SETI - A Serious Thread

[Emperor_Norton_II]

Not quite a continuation of the 200+ post monster thread.

So instead of playing with UFOs, government coverups and being so open-minded that our brains ooze out our ears, let's see if we can't have an actual discussion about the search for extraterrestrial intelligence.

Lots of decent, non-woowoo speculation about SETI and SETI-related topics, so there should be no lack of material. Pretty much everything is fair game - nature of the discovery, nature of the proof, reactions (though lets keep the OMGGUMBETCOVERUP! out of it if we can), means of communicating...

Anybody want to start this one off?

[beam me up scottie]

1. I have an account

with SETI@home.

http://setiathome.ssl.berkeley.edu/

[Emperor_Norton_II]

2. Never set one up for myself

But then, I didn't have broadband until very recently. Got most of the lab computers running it when I was in college, though. ;)

[beam me up scottie]

3. It's an awesome feeling

to be part of something like this.

[Maple]

5. I did it for quite a long time..few years

but was under no illusions we'd find 'aliens' that way.

It was a new method of doing something though, and certainly showed the interest there was in such a search.

Now we have people doing all kinds of interesting things online in the name of science.

[Anarcho-Socialist]

19. I used to have SETI on my PC, I just re-downloaded it

when your post reminded me about it. It's a good thing to be a part of.

[Ian David]

42. SETI@home got me in trouble at work

They told me I had to turn-off my computer at night to save power.

I tried to explain how important it was, and how little power it draws, but no luck.

So, what I did was turn off my computer every night like they asked. But since it was an iMac, I was able to also set it to turn itself back on at 1 A.M. every day, too.

Unfortunately, I got busted for it.

[Salviati]

4. The Drake equation

For those who haven't seen it before is an "equation" that exists, not really to provide answers, but to structure and catalog the questions that one needs to ask when contemplating the existance of extraterrestrial intellegence.



From http://www.setileague.org/general/drake.htm

N = R* fp ne fl fi fc L

where,

N = The number of communicative civilizations

R* = The rate of formation of suitable stars (stars such as our Sun)

fp = The fraction of those stars with planets. (Current evidence indicates that planetary systems may be common for stars like the Sun.)

ne = The number of Earth-like worlds per planetary system

fl = The fraction of those Earth-like planets where life actually develops

fi = The fraction of life sites where intelligence develops

fc = The fraction of communicative planets (those on which electromagnetic communications technology develops)

L = The "lifetime" of communicating civilizations

[Anarcho-Socialist]

7. Thanks for the link

"Frank Drake's own current solution to the Drake Equation estimates 10,000 communicative civilizations in the Milky Way."

[NNadir]

31. This equation is meaningless, since few of the variables are measurable.

In order for an equation to have meaning, there has to be some way of measuring the variables. In the case of this equation, one would have to have some means of meausring fl, fi, and fc. Of course, were you able to measure these variables, there wouldn't be much value to the equation, would there?

[Anarcho-Socialist]

6. I've often wondered

that if there is some advanced alien race out there...

...would they really want to talk to Humans? They might think we're messed-up. OR it could be that as damaging to our egos it is, they might not think we're interesting to talk to.

-------
Irrespective of my conjecture, I'm interested in hearing any science on the plausibility of there being life or intelligent life outside of planet Earth.

[Celebration]

8. I'm interested in the extra dimensional stuff

How long would it take the radio waves to get here, anyway? Wouldn't the civilization have vanished, and even the star possibly gone by the time SETI came up with some data? If so, I am not sure there would be any meaningful two way conversation. Or is my view of time too linear?

[Emperor_Norton_II]

17. It's entirely possible

Radio signals run at the speed of light, which is the ultimate top speed of anything in this universe. The further away the star, the longer the two-way transit time is. So when we get a message from Beeblebrox IX and we reply to it, and Beeblebrox IX is 2,000 light years away, it'll be another 2,000 years before they get the reply, and 4,000 years before we get another signal.

Hell of a way to carry on a conversation. To carry on anything remotely meaningful, the message would have to either carry a hell of a lot of content or it would have to be fairly close. In this case, "close" equates to around 100 light years or so. Not that we'll be able to carry on dialogue in anything less than generations, but close enough that we can send multiple signals and possibly send probes or ships before the end of our current civilization.

