Life In The Universe?

One things for sure, the stars in the sky are SO f-in beautiful. It does a man such good to get out and see em even if he gotta rearrange his life affairs. Frankly I find it inspiring, the thought of the vastness of the universe with a minuscule but veritable portion of hospitable planets in other star systems and galaxies. Friend, check out hubble's deep space photos. The black and white ones are the raw and most genuine as the colored ones have been retouched according to elements (like an artificial map " legend"). Cosmic...

GettinDeepOnYou wrote:

If you really think about space and life, why wouldnt there be other civilizations out there? If you think about it we're practically aliens living on our home planet. I think alot about this stuff when im running at night lookin up

Thinking about it and understanding statistics are two different things. The best guess at the number of galaxies , the subsequent number of suns and the expected number of planets and then making an adjustment for planets that could "possibly" maintain life is significantly and virtually impossible in total based on the factors required to support life. There simply aren't enough stars and planets to make it reasonable to expect that life could exist elsewhere.

Keeping it real wrote:

Thinking about it and understanding statistics are two different things. The best guess at the number of galaxies , the subsequent number of suns and the expected number of planets and then making an adjustment for planets that could "possibly" maintain life is significantly and virtually impossible in total based on the factors required to support life. There simply aren't enough stars and planets to make it reasonable to expect that life could exist elsewhere.

Yes but think about this... there are millions of galaxies in our universe.. and there are billions of planets in just 1 galaxy.. We are just 1 planet in one solar system in one galaxy.. just think about it

Your outlook is out of date. Recent exoplanet discoveries have shown planets to be considerably more common than thought just a few years ago:

"The Kepler space telescope has also detected a few thousand[7][8] candidate planets,[9][10] of which about 11% may be false positives.[11] There is at least one planet on average per star.[3] Around 1 in 5 Sun-like stars[a] have an "Earth-sized" planet in the habitable zone,[c] with the nearest expected to be within 12 light-years distance from Earth.[12][13] Assuming 200 billion stars in the Milky Way,[d] that would be 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if red dwarfs are included"

http://en.wikipedia.org/wiki/Exoplanet

Of course a lot of those planets in the habitable zone will be like Venus or Mars, but 11 billion (in just our galaxy; there are at least 100 billion galaxies in the observable universe) is a big number. And of course much debate still exists on the likelihood of life coming into existence even with the right conditions, and similarly much debate on how likely intelligent life would be to develop, given the development of microbial life. And even if intelligent life develops, the huge expanses of space and time between potential civilizations would likely always be huge, making contact seem improbable if not impossible.

This is pretty much going down the route of the Drake Equation. And the biggest thing to keep in mind when consider the Drake, is that apart from the first part of my post, where we're starting to get a clear picture on the number of potentially habitable planets, we really have no idea what the odds are on any of the other things. Because there are no real statistics on what it takes to develop life, as we only have one example of that so far (earth).

But just like the Kepler and other recent exoplanet hunting programs have helped clear up that first point, other future programs will start to close even closer on finding ET life. Big telescopes with sensitive spectrographs pointed at some of the closer examples of the recently discovered exoplanets in their stars' habitable zones could detect the chemical byproducts of life in the atmospheres of these planets, just as one example.

Are they already selling pot legally in Oregon? Looks like it when I read this thread.

That said. I have a few observations on the matter.

- There are hundreds of trillions of planets in the entire Universe. How can there not be life?

- Amazingly for all the knowledge science has accumulated, its my understanding that scientists still have no idea how life started on Earth. They know the ingredients needed and how it evolves. But not how life starts. If you don't know that, than this whole discussion can be nothing more than wild guesses.

- Its my understanding that an infinite amount of parallel universes really do exist with distinct variations of reality in each one. Its not just science fiction. Scientists are generally in agreement and its solidly within the realm of quantum physics theory. Just something else to think about. The question of life in another parallel universe is arguably closer to home than life at the other end of our own universe.

(1) There are LOTS of planets in the Universe. Therefore there must be life elsewhere. ???!!!??? This passes for logic in your world? Seriously?

(2) Your understanding of infinite parallel universes is incorrect. Some reasonably serious scientists have speculated that this might be the case. That's about it. Established fact? Uh, no.

Turd Ferguson wrote:

Your outlook is out of date. Recent exoplanet discoveries have shown planets to be considerably more common than thought just a few years ago:

Which makes the lack of detected signals all the more frightening.

Consider the Great Filter, in the context of the Fermi paradox. Nick Bostrom put it best (well, FIRST anyway) all the way back in 2008:

Check it.

Woops, sorry: Hanson was first, way back in the 20th century:

http://hanson.gmu.edu/greatfilter.html

Check it.

Ummm...ummm wrote:

(1) There are LOTS of planets in the Universe. Therefore there must be life elsewhere. ???!!!??? This passes for logic in your world? Seriously?

(2) Your understanding of infinite parallel universes is incorrect. Some reasonably serious scientists have speculated that this might be the case. That's about it. Established fact? Uh, no.

Haven't you ever heard of the Drake Equation?

This is exactly the thought - more planets = higher probability that life might exist on some of those planets. It's really not that hard.

maxpower wrote:

Ummm...ummm wrote:

(1) There are LOTS of planets in the Universe. Therefore there must be life elsewhere. ???!!!??? This passes for logic in your world? Seriously?

(2) Your understanding of infinite parallel universes is incorrect. Some reasonably serious scientists have speculated that this might be the case. That's about it. Established fact? Uh, no.

