After reading Seth's awesome thread about the Giant Magellan Telescope (great read by the way) I saw this comment by him: It got me thinking. Scientists are now beginning to think that the universe is infinite in size. But I do not share this view, and here's why. I'd like first let you consider this idea: Think of this - the universe is expanding (which pretty much the entire scientific community agrees is true) and it is widely regarded to have originated from a single, infinitely small point (singularity) some time in the past - estimates suggest this to have been 13.8 billion years ago. Now, if the universe is infinite in size, and the expansion is at a finite speed, how long SHOULD it have taken to get to this point? An eternity. So that throws the 13.8 billion year idea out the window. It also raises the question - so if the universe is infinite in age, how are we still travelling forward in time? This suggests that we have an infinite length of time before us. But this cannot be true, since we can never be in such a situation. How can it have been an eternity ALREADY, when we have already surpassed this eternity? And again. And again. And again. It's like being a falling domino in an infinitely long domino chain - what caused you to fall? The domino before you. And before that? The domino before that one. In an infinitely long chain, this process will go on forever. There cannot be a beginning if an infinite length of time has already passed. Infinity can only ever exist in the future, never the past. Belief in the Big Bang nullifies the possibility of an infinitely old, and infinitely large universe. There is yet another possible proof that the universe is NOT infinite. This proof derives from the Second Law of Thermodynamics. This widely accepted law of nature suggests that over time, the entropy of the universe will increase. What this means is that with time, comes disorder. Put simply, thermodynamic entropy measures the amount of useable energy per unit mass, but kind of in a reverse manner. At total entropy there is no available energy to be used. Even though the energy has not been destroyed ("energy can neither be created nor destroyed"), it has dissipated so much that it can no longer be used. It is in this way that temperature, pressure and density naturally "spread out". Entropy-increase correlates with a change in time. For example, the entropy of deep space is greater than it was a few billion years ago. I have previously shown that if the universe is truly infinite in size, it is also infinite in age. That means an infinite length of time has passed - but surely an infinite period of time means that we should have already reached total entropy? The universe should have already reached a heat death - this describes a universe with total entropy, and consequently a universe existing in absolute zero temperature (-273.15C -- the theoretical temperature at which molecules have 0 kinetic energy), where matter and heat have entirely dissipated. But look around you. This simply isn't true. There are objects and visible matter, and we're not living in absolute zero temperature. This is a proof presented in front of you - the universe cannot be infinite in age, and so it cannot be infinite in size. These proofs were made using the assumption that the universe is expanding, and that the Second Law of Thermodynamics is correct. Considering these two things are widely accepted, it still baffles me that some physicists believe in an infinite universe. This belief is contradicted by these two theories. I hope this thread sparked some thought in you guys. Here are some fascinatingly deep and mysterious questions to consider: - Was the Big Bang really an occurrence? - Is the universe really expanding? - How valid is the Second Law of Thermodynamics? - Is time even real? Thank you for reading!
Re: The Universe is NOT Infinite [Proof] Read my alternative theory on my google+ account "Chuck Urwiler". It's way too much to write out (I am a bit lazy). Just an idea I came up with a little while back, and I think it's pretty cool personally. It's called "Black Phoenix Theory"
Re: The Universe is NOT Infinite [Proof] @THE-SWORD Please edit your comment so it doesn't quote the OP. I'm sure no one appreciates the extra scrolling. EDIT - Thanks
Re: The Universe is NOT Infinite [Proof] You don't have to quote the whole damn thing to reply to the op :roll:
Re: The Universe is NOT Infinite [Proof] Well, NASA... Better get working on that warp drive, I want to see if I bounce off the edge of the universe! Great read, and a wonderful expression of fact (keep in mind a fact doesn't have to be true, a fact is something that can be proven, whether it be true or false). I am of the opinion that time cannot exist, because it is infinite. It has infinite past and infinite future. With that belief, time has infinite speed, but it also doesn't move. Size cannot be measured, because there is no ratio to infinity. You cannot compare something to infinity, because it is infinitely bigger or smaller than whatever object there is in existence.
Re: The Universe is NOT Infinite [Proof] Don't mean to badger but these are fav topics. Time is a human construct .
Re: The Universe is NOT Infinite [Proof] Basic physics law of inertia A body at rest tends to stay at rest A body in motion tends to stay in motion. As for a finite universe there is a theory there r multi-verses. This has neither been proven nor disproven as of yet.
Re: The Universe is NOT Infinite [Proof] Look at it this way - how do you see? By photons. There is no way of knowing what objectively the universe looks like because we are bound by human sensory input limitations. The same goes with the concept of time.
Re: The Universe is NOT Infinite [Proof] This is basically entropy as well, but it isn't (it kind of constitutes as heat death). Einsteins theory of relativity states this, and the universe is expanding. But, because of gravity, and the finite size of the world, it is decelerating, and will soon reach a point of no expansion. At that point, we either reach total entropy, or the universe will then start to shrink, and because everything will start getting compressed, the kinetic energy in everything will increase to a proportion that nothing can survive. <--- heat death.
Re: The Universe is NOT Infinite [Proof] What is more terrifying? We are alone in this universe Or We aren't alone in this universe
Re: The Universe is NOT Infinite [Proof] Ahh but is there a force outside of the universe acting against it, and by the very definition of slowing it down to the point of no expansion define its boundaries?
Re: The Universe is NOT Infinite [Proof] Actually, recently studies seem to suggest that the universe is strangely acceleration in expansion. They've proposed this is as a result of "dark energy", which I've heard is some theoretic "thing" that works against dark matter. It's an incredibly interesting and complex topic that I'm yet to research into.
Re: The Universe is NOT Infinite [Proof] I love this topic, great explanation, you actually got my adhd brain to read the post
Re: The Universe is NOT Infinite [Proof] I'm going to look into that Sounds as intriguing as what we can find with the GMT
Re: The Universe is NOT Infinite [Proof] I guess that's another proof that the universe is finite. If the universe's expansion is either decelerating or accelerating, and it's still expanding, it proves that the universe isn't infinite in age. If it were, the expansion would have surely stopped?