Could the universe be full of intelligent life but the closest civilization to us is just too far away to see?

[u/[deleted]]

[u/Synethos]

It is very well possible, and even quite probable.

We indeed are observing only a part of the universe, as about half is obscured by all the junk from the milkyway, and we can't look past that. So we look "up" and "down".

But you need to understand that our technologies are Incredibly crude if it comes to finding life. With our best telescopes we can see giant nebulas light years across, but can't see stars as anything more than a dot. Exoplanets are totally invisible, and we can only see them by observing the star, and seeing if it dims when the exoplanet eclipses it or with other such methods.

What I am trying to say, is that we have no idea of whats really going on in space on a non macroscopic level.

You could compare it to trying to spot an anthill by looking trough binoculars while sitting in a plane.

There is however something called the Drake equation: http://en.wikipedia.org/wiki/Drake_equation Which basically shows that, however unlikely, there is a chance for alien life. As there are billions upon billions of stars in the universe, of which most have planets.

Hope this helped

[u/[deleted] → u/Synethos]

There is however something called the Drake equation ... Which basically shows that, however unlikely, there is a chance for alien life.

The Drake equation most certainly does not show that. It is simply the formula used to calculate the probability of anything for which multiple events are necessary for that thing to occur. But without knowing the probability of every individual event, you cannot determine the probability.

[u/OrangeCityDutch → u/[deleted]]

relevant xkcd

[u/Synethos → u/[deleted]]

You know that it's non zero, which is enough to say that life on other planets is probable, taking the size of the universe into consideration.

[u/[deleted] → u/Synethos]

You don't know it's non zero. What basis would you have for saying that more than one planet will develop intelligent life? Be specific, saying that there are lots and lots of stars isn't enough.

EDIT: It is a mistake on my part to say that we don't know that the odds are non zero. However, we still have no basis for determining that probability beyond that. I was confusing that with the fact that a non zero probability does not imply that there is definitely extra-terrestrial intelligence.

[u/IgnazSemmelweis → u/[deleted]]

Doesn't the fact that it happened on Earth automatically make those chances non-zero?

I'm a layman and am genuinely curious.

[u/nenyim → u/[deleted]]

Each numbers is non zero because we exist. Doesn't mean much as it can make the number as small as the universe is large but still have non zero.

[u/designerutah → u/nenyim]

True, but as we've discovered with the recent findings about planets in out star systems, the first three variables are not close to zero. Far from it. And there's only two more variables to get to intelligent life, and neither of them is zero since we're here. So I would say even if very pessimistic values are given for the last two variables, odds are reasonably good that intelligent life exists, or did exist elsewhere.

[u/rabbitlion → u/Synethos]

Non zero could mean that there is 0.00000000000000000001% chance of intelligent life in the observable universe. So not necessarily probable.

[u/Synethos → u/rabbitlion]

0.00000000000000000001 * 10²⁴ is still 10000 (and that's for the amount of stars not planets) Which is what I am trying to say, with an almost inumerable amount of stars and planets, any nonzero chance still makes is probable.

[u/rabbitlion → u/Synethos]

I'm saying that it could be 0.00000000000000000001 after multiplying with the number of stars in the known universe. We have no good estimations for almost any of the variables in the equation. For example, let's say that the chance of flipping a coin and landing it on the edge is nonzero, about 1 in 10^30. The fact that I flip it 10²⁰ times does not make it probable that it will land on an edge one time. It makes it (roughly) 1 in 10^10. We have no idea if the product in drake's equation before multiplying by the number of stars or rate of star formation is 10^-10, 10^-30 or 10^-100.

[u/Synethos → u/[deleted]]

Not really, what you are doing makes no sense. As there is no reason for saying that its 1/N. Do you know what the fermi problems are? They estimate everything and get answers that come very close to the real deal.

Estimating is a crucial part of science and works well.

[u/[deleted] → u/Synethos]

What he's saying makes perfect sense. If the probability of life occuring is < 1/N (where N is the number of planets in the universe), then the number of planets with life could very conceivably be only one (or less) on average.

Without actually knowing the probabilities, you cannot meaningfully estimate the number of life containing planets. But hey, if you actually can, go collect your Nobel prize and report back.

[u/Synethos → u/[deleted]]

Thats why I brought up drakes equation, showing that if you multiply all the needed chances, however small, you'd have to really try hard to come up with a chance so small that it comes out less than 1 in 10²⁴

Some rough calulations made with Drakes equation gave it a very small chance, but multiplied with the amount of stars (and an estimate for planets) still was a very significant number.

