If the universe is infinitely old, how did Today ever get here?

[Into the Night]

Given that usually entropy is considered the "hallmark" of time (ie non-symmetrical, one direction), I'm curious how entropy goes "cyclical".

I understand the concept that entropy can be a negative term in those cases where energy is added TO a system, but if we are talking about the universe here and the law that in a closed system (eg the universe) entropy always increases I'm curious about your "demonstration".

Entropy itself is NOT time, but the direction of time is determined by the 2nd law of thermodynamics.

This law states: e(t+1) >= e(t). In other words, entropy always increases or stay the same for any given system (including the entire universe).

Since the universe has no known boundary, time has no meaning, entropy stays the same e(t+1) = e(t), which still satisfies the 2nd law of thermodynamics.

The universe itself is not a closed system, but the 2nd law of thermodynamics still applies. It refers to ANY given system, even an entire universe with no known boundaries.

 

[Into the Night]

I think this is the exact same reasoning that led Aquinas wrong in the "first uncaused cause" argument. It starts off with the predicate that all things that exist must have a beginning based on the idea that everything he was familiar with had a beginning.

The universe is, likely, a "special case".

Ultimately the failure of the Cosmological Argument rests in the fact that it requires a "special case", in that case arbitrarily "God" was set as the ONE THING which didn't have a beginning.

So to point to the Mobius Strip and say that it has an edge which means that everything must have a "boundary" is to slip into the same error mode.

By 'special case', the universe is simply infinite in volume, with no known boundary. \
The predicate that all things must have a beginning is itself an argument. That argument is attached to either the Theory of the Continuum, or the Theory of the Big Bang.

 

[Into the Night]

Like a Carnot heat engine

Look, if you haven't taken physics and thermodynamics it would take me quite a while to explain this to you.

Since you bring up the Carnot engine, you will note that entropy does not increase. It stays the same, even in a theoretically perfect Carnot engine. This still satisfies the 2nd law of thermodynamics: e(t+1) >= e(t); or in your diagram: S(t+1) >= S(t).
Where 't' is time.

 

[Into the Night]

Why would the existence of infinity keep one from counting WITHIN that?

It doesn't. ALL counting is done within a range of infinity.

 

[Into the Night]

If time didn't exist then the universe isn't eternal or infinitely old.

Time still exists, even when there is no point in measuring it.

Saying time didn't exist before the Big Bang is the same thing as saying the universe is finite in age and has a temporal origin point. Why even try to dance around and avoid reaching this perfectly rational conclusion?

Try the phrases:
Before now.
Now.
After now.

They adequately describe any point in time in any universe, even for a universe that has always existed and always will, even where measuring time is quite pointless.

The closest I can come to making Infinity conform to a finite value,

Infinity is not finite. It cannot conform to a finite value.

are the mathematical limits we saw in precalculus. But even limits to infinity only approach infinity asymptomatically. Infinity is always undefined and uncountable.

Calculus not required here at all. Buzzword and strawman fallacies.

 

[Into the Night]

So you didn't read my post before responding. Got it.

I was clear in that I was talking about closed systems where energy could be added which is what you showed.

But I'm curious why you think the universe could contain "cyclic entropy"? Whence does the added energy come?

You cannot consider any energy source or sink from outside any given system with the laws of thermodynamics.

 

[Into the Night]

The energy isn't "add"ed, but rather comes from natural processes within the universe itself. To use a finite example:

You have a mass of atoms that form a star (point D on my graph). The atoms through nuclear and gravitational interaction create energy (point A). The energy is transferred elsewhere in the universe allowing "things" to happen (point B). The energy expended causes the mass involved to cool (point C). That mass through gravity ends up forming a new star and you are back at D.

Now, that's grossly simplified, but hopefully you get the idea.

Since this cycle of an individual case is going on with all stars at the same time, it's effectively continuous rather than being a cycle at all.

Think of an infinitely large Carnot engine. The cylinder is infinite in size.

The biggest problem when discussing these things is the weakness of the language, itself designed around finite events.

