How Did the Universe Come to Be?

[shmogie]

It is possibility 'cyclic' in an open multiverse, and this does not mean that the any possible universe is isolated form other universes.



This a simplistic selective statement that does not reflect what science considers a singularity, and the scientific basis for the singularity. Most of the hypothesis related to the Big Bang theory are dependent on the singularity.

What is the singularity at the center of a black hole ?

Tell me, how does science describe a singularity ? Show how my description is simplistic and selective. What is the scientific basis for the singularity ?

Multiverses are simply another idea, among many. The evidence for them is scanty.

 

[Polymath257]

Did you not see the quotation marks on the word explosion ? Do you not know what these mean ?

I stated that I was using the big bang theory as a reference, and no, in that theory the existence of a singularity, or the nature of it is not known.

First, a 'singularity' is a *description* of what happens in the math as we approach the beginning of time. It is NOT an object. In the *standard* BB model, there *is* a singularity, which simply means, in this context, that time cannot be extended past that 'point'.

Your counter ideas are not accepted by most astronomers, and the place of quantum mechanics in the creation of the universe is not clearly understood, it is one hypothesis among many.

That quantum mechanics will be relevant is not in dispute. HOW it will affect things depends on the specific quantum theory of gravity. THAT is what we do not know.

The 'many' hypotheses concern HOW QM will affect things, not IF.

I suggest that if you are going to criticize, at least do it within the stated parameters of the post i.e. the classic big bang theory.

And in that classic theory there simply was NOT a 'before the Big Bang'. When QM is taken into account, it is possible that singularity is 'smoothed over' and time can be extended further back. But that is NOT the classic BB model.

Well, of course I presuppose God exists, just as others presuppose He doesn't.

A closed universe, which you call a cyclic universe, does not exist.

It is beyond doubt that the universe is expanding at an ever increasing rate, galaxies are getting further and further apart. There is not enough mass in the universe for gravity to draw them back together, which is required in a closed universe. Further dark energy, whatever that may be, is causing the increasing speed of the expansion. Unless something happens totally not known, like dark energy reversing itself, the universe will expand forever, and die. An open universe.

OK, first, if you are talking about dark energy, you are going beyond the classical BB model to include the cosmological constant and possible variants. It does not have to include QM, so in that sense it is classical, but it is NOT the original BB model (which did not have the CC).

Next, it looks like you *are* working under the classical BB model. In that model, there were three basic possibilities: one in which the universe is closed and eiher cyclical or time stops at some point in the future (a future singularity) and a high density, the case where the universe is flat and has a 'critical density', and a case where the universe is open and has a low density.

In each case, though, the term 'closed', 'flat', or 'open' has to do with the *spatial* aspects along some time slice. A closed universe has a finite volume and is positively curved, a flat universe has zero curvature, and an open universe is negatively curved.

And those were the only choices under the BB model without the CC. BUT, if you include the cosmological constant (also known as dark energy), the split between the possibilities isn't so limited. It is possible, for example, to have a spatially closed universe that is infinite into the future. It is possible to have a spatially open universe that is cyclic.

In the context of dark energy, the classical trichotomy no longer holds.

 

[Polymath257]

The singularity is proposed to exist, mathematically it cannot be proven as the laws of physics break down in retrograde before the singularity is reached.

From a Christian view, God is not bound by time, and exists outside of time and outside the universe.

The singularity is a description of what happens as we approach the beginning of time (in the BB model, at least).

 

[Polymath257]

What is the singularity at the center of a black hole ?

Once again, a singularity is a description of what happens mathematically in certain situations. The singularity at the center of a BH has very different behavior than the one at the beginning of the BB model. For one, the BH singularity is static (it happens in space throughout time) while the BB singularity involves time.

Tell me, how does science describe a singularity ? Show how my description is simplistic and selective. What is the scientific basis for the singularity ?

A singularity is when some parameter goes infinite or when the math doesn't allow a 'natural' extension.. often, but not always, that means your mathematical model isn't complete. In the case of a Black Hole, the singularity has the curvature going infinite as the radius goes to zero. In the Big Bang model, the density and temperature go infinite as we approach t->0.