(Minor tangent: If there's sapients living around Tau Ceti who are just about to discover the joys of radio and their own SETI programs, I so pity the poor bastards. They have no idea what'll hit them.)

[Celebration]

23. Radio Waves seem so old fashioned

Is there any way to come up with a SETI message board? There would be an efficiency about it...I have a lot of patience, but waiting even generations to hear a possible answer to our communications might be a little much for me. I think I would rather figure out how to pop in and out of worm holes, or black holes. But I want to send Repugs first... you know, the ones that refuse to enlist. Let's see how another dimension deals with them. You said this is a serious thread and that is a serious proposal!! (I wish).

[Maple]

27. Agreed

And we haven't managed to stick to anything else for 2000 years

[Bill McBlueState]

20. size of the galaxy

Any signal we detect is probably going to come from within the galaxy. The galaxy is about 100,000 light years in diameter. Since the Sun's not on the outermost edge, the distance from any other star in the galaxy to the Sun is less than that. In any case, the fact that it could take tens of thousands of years to send a message and receive a reply could make things difficult!

[Maple]

9. I can't imagine

a universe devoid of all life but us.

If so, we'd best stop killing each other off...we're very rare.

[iconoclastic cat]

11. Maybe that's why we haven't heard a peep! All "advanced" beings die

at their own hands!

[Maple]

13. LOL

Certainly possible!

[Bill McBlueState]

16. that's an interesting thing to consider

What happens to a civilization as it becomes very old and advanced? Will such a civilization inevitably destroy itself, or will it outright lose interest in technological development? Does the exponential increase in technology we see in our own society continue indefinitely, or is it limited by self-destruction, or even changing priorities?

[iconoclastic cat]

18. Maybe they have their own Oppenheimers, their own Nobels, looking for the

next weapon that will make all warfare impossible because of the risk of total annihilation that the users would face. Until it is used, of course.

[Emperor_Norton_II]

21. Saw a paper on that sort of thing the other week...

Hang on, where'd it go...

*rummage*

*rummage*

Aha! Here we go!

http://search.arxiv.org:8081/paper.jsp?p=astro-ph/0506110&qid=1121751462657674526958

Motivated by recent developments impacting our view of Fermi's paradox (absence of extraterrestrials and their manifestations from our past light cone), we suggest a reassessment of the problem itself, as well as of strategies employed by SETI projects so far. The need for such reevaluation is fueled not only by the failure of searches thus far, but also by great advances recently made in astrophysics, astrobiology, computer science and future studies, which have remained largely ignored in SETI practice. As an example of the new approach, we consider the effects of the observed metallicity and temperature gradients in the Milky Way on the spatial distribution of hypothetical advanced extraterrestrial intelligent communities. While, obviously, properties of such communities and their sociological and technological preferences are entirely unknown, we assume that (1) they operate in agreement with the known laws of physics, and (2) that at some point they typically become motivated by a meta-principle embodying the central role of information-processing; a prototype of the latter is the recently suggested Intelligence Principle of Steven J. Dick. There are specific conclusions of practical interest to be drawn from coupling of these reasonable assumptions with the astrophysical and astrochemical structure of the Galaxy. In particular, we suggest that the outer regions of the Galactic disk are most likely locations for advanced SETI targets, and that intelligent communities will tend to migrate outward through the Galaxy as their capacities of information-processing increase, for both thermodynamical and astrochemical reasons. This can also be regarded as a possible generalization of the Galactic Habitable Zone, concept currently much investigated in astrobiology.

[Maple]

22. Evolution?

I don't have anything to compare it to here...primates standing upright perhaps...or maybe the Organians on Star Trek, something along that line.

A mental evolution, rather than more tech.

Transhumanism.

PS. Luv your sig line. :D

[beam me up scottie]

25. OMG !

I just saw that !!!
Thanks.

[beam me up scottie]

24. I'm afraid we may suffer the same fate

as the residents of Easter Island.

[Ian David]

45. Easter Island and something else that was said just got me thinking...

The folks on Easter Island built the giant heads for cultural or religious purposes, rather than anything (we're pretty certain) we would consider "practical."