 

[Into the Night]

What you are describing is the state within the current universe. Locally entropy can be negative (as I clearly stated) but what you have suggested would have to act on the overall universe itself which means you want the universe to be an OPEN system which can take in more energy.

There is no 'local entropy'. The given system MUST be consistent. You cannot compare two different systems as if they are the same system!
Entropy can never decrease. It MUST increase or stay the same.

In order for your explanation to apply to the universe it would have to be leveraging some "hyper-universe" within which the universe exists as a closed system.

The universe is an open system, but the 2nd law of thermodynamics still applies across THAT system, open as it is.

(Also when describing the actions of a Carnot cycle, stick with steam engines which is more applicable than whatever you were talking about with clusters of atoms etc. I mean you obviously have had a thermo class and all so I shouldn't question your "lecture".

The Carnot engine is not a steam engine, Gunky.

 

[T. A. Gardner]

Since this cycle of an individual case is going on with all stars at the same time, it's effectively continuous rather than being a cycle at all.

Think of an infinitely large Carnot engine. The cylinder is infinite in size.

The biggest problem when discussing these things is the weakness of the language, itself designed around finite events.

The biggest weakness is we don't know the true nature of the universe. We can only speculate on what we can see of it, and that's not all of it. Without knowing for sure the shape, size, and nature of it we're just guessing.

 

[Into the Night]

I don't think the question is an engineering question, and whether we can engineer a system where entropy does not increase.

Don't need to. That's already the natural state of the universe. Entropy does not increase. It just stays the same.

Every cosmologist and physicist I've ever read says the universe has an arrow of time defined by the increase of entropy from a lower entropy past.

There is no 'arrow of time' where time has no significant meaning and where entropy does not change.

I've never heard anything about a cyclical cosmic entropy, though I appreciate you bringing it to my attention.

Entropy is not 'cosmic'. It simply exists.

 

[Into the Night]

Yeah that would be engineering a closed system with decreasing entropy which is not allowed by the Second Law of thermo.



Pretty much everything I've read in the literature indicates entropy is what gives time its "direction".

If entropy stays the same, it is not decreasing.
Entropy is not time and does not give time a direction.

But the 2nd law of thermodynamics gives time a direction, IF and ONLY IF entropy is increasing.

If entropy stays the same, there is no 'direction of time' or even a significant meaning of time at all.

 

[Into the Night]

actually NOT wordplay. Relativity. My simplistic understanding of the paradox is that since the second person is in motion ergo time is moving differently for them (this is a known effect of relativity) that when the two simultaneously look at the "events" time will be different for them and the events will be different.

Wordplay.

You cannot consider two closed systems as the universe or any other open system.

Time has no significant meaning a universe with no known boundary.

 

[Into the Night]

The biggest weakness is we don't know the true nature of the universe. We can only speculate on what we can see of it, and that's not all of it. Without knowing for sure the shape, size, and nature of it we're just guessing.

A rash assumption to be sure. What's to guess? There is no known boundary to the universe, so it has no shape or size.

 

[Into the Night]

It could be a closed system where the energy moves around but isn't increased or decreased, just changed in form.

E = mc^2. Energy cannot be created or destroyed, but it can become matter or matter converted to energy...

That is NOT what this equation means.

Energy cannot be created or destroyed.
Matter cannot be created or destroyed.

E = mc^2 ONLY FOR A SPECIAL CASE. This is NOT the full equation, which is simply applying the Pythagorean Theorem across the dimensions of space and time, using matter as the reference, and where nothing is moving at the speed anywhere near light.

This special case is for most practical speeds we experience in every day life. The faster mass moves, the heavier it becomes, due to it's energy.
This is related to the speed of light.

At the speed of light, mass becomes infinitely massive, making it impossible to move any faster, or it ceases to be mass at all. It's pure energy (a photon).

A photon moving at the speed of light in a vacuum has no mass. When it slows down because it is traveling through something denser, it has mass.
It's this mass that makes a metal like selenium give off electrons when struck by light, making a very useful sensor for elevator doors and the like. This is the other part of the equation that you did not show.

Another way to think of a photon is an energy packet.

