Can Stephen Hawking really claim that there was no time at all before the Big Bang?

cdux

Can Stephen Hawking really claim that there was no time at all before the Big Bang when a black hole can have an outside observer on normal time? And what about other Universes in relation to our Universe? Don't they have a normal time at the time of our Big Bang?

Naty1

No one yet knows exactly what the BIG BANG was. It lies outside our best current models. No one knows if time existed before such a bang. No one knows exactly what caused the big bang.

And there are different ideas about what existed before such a bang, if anything. No one knows if there was a single big bang, multiple big bangs, or simply a series of repeated finite bangs. The standard model of cosmology used in these forums is the Lambda CDM model which applies observed parameters to the more general FLRW cosmological model, and these start after the big bang. They do not explain the initial bang itself.

It is believed everything we currently observe around us, all the particles and different energies, for example, like gravity, the strong force, the electromagnetic force, maybe time and space, originated from such an initial high energy and unstable beginning in what is called spontaneous symmetry breaking.

Many of the core ideas of the Big Bang, like the expansion, the early hot state, the formation of helium, and the formation of galaxies, are derived from and confirmed by observations that are independent of any cosmological model.

So we know our models fit what we observe pretty well because we made them that way; whether they are the final solution remains an open question. The cosmological models, theories of the very large, are based on Einstein's General Relativity; It may be more likely that what caused the big bang will eventually emerge as a result of the theory of the very small, related more closely to quantum theory. Stay tuned!

rashi

Big bang is not fact just a theory, for sure not start of the universe or time.

phinds

I agree completely with both of those statements, but I feel that saying the big bang is "just a theory" is overly dismissive.

It is a theory in the same sense that evolution is a theory. It fits all the facts and is the best theory we've got.

Theories in science are ALWAYS "just theories" because they are always open to being disproved.

rashi

In a simple logical way for teh big bang to be happen, we need mass, energy and space.

Where they come from? obvoisly it was there before the big bang, clearly Big bang is not the start of the universe then?
Even the law of nature were existed before the big bang!

phinds

You are just making this up. You have no evidence for any of this and it is pure speculation on your part. Personal theories are not allowed on this forum.

There ARE theories that included some of what you say, but you need to reference those theories, not just say something is true becuase you think it is true.

rashi

Science is the subject where opinion and speculation realy matter! Where is your evidance to disprove me. Do not just say 'there are theories'!! wheer are they?

phinds

You misunderstand how this forum works. When you make a statement, YOU have to back it up with references. We don't have to disprove it.

Personal speculation is not allowed on this forum.

HallsofIvy

"Opinion and speculation" matter as the basis for theories that then need to be proven by experimentation. You asserted several matters as if they were fact. It is your responsibility to support them.

Drakkith

Logic? The universe cares not for our logic. It is we who must bend our logic to fit the universe. This is why pure philosophy and logic don't do squat to figure out the natural world. One MUST have empirical evidence.

Mordred

How so? Energy does not require space to exist, Energy can form into matter so mass would not have been necessary. You cannot have time without mass so Time isn't even a factor.
When we refer to the universe we are stating the visible, Observable universe. There have been plenty of theories as to what lays beyond our universe. However as we have no way to detect anything beyond our universe assuming there is other universes. Scientists will not state any definitive answer to where the energy came from for the big Bang. All current accepted theories are based on countless tests, observations etc. The CMB confirms that space did in fact start from a point and inflated. The big bang theory at one time was one of the more controversial theories. After years of arguments its born out to be the most accurate to those observations.


On a side not note of this If the Higgs field proves true and its certainly looking that it will do so, Then in order to get mass there would have to first be a Higgs field. I'd be curious at to a projected order of formation of the fundamental particles leading up to the first mass particles. However thats a different post lol. Particularly since its evident that the standard model of particles is no where near complete.

Naty1

Post #11 is full of more speculation.
If you guys don't stop it, this discuss will be closed.

phinds

Nonsense ! There is not only no evidence that it started as a POINT, it would not make sense for it to have done so. It started as an incredibly hot dense "plasma" of energy of undetermined size.

