. If both our planets are stationary the light is
> traveling at 186,000 miles a second. If your planet is stationary but I'm
> rotating in a normal earth orbit, traveling to you, then the light is
> traveling 186,000 mile a second plus 67,000 miles and hour(for the speed
> around the sun). So as I go around the sun and travel away from the
> perspective of that very first leading wave or beam of light I'm traveling
> faster than the speed of light. Not only that I'm rotating around the earths
> axis at about a thousand miles an hour at the same time. That's faster than
> the speed of sound. It wasn't that long ago we were debating if a person could
> travel faster than the speed of sound and we were doing it all along while we
> were setting there figuring.
>


*lol*
maybe you'll have to read some einstein literature another time to understand what nonsense this is :P

"If your planet is stationary but I'm rotating in a normal earth orbit, traveling to you, then the light is traveling 186,000 mile a second plus 67,000 miles and hour(for the speed around the sun)."

THIS is just NOT true !

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i can't find the article, but i know that Dr. Frank Drake recently stated that here on earth, we are about to pass out of the time-frame that ET civilizations running a SETI project would be able to detect us. Using earth as the reference, there is only about 50 years as a civilization evolves to be able to detect the radio waves.
Here on earth, we will be soon using only data streams that pass only through cable or direct to satellite giving no bleed over into space.

so we are essentially trying to find the single grain of salt out of all the grains of sand in the sahara.
but all my computers will be searching anyay ;)

Micah

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S@h Berkeley's Staff Friends Club

Well the frequency of 1420 Mhz (or 1.42Ghz) was decided upon because that is the absorption frequency of Hydrogen the most abundant element in space. This was waaaaaay back in 1959. Then OH was discoverd in space, so the whole "water hole" freqency thing developed and we started listening at 1.42 - 1.62 Ghz, but many agree that this is not effective.

The new suggested frequency is 2.5568 Ghz and this is derived through a complicated process I don't want to write about but it uses the speed of light in its calculation. You can learn more about it by looking up the "Kuiper-Morris" frequency.

The bottom line is that it's wishful thinking to assume that extraterrestrial astronomers all agree to broadcast on one frequency or another.

It is also wishful thinking to believe they would broadcast only using one type of polarization so ulitmately, to be effective, you need to be listening across a very broad range of frequencies, say 1.4Ghz to 2.6Ghz and you need to use what's called circular polarization. I know SETI started doing a frequency sweep from 1.2 - 3.0 Ghz but I'm not sure if that's what they do today and I'm not sure if they use circular polarization. I would assume that they do on all accounts but I'm not sure.

The Allen Telescope Array will bring a lot more to the table.

We detect various molecules in space just as we would or could detect an extrasolar planets atmosphere, by looking at the atoms freqency of radio absorption. All atoms spin at a specific frequecy so using radio astronomy you can tell what a molecular cloud is made of by looking at its radio absorption frequencies. We don't have the capability quite yet to look at an extrasolar planet and tell what it's atmosphere is.

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> i can't find the article, but i know that Dr. Frank Drake recently stated that
> here on earth, we are about to pass out of the time-frame that ET
> civilizations running a SETI project would be able to detect us. Using earth
> as the reference, there is only about 50 years as a civilization evolves to be
> able to detect the radio waves.
> Here on earth, we will be soon using only data streams that pass only through
> cable or direct to satellite giving no bleed over into space.
>
> so we are essentially trying to find the single grain of salt out of all the
> grains of sand in the sahara.
> but all my computers will be searching anyay ;)
>
> Micah

Yeah it has to be a "Contact" type of scenario. They have to be specifically broadcasting to us or we have to be specifically broadcasting to them.

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About the light speed as the speed: the number they (or we ) talk of is speed of light in empty space. One can easily approximate this with vacuum tube.

The speed of light travelling through some real matter (air, water, diamond, ...) is actually much lower. And this is where one can observe a particle traveling at speeds higher than light-speed.
A Russian physicist Cherenkov was first to observe a phenomenon when a high-speed neutron (obviously produced in some kind of nuclear reaction) enters water where (before it decelerates due to coliding with water molecules) it travels with speed higher than speed of light in water (but slower than speed of light in vacuum). While doing that, one can observe a very similar thing to Mach's wave front (which forms at the point when an object superseedes speed of sound) as a short flash of blue light.

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Metod ...

Cochise touched on this but I think it is worth repeating as it is a common mis-conception. We are NOT looking for EM "leakage" that would be produced by a planet-bound omnidirectional transmitter such as a TV or radio station. The power of such signals is simply not enough to be detected from interstellar distances. I believe our own EM leakage wouldn't be distinguishable from background noise after just a couple light years. They (the little green men) have to be AIMING at us with a highly focused radio signal for us to hear it at all. Some people think it is more likely that some kind of laser would be used since a laser beam would be more focused than radio. But it all comes down to "who knows WHAT the aliens are thinking" and if we don't looking, there is exaclty a 0% chance of finding anything.

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A member of The Knights Who Say NI!
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> [...] and if we don't looking, there is exaclty a 0% chance of finding anything.

Amen to that! Well, I've certainly learned a lot through this discussion. Thanks all for your input. I guess we can agree that there are many unanswered questions and that we are only in the beginning of our quest for answers. Myself, I'm quite certain we'll make giant leaps forward very soon - both in discoveries and in technology break-throughs.

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