A bit like a BB shot from a gun in space, the BB does not impart any energy to anything, until it hits something. It's just an energy packet, so to speak (this also ignores gravity for this simile).

 

[Into the Night]

Interesting.
I don't think entropy is defined by the amount of energy. It's defined by the number of microstates, aka the arrangements of the particles in the system.

A closed system should almost always be evolving to a higher entropy, though in theory entropy could stay the same. I've never heard of this universe maintaining constant entropy. I don't even think life or a biosphere is possible at constant entropy.

It's widely accepted that this universe evolved from an initial low entropy state, to increasing entropy, and that's what gives us an arrow of time.

The universe has no know boundary. How do you measure entropy in an infinite volume?

The definition of entropy is the energy available to perform work (applying a force over time), expressed as a negation.

In other words, at zero entropy, ALL the available energy is available for work. At high entropy, the energy is dissipated and none is available for work.

In a system that has no known boundaries, entropy simply stays the same. It does not increase or decrease.

 

[Into the Night]

Again, what you seem to be proposing is the antithesis of the Second Law of Thermodynamics. There's literally no other way to characterize your position.

TA happens to be most correct here. Entropy does NOT HAVE TO INCREASE. It can simply stay the same.

The 2nd law of thermodynamics: e(t+1) >= e(t) wher 'e' is entropy and 't' is time. Entropy is best described as how dissipated the energy is and is not available to perform work.

 

[T. A. Gardner]

That is NOT what this equation means.

Energy cannot be created or destroyed.
Matter cannot be created or destroyed.

E = mc^2 ONLY FOR A SPECIAL CASE. This is NOT the full equation, which is simply applying the Pythagorean Theorem across the dimensions of space and time, using matter as the reference, and where nothing is moving at the speed anywhere near light.

This special case is for most practical speeds we experience in every day life. The faster mass moves, the heavier it becomes, due to it's energy.
This is related to the speed of light.

At the speed of light, mass becomes infinitely massive, making it impossible to move any faster, or it ceases to be mass at all. It's pure energy (a photon).

A photon moving at the speed of light in a vacuum has no mass. When it slows down because it is traveling through something denser, it has mass.
It's this mass that makes a metal like selenium give off electrons when struck by light, making a very useful sensor for elevator doors and the like. This is the other part of the equation that you did not show.

Another way to think of a photon is an energy packet.

A bit like a BB shot from a gun in space, the BB does not impart any energy to anything, until it hits something. It's just an energy packet, so to speak (this also ignores gravity for this simile).

It is the case for determining energy from mass and vice versa.

E = amu x 931 Mev

 

[Matt Dillon]

Universe May Have Had No Beginning​

If a new theory turns out to be true, the universe may not have started with a bang.

In the new formulation, the universe was never a singularity, or an infinitely small and infinitely dense point of matter. In fact, the universe may have no beginning at all.

"Our theory suggests that the age of the universe could be infinite," said study co-author Saurya Das, a theoretical physicist at the University of Lethbridge in Alberta, Canada.

Steady State Theory's View on the Universe's Origins and Age​

The Steady State Theory posits that the universe is eternal, with no beginning or end. This theory rejects the idea of a singular cosmic origination event, such as the Big Bang, and instead suggests that the universe is constantly evolving through the continuous creation of matter. The universe's age is not a fixed value, as it is considered to be infinitely old.


https://www.livescience.com/49958-theory-no-big-bang.html

 

[Hume]

If time didn't exist then the universe isn't eternal or infinitely old.

Saying time didn't exist before the Big Bang is the same thing as saying the universe is finite in age and has a temporal origin point. Why even try to dance around and avoid reaching this perfectly rational conclusion?

The closest I can come to making Infinity conform to a finite value, are the mathematical limits we saw in precalculus. But even limits to infinity only approach infinity asymptomatically. Infinity is always undefined and uncountable.

How can time measure infinity? If by definition a measure must be finite.

 

[Hume]

The biggest weakness is we don't know the true nature of the universe. We can only speculate on what we can see of it, and that's not all of it. Without knowing for sure the shape, size, and nature of it we're just guessing.

All of science is quessing, then.