Interstellar travel?

[red_elk]

This has to be a very long tail distribution - with huge number of universes completely devoid of life and a handful with exactly one habitable planet. But such possibility cannot be ruled out, yes.
The possible values of probability in this case are quite limited though, it must not be extremely low so that life appears at least somewhere, but still low enough so that out of trillions planets in the universe only one will be habitable.

 

[innonimatu]

I'm sitting around on my throne and I get a bug up my butt and say. Gosh darn it, imma make me a big ol' batch of universes (let's say 10^75 of 'em).

So here's what I do, first I make a barren universe with 10^25 stars. Then for each star I roll a fair n-sided die, if it's 1 I put some life on it, if not I move on without the life.

Now with this talk you've just gotten me replaying Masters of Orion

 

[Perfection]

That's my argument though, that we can pretty much rule out that we are in a life-poor universe. I mean, it's possible, but the claim is that it is likely that we are the only life here. As likely as there being life elsewhere! That means we are in an extremely life-poor universe and got super lucky to have ended up being seeded.

(Quick note: I'm not arguing for a strict 50/50 on the alone not alone question, I'm fine with people attempting to bend the consideration by making speculative arguments, what I am arguing more against is strongly favoring one over the other, especially by dubious statistical means.)

My claim is we could mostly rule that out our batch of universes contains life-poor universes if we could randomly sample a universe and see if it has life. Just like we could rule that our batch of universes is likely not life-rich if we randomly sampled a universe and found no life. However, we have not randomly sampled the batch of universes we're a part of and seen if it has life or not. We have randomly sampled a world with life and are trying to make claims about the nature of the universe. We have no information that allows us to guess the frequency of life in universes like ours or universes more generally. The fact that we live in a universe with life is not a statistical datapoint because we necessarily must life in a universe with life.

Given all the scenarios it is far more likely we are in one of the other types of universes, whether it's "life-rich" or "life-super-scarce-but-it-appears-twice-or-thrice" or "life-kinda-poor-but-each-galaxy-has-1" or whatever you can imagine. There are so many more options out there in way of probability, it towers way above the "we got lucky with the die throw and are in a life-only-once" universe. The way you described the set-up helps illustrate that concept better than my write-up earlier

I don't see the basis on how you can make that claim. We don't have a general handle on what kinds of universes are out there with what frequency. You can make guesses but that's assumption laden and shouldn't be taken as more than a guess, you'll always be able to make counter assumptions to skew it in a different direction and I see no firm method to arbitrate the claims.

 

[Kyriakos]

There's probably aliens out there who live to be millions of years old, who can easily travel the distance between the stars without having to worry about building generational ships.

I bet there's also ways to travel through parts of space-time we haven't discovered yet

Who would come here to watch us though? Would you fly to Africa to watch an anthill for a couple hours, then go home? If they came here, they came here for other reasons, and we just happen to be here

Supposing those very long living aliens exist, and supposing (ok, unlikely) that they are composed of matter that also decays in similar way; just very slower, isn't it then likely they would experience time as something passing faster? Iirc even slow-moving and very long-living animals on earth (eg some turtles) experience time as something which is faster (ie they don't sense their own moves as slow) and some very fast moving insects are said to experience time as a lot slower (and thus they don't sense their own moves as fast).

Imo it isn't likely that 3d-based (for lack of a better term) aliens would use interstellar or ftl or a combination of those. Other types (if they exist) which are not identified as matter-based may already be -so to speak - all over the place.

Maybe our so-called "natural laws" are just residue from stuff those alien beings have plugged in. Alien Mario 2525, or whatever game they are into this millenium.

 

[Timsup2nothin]

I think the critical development would be getting over stellar dependence, which I think is all in our heads anyway.

 

[Kyriakos]

Maybe the stars are alien megastructures. I mean ants seem to think that furniture are also natural formations.

 

[warpus]

My claim is we could mostly rule that out our batch of universes contains life-poor universes if we could randomly sample a universe and see if it has life.

That matches up to my position though, as I also think that if you find life in a universe, chances are that it isn't a life-only-once-poor universe, which is a tiny subset of life-poor universes.

I don't see the basis on how you can make that claim. We don't have a general handle on what kinds of universes are out there with what frequency. You can make guesses but that's assumption laden and shouldn't be taken as more than a guess, you'll always be able to make counter assumptions to skew it in a different direction and I see no firm method to arbitrate the claims.