Here on Earth, we created radio technology for a particular purpose. Namely, sending "wireless telegraphs" and other signaling purposes. When it emerged, the technology was needed for human purposes.

What if on some other planet radio technology emerged earlier for reasons other than why we would use it?

For example:

1) A planet where there are natural sources of microwave radiation, where perhaps their civilization invented a primitive "Radar-Range Oven" before discovering fire.

2) Some sort of religious fetishism, similar to the heads on Easter Island. Primitive civilizations building Gilligan's Island radio transmitters because they hear the voices of their gods in the static, for example.

In either case, there are a few things that could come of that:

A) A tremendous jump-start in the mastery of radio technology, creating an otherwise primitive but radio-using society.

B) A tremendous jump-start in the mastery of radio technology, creating a society that progresses even faster than our own.

C) A society that enshrines radio waves in religious beliefs and refuses to make advances in the technology that could have actually put it to good use.

[beam me up scottie]

47. You could write

a novel.

Seriously.

[Ian David]

48. Thanks! But what I really want to do is direct.

[beam me up scottie]

26. Mr. Resident Astrologer,

:loveya:

[Emperor_Norton_II]

12. I've always wondered why they had to be advanced

I mean, we tend to simplify "advanced" into something like the prototypical Space Brothers or the Vulcans: beings that are better than us in most, if not all ways. When it comes to contact, I don't think that's absolutely necessary. All they really need is to be able to send and recieve messages transmitted over vast distances, and the patience to decipher incoming mail. We can do that now - maybe not the patience, but we're technologically there at any rate. They don't need to be advanced, just able to hear the message and respond.

[Maple]

15. They never were

until Star Trek. Before that we got creatures from black lagoons that ate teenagers at Lookout point.

Spock was a whole new veiw.

But anyone on our level could also have a SETI of their own. As you say, they don't need to be advanced to do that.

[Ian David]

43. They could see us as cosmic spammers

For all we know, SETI messages from primitive civilizations are treated like annoying spam by advanced races, and they have "filters" to avoid having to hear us.

Advanced species could be getting bombarded with "we come in peace" messages as often as we get "The Nigerian government has my money" messages.

For that matter, maybe we can't hear them because they use something similar to steganography to hide their transmissions. In other words, their planet-to-planet messages may be disguised to look like the CBR or other natural signals.

Maybe they would do it to hide from less-advanced civilizations.

Or maybe they do it for the same reason we encrypt credit card transactions and cellphone conversations.

[woodsprite]

10. I don't have one now, but did a few years back.

I ran a computer lab for our college and set all the machines up for Seti - 106 machines. A couple of times we got some interesting blips, but nothing that pops out at me now.

[donco6]

14. I seriously think this should be one of our top scientific priorities.

Sadly, we've been derailed with religion - so many people thinking that no matter what kind of mess we get ourselves into, God is "in control", and He won't allow us to destroy ourselves.

Well, that kind of thinking has led us into a pie-in-the-sky delusion for 2,000 years or so - and has kept us from seeking outward for answers to why we are here. Or even - if there is a "why."

SETI is one of the first steps you have to take to figure out if there is any way off this rock.

[Pepperbelly]

28. I am unconvinced as to the basics of SETI ... here's why.

We have been blasting RF energy on virtually all freqs in virtually all directions for the past 85 years and even more intensely if you look at the last 50 years.

So, years and years before SETI, we were broadcasting in the universe. That tends to move the neighborhood out to about 50 light years at this point. With the Drake equation, shouldn't we have elicited a response by now? Assuming of course that any sentient beings have and use radio energy.

[Emperor_Norton_II]

29. It depends

A 50 light year bubble is damn big, no question. But compared to the rest of the galaxy it's tiny. Only a bare fraction of the total population of the Milky Way. If the Drake number turns out to be very high and distribution is regular throughout the galaxy, then yes, it's entirely possible that our transmission bubble has crossed the paths of one or another ETI civilization. The lower the Drake number and/or the more uneven the distribution, the less likely it is that there's a civilization within our bubble period.

