A Can of Worms: Did the Universe Start from a Singularity?

[Heyo]

Hello scientists,

I guess this discussion will not have too many participants as I think not many here have interest and knowledge in the topic. @Meow Mix is rarely seen lately and @Polymath257 is the only other who might have thought about this problem. Anyhow, here it is:

We assume the universe was once in a state known as a singularity. This assumption is not falsifiable by observation, it is just a consequence of tracing back the expansion of the universe. We also think that Black Holes have singularities in their centre but that is likely unobservable. We assume that no force exists that can stop the collapse due to gravity. Usually the electromagnetic force stops things from compacting but it is no match to gravity within a Black Hole.

But while the matter in a Black Hole leaves our observable universe, it can come back through the hypothesised Hawking radiation. It is still connected to our reality and our space-time geometry. A very small Black Hole could also evaporate by simply radiating away energy due to Heisenberg's uncertainty principle.

And here comes my question: from a quantum physics view, can there be such a thing as a singularity?
Are not the particles uncertain to be at a single point?

And if we apply that to the universe, is it allowed to assume a time reversal? Could the universe be put back "in the can"?
From my layman's perspective, quantum mechanics would prevent that.

Your thoughts (and corrections to my naïve view of the problem)?

 

[Subduction Zone]

Hello scientists,

I guess this discussion will not have too many participants as I think not many here have interest and knowledge in the topic. @Meow Mix is rarely seen lately and @Polymath257 is the only other who might have thought about this problem. Anyhow, here it is:

We assume the universe was once in a state known as a singularity. This assumption is not falsifiable by observation, it is just a consequence of tracing back the expansion of the universe. We also think that Black Holes have singularities in their centre but that is likely unobservable. We assume that no force exists that can stop the collapse due to gravity. Usually the electromagnetic force stops things from compacting but it is no match to gravity within a Black Hole.

But while the matter in a Black Hole leaves our observable universe, it can come back through the hypothesised Hawking radiation. It is still connected to our reality and our space-time geometry. A very small Black Hole could also evaporate by simply radiating away energy due to Heisenberg's uncertainty principle.

And here comes my question: from a quantum physics view, can there be such a thing as a singularity?
Are not the particles uncertain to be at a single point?

And if we apply that to the universe, is it allowed to assume a time reversal? Could the universe be put back "in the can"?
From my layman's perspective, quantum mechanics would prevent that.

Your thoughts (and corrections to my naïve view of the problem)?

Form my very layman's understanding the "singularity" is when the laws of physics break down and we can no longer apply any of them to describe what should be happening. That occurs sometime before the universe or a black hole becomes infinitely dense. This short video explains why the phrases "Big Bang" and "singularity" are misleading:

 

[Revoltingest]

Hello scientists,

I guess this discussion will not have too many participants as I think not many here have interest and knowledge in the topic. @Meow Mix is rarely seen lately and @Polymath257 is the only other who might have thought about this problem. Anyhow, here it is:

We assume the universe was once in a state known as a singularity. This assumption is not falsifiable by observation, it is just a consequence of tracing back the expansion of the universe. We also think that Black Holes have singularities in their centre but that is likely unobservable. We assume that no force exists that can stop the collapse due to gravity. Usually the electromagnetic force stops things from compacting but it is no match to gravity within a Black Hole.

But while the matter in a Black Hole leaves our observable universe, it can come back through the hypothesised Hawking radiation. It is still connected to our reality and our space-time geometry. A very small Black Hole could also evaporate by simply radiating away energy due to Heisenberg's uncertainty principle.

And here comes my question: from a quantum physics view, can there be such a thing as a singularity?
Are not the particles uncertain to be at a single point?

And if we apply that to the universe, is it allowed to assume a time reversal? Could the universe be put back "in the can"?
From my layman's perspective, quantum mechanics would prevent that.

Your thoughts (and corrections to my naïve view of the problem)?

We don't need those posters' fancy math to discuss
this. Hawking radiation won't defeat the envisioned
"heat death" of the universe. This is because it does
not end the universe's expansion, nor does the radiation
have the concentration necessary to do work (in the
thermodynamic sense). It's gonna get cold & dark,
people. (I offer a money back guarantee on this
prognostication.)
As for other things the universe (or universes) might do,
I've no idea.

