Odds of intelligent life occuring?

[Jehanne]

It's not from ET. Get over it.

It is not convincingly from ET.  We have no fricking clue whether it is from ET or not.

I agree with that.  But, the Big Ear is now a golf course.  If it was an ET beacon and had we been looking continuously since it was discovered in 1977, it may have been the greatest discovery of all time.  May have done more for international peace and goodwill than the International Space Station and McDonald's combined!

[Gawdzilla Sama]

Too bad we don't have some sort of group to listen for these kind of signals.

[Aegon]

Something I L O V E reading about is the Fermi Paradox. Basically it says that the math supports there being intelligent life in the universe other than ours, yet we have no evidence of any. The article seeks to answer why. Here are the cliffnotes:

Explanation Group 1: There are no signs of higher (Type II and III) civilizations because there are no higher civilizations in existence.
-The Great Filter theory says that at some point from pre-life to Type III intelligence, there’s a wall that all or nearly all attempts at life hit. There’s some stage in that long evolutionary process that is extremely unlikely or impossible for life to get beyond. That stage is The Great Filter. When it comes to the Great Filter, there are 3 possibilities:

1) We’re Rare (The Great Filter is Behind Us)
-One possibility: The Great Filter could be at the very beginning—it might be incredibly unusual for life to begin at all.
-Another possibility: The Great Filter could be the jump from the simple prokaryote cell to the complex eukaryote cell.
-Most leaps do not qualify as Great Filter candidates. Any possible Great Filter must be one-in-a-billion type thing where one or more total freak occurrences need to happen to provide a crazy exception—for that reason, something like the jump from single-cell to multi-cellular life is ruled out, because it has occurred as many as 46 times, in isolated incidents, just on this planet alone. For the same reason, if we were to find a fossilized eukaryote cell on Mars, it would rule the above “simple-to-complex cell” leap out as a possible Great Filter (as well as anything before that point on the evolutionary chain)—because if it happened on both Earth and Mars, it’s almost definitely not a one-in-a-billion freak occurrence.

2) We’re the First to Reach It
-For Group 1 Thinkers, if the Great Filter is not behind us, the one hope we have is that conditions in the universe are just recently, for the first time since the Big Bang, reaching a place that would allow intelligent life to develop. In that case, we and many other species may be on our way to super-intelligence, and it simply hasn’t happened yet. We happen to be here at the right time to become one of the first super-intelligent civilizations.
-One example of a phenomenon that could make this realistic is the prevalence of gamma-ray bursts, insanely huge explosions that we’ve observed in distant galaxies. In the same way that it took the early Earth a few hundred million years before the asteroids and volcanoes died down and life became possible, it could be that the first chunk of the universe’s existence was full of cataclysmic events like gamma-ray bursts that would incinerate everything nearby from time to time and prevent any life from developing past a certain stage. Now, perhaps, we’re in the midst of an astrobiological phase transition and this is the first time any life has been able to evolve for this long, uninterrupted.

3) We're Fucked (The Great Filter is Ahead of Us)
-If we’re neither rare nor early, Group 1 thinkers conclude that The Great Filter must be in our future. This would suggest that life regularly evolves to where we are, but that something prevents life from going much further and reaching high intelligence in almost all cases—and we’re unlikely to be an exception.
-One possible future Great Filter is a regularly-occurring cataclysmic natural event, like the above-mentioned gamma-ray bursts, except they’re unfortunately not done yet and it’s just a matter of time before all life on Earth is suddenly wiped out by one. Another candidate is the possible inevitability that nearly all intelligent civilizations end up destroying themselves once a certain level of technology is reached.