Multiverses are simply another idea, among many. The evidence for them is scanty.

True, but it also isn't non-existent.

 

[Polymath257]

You could have just stated:

"I don't know."

And saved everyone some reading time.

Well, what I wrote isn't the same as what you said.

 

[shunyadragon]

What is the singularity at the center of a black hole ?

A singularity at the middle of a black hole.

Tell me, how does science describe a singularity ?

What Is A Singularity? - Universe Today

Ever since scientists first discovered the existence of black holes in our universe, we have all wondered: what could possibly exist beyond the veil of that terrible void? In addition, ever since the theory of General Relativity was first proposed, scientists have been forced to wonder, what could have existed before the birth of the Universe – i.e. before the Big Bang?

Interestingly enough, these two questions have come to be resolved (after a fashion) with the theoretical existence of something known as a Gravitational Singularity – a point in space-time where the laws of physics as we know them break down. And while there remain challenges and unresolved issues about this theory, many scientists believe that beneath veil of an event horizon, and at the beginning of the Universe, this was what existed.

Definition:
In scientific terms, a gravitational singularity (or space-time singularity) is a location where the quantities that are used to measure the gravitational field become infinite in a way that does not depend on the coordinate system. In other words, it is a point in which all physical laws are indistinguishable from one another, where space and time are no longer interrelated realities, but merge indistinguishably and cease to have any independent meaning.


This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. Credit: ESA/Hubble, ESO, M. Kornmesse
Origin of Theory:
Singularities were first predicated as a result of Einstein’s Theory of General Relativity, which resulted in the theoretical existence of black holes. In essence, the theory predicted that any star reaching beyond a certain point in its mass (aka. the Schwarzschild Radius) would exert a gravitational force so intense that it would collapse.

At this point, nothing would be capable of escaping its surface, including light. This is due to the fact the gravitational force would exceed the speed of light in vacuum – 299,792,458 meters per second (1,079,252,848.8 km/h; 670,616,629 mph).

This phenomena is known as the Chandrasekhar Limit, named after the Indian astrophysicist Subrahmanyan Chandrasekhar, who proposed it in 1930. At present, the accepted value of this limit is believed to be 1.39 Solar Masses (i.e. 1.39 times the mass of our Sun), which works out to a whopping 2.765 x 1030 kg (or 2,765 trillion trillion metric tons).

Another aspect of modern General Relativity is that at the time of the Big Bang (i.e. the initial state of the Universe) was a singularity. Roger Penrose and Stephen Hawking both developed theories that attempted to answer how gravitation could produce singularities, which eventually merged together to be known as the Penrose–Hawking Singularity Theorems.


The Big Bang Theory: A history of the Universe starting from a singularity and expanding ever since. Credit: grandunificationtheory.com
According to the Penrose Singularity Theorem, which he proposed in 1965, a time-like singularity will occur within a black hole whenever matter reaches certain energy conditions. At this point, the curvature of space-time within the black hole becomes infinite, thus turning it into a trapped surface where time ceases to function.

The Hawking Singularity Theorem added to this by stating that a space-like singularity can occur when matter is forcibly compressed to a point, causing the rules that govern matter to break down. Hawking traced this back in time to the Big Bang, which he claimed was a point of infinite density. However, Hawking later revised this to claim that general relativity breaks down at times prior to the Big Bang, and hence no singularity could be predicted by it.

Some more recent proposals also suggest that the Universe did not begin as a singularity. These includes theories like Loop Quantum Gravity, which attempts to unify the laws of quantum physics with gravity. This theory states that, due to quantum gravity effects, there is a minimum distance beyond which gravity no longer continues to increase, or that interpenetrating particle waves mask gravitational effects that would be felt at a distance.

Types of Singularities:
The two most important types of space-time singularities are known as Curvature Singularities and Conical Singularities. Singularities can also be divided according to whether they are covered by an event horizon or not. In the case of the former, you have the Curvature and Conical; whereas in the latter, you have what are known as Naked Singularities.

A Curvature Singularity is best exemplified by a black hole. At the center of a black hole, space-time becomes a one-dimensional point which contains a huge mass. As a result, gravity become infinite and space-time curves infinitely, and the laws of physics as we know them cease to function.

