h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Has anyone else noticed that a possible problem with the SETI project is that they are searching for electromagnetic (ie radio, microwave, light, etc) waves.

Here is the maths:

Age of planet: 4,500,000,000 years
Probable maxmimum age of planet: 10,000,000,000 years
Existence of humans: 30,000 years
Probable maximum inhabitance of planet by humans: 5,499,970,000 years
Widespread use of radio transmissions: 80 years

If a new technololgy is discovered in the next, say, 20 years that supplants radio waves, and assuming parallel development timescales for an extraterrestrial civilisation, then searching for radio waves has, under optimum receiving conditions, only a 1 in 54,999,700 chance of detecting a civilisation even if it exists.

Extraterrestrial life almost certainly exists. Extraterrestrial civilistations seem pretty likely too. The chance of SETI finding one? Ridiculously unlikely.

The only way we will know about extraterrestrial civilisations is if they come to find us, or we go to find them. And the first one hasn't happened. Because I can't imagine the Sirian equivalent of NASA going to the Sirian equivalent of the Senate and asking for funding:

"We've got a new project that we need some money for."
"What? More money for that lunatic space program? I hope you're going to produce some results from this one.
"Yes, siree! We're going to flatten some wheat in a field on planet Squarg."
"Oh, OK. For a moment, I thought you were going to suggest we contact an alien civilisation and educate/destroy* them. Go for it!"

(* delete according to your own paranoia)

SmileyMan

Seti is like the drunk looking for his keys under the streetlight. They might not be there, but it's the only place he's going to find them.

That is actually a very good description.

I agree, although I do use SETI (or should that be: I allow SETI to use me?), there are some problems associated with it. Not least of which is the fact that we are actually searching for extra-terrestrial telecommunications; we could be happily sweeping over numerous intelligent civilisations, neither of which have got to the stage of developing electromagnetic telecommunication. Simply consider what our world was like, say, 2000 years ago: plenty of intelligent life, but electromagnetic telecommunications companies a little thin on the ground.

The counter argument to all this is the life-cycle of our planet, or more specifically, our entire solar system. Every 60 million years or so, our solar system is plunged through the galactic plane potentially causing major disturbances in the outer halo of debris that surrounds it. These disturbances coincide with large-scale extinction on the planet. Solar systems further out of the galactic plane, or in areas of lesser galactic density, or that don't have a lot of debris on the boundaries of their systems, or have longer periods between oscillations, or a whole bunch of other conditions, may not ever have experienced such drastic events.

What I'm saying is this: consider, for example, what may have happened if the dinosaurs weren't wiped out, and evolution continued uninterrupted. Maybe, just maybe, we would have a civilisation 60 million years in advance of the one we have now. But it's irrelevant to consider what may have happened on this planet, simply consider the possibilities that already established, dominant lifeforms could evolve uninterrupted somewhere for much, much longer than 60 million years, and the distance their communications technology may have travelled in that time. I realise this is a mere possibility potentially smothered by a plethora of impossibilities, but we shouldn't allow the uniqueness of our planet rule out the uniqueness of others.

Of course, in that time, they may have developed beyond electromagnetic communications entirely, but that's another argument.

Sorry, it should read "Solar systems further out from the galactic axis..."

We had dinosaurs for what, 200 million years? So if we gave them another 60 million years, is there any reason to believe they would have developed technology? It's only a few million years ago man started being special from other animals. So there's no reason why any rather complicated animal couldn't develop technology given a few million years extra. Perhaps one day after having lived in space for a few million years man will return to Earth to find it inhabited with smart racoons.

Anyway, what I am saying is that intelligence is not something that will necessarily happen if you give a species a certain amount of time.

I think you're right. For example, reptilian brains are far inferior to mammalian brains, and it is argued that it was the wiping out of the dinosaurs that enabled the mammals to evolve as much as they (we) have - bearing in mind that mammals evolved from reptiles in the first place.

But as I said it's not what happened on this planet that's relevant, so much as the possibilities of what could happen on other planets, given a long enough uninterrupted evolutionary timescale. Given this much time, intelligence (whatever that means) which we know can appear very quickly, could have been around for a lot longer in near enough regions of the galaxy than our intelligence.

I think this very thread indicates the degree to which you can simultaneously argue and counter-argue the existence and non-existence of ETI (as well as the nature of intelligence itself), and we aren't going to know for sure until we find any. Even not finding any won't make us sure there isn't ETI within a few tens of light-years. It seems our choices are these:
a) Find some, or
b) Speculate about the (im)possibility of finding some.

a) is far more exciting than b), but that is what makes b) so interesting!

