The speed of light, etc

[Sephiroth]

The "Big Bang" is highly controversial, imo. The expansion has an empirical basis of observation of the red-shift of light from receding galaxies. There is some evidence that the expansion is taking place at an accelerating rate, which is not consistent with big-bang.

The scientists are beginning to bottom out what the elementary particles do and how they combine in chaos to create matter as we know it. We are made of that matter and our molecules and bodies all hang together notwithstanding the atomic forces going on in said atoms/molecules.

Eventually, I expect all that research to reach a hard stop when everything about matter, elementary particles is known - in the frame of the tangible universe.

The rest will be speculation - like how were the elementary particles created? Have they always existed and were never created? After all, without these elementary particles, we couldn't be having this discussion.

Originally Posted by Sephiroth

The "Big Bang" is highly controversial, imo.

Well the thing about opinions is everyone has one.
There is certainly some debate over it, but "highly controversial" ? Not really.

The simple fact is we dont know, and since we cannot time travel, almost certainly never will.
All we can do is build theories that match the things we know and/or can observe. Those theories change over time.

[idi banashapan]

Originally Posted by Sephiroth

First, though - a correction: Blue shift occurs when an object is approaching an observer, not receding. Local galaxies might be approaching but expansion of the universe outside any locality is generally accepted due to the red shift observations.

You're absolutely correct. My brain skipping ahead and leaving the fingers behind! Thank you for correcting

---------- Post added at 21:58 ---------- Previous post was at 21:56 ----------

Originally Posted by GrimUpNorth

If the universe is expanding, and everything is moving away from everything else, how can we be on a collision course wth Andromeda?

I've watched every episode of How The Universe Works on Discovery and still don't understand it.

If that was all it that was needed to understand the universe, we would all be experts!

[Sephiroth]

Originally Posted by downquark1

The universe is seen to be expanding, if you run it in reverse it looks like it came from a point. That is empirical backing.

There are other problems with the model but that bit is uncontroversial.

I wish that were so; it would solve a lot of problems associated with creation. But that is no longer the scientific consensus - hence it is a controversial assertion that there was a big bang.

[daveeb]

I think the most controversy lies in how the proposed big bang came about and what, if anything, preceeded it. The true answer is possibly beyond any current understanding.

[Sephiroth]

The stuff in the universe has always been there should be within general understanding. I wonder what the reason is for resistance to that notion?

[downquark1]

Originally Posted by Sephiroth

The stuff in the universe has always been there should be within general understanding. I wonder what the reason is for resistance to that notion?

The old logical paradoxes are. If the universe is eternal why hasn't everything happened yet? If the universe had a beginning then what caused it.

[Sephiroth]

Originally Posted by downquark1

The old logical paradoxes are. If the universe is eternal why hasn't everything happened yet? If the universe had a beginning then what caused it.

Surely, if the universe is eternal, anything can happen within the bounds of the laws of physics (whatever those bounds may be). If there's a future (which there obviously is) there is still time for more things to happen.

The logic of the universe that I'm putting forward is that it cannot have been created because anything that might have caused its creation then has to be explained; which it cannot be.

The big bang is not precluded by my logic it's just that it needn't have happened. If it did happen, then logically I surmise that it happened as soon as the singularity had formed because the elementary particles in there would be in chaos from which the instability could have occurred. But it comes back to one thing: The material of the universe has always existed together with any means of creating matter to replace that which is mutually destroyed.

[downquark1]

Right so you are advocating a steady state model. https://en.wikipedia.org/wiki/Steady-state_model

It may be true but we have no understanding how the additional matter would come into existence or any confirmation that it happens.

[Jaymoss]

Originally Posted by Sephiroth

Surely, if the universe is eternal, anything can happen within the bounds of the laws of physics (whatever those bounds may be). If there's a future (which there obviously is) there is still time for more things to happen.

The logic of the universe that I'm putting forward is that it cannot have been created because anything that might have caused its creation then has to be explained; which it cannot be.

The big bang is not precluded by my logic it's just that it needn't have happened. If it did happen, then logically I surmise that it happened as soon as the singularity had formed because the elementary particles in there would be in chaos from which the instability could have occurred. But it comes back to one thing: The material of the universe has always existed together with any means of creating matter to replace that which is mutually destroyed.

Thing is when something can not be explained literally nothing can be disclaimed therefore it might have been created no one can say for sure it was not . They can profess it loudly often violently but no one knows

[Sephiroth]

If the elementary particles that are generated by collisions in supernovae (or something) create replacement matter, which is one of the theories going round somewhere, then we have the answer.

I don't think that's such a big "if". Neutron Stars, for example, when they explode, Neutrons break apart; particles collide and stuff is formed. Obviously something has to happen when particles collide. Seems logical to me.

Originally Posted by Sephiroth

The logic of the universe that I'm putting forward is that it cannot have been created because anything that might have caused its creation then has to be explained; which it cannot be.

This reasoning is not logical.

I get where you’re coming from, that there cannot ultimately have been a first moment, because spontaneous creation ex nihilo defies every physical law we have ever conceived of. But it does not follow that this present universe is eternal.

Its cause however may have originated with an eternal source. Discussion of that is the purview of philosophers and theologians, at least some of whom seek meaning within creation as a means of getting at who or what the eternal cause of the universe is.

I have always openly been Christian on this forum so my position on who the first cause of this universe is, is hardly a secret. But I don’t want to bend this into a religion thread - the discussion of celestial mechanics is quite interesting enough, and besides, I’m on holiday.

[Sephiroth]

Originally Posted by Chris

This reasoning is not logical.

<SNIP>

I have always openly been Christian on this forum so my position on who the first cause of this universe is, is hardly a secret. But I don’t want to bend this into a religion thread - the discussion of celestial mechanics is quite interesting enough, and besides, I’m on holiday.

I can see how a theological perspective would challenge my assertions.

But from the non-theological/non-religious-believer perspective, my reasoning is logical.

[downquark1]

Originally Posted by Sephiroth

If the elementary particles that are generated by collisions in supernovae (or something) create replacement matter, which is one of the theories going round somewhere, then we have the answer.

I don't think that's such a big "if". Neutron Stars, for example, when they explode, Neutrons break apart; particles collide and stuff is formed. Obviously something has to happen when particles collide. Seems logical to me.

Particles are generated in supernova however these are from the energy already existing in the star. Not additional things entering the universe. Or so is understood.

[Sephiroth]

Originally Posted by downquark1

Particles are generated in supernova however these are from the energy already existing in the star. Not additional things entering the universe. Or so is understood.

Yes indeed. The sum energy remains the same but the chaos converts the energy in waveforms and matter],