Conical singularities occur when there is a point where the limit of every general covariance quantity is finite. In this case, space-time looks like a cone around this point, where the singularity is located at the tip of the cone. An example of such a conical singularity is a cosmic string, a type of hypothetical one-dimensional point that is believed to have formed during the early Universe.

And, as mentioned, there is the Naked Singularity, a type of singularity which is not hidden behind an event horizon. These were first discovered in 1991 by Shapiro and Teukolsky using computer simulations of a rotating plane of dust that indicated that General Relativity might allow for “naked” singularities.

In case, what actually transpires within a black hole (i.e. its singularity) would be visible. Such a singularity would theoretically be what existed prior to the Big Bang. The key word here is theoretical, as it remains a mystery what these objects would look like.
the moment, singularities and what actually lies beneath the veil of a black hole remains a mystery. As time goes on, it is hoped that astronomers will be able to study black holes in greater detail. It is also hoped that in the coming decades, scientists will find a way to merge the principles of quantum mechanics with gravity, and that this will shed further light on how this mysterious force operates.

We have many interesting articles about gravitational singularities here at Universe Today. Here is 10 Interesting Facts About Black Holes, What Would A Black Hole Look Like?, Was the Big Bang Just a Black Hole?, Goodbye Big Bang, Hello Black Hole?, Who is Stephen Hawking?, and What’s on the Other Side of a Black Hole?

If you’d like more info on singularity, check out these articles from NASA and Physlink.

Astronomy Cast has some relevant episodes on the subject. Here’s Episode 6: More Evidence for the Big Bang, and Episode 18: Black Holes Big and Small and Episode 21: Black Hole Questions Answered.

 

[LegionOnomaMoi]

The singularity is proposed to exist, mathematically it cannot be proven as the laws of physics break down in retrograde before the singularity is reached.

This "singularity" is the big bang. That "point" of "infinite density/gravity" is called a singularity. The reason for the "infinite" is because singularities in this case are points at which the physical laws breakdown and yield infinities that cannot be dealt with using methods such as resummation, renormalization, regularization, or other methods from classical field theories. The classical big bang theory itself is an extrapolation beyond the point at which classical general relativity breaks down. Physically, you cannot have the big bang without a singularity because you cannot have infinite energies or densities or gravity or anything, let the whole universe reduced to anything approaching a point without a singularity.
Again, the big bang IS THE NAME for a particular singular limit to the Einstein Field Equations (or some extension of them) when we look at the universe contracted into a region approaching its original "point".

Please explain to me how the universe can be cyclical if it is open. Perhaps my understanding of "cyclical" is incorrect.

How familiar with topology are you?

 

[shmogie]

A singularity at the middle of a black hole.



What Is A Singularity? - Universe Today

Ever since scientists first discovered the existence of black holes in our universe, we have all wondered: what could possibly exist beyond the veil of that terrible void? In addition, ever since the theory of General Relativity was first proposed, scientists have been forced to wonder, what could have existed before the birth of the Universe – i.e. before the Big Bang?

Interestingly enough, these two questions have come to be resolved (after a fashion) with the theoretical existence of something known as a Gravitational Singularity – a point in space-time where the laws of physics as we know them break down. And while there remain challenges and unresolved issues about this theory, many scientists believe that beneath veil of an event horizon, and at the beginning of the Universe, this was what existed.

Definition:
In scientific terms, a gravitational singularity (or space-time singularity) is a location where the quantities that are used to measure the gravitational field become infinite in a way that does not depend on the coordinate system. In other words, it is a point in which all physical laws are indistinguishable from one another, where space and time are no longer interrelated realities, but merge indistinguishably and cease to have any independent meaning.


This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. Credit: ESA/Hubble, ESO, M. Kornmesse
Origin of Theory:
Singularities were first predicated as a result of Einstein’s Theory of General Relativity, which resulted in the theoretical existence of black holes. In essence, the theory predicted that any star reaching beyond a certain point in its mass (aka. the Schwarzschild Radius) would exert a gravitational force so intense that it would collapse.

