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View Full Version : Why SETI is Statiscally Impossible (or at least very improbable)




Durandal7
Jul 18, 2003, 12:34 AM
The following is a compilation of some of my posts from another thread. Please read this if you are deciding wheter to join SETI or to Fold:

SETI will never find anything. SETI operates on the assumption that another civ is transmitting open radio transmissions like we do now in the form of TV and Radio. But every day we stop these signals, XM Radio is gaining momentum, cable and sat TV will soon supplant broadcast and most of our communications are handled by direct beam sattelites. Logically, in about 50 years we will be transmitting next to nothing when it comes to wide band signals that can bleed into space. If an alien civilization follows a similar course of progress to us then they would only have radio transmissions that bleed into space for 100-200 years. A few centuries is a blink of the eye on the galactic scale and it is my observation that SETI is hopeless due to this narrow, limited method of detection.

Odds are that there are no nearby alien cultures at the exact same point of development.

Let's assume that there are 6 million advanced civilizations in the galaxy at any given time. Let's define an "advanced" civilization as a culture that has reached approx. 1800 AD technology level. Let's also assume that the average culture survives for around 4000 years past that point until their genetic stagnation finishes them off (assumiing they're brighter then humans, who will be gone in 200 years.)

If they progress at a rate similar to our culture then they would transmit "wide band" EM signals for about 200 years or %5 of their lifespan.This means that there is 300000 civilizations that are on par with us and waste energy by bleeding it off into space. The Milky Way galaxy has anywhere from 200 billion to 400 billion stars. Let's say 300 billion stars for the sake of simplicity.

We can then determine that the odds that SETI happens to be looking at one of the stars that happens to one of the 300000 cultures similar to our own is %.0000001. You are right about interference, if you assume that our odds of noticing the signal are bad it goes down to around %.0000000000001 that SETI will see anything when it looks at a star.

I personally think that 6 million may be a bit too high and that many civilizations will last more then 4000 years, in which case the probability is even lower.


In conclusion, it is nearly statiscally impossible that SETI will ever find anything. I personally believe that there are plenty of alien races in this galaxy alone. I just think that, like many NASA initiatives nowadays, SETI is doomed. The prospect of alien life has always intriuged me and as a result I have given quite a deal of thought to the SETI project and this is my conclusion.



MrMacMan
Jul 18, 2003, 01:08 AM
Thats some great stuff.

Putting it into math have re-affered my dedication to MacRumors Folding! :D

MacBandit
Jul 18, 2003, 01:15 AM
It's good to see my input went to good use and inspired some further thought.

LordMord
Jul 18, 2003, 06:10 AM
but, even if we do find them, we have to get there or invite them here for the really cool OR really nasty stuff.

If a civilization out there is advanced enough to actually travel here they will no doubt already know we are here...

AND looking at the way we treat each other (animals even worse) would YOU want to come and hang out here?

:p :D :confused: :rolleyes:

People ARE suffering from diseases here and now :mad:

Make a difference and start Folding :)

maradong
Jul 18, 2003, 07:11 AM
:eek: great work.
that s a clear "thumb up" from me :D

cc bcc
Jul 18, 2003, 08:21 AM
Though I agree with the improbability of ever finding anything throught the seti program, I have some thoughts to share.

You are correct with radio signals being taken over by directs beams to a satellite, which makes the window of opportunity to find such a signal very low. But some satellites don't send back direct beams, instead they cover the whole side of the planet they are facing, and probably overlapping it a bit, so transmissions will keep on leaking.

I do think that seti is looking to much for human like civilizations. Perhaps our discovery of "light" being just a small part of the electromagnetic spectrum, triggered the research for electromagnetic radiation, which resulted in radio communication.
I don't think it's right to assume that other races also use "light" or eyes as their primary sensors. Many other animals on earth use other senses more, like ears to detect differences in air/water pressure.
Assuming all life evolves in another way, so will technologic ways of communication.
So you'll have to divide that chance of alien civilizations broadcasting radiosignals by the number of different ways of possible broadscale communication. I have no idea of how many there are, though I guess there are numerous.