More to the point, unless the ETIs are very close to us, we may not know about them until they start broadcasting back. Let's take a hypothetical ETI that's not entirely dissimilar from us in 2005 technologically on the far edge of our transmission bubble. They pick up the signal, deduce where it came from and send a message back. If they send it right now, we won't know it's even on the way until it arrives on July 23, 2055.

More to the point, we don't know how far information really travels in our transmission bubble. ISTR seeing on Slashdot (but can't find the damn thing on a search - argh) an article suggesting that normal radio transmissions degrade to noise within only a few light years. So the bubble may be smaller than we normally think.

[muriel_volestrangler]

30. Your last paragraph was just what I was going to ask

Has anyone any idea of the effective range of our 'random' emissions?

As well as those, there's the possiblity of signals designed to contact other intelligences. Those would, presumably, be designed with a larger range in mind. But that depends on the other being not just intelligent, but interested in telling the galaxy about themselves. They might not think its worth it, or they may think its a bad idea - the "prime directive" principle (sorry to drag Star Trek into this). However, the multi-generational lags that we think likely, which might put us off, might be less than a generation to them - in which case you'd think their interest would be higher than ours. It's very difficult to know if our example of intelligent life is typical, or if intelligence can develop in all kinds of ways.

[Pepperbelly]

32. How could they know that?

With some of our more far ranging probes, we still get transmissions from very small transmitters. Now I know that there is a relationship between transmitter power and the distance a signal will propogate in the atmosphere (that environment being the only one that I have personally dealt with high power, focused transmission of RF energy) but I sense that the relatonship might be different through vacumn. Of course, I do not know that and haven't, my bad, bothered to look it up (in my defense, it is so fucking HOT here I can barely breathe) yet I do know that the signals from our probes are constantly received, even as they leave the solar system and plunge through intersteller space.

I realize that they have not travelled a light year as yet but still, they have travelled a measureable portion of one. My experience with tightly focused high power transmitters does, now that I think about it, give rise to some agreement in principle with those that suggest substantial degradation of signal over distance. Does that not bode ill for the whole concept of SETI? I mean, it is difficult to imagine a transmitter as powerful as nature's own RF transmitters, no?

[Emperor_Norton_II]

33. Probes and whatnot

The two Voyager probes have traveled roughly 90 AU and are still sending back some data. As far as fractions of a light year go, they've gone .0014% of a light year away from Earth. So we still don't have any good data on signal loss at extreme distance.

As for signal degradation invalidating SETI, not necessarily. It casts doubt on finding ETI through completely passive methods - looking for background RF sources containing signal. But finding ETI that way was always pretty low-probablity anyway; most historical SETI programs look for active signals, like the one Carl Sagan famously described in Contact, the strong radio source pulsing in a repeating sequence of prime numbers. The information content on a signal like that is going to be pretty low - we won't be getting a record of all their culture or anything spectacular - but it would constitute proof of ETI.

There are also other avenues down which SETI can go. If the ETI in question uses starships, then visible astronomy will be able to pick up the light coming off the drives - fusion and antimatter engines give off easily identifiable spectral lines and are brighter than all hell. Plus the source will show unusual red or blueshift. If ETI is close but outside the range of being able to pick up useful signal from passive RF transmissions, then telescopes designed to locate terrestrial planets should be able pick up evidence of civilization within a few dozen light years.

[Pepperbelly]

34. But the problem with even transmissions ...

As the distance increases, the signal gets weaker. Like visible light, the signal strength is inversely proportional to the square of the distance. When it gets to the distance of Pioneer 10 outside the solar system, the signal is just marginally available over the background radiation manifesting as static. When the signal becomes weaker than the static, we will lose it altogether. And that is at less than an A.U. distance. What happens when you multiply that by orders of magnitude?

[Emperor_Norton_II]

35. Not quite the same thing

The transmissions coming from the probes are extremely low-power signals, only a few watts or so. It's possible that the aggregate noise of a civilization only propagates as signal only a few light years before it degrades into just another radio source.

OTOH, an active pulse signal should be picked up pretty easily at distance. It's not a question of encoding anything into the pulse itself, all you have to do is set up a strong radio transmitter and turn it off and on in a precise sequence.

