Has the Big Crunch theory been disproven?

Question

Why was the Big Crunch previously the generally accepted theory for the fate of the universe? Was there any actual evidence supporting it? What made physicists move away from the Big Crunch and towards an infinitely expanding universe and Big Freeze?

Answer 1

Yes. Now we have the Big Freeze.

Answer 2

Not that long ago - figure 20, 25 years - it was thought that the Big Bang *should* be slowing.... the sudden expansion acted something like a bomb burst (hence the cheeky name), and that the matter within the universe should be pulling on all the other matter, slowing that expansion.... The big question was, did the matter flying apart from all other matter have enough velocity to continue expanding forever, or was it going to stop at some point, then reverse?

After years of study, it was actually discovered that the expansion isn't slowing down as expected, but speeding up - which was a surprise for many. We don't know *why* this is happening - the effect is called "Dark Energy" - Dark, in that we don't know what it is, and Energy, in that the acceleration is due to some energy...



So, right now, it's not *looking* like the Big Crunch is currently on the table... While there must be some attraction of matter in the universe, limiting the expansion's speed - there's another, unseen component that is stronger, causing the expansion to accelerate.

Answer 3

At this point dark matter has been ruled out by several theorists. With out dark matter or absolute mass there does not appear to be enough known mass in the universe to generate enough gravity to stop the expansion of the universe.

Actually given the known mass in the universe and known energy in the universe the singular and big crunch theories both can be considered disproven. The dispersal pattern of mass and energy does not match a singular. This means that science courses can not keep up with the actual status on our models. What students are taught today in science in this case is already known to be wrong, but it allows the perpetration of myth.

Answer 4

The 1998 observation of the accelerating expansion of the universe, aka dark energy. Something else could be discovered to make it shift back to Crunch. Who knows.

Answer 5

The big crunch is a hypothesis. There is nothing to support it . Apart from the Andromeda galaxy, most objects are getting further away from us and at a faster rate due possibly to dark matter and dark energy

Answer 6

Yes, ..., Big Crunch has been disproved.



Basically, there id not enough mass in the universe to re-attract the universe to itself. Also, with the acceleration of expansion of the universe increasing do to dark Energy, it is more likely that the Universe will end with the Big Rip.

Answer 7

The Big Crunch vs the Big Freze has always been critically dependent on the average energy density of the universe. An energy density at the so called 'critical' energy density would result in an infinite flat universe. Energy density less than that critical density would lead to a negatively curved universe that would continue to expand forever. Energy density greater than that critical density would lead to a positively curved universe which would eventually collapse to the Big Crunch.



There have always been issues related to estimating what the energy density of the universe is, but it was believed to be close to that critical density. It had been believed that regardless of the energy density, gravity would be acting against the expansion, overcoming the expansion in the case of energy densities greater than the critical density (resulting in the Big Crunch). Some time ago however, it was observed that the expansion of the universe was accelerating. That has been attributed to so called 'dark energy'. The accelerated expansion of the universe from dark energy can be explained by General Relativity solutions at the cosmological level.



There are two ways the cosmological general relativity solutions can result in a universe with accelerated expansion. Both are based on the idea that the energy density of dark energy remains constant as the universe expands. That means the total amount of dark energy increases with the increase in the volume of the universe. It can be shown that if this is true, a negative pressure is generated that will accelerate the expansion. Some argue against the need of the concept of negative pressure, since it can also be shown with general relativity that one can explain the accelerated expansion by simply requiring that dark energy remain constant as the universe expands.



So, if observations of accelerated expansion are correct, there is no accepted physics that would explain how the process could reverse itself (expansion decreasing again). So, it is likely the big freeze is inevitable.

Answer 8

We can say that the discovery of the expansion of the universe led to a another discovery, (even if not totally confirmed but logically should exist), that of Dark Energy.

Astronomers and astrophysicists are now dedicating more and more time studying the phenomenon. Dark Matter, too, is another previous dilemma: it is holding the stars in the galaxies and not making them escape from them.

So scientists have much concern now in finding out the "source" of these two phenomena. The big crunch was not a dilemma. It was merely a hypothesis reached by an "obvious" physics problem: if something started to make the universe expand, gravity will sooner or later make it contract.

Answer 9

I don't remember the big crunch ever being the generally accepted theory - it was one of three possibilities, and never the front runner.