Explanation Group 2: Type II and III intelligent civilizations are out there—and there are logical reasons why we might not have heard from them. Here are the ones outlined:
-Super-intelligent life could very well have already visited Earth, but before we were here.
-The galaxy has been colonized, but we just live in some desolate rural area of the galaxy
-The entire concept of physical colonization is a hilariously backward concept to a more advanced species
-There are scary predator civilizations out there, and most intelligent life knows better than to broadcast any outgoing signals and advertise their location
-There’s only one instance of higher-intelligent life—a “superpredator” civilization (like humans are here on Earth)—that is far more advanced than everyone else and keeps it that way by exterminating any intelligent civilization once they get past a certain level
-There’s plenty of activity and noise out there, but our technology is too primitive and we’re listening for the wrong things
-We are receiving contact from other intelligent life, but the government is hiding it (pretty dumb in my opinion as well as the author's)
-Higher civilizations are aware of us and observing us (AKA the “Zoo Hypothesis”)
-Higher civilizations are here, all around us. But we’re too primitive to perceive them. (MY PERSONAL FAVORITE THEORY)
-We’re completely wrong about our own reality

[Jehanne]

Here's Explanation Group 3:  Intelligent Life exists but Special & General Relativity are true.
- Faster than Light travel is a physical, hence, absolute impossibility.
- As the physical laws are constant throughout the Universe, only carbon-based lifeforms are possible.
- All life requires water & oxygen, no matter its forms.
- Per the Conservation of Energy, interstellar space travel is an absolute impossibility.  The distances between stars are too vast to send life into space with sufficient amounts of air, water and food to survive the tens of thousands of years journey between the stars.
- Robotic probes are infeasible, as they cannot be controlled beyond one's solar system.
- Stars are moving far too fast for there to be anything but a short radio beacon from one civilization to another.  For instance, the Sun goes around the center of the Galaxy at nearly 600,000 miles per hour, some 781 times the speed of sound, well over 200 times faster than the fastest rifle bullet.  It is simply impossible for one civilization to reliably point a radio transmitter at another civilization.
- Physics beyond the standard model does not exist, which means that ideas such as a positive energy source from thermonuclear fusion are physical impossibilities; as such, every intelligent civilization will, ultimately, face its own energy crises.
- As with bridges and skyscrapers, rockets can only be made so big (eventually, they would collapse under their own weight), which means that lifeforms can only venture into space close to their home worlds.
- The sky is too vast for any civilization to monitor all the stars in its own sky for evidence of extraterrestrial communications; as such, most advanced civilizations simply do not bother to do so.

[Gawdzilla Sama]

Why does the Prime Directive only apply to OTHER planets?

[ignoramus]

Yeah.
Peace Minister of planet Xerox says:

Those war mongering apes from that far away place in the milky way are always trying to make contact with us.
We will not reply. All we'll be doing is encouraging them.
They'll destroy themselves soon enough...

[Fireball]

- As the physical laws are constant throughout the Universe, only carbon-based lifeforms are possible.

Not sure that I agree. It may be true, but life could form with silicon instead of carbon. The life forms might require a lot higher temperature and other things, but I think it could happen.

As far as a "great filter" is concerned, I consider the earth's oceans and tidal pools as like a great array processor, in which many processes can take place. In some places, just the right number of the right type of atoms slosh together enough times, and molecules get built up. And it happens all over the planet. Something's got to come from all that. Something did- life as we know it.

[Whateverist]

- As the physical laws are constant throughout the Universe, only carbon-based lifeforms are possible.

Not sure that I agree. It may be true, but life could form with silicon instead of carbon. The life forms might require a lot higher temperature and other things, but I think it could happen.

As far as a "great filter" is concerned, I consider the earth's oceans and tidal pools as like a great array processor, in which many processes can take place. In some places, just the right number of the right type of atoms slosh together enough times, and molecules get built up. And it happens all over the planet. Something's got to come from all that. Something did- life as we know it.

Yep, very hard to rule out other possibilities.  While the physical laws of the universe may be constant, local conditions do vary.  But it wouldn't shock me if turned out that only carbon based life does in fact arise any where.  A lot of speculation without hope of verification.

[The Valkyrie]

Yeah.
Peace Minister of planet Xerox says:

Those war mongering apes from that far away place in the milky way are always trying to make contact with us.
We will not reply. All we'll be doing is encouraging them.
They'll destroy themselves soon enough...

Working on it.

[Gawdzilla Sama]

Yeah.
Peace Minister of planet Xerox says:

Those war mongering apes from that far away place in the milky way are always trying to make contact with us.
We will not reply. All we'll be doing is encouraging them.
They'll destroy themselves soon enough...

Working on it.

"THIS PRIME REAL ESTATE AVAILABLE SOON."