*beep*
*beep* *beep*
*beep* *beep* *beep*
*beep* *beep* *beep* *beep* *beep*

...and so on. All that signal carries is an indication that it's artifical in nature and that it's coming from... wherever it's coming from. That's the bare minimum to confirm ETI.

[Pepperbelly]

36. Interesting now that you mention it ...

I did a little more research into Pioneer 10 and as it turns out, the distance was not the reason for the signal loss at all. The power plant was the problem. "NASA engineers report that Pioneer 10's radioisotope power source has decayed, and it may not have enough power to send additional transmissions to Earth." http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html

I am still left with no data. There seems to be an absence of information regarding these radio signal characteristics in tabular fashion although it is available if you have the data and want to do the math. However, with that said, if you use this as a standard ...

transmitter power of .5 milliwatt (-3 dB); receiver bandwidth of 230 kh; receiver noise figure of 4 dB; link margin of 0 dB; transmit antenna gain of 0 dB; receive antenna gain of 2 dB; carrier wavelength at 915 mhz of 0.328 m, over ground, with a transmitter and receiver height of 1 meter, you're good to a little over 4000 yards (less in our rf rich environment where signals have to fight to get their figurative heads about water.)

Not the perfect setup ... but one I was able to crib rather than bonehead the math ... but just simple arithmetic tells us that a 1 watt transmitter should, with the spreading loss of signal, be good for about 4,000 nautical miles. Whew!

There are 5,878,499,812,499 miles in a light year. That should take something along the magnitude of a 1,469,624,953 watt transmitter. All numbers very approximate, of course. Whoa. Surely not.

So what do you think? How large a transmitter would you need to send a rf signal one light year?

[Emperor_Norton_II]

37. Gigawatt transmitter ought to do the job

Use the right frequency and it should go pretty far and still be detectable.

[Pepperbelly]

39. Who has one of those?

Just curious...

[Emperor_Norton_II]

40. AFAIK, nobody

The only use for a billion watt transmitter would be to send messages across stupidly large distances. So far, nobody's gone far enough to require the bandwidth.

[Taxloss]

38. I would love to make contact, but I am a deep pessimist about it.

The odds are against it. We will never communicate with an understandable intelligence. I can only imagine the following scenarios:

1. Exploring another planet, we discover evidence of a long-gone alien race.

2. We receive a single signal saying "Hello!", but nothing else.

3. We get a probe like the Voyager.

But we'll never, ever engage in dialogue - it will be artifacts and traces, if we find them at all.

[rman]

41. Not much to say about it...

there's some chance that SETI will help find something, eventually.
All i can do is wish them luck.

[Ian David]

44. OK, here are some of my super-grand-scale SETI ideas

Almost everyone here has probably read one or more of Larry Niven's Ringworld books, right?

Anyway, what if, instead of a ring "world" you made a giant "Piano Roll?"

Anyone here old enough to remember the old-fashioned paper piano rolls?

In short, you would build a gargantuan "SETI ROLL" (made of Unobtainium) that orbits around the equator of a sun. Sunlight would pass through the holes in the SETI Roll creating a predictable and repeating pattern of light.

I suppose for a super-focused, super-charged version you could use a Pulsar.

Now, if you wanted to REALLY spend the space-bucks, how about this:

Turn a sun into a giant "Signal Lantern" by building a Dyson Sphere around a sun, and build a giant iris and shutter into one side of the sphere.


Helpful links:

Ringworld
From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Ringworld

Dyson sphere
From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Dyson_Sphere

Pulsar
From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Pulsar

Unobtainium
From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Unobtanium


Piano roll
From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Piano_roll

[Orsino]

46. Reading Ward and Brownlee's RARE EARTH...

...concerning the necessary factors for the evolution of complex life.

They've got me convinced that although life may be fairly common throughout the universe, complex life has special needs that may make it extremely rare.

Their Life and Death of Planet Earth elegantly makes the point that out of the estimated twelve-billion-year existence of Earth, multicellular life is only possible in a one-billion-year window.

Not only will complex life forms be ultra-rare, they won't stick around that long, either.

It gets me down, and makes me less hopeful that any radio contact will ever be made with ETs. I'm still motivated to join SETI@home, though.