At this point, nothing would be capable of escaping its surface, including light. This is due to the fact the gravitational force would exceed the speed of light in vacuum – 299,792,458 meters per second (1,079,252,848.8 km/h; 670,616,629 mph).

This phenomena is known as the Chandrasekhar Limit, named after the Indian astrophysicist Subrahmanyan Chandrasekhar, who proposed it in 1930. At present, the accepted value of this limit is believed to be 1.39 Solar Masses (i.e. 1.39 times the mass of our Sun), which works out to a whopping 2.765 x 1030 kg (or 2,765 trillion trillion metric tons).

Another aspect of modern General Relativity is that at the time of the Big Bang (i.e. the initial state of the Universe) was a singularity. Roger Penrose and Stephen Hawking both developed theories that attempted to answer how gravitation could produce singularities, which eventually merged together to be known as the Penrose–Hawking Singularity Theorems.


The Big Bang Theory: A history of the Universe starting from a singularity and expanding ever since. Credit: grandunificationtheory.com
According to the Penrose Singularity Theorem, which he proposed in 1965, a time-like singularity will occur within a black hole whenever matter reaches certain energy conditions. At this point, the curvature of space-time within the black hole becomes infinite, thus turning it into a trapped surface where time ceases to function.

The Hawking Singularity Theorem added to this by stating that a space-like singularity can occur when matter is forcibly compressed to a point, causing the rules that govern matter to break down. Hawking traced this back in time to the Big Bang, which he claimed was a point of infinite density. However, Hawking later revised this to claim that general relativity breaks down at times prior to the Big Bang, and hence no singularity could be predicted by it.

Some more recent proposals also suggest that the Universe did not begin as a singularity. These includes theories like Loop Quantum Gravity, which attempts to unify the laws of quantum physics with gravity. This theory states that, due to quantum gravity effects, there is a minimum distance beyond which gravity no longer continues to increase, or that interpenetrating particle waves mask gravitational effects that would be felt at a distance.

Types of Singularities:
The two most important types of space-time singularities are known as Curvature Singularities and Conical Singularities. Singularities can also be divided according to whether they are covered by an event horizon or not. In the case of the former, you have the Curvature and Conical; whereas in the latter, you have what are known as Naked Singularities.

A Curvature Singularity is best exemplified by a black hole. At the center of a black hole, space-time becomes a one-dimensional point which contains a huge mass. As a result, gravity become infinite and space-time curves infinitely, and the laws of physics as we know them cease to function.

Conical singularities occur when there is a point where the limit of every general covariance quantity is finite. In this case, space-time looks like a cone around this point, where the singularity is located at the tip of the cone. An example of such a conical singularity is a cosmic string, a type of hypothetical one-dimensional point that is believed to have formed during the early Universe.

And, as mentioned, there is the Naked Singularity, a type of singularity which is not hidden behind an event horizon. These were first discovered in 1991 by Shapiro and Teukolsky using computer simulations of a rotating plane of dust that indicated that General Relativity might allow for “naked” singularities.

In case, what actually transpires within a black hole (i.e. its singularity) would be visible. Such a singularity would theoretically be what existed prior to the Big Bang. The key word here is theoretical, as it remains a mystery what these objects would look like.
the moment, singularities and what actually lies beneath the veil of a black hole remains a mystery. As time goes on, it is hoped that astronomers will be able to study black holes in greater detail. It is also hoped that in the coming decades, scientists will find a way to merge the principles of quantum mechanics with gravity, and that this will shed further light on how this mysterious force operates.

We have many interesting articles about gravitational singularities here at Universe Today. Here is 10 Interesting Facts About Black Holes, What Would A Black Hole Look Like?, Was the Big Bang Just a Black Hole?, Goodbye Big Bang, Hello Black Hole?, Who is Stephen Hawking?, and What’s on the Other Side of a Black Hole?

If you’d like more info on singularity, check out these articles from NASA and Physlink.

Astronomy Cast has some relevant episodes on the subject. Here’s Episode 6: More Evidence for the Big Bang, and Episode 18: Black Holes Big and Small and Episode 21: Black Hole Questions Answered.