Also possible aliens that are thousands of lightyears away from here must have reached our point in technology thousands of years ago.
Perhaps someone else can say something about this, but our earth is like 4 billion years old in a 15 billion year old universe, so a l part of the planets are not old enough to have such highly evolved biological life.

Freg3000
Jul 18, 2003, 08:54 AM
Ok, please don't flame me.....

I know this was written from an anti-SETI position, but was it also written from a pro-F@H position?

Regardless if it was or was not, may I ask, what has folding ever done? I understand the theoretical possibilities, but has anything substantial ever come out of it?

I fold myself (I begun just recently) and was just wondering. If I am completely wrong, then excuse me for my ignorance.

britboy
Jul 18, 2003, 10:58 AM
Originally posted by Freg3000

Regardless if it was or was not, may I ask, what has folding ever done? I understand the theoretical possibilities, but has anything substantial ever come out of it?



Not that any of it means much to me, but you could check out the f@h papers page: http://www.stanford.edu/group/pandegroup/folding/papers.html

Whether that means they've acheived something useful or not......your guess is as good as mine ;)

mc68k
Jul 18, 2003, 12:48 PM
all distributed ventures have noble goals, but most of them are long-term goals

sort of goes with the territory. macs (PPC to be specfic) do best at rc5, btw

Durandal7
Jul 18, 2003, 03:05 PM
Originally posted by Freg3000
Ok, please don't flame me.....

I know this was written from an anti-SETI position, but was it also written from a pro-F@H position?

It wasn't especially written from a pro F@H position. All it really is is my observations on why SETI probably won't ever find anything. I had caught on to this even before the SETI@Home project had started and I decided to take this oppurtunity to post it to the forums.

I couldn't write a pro or anti-F@H post because I honestly don't know enough about Folding@Home for it to be more then uninformed prattle.

You are correct with radio signals being taken over by directs beams to a satellite, which makes the window of opportunity to find such a signal very low. But some satellites don't send back direct beams, instead they cover the whole side of the planet they are facing, and probably overlapping it a bit, so transmissions will keep on leaking.


True, but that is why my definition of a transmitting culture spans 200 years. In my mind we will continue to bleed off signals into the 2080s or so. If you take into account the exponential nature of technology then it goes to figure that in 80 years we will have very focused signals. By that point we may even have figured out how to use quantum coupling for instant communication.

Even with that large a window you have to remember that there wasn't a huge volume of signals before 1940 and that signals will begin dropping off in volume past around 2015, making the odds even slimmer that we would detect a stray transmission.

Vlade
Jul 18, 2003, 09:54 PM
I think SETI may be more usefull years later when we know more, but they should switch over to folding now :p.

bbarnhart
Jul 18, 2003, 09:57 PM
I believe that we are also sending signals into space just for the purpose of letting someone find them. An intergalactic life-form may be doing the same thing.

MrMacMan
Jul 18, 2003, 10:02 PM
Originally posted by bbarnhart
I believe that we are also sending signals into space just for the purpose of letting someone find them. An intergalactic life-form may be doing the same thing.

Yeah ok, we are doing that anyways, why do we need to look for them, maybe they have quantam computers and can can a galaxy in a fraction of the time, let them find us.

MacBandit
Jul 20, 2003, 07:35 PM
Originally posted by MrMacman
Yeah ok, we are doing that anyways, why do we need to look for them, maybe they have quantam computers and can can a galaxy in a fraction of the time, let them find us.

Anyone that can (CAN) a galaxy definitely has my respect.:D

Sir Fart
Jul 24, 2003, 11:00 AM
The reason you boneheads should be crunching Seti is so that the Knights Who Say NI can pass you in the folding Project stats :D .

Ni !!!

MacBandit
Jul 24, 2003, 12:15 PM
Originally posted by Sir Fart
The reason you boneheads should be crunching Seti is so that the Knights Who Say NI can pass you in the folding Project stats :D .

Ni !!!

I think not ni. Go away or I shall have to taunt you another time!