If you are going to make definitive statments on this forum you need to get your facts straight.

Mordred

Every article I have ever read describes it as an infitismally small point. Perhaps all those articles are wrong.
here is one example

http://burro.astr.cwru.edu/stu/cosmos_bigbang.html

perhaps we should look more at the intent of a post rather than the wording itself if my post was poorly worded I apoligize for that. However I do not visit a forum to get lectured but rather to learn if that is against forum policy to try and assist others, and then get lectured for simple mistakes in wording then iwill find a more flexible forum.

Naty I had no speculations in my post we do not care what is outside our universe as we cannot ever examine it other than looking for a collision in the CMB. Many papers describe that without space there is no time. You cannot have spacetime withut matter so where is the speculation????

Drakkith

Don't let Phinds upset you. He is notoriously grumpy in the mornings, afternoons, and nights. In fact, I recently went to dinner with him and his teeth leaped out of his mouth and nearly bit my finger off! I had to leap from table to table using a makeshift rapier to defend myself! It as quite a spectacle!

What he means is that the singularity pointed out by these articles is a result of our math breaking down, most likely because our knowledge of physics at that density and energy level is incomplete. Word around the forums is that most professionals do not believe there was an actual singularity, but that we simply need to learn more.

Naty1

Mordred:

You will be 'lectured' here when you post inaccurate, unproven or misleading statements. In class, you get points deducted for mistakes; here you will be critiqued.
[I've gotten my share of 'lectures'....]

Man up when you are wrong and you have a good chance of learning something. That's what's so good about this forum; if I say something crazy, somebody will hopefully catch it and set me straight.


On the other hand, when you read something like

. it is understandable you would be misled. No reputable physics source would state the origin of the big bang that way.

[By the way, I only read a few paragraphs from that source and but not like it. Very loosely written, I suspect hardly edited. One of the positive aspects of these forums it that you will be referred to scientifically correct sources. One solid source I learned from these forums:
http://www.astro.ucla.edu/~wright/cosmolog.htm


If the big bang were a POINT,say in space and time, why do we see relic radiation the same from all directions?? That is what has led scientists to conclude it happened everywhere. [Either that or we are by mere chance at the very center of the universe?]


A few other speculations you posted:
No such theory exists.


no, when someone refers to the portion of the universe we can observe, you will almost always see it in the context of 'OBSERVABLE' universe. For example, Wikipedia says it this way:

http://en.wikipedia.org/wiki/Univers...rvable_reality

[QUOTE][The Universe is commonly defined as the totality of existence,.....The farthest distance that it is theoretically possible for humans to see is described as the observable Universe. ...Since we cannot observe space beyond the limitations of light (or any electromagnetic radiation), it is uncertain whether the size of the Universe is finite or infinite./QUOTE]

But even what is 'observable is tricky...to learn more you can search these forums or do some reading on 'horizons'. [Some parts of the universe are causally disconnected from others.] Two common ones are the Hubble and cosmological event horizons, and of course there are also black hole horizons. Objects at the Hubble limit have a 'speed' of c relative to an observer here on the Earth but the Hubble parameter is decreasing as time passes, so that the Hubble limit does not, in general, coincide with a cosmological event horizon. This means in the future we can detect signals [observe] of some entities receding at superluminal [greater than c] speed...somewhat past that horizon. A cosmological event horizon is one beyond which we'll never detect signals.
The 'universe' encompasses all that.

Mordred

If the big bang were a POINT,say in space and time, why do we see relic radiation the same from all directions?? That is what has led scientists to conclude it happened everywhere. [Either that or we are by mere chance at the very center of the universe?]

I never stated it was a point in space/time nor did the paper I posted as far as I read I took it to mean that space/time was infitismally small. but anyways
a question on that in regards to CMB detection. with the expansion of space time the CMB would also expand at the same rate would it not? So the CMB would never show it as a point that wasn't my intent on the mention of the CMB. I probably needed to be more specific on what they detected in regards to the CMB to support the big bang model.
Thank you for pointing out some of the errors or what you referred to as speculative, Your previous comment makes more sense now