Yes, the internal arrangement will change . . . and this part of my point, as I equate the inside of a perfectly sealed box (nothing in or out) with the Universe.
I might not have communicated well (I am autistic, and sometimes I have trouble expressing myself).
So, let’s go back to Brownian motion.
If I attach an elastic cord to a pollen grain and anchor the other end to a fixed surface, and the Brownian motion pulls the grain against the resistance of the cord and the grain sticks to whatever it bumped into . . . then where does the potential energy in the elastic cord come from?
Lifting the jar (with an extremely unlikely series of coherent collisions) in the Earth’s gravitation field, is work that the gas has performed, and it’s internal energy (temperature) will be accordingly reduced.
eta: this video and the couple after it in the series might be helpful. It is a rather confusing subject:
You’re talking about freak physics here. You wait until freak things happen. But then you neglect to wait until the next freak thing happen, namely that the internal state of the velcro lets go of the jar, and the surface the pollen grain sticks to lets go. If you allow one freak thing to happen statistically, you should also let the other freak thing happen, negating the first. Averaged over (extremely long) time, you are back to the initial state, and averaged over time, nothing has happened.
Of course it will, as the heat will be turned into potential energy in the spring. The point of the thought experiment is after this happens, we have a gradient that didn’t exist before.
This is what I believe happens in an infinitely old Universe.
Every once in a while, somone hits a billiard ball on a pool table of scattered balls, and they all rack themselves up.
That is actually a point I hadn’t considered. I feel (note that I didn’t say “know”, as we all understand that wanting something to be true and actual truth are two different things) that you’re wrong, so I have to think about your objection, and get back to you.
My take is that the overwhelmingly vast majority of the time, The Universe is in a state of heat death, or maximum entropy (ie: “nothing happens”).
Very, very, very rarely, entropy may decrease, and the steadily winding down of the Universe is what we see as the 2nd law of thermodynamics until we are back at maximum entropy (or heat death).
Oh by the way, the way water molecules evaporate at temperatures below 100 C works in a very similar way. Once in a while though an unlikely series of collisions, one of the molecules will gain considerably more speed and break away from the rest of the liquid water and fly away (it has evaporated into a gas). Since the fastest molecule in the set got away, the average speed of the remaining molecules must be lower than it was before the fastest one got away. This is where the cooling comes from that is associated with evaporation.
Yes, this is the conventional interpretation, and what will normally happen. But what @Kevin_Levites was talking about was the corner case where, by freak chance, all molecules have a position/velocity vector that is near/points towards the lid. Highly unlikely, yes, but still a valid microscopic state. It would, of course, quickly develop into a more likely state due to collisions etc. My gut feeling is that if you base your argument on the statistics of waiting long enough for this to happen, you should also wait long enough for other freak states to occur, in order to get valid sampling for the statistics and a proper time average. But in reality this whole scenario reminds me too much of a Maxwell demon-esque situation that I’m quite unwilling to accept it actually happening.
Of course, the braneworld cosmology I’ve mentioned several times here postulated by Steinhardt & Turok provides a mechanism for the sort of cyclic universe you’re thinking of …
Too bad there isn’t any evidence for branes, nor for most of string theory for that matter. It seems like an interesting theory, but without any way of testing it, strictly speaking it should really be a conjecture and not a theory.
My understanding of that is an analogy tied to the laws of logic. There is no evidence for them as well, but they are useful.
YEP! The time to believe something is ‘After’ it has been demonstrated. I can not argue with that… So, I just have a ‘Wait and see,’ attitude. I find the stuff interesting.
Actually, as I’ve stated repeatedly, Steinhardt & Turok’s braneworld cosmology produces a testable prediction, namely that the power spectrum of primordial gravitational waves will be biased toward short wavelengths. Which is why scientists are busy building gravitational wave detectors.
I think the article mentions that towards the end. The tests have not yet been conducted but even if they fail, string theory is going to be around for a long time. (I read the article in the AM and its 11PM now. I don’t want to read it again. But I think that is what I read.)
Gravitational waves are extraordinarily difficult to detect, so I wish them luck.
Although the original ekpyrotic theories, like Steinhardt & Turok’s, were based on string and M theory, most of the newer ones are not, and I expect a correct one, if it exists, will fall into this latter category.
String theory originally had lots of promise as a theory offering a simple explanation for the large number of particles in that it modeled all particles as simple open or closed strings vibrating in various modes. Then it started requiring things like 26 dimensions (at first) or 10 or 11 dimensions (later) and even objects other than strings (branes), not to mention the 10 to the 500th possible vacuum states.
String theory has been around now for what, nearly 50 years, with hardly any concrete results beyond a bunch of complex mathematics (it’s somewhat telling that Witten has won the Fields Medal, not the Nobel Prize…) As Feynman said, “string theorists don’t make predictions, they make excuses”.