Haven't you ever heard of the Drake Equation?

https://www.youtube.com/watch?v=MlikCebQSlY

This is exactly the thought - more planets = higher probability that life might exist on some of those planets. It's really not that hard.

Did you really just post that? Seriously?

EVERYONE has heard of the Drake Equation.

Have you ever heard of relative probabilities?

Seriously dude, get a clue. OK, so let's assume that there are a trillion planets out there. That is 10^12. You want to use a larger number? OK, let's use 10^24 (a trillion trillion).

Now, what is the probability that any given one of these planets actually do (or did) support life? Maybe it is 10^(-1) in which case there is an awful lot of life out there. On the other hand, maybe it is 10^(-300) in which case the probability that there is even a single planet out there with life is on the order of 10^(-276). Just in case such a number mystifies you I'll let you in on a little secret - it is essentially zero.

How do we know what this probability is? Here's another clue for you - we don't. We have no friggin idea. As a result we have absolutely no clue as to if there is life elsewhere or how common it may be.

Please try thinking before posting.

There are an infinite number of Universes and an infinite number of possibilities.

Sheesh! Don't cry.

Why are people always talking about signals from other intelligent beings?

For the longest time we weren't sending out signals.

Other planets could be at a stage of development from single cells up to just a little past cave-men.

A protozoa isn't going to be attempting first contact even if it is the pinnacle of development on its particular planet.

ivygradgrad wrote:

Turd Ferguson wrote:

Your outlook is out of date. Recent exoplanet discoveries have shown planets to be considerably more common than thought just a few years ago:

Which makes the lack of detected signals all the more frightening.

Consider the Great Filter, in the context of the Fermi paradox. Nick Bostrom put it best (well, FIRST anyway) all the way back in 2008:

http://www.nickbostrom.com/extraterrestrial.pdf

Check it.

Bostrom is generally right. Although his concern for the demise of humans is unfounded. We are doomed, just like every other species. He trucks in this fear of how humans will come to an end. But there is no, "if" but "when".

As for densities, the Drake equation etc. We are basically barbaric. We need natural phenomena to move water, have only been calculating information for 50-60 years, have not mastered fusion, etc. We are so completely primitive that it is reasonable to think that we are invisible within any spectrum of sophisticated communication. Our signals would miss more intelligent beings just like a dog whistle is silent to us.

In addition, unless these advanced beings have mastered the use of wormholes, they are not showing up . This might be impossible. Or it might take another 10bn years for other species to master it.

There are enough unknown variables that nobody can answer the OP's question with any certainty. So have at it.

Why would extraterrestrial life be civilizations? Earth life has existed for billions of years, but its civilizations for only 5000 years - and all the oldest ones have long since collapsed. Current civilization is living on borrowed time too as it exhausts its resources, destroys the environment and generates vast overpopulation. Civilization is unstable and may never meet the expectations of science fiction.

Also why would it have to be on planets? Some Earth microbes and tardigrades have been able to survive exposure to outer space for a long time, long enough that some are worried Mars may have already been contaminated by them. It's no great stretch to imagine microbes living and reproducing permanently in space under the right conditions. If so, why can't there be multicellular space life too? Maybe there are nebula people floating around out there.

The lack of radio signals is no big deal. Radio is a useless method of interstellar communication so it's silly to expect any aliens to be using it for that. If there are more advanced beings out there, chances are they never heard of Einstein and have long since found a way to send information faster than light.

Also how do we know we're not simply the first, or one of the first civilizations in the universe? I mean there has to be a first, and the universe is actually extremely young compared to the amount of time it's going to last.

It doesn't necessarily follow that we will come to an end. If we can colonize another planet, from that one, we can colonize another. Springing from planet to planet, so long as there are habitable planets, we can insure humanity's perpetuity. It is likely that we will develop advanced techniques, increasing the range of planets that are habitable (ie terraforming). So long as we don't come into a problem such as the distance between habitable planets is too great for us to reach or we encounter intelligent life bent on erradicating us and possessing the means to do so. The only way humanity ceases to exist before the universe ceases is if we fail to leave this rock.

edward teach wrote:

It doesn't necessarily follow that we will come to an end. If we can colonize another planet, from that one, we can colonize another.

Or we could shotgun interstellar probes replete with organic molecules throughout the known galaxy, at least ensuring survival of life, if not the species!

Oh... wait.

ivygradgrad wrote:

Turd Ferguson wrote:

Your outlook is out of date. Recent exoplanet discoveries have shown planets to be considerably more common than thought just a few years ago:

Which makes the lack of detected signals all the more frightening.

Consider the Great Filter, in the context of the Fermi paradox. Nick Bostrom put it best (well, FIRST anyway) all the way back in 2008:

http://www.nickbostrom.com/extraterrestrial.pdf

Check it.

An interesting read, but it seems built on the assumption that there is one significantly small probability event, that precludes evolution of life, the so called "Great Filter". But consider P(x) = (1/2)^N for N a positive integer. This represents a sequence of N events, say coin flips. This probability can become arbitrarily small, by increasing N, even though the probability for a single event is relatively large.

We can even expand this and say P(x) = (1-1/m)^(N) and push m to a large positive integer, thus making the probability of a single event arbitrarily close to 1, and then push N to an even larger integer to make the total probability small. Thus each event could be very probable, but there are so many events that that exact sequence may be very improbable.

So one cannot claim that the "Great Filter" even exists.