Tag Info

Hot answers tagged

4

I'll answer your question with an analogy. Imagine a really small balloon, so small that it occupies a point. Now, imagine that the balloon is expanding uniformly outward from that point. Note that that central point is not part of the balloon. It's the same idea as to what happened with the BB. In this analogy, the universe is the surface of the balloon. ...


3

The link Qmechanic has suggested is a duplicate and does discuss the question you ask. However there is another point that is worth making here. In general relativity we describe the universe as a manifold equipped with a metric, and the metric is the FLRW metric that desciribes expanding spacetime. However the FLRW metric does not include the point(s) at ...


3

The problem is analogous to the physics of gases. Do we need to describe the chaotic motion of every molecule before we can determine overall properties? No.


2

I'm not sure if that touches your question, but the universe is thought to be non-chaotic in the long term behaviour because of some anisotropy in the initial conditions (at least this is the general opinion). I watched a cool vid about that a couple of days ago. The point for which I agree with you, is that if looking at a certain situation, in general one ...


2

You seem to be misunderstanding the depth of the prediction we've made of the past in saying that the Big Bang happened. You do make a very valid point that chaotic systems even with as few elements as the solar system are practically impossible to past-predict (I'm going to start using the word "postdict"1 because it makes me feel better). I'm more than ...


2

The problem with this question is in the premise that where dynamical chaos is applicable nothing is predictable or can be extrapolated to the past. This is a wrong premise. Take this demonstration of a chaotic system. Note that it is computer simulation and of course it fits real data. Computer simulations are time symmetric, so the individual points can ...


1

Gravity is the retarding force. I don't think that non-conservative forces are customarily considered.


1

it must have started from a single point This is a common misconception popularized buy the media. Imagine this grid: Imagine each square getting larger. If you think about it, you will see that each point on the grid is expanding. The grid is the universe. Each point on the universe is its own "singularity".


1

The balloon analogy imagines the universe as a 2D surface expanding around a central point as it moves through a 3rd dimension of time. This may be the origin of confusion as in reality there is no 2D surface of expansion, like a wave front, but rather an expansion of 3D spacetime, wherein every point in space quite literally is its own central point from ...



Only top voted, non community-wiki answers of a minimum length are eligible