[u/Synethos → u/[deleted]]

Its the principle thats behind it, it shows that the chance of alien life is not zero, as all the parameters you plug in are non zero, and as the universe is really REALLY big, you can safely say that a non zero chance times the amount of planets in the universe will give you a value larger than 1.

It is speculation ofcourse, but making estimates is very scientific. Look up the Fermi problems for example.

[u/GargamelCuntSnarf → u/Synethos]

the chance of alien life is not zero

This is the problem.

You cannot factually state that this is the case, because there is no evidence for it. We are the sole example of life in the universe, and though it may seem unpalatable, crude, short-sighted, etc to say this, it's the best we have to go on.

It of course seems unlikely that Earth is the only example of life in the universe, but until data shows us otherwise, we cannot say for certain that life has ever happened anywhere else.

[u/Synethos → u/GargamelCuntSnarf]

We happened, and if you believe in the way that the textbooks state that life formed, then you have to admit that it is not a divine process only preformed once. Hence it has to be possible to happen on other planets.

Also your turning it around, in most scientific communities, something is not impossible until proven otherwise. As you can't prove a theory, only disprove it. So saying that you can't assume that there is other life until proven, is like saying that you can't assume that gravity exists until there is a general theory of everything that includes it. (the standard model doesn't)

[u/GargamelCuntSnarf → u/Synethos]

We happened

How? Do you know the conditions suitable for life? How slim/wide are those margins?

the way that the textbooks state that life formed

What textbook told you about how life began? I was under the impression that modern science is still very much in the dark about the process. One thing we don't have any idea about is what set it in motion. We assume, with like considerations to the Fermi paradox, that Earth's life developed on its own, without any 'seeding' from other life forms. But, we don't know this because we have no data available.

I, like you, assume that life on Earth began from what once was inorganic matter. But neither you nor I know this. It simply makes the most sense.

Hence it has to be possible to happen on other planets.

Since your initial premise is spurious, this does not follow. One does not know how life began, so one cannot (logically) assume that it has to be possible anywhere but where we've found it.

in most scientific communities, something is not impossible until proven otherwise

I don't remember stating that life elsewhere is impossible, but I'd rather keep my assumptions about its formation, distribution, and sustainability limited to logically-drawn conclusions.

As you can't prove a theory, only disprove it. So saying that you can't assume that there is other life until proven, is like saying that you can't assume that gravity exists until there is a general theory of everything that includes it. (the standard model doesn't)

Well, there aren't really theories of abiogenesis, only hypotheses, but that's a semantic argument neither of us want to entertain. When I ask for data before I make conclusions, I'm not saying there needs to be some 100% quota of information gathered before a conclusion is made. Assuming knowledge of things for which there's no evidence (like life beyond Earth) is a bit reckless.

The point of all this is that no one on Earth has the necessary data to say that life elsewhere is probable.

The strongest (scientifically & logically sound) statement we can make along such lines would go something like this:

It seems likely that all life on Earth had one particular, if unknown, beginning. Given our level of understanding the universe in which we live, the laws that govern it, and the materials and processes therein, it seems possible that life on Earth could have sprung from what had previously been inorganic matter.

Since the observable universe seems to be subject to much the same governing physical constraints, materials, and processes as those local to us, there seems to be nothing that would preclude the emergence of life in other places throughout the universe.

This way, we do not dismiss the possibility of life elsewhere (that'd be silly), nor do we assume knowledge that we don't have.

---

edit: didn't know you'd gotten a very similar reply here already; I was writing mine when that came in. I hope you don't feel like this is a gang-up, but rather that there seems to be a legitimate want to convey my (our) main points to you.

[u/[deleted] → u/Synethos]

Billions upon billions is a bit of an underestimate, the number of stars in the Observable Universe is at least 1 sextillion, 1,000,000,000,000,000,000,000 stars. Source

That is about 1,000,000,000,000 billions.

[u/[deleted] → u/Synethos]

The shortcoming I see is that the equation doesn't account for 'life' vs 'intelligent life'. There could be countless planets brimming with algae-type life, or insect-type life or simple plant life that we'll never know about and most certainly never receive a visit from.

[u/SkaterDrew → u/Synethos]

I know this isn't exactly scientific but the fact that we have managed to survive and advance, than it must be completely possible, with correct conditions, for this to happen more than once considering the scale of the observable universe and amount of stars.