Like you said yourself, chances are we are not in a life-poor universe, but instead probably one of the many other kinds. By implication a subset of life-poor universes (which life-only-once is) is going to be even less probable.

Let me make an example where this type of reasoning falls apart: Suppose you have two bags of marbles with 10 marbles each. One of them has 10 white marbles, the other one only 1. Now you chose one bag at random, take one marble out and it is white. The probability that the bag you chose was the one with 10 white marbles is 10/11 = 91%. But now consider the situation when there is one bag with 10 white marbles and 1000 bags with 1 white marble. Again you chose one bag at random and take out a white marble. In this case, because there are so many of the 1-white-marble-bags, the probability that you chose the one with 10 white marbles is only 10/1010 = 1%.

The issue I have with this is that you are setting up the universes ahead of time. You have to assume that you just don't know what sort of distribution it will be, so you can't just pretend you have 9 bags with only 1 white marble in it. That is just one of the many possible combinations of bags possible, you have to consider all the other scenarios as possibilities.

The way the bags are constructed, each time you decide whether you put a black or white marble in a bag, you roll a die. If a certain number appears, you put a white marble in, otherwise you put a black marble in the bag.

A situation in which 9 bags will only have 1 marble and all black marbles, and 1 bag containing all white marbles, is not very probable. Statistically speaking when constructing your bags like this, even if you don't know the probabilities, you will not expect to end up with such a situation after all the dice have been rolled. It's of course possible but if you repeat this exercise 100 times, you will not expect 1 of those situations to result in such a distribution of marbles.

The essence of my argument is that statistically speaking ending up with 1 white marble and 5.6 x 10^20 black marbles is not as likely as all the other possible scenarios, of which there are many. It's simply because "just 1 white marble" is one tiny data point, while all the other possible scenarios overwhelm it to a rather large degree. If you were a betting man, you would not bet on a bag containing only 1 white marble, you would assume that the weight of all the other scenarios is a far more likely situation

 

[uppi]

The issue I have with this is that you are setting up the universes ahead of time. You have to assume that you just don't know what sort of distribution it will be, so you can't just pretend you have 9 bags with only 1 white marble in it. That is just one of the many possible combinations of bags possible, you have to consider all the other scenarios as possibilities.

The way the bags are constructed, each time you decide whether you put a black or white marble in a bag, you roll a die. If a certain number appears, you put a white marble in, otherwise you put a black marble in the bag.

A situation in which 9 bags will only have 1 marble and all black marbles, and 1 bag containing all white marbles, is not very probable. Statistically speaking when constructing your bags like this, even if you don't know the probabilities, you will not expect to end up with such a situation after all the dice have been rolled. It's of course possible but if you repeat this exercise 100 times, you will not expect 1 of those situations to result in such a distribution of marbles.

The essence of my argument is that statistically speaking ending up with 1 white marble and 5.6 x 10^20 black marbles is not as likely as all the other possible scenarios, of which there are many. It's simply because "just 1 white marble" is one tiny data point, while all the other possible scenarios overwhelm it to a rather large degree. If you were a betting man, you would not bet on a bag containing only 1 white marble, you would assume that the weight of all the other scenarios is a far more likely situation

Statistics says you are wrong. Obviously, my bag setup was constructed to get the point across without making the calculations to complicated. But the point stands even with the setup you are proposing. So let's put some numbers to it that provide a counterexample:

Suppose the dice you are rolling is 20-sided and you put in a white marble when you roll a 20. You give that bag to me and I take one marble from it that turns out to be white. I calculated the odds how many black marbles were in that bag:
1: 0.63
2: 0.30
3: 0.06
4: 0.008
5: 0.0006
6: 3e-5
7: 1e-6
8: 3e-8
9: 3e-10
10: 2e-12

So if you gave me even odds that there is no other white marble in the bag besides the one, I would take that bet and statistically I should win it.

The reason is, that the chance that you rolled a 20 ten times is so low that even the higher probability of pulling a white marble from it does not even remotely begin to make up for that.

Now suppose you were rolling a 6-sided dice and put in white marbles on a 6. The same calculation results in the chance that there is no other white marble in a bag after having taken one white out is only 19%. The point is, when we have no idea what dice were rolled, there is no way you can make a statistical argument about the other marbles when a white one has been pulled from the bag.

