User talk:2603:9000:9009:ECD1:B17C:397A:7BEE:B2F8

There was no singularity The part in the main description about a big bang singularity is outdated and wrong. It says, "Extrapolating this cosmic expansion backwards in time using the known laws of physics, the theory describes an increasingly concentrated cosmos preceded by a singularity in which space and time lose meaning (typically named "the Big Bang singularity")"

Only some of the "laws of nature" were taken into account: for example, none of quantum mechanics was taken into account. Further, the main "law of nature" that was used was general relativity, which breaks down before reaching a singularity. That means the conclusion that a singularity existed are not based on the laws of nature, but (a) only some of them, and (b) the main one used is known to break down at the extremes where a singularity would come out mathematically.

Here are some physicists supporting the above, or actually stating parts of it.

- “We know that Einstein’s theory of general relativity is a good description of the universe. And if we take his theory as being perfect and run the clock backward, then the entire visible universe is compressed into a volume of 0 size. Literally, mathematically, 0.

But - and here’s the super key point - we know that general relativity doesn’t work for something with 0 size. The theory definitely breaks under those conditions.

So what’s really true? Well, we actually don’t know. We don’t’ have a theory of quantum gravity. So we don’t know what happens to space compressed to such tiny sizes. Maybe space becomes quantized. Maybe the meaning of space, well, doesn’t mean what we think it does. But we can be certain that a mathematical singularity of 0 size - with no space and no time - is completely wrong.”

(28 Subatomic Stories: Before the Big Bang. Fermilab.  Fermilab’s Dr. Don Lincoln.  Starting at 10:18) -

- “Observations of the retreating galaxies by Edwin Hubble and Vesto Slipher, combined with Einstein’s then-brand-new general theory of relativity, revealed that our universe is expanding. And if we reverse that expansion far enough – mathematically, purely according to Einstein’s equations, it seems inevitable that all space and mass and energy should once have been compacted into an infinitesimally small point – a singularity. It’s often said that the universe started with this singularity, and the Big Bang is thought of as the explosive expansion that followed. And before the Big Bang singularity? Well, they say there was no “before”, because time and space simply didn’t exist. If you think you’ve managed to get your head around that bizarre notion then I have bad news. That picture is wrong. At least, according to pretty much every serious physicist who studies the subject … We used general relativity to rewind the [expansion of the] universe. But we already know that despite its incredible successes, GR is an incomplete theory. At the crazy densities and temperatures of the [assumed] Big Bang singularity, and just after, GR comes into terrible conflict with quantum mechanics. … [T]he upshot is that we just don’t know how the universe behaves in those conditions. But we do know that pure general relativity is not a good description and so we probably shouldn’t believe its prediction that all space was compacted into a single point and that this is where time started.”

(Did Time Start at the Big Bang? PBS Space Time.  Second part starts at 8:42) -

- "I don't think anybody believes that the universe started off with a singularity. That just tells us that Einstein's classical theory of general relativity breaks down. So that classical theory of gravity doesn't apply when you get to very high energies.  So it's replaced by some consistent quantum theory of gravity." (George Efstathiou. Before the Big Bang 4: Eternal Inflation & The Multiverse. Stating at 31:37) -