Where is everybody? (Fermi paradox)

Bullgrit · Jan 31, 2014

What are your thoughts on the Fermi paradox?

http://en.wikipedia.org/wiki/Fermi_paradox said:
The Fermi paradox (or Fermi's paradox) is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilization and humanity's lack of contact with, or evidence for, such civilizations. The basic points of the argument, made by physicists Enrico Fermi and Michael H. Hart, are:

The Sun is a young star. There are billions of stars in the galaxy that are billions of years older;

some of these stars probably have Earth-like planets which, if the Earth is typical, may develop intelligent life;

presumably, some of these civilizations will develop interstellar travel, a technology Earth is investigating even now;

at any practical pace of interstellar travel, the galaxy can be completely colonized in a few tens of millions of years.

According to this line of thinking, the Earth should already have been colonized, or at least visited. But no convincing evidence of this exists. Furthermore, no confirmed signs of intelligence elsewhere have been spotted, either in our galaxy or in the more than 80 billion other galaxies of the observable universe. Hence Fermi's question, "Where is everybody?"

Italian physicist Enrico Fermi suggested in the 1950s that if technologically advanced civilizations are common in the universe, then they should be detectable in one way or another. (According to those who were there,[65] Fermi either asked "Where are they?" or "Where is everybody?")

The Fermi paradox can be stated more completely as follows:

The size and age of the universe incline us to believe that many technologically advanced civilizations must exist. However, this belief seems logically inconsistent with our lack of observational evidence to support it. Either
(1) the initial assumption is incorrect and technologically advanced intelligent life is much rarer than we believe, or
(2) our current observations are incomplete and we simply have not detected them yet, or
(3) our search methodologies are flawed and we are not searching for the correct indicators.

Say there was another planet with a civilization at least equal to our own out there rather close -- like only a few hundred light years away, (right next door by galactic distances) -- could we even detect them? Would they have to wait for our electromagnetic signals to reach them in another hundred-plus years before they'd know we were here?

Assuming that the speed of light truly is the limit for travel and communication, couldn't the galaxy/universe be full of hundreds or millions of civilizations, but none of them/us can contact with one another, or even find/acknowledge one another because of the distances?

Is the search for other civilizations moot because of the distances and physics?

Bullgrit

Alzrius · Jan 31, 2014

I personally prefer answer number 1 - that we're likely alone in the universe. That said, I think that there's something to be said for our abysmal detection capabilities (see the Wow! signal for an example of one of the most likely signs of contact).

Morrus · Jan 31, 2014

Small light bubbles. The speed of light is slow, galactically speaking. The galaxy is 100K light years across. In 100K years we'll be annoyed by the radio clutter. Except that we won't be using radio (we 're using less and less broadcast TV in favour of cable and fibre, so out TV bubble will probably stop shortly after it started).

trappedslider · Jan 31, 2014

Kramodlog · Jan 31, 2014

From the wiki article:

The Sun is a young star. There are billions of stars in the galaxy that are billions of years older;

Maybe we're late to the party. The universe is very old and not all intelligent life needs to evolve at the same time. That is just anthropocentric. Maybe other intelligent species have risen and disppeared before homides started walking on two legs and faced extinction. Maybe an intelligent species can't live more than a few thousand years before going extinct.

Maybe they also ruined their environment and that is the greatest thread any intelligent species has to face.

If life appeared in an older universe, when more astroids were flotting around, maybe more intelligent life forms have been dinosaured.

Given how dangerous the universe is and how self-destructive intelligent lie can be, maybe intelligent life that can travel beyond their star system is a much smaller number than we'd like to think.

Right now just getting off this world is nearly impossible. We can't even colonize our own satelite. At any point an asteroid could ram us and kil us all. We could lose our magnetic field and the sun would kill all life. We could nuke ourselves. We could experience a pendemic that sends us back to the stone age, etc, etc... So before we have more chances to go extinct before we can make contact with another intelligent life form.

Morrus · Jan 31, 2014

goldomark said:
Given how dangerous the universe is and how self-destructive intelligent lie can be,

People say that, but 100% of our sample of 1 intelligent species has failed to destroyed itself. It's a heck of an assumption.

Umbran · Jan 31, 2014

Bullgrit said:
What are your thoughts on the Fermi paradox?

It is a bummer, and one clue that perhaps FTL isn't possible.

Or, if it is possible, that interstellar material commerce and conquest are simply not economically viable. It may be the only thing of sufficient value to trade across these distances is information, and a civilization isn't worth contacting until they have figured out FTL communication. There could be a galaxy of folks chattering away on the hyperwave radio...

Say there was another planet with a civilization at least equal to our own out there rather close -- like only a few hundred light years away, (right next door by galactic distances) -- could we even detect them?

If they use a lot of radio, yes. Eventually, if we get really good at doing spectroscopy of exoplanet atmospheres, we might be able to infer their presence by their impact on their atmosphere....

Would they have to wait for our electromagnetic signals to reach them in another hundred-plus years before they'd know we were here?

At the moment, there's no known way of signalling faster than light. So, yeah, we'd have to wait until our signals got to them (and theirs to us).

Assuming that the speed of light truly is the limit for travel and communication, couldn't the galaxy/universe be full of hundreds or millions of civilizations, but none of them/us can contact with one another, or even find/acknowledge one another because of the distances?

Yep. Though, the Milky Way galaxy alone could have hundreds or millions of civilizations. The universe is so big it would have gazillions...

Is the search for other civilizations moot because of the distances and physics?

You can't strictly speaking prove a negative. You can't prove we'll never find another civilization, or that if we do, we'll get nothing of value from them. SO, we cannot say if it is pointless. So long as we don't *know* it is pointless, it seems to me we should try.

This being NASA's Remembrance Day, you aren't going to see me saying we shouldn't try, darn it!

tomBitonti · Jan 31, 2014

Maybe, as a variation of one of the given answers, the window of opportunity for detecting an advanced civilization is very small. A civilization may change such that it's visible impact to the universe is undetectable to any other civilization not at a close level of advancement.

The result is curious, in any case.

Thx!

TomB

Kramodlog · Jan 31, 2014

Morrus said:
People say that, but 100% of our sample of 1 intelligent species has failed to destroyed itself. It's a heck of an assumption.

Where pretty young as a species. Homo sapiens sapiens is about 100,000 years old and we have all the tech to accomplish our extermination. Not to mention what we are doing to our environement.

Morrus · Feb 1, 2014

goldomark said:
Where pretty young as a species. Homo sapiens sapiens is about 100,000 years old and we have all the tech to accomplish our extermination. Not to mention what we are doing to our environement.

And yet here we most emphatically still are, and thinking about colonization of Mars.