First cause of the universe.

[mikkel_the_dane]

It says Universe is all of space, time, and their contents. If I am not understanding something, perhaps you can explain.

But that doesn't make it so, just because it says so.

 

[Kfox]

You have to learn that words in general don't cause anything. So if I say that the universe means everything that exists, those word here on the screen doesn't make it so that the universe is everything that exists.

If Universe is defined as "all that exist", then that is exactly what it means until they change the term to mean something else.

 

[Kfox]

But that doesn't make it so, just because it says so.

So you are saying that definition is wrong? If so, what do you think Universe means?

 

[mikkel_the_dane]

If Universe is defined as "all that exist", then that is exactly what it means until they change the term to mean something else.

But it doesn't make it a fact that the universe is all that exist.

 

[mikkel_the_dane]

So you are saying that definition is wrong? If so, what do you think Universe means?

Right and wrong don't apply to definitions. The question is, if it is a fact that the universe is all that exist.
It is no different than a definition of God that say God means the creator of everything. That doesn't make it a fact. The same applies to the definition of the universe.

 

[ChristineM]

You can't have interaction without something to interact... Again what starts the process? Everything we see in the universe has a beginning.

Unlike you i am not afraid to shout ro the world "I DON'T KNOW"

What happened prior to 10e-43 of a second following the bb is unknown, unknown by you, unknown by you, unknown by everyone including the worlds most prominent cosmologist.

Of course some will guess to massage their ego but its nothing more than guess

How about everything we don't see in the universe?

 

[RestlessSoul]

If Universe is defined as "all that exist", then that is exactly what it means until they change the term to mean something else.

I think some confusion arises because when astronomers talk about the universe, they are referring to something specific, ie. all of space and time.

When metaphysical considerations arise about what, if anything, might exist or have existed beyond space and time, we are straying outside the boundaries of the universe, and of science. Perhaps.

 

[Subduction Zone]

It says Universe is all of space, time, and their contents. If I am not understanding something, perhaps you can explain.

That does not include other possible universes outside of our space and time. I am not a mathematician, but there are physicists that can support their arguments that the math of the Special Theory of Relativity tell us that there could be many universes. Now I personally do not know of any evidence for their existence outside of the math, but math in theoretical physics is an extremely powerful tool and has been right quite often. If I made such a claim on my own it would be worthless, but it is not my claim. I could pull up some peer reviewed articles on it, but I can guarantee that I would not be able to explain them.

At any rate now the term "Cosmos" is often used to include not only our universe but also any other possible universes. There may be only the one universe and the Big Bang may explain the very early history of it.

As to why it started I can't say why, but just because it may be unknown is not a valid excuse to try to sneak a god into the equation. You need your own evidence for a god if you want to claim that one exists. No one has demonstrated that a god is needed. The closest that people can get to is "we don't understand this yet".

 

[Subduction Zone]

I think some confusion arises because when astronomers talk about the universe, they are referring to something specific, ie. all of space and time.

When metaphysical considerations arise about what, if anything, might exist or have existed beyond space and time, we are straying outside the boundaries of the universe, and of science. Perhaps.

Yes, the multiverse may or may not exist, but one needs to take that possibility into consideration when speaking of "everything".

 

[ChristineM]

we have no explanation for anything coming from nothing.

Ehmmm.

Spontaneous creation of the universe from nothing

 

[RestlessSoul]

Yes, the multiverse may or may not exist, but one needs to take that possibility into consideration when speaking of "everything".

And there are multiple Multiverse theories, some from cosmology, some from QM (though Hugh Everett called his the Relative State interpretation. Bryce deWitt named it the Many Worlds theory).

 

[Polymath257]

And as long as you are here, one more. I know that particles are frequently detected using some sort of cloud chamber. Running over the basic physics it seems that one uses some knowledge of the particle that one is working with to determine what is observed. So does the rate of change of curvature tell us the mass? i know that the curvature is going to be the result of a combination of the mass and the velocity of the particle. But a heavy particle would probably slow down at a slower rate than say an electron does. The few articles that I read did not give any details on how one tells the difference between an electron and a proton. Oh, almost forgot, and clockwise or counterclockwise would tell us positive or negative.

Is that basically right or am I off again?

First, cloud chambers are old technology. Most detection these days is done by calorimeters. We essentially detect the energy released as the particles interact with matter.

In a cloud chamber, there is a strong magnetic field set up. That indues a force on any moving charge. The amount of force is determined by the charge and the velocity of that charge. The mass of the particle determines its path through F=ma.

So, first, whether the particle is positively charged or negatively charged can be determined by the *direction* of curvature: electrons will curve one direction and protons will curve in the opposite direction.

The amount of curvature is determined by both the velocity and the mas, so a larger mass or a larger velocity will lead to less curvature. Electrons are much less massive, so at equivalent energies will curve much more than something heavy like a proton. In the photo you gave, you can see both positively and negatively charged, relatively low mass particles. Without knowing the direction of the magnetic field, I can't tell which is which.

One issue with cloud chambers is that neutral particles (like neutrons) don't leave a path: It is the interaction with the charge that causes the bubbles to form. I see a number of places where neutral particles were formed and then decayed, producing charged particles.