Is there any proof that mammals developed from reptiles. I don't believe that life developed from a single organism but from a multitude of organisms. There were small mammals around during the age of the dinosaurs but they did not develop untill most of the dinosaurs died out.

Without getting int the proof, just because there were mammals around during the dino age doesn't mean they can't have evolved from reptiles. It just happened at the same time.

I believe I saw some proof once, but I can't remember much about it. Something about some intermediate stages.

I found this after doing a search for evolution :-
Life began more than 3 billion years before the Cambrian, and gradually diversified into a wide variety of single-celled organisms. Toward the end of the Precambrian, about 570 million years ago, a number of multicelled forms began to appear in the fossil record, including invertebrates resembling sponges and jellyfish, and some as-yet-unknown burrowing forms of life. As the Cambrian began, most of the basic body plans of invertebrates emerged from these Precambrian forms. They emerged relatively rapidly, in the geological sense -- over 10 million to 25 million years. These Cambrian forms were not identical to modern invertebrates, but were their early ancestors. Major groups of living organisms, such as fish, amphibians, reptiles, birds, and mammals, did not appear until millions of years after the end of the Cambrian Period.

Okay I think we all knew that. So what is your point?

The point is we may have a common ansestor but we are different branches of the tree. Mammals did not evolve from reptiles as did birds and some mammals returned to the sea but the reptile/mammal seperation came earlier.

Just because the text grouped mammals and reptiles together doesn't mean they didn't evolve from one another. Just that it all happened within a relatively short amount of time.

And life evolved from a single organism, not from many organisms.

Cor, a thread I started which is still alive later on. Lucky me!

We seem to be going off topic, but for the record, mammals and reptiles both evolved from the Synapsids, so it is incorrect to state that mammals evolved from reptiles.

Cheery Chops

Smiley

Yes, going off topic perhaps, but still interesting!

My thoughts on SETI question just what it is we are listening out for. Is it the normal radio traffic of a planetary civilization such as our own, the normal radio traffic of an interplanetary civilization (one step ahead of ours), an interstellar civilization, or are we listening for deliberate contact broadcasts?

It seems to me that statistically we are unlikely to be close enough to the source to pick up signals from the first two, the third possibility seems to imply technologies that transcend our current understanding of physics (or timescales way beyond our range) - would radio be more than a local tool to such a civilization?, and as for deliberate contact broadcasts - what makes us think they would do this, i.e. we make precious little effort at active contact, what is the basis for expecting others to?

I don't doubt there are other civilizations out there - anyone who's seen the Hubble deep field images with all their millions of galaxies should realise that even with odds of billions or trillions-to-one against, there are likely to be plenty of civilizations, but what are the odds of detecting them in other galaxies?

For what percentage of our own galaxy does SETI anticipate a reasonable chance of detecting an artificial signal?

Higgsy, AKA Djob

Higgs, could you tell me where you are to be found? I'll credit you in my Nobel prize acceptance speech .

I think if we scanned all radio frequencies we would be most likely to detect normal radio traffic, after all we ourselves send out vastly more of this than any deliaberate measurements. But we don't. SETI concentrates on certain 'universal' frequencies - the natural vibrational frequency of hydrogen or something like that. My Seti@home screensaver is always looking at about 1.4GHz. This is because we think that aliens will choose this frequency to send deliberate messages. Our normal radio traffic is, of course, in the kHz/MHz range.

A civilization that has inverted faster than light travel (if this is possible) will not use radio except for locally because their spaceships would be much faster. We might still pick this up, though.

Basically, I think Seti searches in hope rather than expectation. If we don't look, we're certainly not going to find anything.

for measurements read messages

Sorry, I'm new here... What do you mean by 'where you are to be found'?

I certainly wouldn't turn down a credit in your Nobel prize speech, though!

If SETI is searching on the Hydrogen band, I guess they're restricting themselves to deliberate commnications, which reduces the odds a fair bit.

Still, it would be nice if something turns up!

The Higgs Boson is (or might be) a particle. It's the Holy Grail of particle physics. I thought you probably knew, from your name.

And another joke bites the dust...

OIC! I'm sorry, I was distracted by other things and completely missed your joke. I'm not usually that dim

Where am I? In the words of a 60's pop ditty, "I'm everywhere and nowhere baby, that's where I'm at..."

See my personal space for more details - I've recently installed an updated introduction.

Be seeing you,

Higgsy