Universe Age and Size: A Matter of Perspective?

[PeterDonis]

a black hole is a gravitational singularity...

What is the source of this quote?

 

[Ibix]

"a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate." Sounds like the original universe to me.

A very dense point surrounded by vacuum sounds like an entire universe filled with hot dense matter to you?

 

[jbriggs444]

What is the source of this quote?

Chris said in #30 that he had located that quote on Google. Indeed, it can be found in. http://www.physicsoftheuniverse.com/topics_blackholes_singularities.html

Chris quoted with context in #30:

"In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate."

And without context in #34:

"a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate."

Note how the lack of four words completely obliterates the intended meaning of the passage in question.

 

[Chris Miller]

But you have quoted out of context, destroying the meaning of the passage you cite.

Apologies, all. And thank you, yes, I see what you mean. Wasn't trying to distort, only pare down, the description. Let me change my post to read, The centre of a black hole sounds like the original universe to me.

 

[jbriggs444]

Apologies, all. And thank you, yes, I see what you mean. Wasn't trying to distort, only pare down, the description. Let me change my post to read, The centre of a black hole sounds like the original universe to me.

The universe shares one of the attributes of a black hole -- that it has a singularity. However there are a number of posts on these forums in which members try to ask things like "is the universe a black hole?". The answer is no.

 

[Chris Miller]

It shares one of the attributes -- that it has a singularity. However there are a number of posts on these forums in which members try to ask things like "is the universe a black hole?". The answer is no.

It's difficult to make assertions about something for which so much is unknown/inexplicable. But no, of course not, which is why I used a simile. Scrolling further down that page I see there is a "naked singularity" hypothesis for the Big Bang.

 

[PeterDonis]

Let me change my post to read, The centre of a black hole sounds like the original universe to me.

Any such apparent resemblance is illusory. One big difference is that there is nothing corresponding to the black hole's event horizon in the FRW spacetime we use to describe the universe. Another is that a black hole is a vacuum solution; FRW spacetime is not.