Thank You. This pretty much verifies what I stated about the singularity at the beginning of the expansion of the universe.

 

[LegionOnomaMoi]

What is the scientific basis for the singularity ?

Exactly the same as that for the big bang. Quite literally. The big bang is the name Fred Hoyle gave to the idea that we should interpret this singular limit as some kind of physically meaningful origin point for the universe. You spoke of a "point" of infinite density. That "point" is called a singular point, and it is the singularity we call the big bang.

 

[shunyadragon]

Thank You. This pretty much verifies what I stated about the singularity at the beginning of the expansion of the universe.

It verifies, it did not reflect the whole story, nor the fact that there are different kinds of singularities, and the relationship with Quantum Mechanics.

 

[shmogie]

It verifies, it did not reflect the whole story, nor the fact that there are different kinds of singularities, and the relationship with Quantum Mechanics.

I asked you to show the relationship of singularities"s to quantum mechanics.

Could you do so?

 

[shmogie]

Exactly the same as that for the big bang. Quite literally. The big bang is the name Fred Hoyle gave to the idea that we should interpret this singular limit as some kind of physically meaningful origin point for the universe. You spoke of a "point" of infinite density. That "point" is called a singular point, and it is the singularity we call the big bang.

My understanding is that mathematically, in retrograde in the expansion, the singularity cannot be identified because of the breakdown of known physical laws 1-2 Planck times before reaching the singularity.

So, re the BB, the singularity exists, because it must. Not because a mathematical formula showing it existed.

Correct?

 

[shmogie]

First, a 'singularity' is a *description* of what happens in the math as we approach the beginning of time. It is NOT an object. In the *standard* BB model, there *is* a singularity, which simply means, in this context, that time cannot be extended past that 'point'.



That quantum mechanics will be relevant is not in dispute. HOW it will affect things depends on the specific quantum theory of gravity. THAT is what we do not know.

The 'many' hypotheses concern HOW QM will affect things, not IF.



And in that classic theory there simply was NOT a 'before the Big Bang'. When QM is taken into account, it is possible that singularity is 'smoothed over' and time can be extended further back. But that is NOT the classic BB model.



OK, first, if you are talking about dark energy, you are going beyond the classical BB model to include the cosmological constant and possible variants. It does not have to include QM, so in that sense it is classical, but it is NOT the original BB model (which did not have the CC).

Next, it looks like you *are* working under the classical BB model. In that model, there were three basic possibilities: one in which the universe is closed and eiher cyclical or time stops at some point in the future (a future singularity) and a high density, the case where the universe is flat and has a 'critical density', and a case where the universe is open and has a low density.

In each case, though, the term 'closed', 'flat', or 'open' has to do with the *spatial* aspects along some time slice. A closed universe has a finite volume and is positively curved, a flat universe has zero curvature, and an open universe is negatively curved.

And those were the only choices under the BB model without the CC. BUT, if you include the cosmological constant (also known as dark energy), the split between the possibilities isn't so limited. It is possible, for example, to have a spatially closed universe that is infinite into the future. It is possible to have a spatially open universe that is cyclic.

In the context of dark energy, the classical trichotomy no longer holds.

The astronomical definition of the singularity, at least the one I was taught, appears different than the one you propose, perhaps from the physics perspective.

Astronomy proposes that the singularity was a thing, a thing that rapidly expanded.

The same as to an open or closed universe.

The definition I was taught is that a closed universe, or rebounding universe, ceases expansion, and begins retraction to the point of the singularity, to begin expansion again. The force of the retraction was considered to be gravity, which "overcomes" the"momentum" of the expansion.

Hubble put the dagger in the heart of the static universe, showing it is expanding.

Pelmutter (sp?) put the dagger in the heart, apparently, of the closed universe, showing that the expansion is increasing in speed, not slowing. Leaving an open universe

meaning

The universe will continue to expand, forever, it will fragment, forever, till all fuel for energy is exhausted, and there is no mechanism to convert mass to energy.

As you point out, dark energy is unknown and is simply a term applied to the unknown, like what is causing the increasing speed of the expansion.

This is the view of astronomers, as I understand it, and the terms as astronomers use them.