 

[Polymath257]

If Universe is defined as "all that exist", then that is exactly what it means until they change the term to mean something else.

And if that is the case, then we don't know if the universe 'had a start'. What we know is that the current expansion phase had a start about 13.8 billion years ago. But, we don't know if that is the whole universe according to that definition.

 

[Polymath257]

I think some confusion arises because when astronomers talk about the universe, they are referring to something specific, ie. all of space and time.

When cosmologists speak of the universe, they mean specifically the current expansion phase we are in since the Big Bang.

That may or may not be 'all of space and time'.

That is why the term multiverse has been developed (well, one reason): there is a possibility (even a likelihood) that there is a larger region of space and time and what we observe is just a small part of the whole. There may be other regions of expansion similar to ours (called other universes).

In this context, there are two very different questions:

1. How did the expansion phase we are in start?

2. Did the multiverse (all of space and time) have a start?

The most likely answer to the second is NO.

The answer to the first depends on which version of quantum gravity is correct, so we don't know. So, brane theory gives a different answer than quantum loop gravity, which is different than some versions of string theory, which is different than cyclic scenarios, etc.

When metaphysical considerations arise about what, if anything, might exist or have existed beyond space and time, we are straying outside the boundaries of the universe, and of science. Perhaps.

At that point, the question I have is what the term 'exists' even means.

 

[mikkel_the_dane]

...
At that point, the question I have is what the term 'exists' even means.

In general "exists" is an old idea in philosophy that then got tangled up in the idea of "matter" and a fundamental "thing". You don't need any of these to do science as far as I can tell. You need as set of axioms and observational terms. There is more of course, but the joke is that you can't observe "existence", "matter" and "things". They are philosophical concepts in the mind.

 

[RestlessSoul]

When cosmologists speak of the universe, they mean specifically the current expansion phase we are in since the Big Bang.

That may or may not be 'all of space and time'.

That is why the term multiverse has been developed (well, one reason): there is a possibility (even a likelihood) that there is a larger region of space and time and what we observe is just a small part of the whole. There may be other regions of expansion similar to ours (called other universes).

In this context, there are two very different questions:

1. How did the expansion phase we are in start?

2. Did the multiverse (all of space and time) have a start?

The most likely answer to the second is NO.

The answer to the first depends on which version of quantum gravity is correct, so we don't know. So, brane theory gives a different answer than quantum loop gravity, which is different than some versions of string theory, which is different than cyclic scenarios, etc.



At that point, the question I have is what the term 'exists' even means.

Okay. Then if by the universe, we are conceding ourselves with the observable universe, we may also ask ourselves what exactly we mean by ‘observable’.

The extent and significance of observability is not simply determined by the limits of current and potential technologies. There is also the question of the observable, as opposed to theoretical, elements of an ontology.

 

[mikkel_the_dane]

Okay. Then if by the universe, we are conceding ourselves with the observable universe, we may also ask ourselves what exactly we mean by ‘observable’.

The extent and significance of observability is not simply determined by the limits of current and potential technologies. There is also the question of the observable, as opposed to theoretical, elements of an ontology.

Or if you avoid ontology and only do some form of phenomenology.

 

[Kfox]

Right and wrong don't apply to definitions.

Of course it does. There are right definitions, and there are wrong definitions

The question is, if it is a fact that the universe is all that exist.

That’s like asking is it a fact that all circles are round! (like you gonna find one with 4 sides or something)

It is no different than a definition of God that say God means the creator of everything. That doesn't make it a fact. The same applies to the definition of the universe.

Poor analogy. The definition of God changes from person to person; not everybody defines God as creator of everything, even though some do. The definition of the Universe is the same for everybody

But it doesn't make it a fact that the universe is all that exist.

Then provide a scenario where something could possibly exist outside of the Universe.

 

[Subduction Zone]

Of course it does. There are right definitions, and there are wrong definitions

That’s like asking is it a fact that all circles are round! (like you gonna find one with 4 sides or something)

Poor analogy. The definition of God changes from person to person; not everybody defines God as creator of everything, even though some do. The definition of the Universe is the same for everybody
Then provide a scenario where something could possibly exist outside of the Universe.

It is not so black and white, you have been trying to use an outdated definition. At one point it was believed that our universe was all that there was. Now we re not so sure. If one wants to talk about everything a more inclusive term is needed.

 

[Polymath257]

Of course it does. There are right definitions, and there are wrong definitions

Not true. There are *useful* definitions and there are *useless* definitions. But a definition just declares how we decide to use the language, nothing else.

That’s like asking is it a fact that all circles are round! (like you gonna find one with 4 sides or something)

Well, that will depend on what you mean by a 'side' and what you mean by 'round'. And, of course, what you mean by a 'circle.

There *are* definitions in math that lead to 'circles' with 4 sides, by the way. The taxicab metric gives 'circles' that are squares.

Poor analogy. The definition of God changes from person to person; not everybody defines God as creator of everything, even though some do. The definition of the Universe is the same for everybody
Then provide a scenario where something could possibly exist outside of the Universe.

Unfortunately, the definition of 'the universe' does change from person to person as I explained above.