 

[QuestioningMind]

Hello scientists,

I guess this discussion will not have too many participants as I think not many here have interest and knowledge in the topic. @Meow Mix is rarely seen lately and @Polymath257 is the only other who might have thought about this problem. Anyhow, here it is:

We assume the universe was once in a state known as a singularity. This assumption is not falsifiable by observation, it is just a consequence of tracing back the expansion of the universe. We also think that Black Holes have singularities in their centre but that is likely unobservable. We assume that no force exists that can stop the collapse due to gravity. Usually the electromagnetic force stops things from compacting but it is no match to gravity within a Black Hole.

But while the matter in a Black Hole leaves our observable universe, it can come back through the hypothesised Hawking radiation. It is still connected to our reality and our space-time geometry. A very small Black Hole could also evaporate by simply radiating away energy due to Heisenberg's uncertainty principle.

And here comes my question: from a quantum physics view, can there be such a thing as a singularity?
Are not the particles uncertain to be at a single point?

And if we apply that to the universe, is it allowed to assume a time reversal? Could the universe be put back "in the can"?
From my layman's perspective, quantum mechanics would prevent that.

Your thoughts (and corrections to my naïve view of the problem)?

It's my understanding that all of the physical laws that exist didn't begin to exist until the singularity began to expand. Thus there were no quantum mechanics to prevent anything.

 

[ChristineM]

Hello scientists,

I guess this discussion will not have too many participants as I think not many here have interest and knowledge in the topic. @Meow Mix is rarely seen lately and @Polymath257 is the only other who might have thought about this problem. Anyhow, here it is:

We assume the universe was once in a state known as a singularity. This assumption is not falsifiable by observation, it is just a consequence of tracing back the expansion of the universe. We also think that Black Holes have singularities in their centre but that is likely unobservable. We assume that no force exists that can stop the collapse due to gravity. Usually the electromagnetic force stops things from compacting but it is no match to gravity within a Black Hole.

But while the matter in a Black Hole leaves our observable universe, it can come back through the hypothesised Hawking radiation. It is still connected to our reality and our space-time geometry. A very small Black Hole could also evaporate by simply radiating away energy due to Heisenberg's uncertainty principle.

And here comes my question: from a quantum physics view, can there be such a thing as a singularity?
Are not the particles uncertain to be at a single point?

And if we apply that to the universe, is it allowed to assume a time reversal? Could the universe be put back "in the can"?
From my layman's perspective, quantum mechanics would prevent that.

Your thoughts (and corrections to my naïve view of the problem)?

I go with this...

It's my understanding that all of the physical laws that exist didn't begin to exist until the singularity began to expand. Thus there were no quantum mechanics to prevent anything.

The natural laws of science did not begin to coalesce until some 10e-43 of a second after the universe began to expand, and did not fully form until 10e-32 of a second. What happened before 10e-43 of a second is unknown because theories break down.

 

[sun rise]

Nice video. I particularly liked Singularity=>Ignorance.

His last suggestion that the universe might contract and be reborn is also similar to a Vedic idea

-> The life span of the universe is one "maha kalpa". i.e. 311.04 trillion human years. This time span is also the duration of one breath of "Vishnu" (the ultimate god in hindu religion). When he exhales, thousands of universes emerges and one "Brahma" is born in each universe. When "Vishnu" inhales, all universes get sucked and Brahma dies.

-> This cycle is non-ending and eternal. Thats why "Vishnu" is considered eternal in Vedic Science (or religion).

Age of Universe according to Vedas

 

[Polymath257]

The term 'singularity' is one fraught with ambiguities.

For example, when water freezes, there is a 'singularity' in the heat capacity of the water. During freezing/melting changing the energy of the water does not change the temperature of the water (it produces more ice or water).

So, a singularity is when some variable of interest goes infinite.

In the case of black holes, the spacetime curvature goes infinite at the center (not at the event horizon). At least, that is what happens classically. Similarly, as we approach the Big Bang, density and temperature as well as curvature go infinite (again, at least classically).

So there are two questions:

1. If quantum mechanics is taken into account, do these quantities still go infinite?

2. If so, does this represent our choosing the wrong variables (as in the case of melting water: heat capacity isn't the best variable to use here)? So, it is possible there is a 'phase transition' that describes what happens/happened?

The answer to 1 seems to depend on which theory of quantum gravity we use. Since NONE of them have been extensively tested, the best answer is to say we don't know.

For 2, again, the answer seems to depend on which theory of quantum gravity is used. But such things as multiverses and colliding branes are related to this possibility.

So, basically, we don't know. But remember Hawking radiation in black holes has not been established either.