 

[Kyriakos]

There may be one copy of the Odyssey in room x, and then another copy in room y. While one could, in such a case, if travel to y (or other means of establishing the existence of the copy is there) is possible, note that there are at least those two copies, even if it is there it doesn't add or subtract anything from the one we already know of. Books don't feel anything, thus they would be indifferent to others of a deemed tied type. Humans seem to want to play the role of object outside the object, and seek others to project more of their own self onto. Personally i don't think that getting into contact with aliens will solve anything at all, or even should mean anything at all; though it likely will spell the end of our species in one way or another.
Tbh, the human species is very self-destructive, and far too complicated for its avarice and needs. Mentally (not technologically) we seem to be on the same level as thousands of years ago. And the complexity keeps piling up below the surface. My intuition tells me that this likely is due to humans having been shipwrecked to this way of life, exactly so as to keep the inner complexity at some distant and haze-covered bay. Running away from the actual importance of the mental world.

 

[red_elk]

Suppose the dice you are rolling is 20-sided and you put in a white marble when you roll a 20. You give that bag to me and I take one marble from it that turns out to be white. I calculated the odds how many black marbles were in that bag:
1: 0.63
2: 0.30
3: 0.06
4: 0.008
5: 0.0006
6: 3e-5
7: 1e-6
8: 3e-8
9: 3e-10
10: 2e-12

You mean, the odds how many white marbles were in that bag?
I think you should use binomial distribution with n=10 (instead of 9) and p=1/20, discounting the possibility that all marbles are black (since we pulled one white already).
That gives the probability that there is only one white marble as ~0.785.
But conclusion is the same.

 

[uppi]

You mean, the odds how many white marbles were in that bag?
I think you should use binomial distribution with n=10 (instead of 9) and p=1/20, discounting the possibility that all marbles are black (since we pulled one white already).
That gives the probability that there is only one white marble as ~0.785.
But conclusion is the same.

That is what I did. However, I also accounted for the fact that we have already taken a white marble from the bag. This means we are not sampling the bags at random, but there is a preference for bags with a higher amount of white marbles in them, since those have a higher probability of producing white marbles. This factor reduces the probability of there only being one white marble to ~0.63.

 

[red_elk]

Ok, your results look like binomial distribution of the remaining 9 marbles. Which is correct, I guess, in case if you are picking a random white marble and then, see what bag it comes from. But if you are picking a random bag with at least one white marble, the result will be different a bit.

The phrase "You give that bag to me and I take one marble from it that turns out to be white" made me think you are sampling bags with equal probability.

 

[uppi]

Ok, your results look like binomial distribution of the remaining 9 marbles. Which is correct, I guess, in case if you are picking a random white marble and then, see what bag it comes from. But if you are picking a random bag with at least one white marble, the result will be different a bit.

The phrase "You give that bag to me and I take one marble from it that turns out to be white" made me think you are sampling bags with equal probability.

No, this isn't a binomial distribution any more. I calculated the conditional probability for situation when I have a randomly filled bag and pick one marble and random and it is white. This eliminates all the possible cases where the first marble would have been black, so it skews the distribution away from being binomial.

 

[red_elk]

No, this isn't a binomial distribution any more. I calculated the conditional probability for situation when I have a randomly filled bag and pick one marble and random and it is white. This eliminates all the possible cases where the first marble would have been black, so it skews the distribution away from being binomial.

Well, sorry for nitpicking - I trust that you calculated it using conditional probabilities, but your end result still looks very much like unskewed binomial distribution
Here's the table of binomial PMF for n=9, p=1/20 and k in [0,9], and it seems identical to your results:

Spoiler :

0 0.6302494097246094
1 0.29853919408007784
2 0.06285035664843745
3 0.007718464851562495
4 0.0006093524882812499
5 3.207118359375e-05
6 1.125304687499999e-06
7 2.5382812500000008e-08
8 3.339843749999995e-10
9 1.9531250000000034e-12

Anyway, that's most likely how it should be in your experiment. Just unexpected side effect. We essentially throwing away white marble (since it cannot be considered as independent observation) and sampling the remaining 9 of them.

