On ‎4‎/‎11‎/‎2018 at 12:40 PM, Mordred said:

We don't know, the physics we understand breaks down at the singularity conditions. 

I thought physics breaks down before the singularity condition.  Isn't the singularity undefined and just theoretical?  The "singularity conditions" would be high density and high temperature, that's all.  It says nothing about the size or shape of the big bang at the beginning.

4 minutes ago, Airbrush said:

I thought physics breaks down before the singularity condition.  Isn't the singularity undefined and just theoretical?  The "singularity conditions" would be high density and high temperature, that's all.  It says nothing about the size or shape of the big bang at the beginning.

No. 10^-43 seconds from the singularity condition; a Planck time after.

Edited April 13, 20187 yr by StringJunky

There is two meanings behind singularity. One is as per a BH, while the other is any condition that leads to nonsensical infinities regardless of volume. The BB is the latter

6 hours ago, StringJunky said:

No. 10^-43 seconds from the singularity condition; a Planck time after.

So what you are saying is that at 10^-43 seconds AFTER the singularity condition the physics start to make sense, and the "singularity condition" does not make sense?

Edited April 13, 20187 yr by Airbrush

7 minutes ago, Mordred said:

There is two meanings behind singularity. One is as per a BH, while the other is any condition that leads to nonsensical infinities regardless of volume. The BB is the latter

Both though are evident by the failure and/or limitations of our current theories, are they not?

So couldn't we simply define a singularity [ both BB and BH] as a non physical epoch where our models break down?

10 minutes ago, Mordred said:

There is two meanings behind singularity. One is as per a BH, while the other is any condition that leads to nonsensical infinities regardless of volume. The BB is the latter

Yes we are only discussing the BB at this point.

4 minutes ago, Airbrush said:

So what you are saying is that at 10^-43 seconds AFTER the singularity condition the physics start to make sense, and the "singularity condition" does not make sense?

That's the closest point we can get to the moment of the big bang and then GR  doesn't work.... beyond that is an infinity, as Mordred said.

Both can be treated as a point where our understanding /model/math breaks down. Though I will note a true singularity is of the same criteria to all observers and all known coordinate/metrics

 You can have false singularities due to a breakdown in a particular metric. One example being the Schwartzchild metric, which changing to a different metric such as Tortoise coordinates can eliminate.

 

Edited April 13, 20187 yr by Mordred