 

[uppi]

Well, sorry for nitpicking - I trust that you calculated it using conditional probabilities, but your end result still looks very much like unskewed binomial distribution
Here's the table of binomial PMF for n=9, p=1/20 and k in [0,9], and it seems identical to your results:

Hmm, you right. I assumed it was a skewed distribution, but I didn't compare it to the binomial distribution for n=9 and as you correctly point out, they are the same. Maybe it is because the probability of each of the marbles is independent of each other, so the conditional probability reduces to an independent probability again. I just checked for p=1/6 and there the same thing happens (conditional probability equals probability for n=5).

So in this case, with the most obvious distribution for filling the bags, the fact that we have found a white marbles tells us exactly nothing about how many other white marbles are in the bag. Interesting. This underlines the point that having found life on earth tells us exactly nothing about how probable life is in the rest of the universe.

 

[red_elk]

So in this case, with the most obvious distribution for filling the bags, the fact that we have found a white marbles tells us exactly nothing about how many other white marbles are in the bag. Interesting. This underlines the point that having found life on earth tells us exactly nothing about how probable life is in the rest of the universe.

I agree! Interesting and somewhat counter-intuitive result.
The life on Earth is a necessary prerequisite for our observation, so the distribution of other habitable planets in our thought experiment doesn't depend on it at all.

 

[MagisterCultuum]

Consider that the wheel was never invented in South America, for 2 reasons.. IIRC.. The terrain and a lack of animals to pull anything with.

I'm not really sure which "side" this helps though

They actually did invent wheels, but only used them in small toys rather than big wagons.

 

[warpus]

I just got back from a family baptism excursion/extravaganza so I have only been able to read uppi's post. I saw earlier that there was one, so I wanted to put aside some time tonight to read it, understand it, and respond to it. I have done so below, but unfortunately I have not had any more time to read any of the subsequent posts, it looks like this has been discussed quite a bit more, so by the point I post this my comments might very well feel a bit stale..

So if you gave me even odds that there is no other white marble in the bag besides the one, I would take that bet and statistically I should win it.

In this situation you know what bet to make, because you have seen the odds and have as such calculated the expected value. Assuming you did the math correctly (I would assume so! but I just did not check). Plus you have a rather small bag.

If you don't know the odds, you bet that there are more white marbles in your bag, unless it's a fairly small bag. (Small bags can distort things quite a bit here. For instance I can easily roll a 4 with 6 sided die. Just give me like a couple attempts, man. But I don't personally know anyone who is able to pick 6 out of 49.)

If someone gives me a giant bag, and I pick a white marble out of it.. A betting man will see two possible scenarios here:

A. I got really lucky! The bag had only 1 white marble and 50 billion black ones, and I happened to pick out the white one. I have never been this lucky before, but it's possible that today is the day

B. 50 billion marbles and I got the only white one? It makes a lot more sense to bet that there is at least one more white marble in the bag. Easy money!

 

[NukeAJS]

Interstellar FTL travel might be possible if you could shrink things really, really small like elementary particles small and then shoot them through a mini wormhole and then have them somehow reconstruct on the other side? If you wanted to get back up to macrosize, that shouldn't be a huge problem as your micro-particles would look for some kind of planet and then start upscaling itself. Eventually, you'd be able to recreate "yourself" on the other side assuming that you had all the necessary ingredients.

DNA probably isn't small enough to do the traveling bit, but it certainly fits the bill for the self-recreation bit.

The actual FTL part would be extremely quick but the wandering through space until you hit a planet that has the necessary elements could be mindbogglingly or improbably long. However, once it did happen, it should only take a couple million to billion years to recreate "yourself."

The main problem with this idea isn't whether it's possible -- it probably is (we just can't find, let alone "aim", mini wormholes). The main problem is what do you consider "you?" If we mean a bit by bit copy -- this obviously isn't it. But if you have a much bigger version of what you is -- this certainly fits the bill.

 

[Manfred Belheim]

If someone gives me a giant bag, and I pick a white marble out of it.. A betting man will see two possible scenarios here:

A. I got really lucky! The bag had only 1 white marble and 50 billion black ones, and I happened to pick out the white one. I have never been this lucky before, but it's possible that today is the day

B. 50 billion marbles and I got the only white one? It makes a lot more sense to bet that there is at least one more white marble in the bag. Easy money!

Yeah but you only even exist to talk about it if you pick out the white one. Or rather if someone else picks out the white one for you. If you have a bag of 50 billion black marbles and 1 white one, then painstakingly pick them out of the bag one at a time, you will eventually pick out the white one.