Infinite number of universes

[Bestbank Tiger]

But this universe still contains John McCain, Saddam Hussein, and the Deepwater Horizon oil well. (Even though Saddam Hussein is dead, remember, he does exist between the two points in spacetime known as Al-Awja, Iraq, 28 April 1937 and Kadhimiya, Iraq, 30 December 2006)

Would Saddam have died in all universes when he died in ours?

Or can he die in one universe and live in another like Jet Li in The One?

 

[BasketCase]

That doesn't really sound right... maybe I'll go check it out myself.

Yeah, I did that part wrong. At this moment Earth's pull on you is what it is because you're 6,300 kilometers away from the center of mass. If the Earth became a black hole (with its center of mass in the same place) its pull on you would remain the same if you also remained in the same place--6,300 kilometers away from the singularity. Move closer and it goes up, though I don't know how much.

Of course there could be different objects. If your parents didn't meet, you wouldn't be around.

Then it seems to me that one's parents must meet (in the same place and time) in all universes.

Would Saddam have died in all universes when he died in ours?

Letsee.....regardless of where Saddam exists in the higher dimensions, he exists at a particular location in the first four. If you viewed Saddam from the 8th dimension at this moment (i.e. from our current location in the fourth dimension, time) Saddam's position in the first three dimensions is still the same: wherever his grave site is. So if he's alive in some other dimension, he would have to be sitting still. Permanently. Which would be kind of a bummer for him.

So I probably gave some bad examples: the Trojans would most likely still have lost, Hector would still be dead, Saddam would still have died at the same time. And George Bush would still be President from 2001 to 2008, which I'm sure must bum out some of you.

In the same way that a square, viewed from a different position in three dimensions, can appear to be a trapezoid (but is still a square), I'm thinking that our universe would only look different when viewed from other dimensions, but would still act the same.

Changing the physical constant neither invalidates nor creates new interactions, it just changes the strength of them. So your point is invalid.

Fine. So it changes the strength of interactions. Thereby bringing into play interactions that you hadn't predicted.

And we could test it by building a quantum simulator in which we engineer the Hamiltonian to simulate a system with these different constants.

Have we....?

And here's another thought: suppose it's not possible for the physical constants of the universe to be anything else? "If they were" is currently only a thought exercise (that hasn't been tested), just as "what if rap music didn't suck". We can imagine it even though it's impossible. Take gravity. Drop that bottle of Zima you're drinking and it will move towards the floor at a velocity that increases by 32 feet per second, every second. The physical constant known as gravitational acceleration is always the same. Whenever you're exactly 6,300 kilometers away from the center of mass of an object that has a mass of one Earth, the gravitational pull on you will always be the same.

It cannot be any different. Because the property known as gravitational acceleration is completely dependent on other physical laws. The amount of light produced by a 100-watt light bulb is controlled entirely by movements in electron shells when propelled by electrical currents; electrical currents are controlled by the physical constants governing electrical and magnetic fields. And God only knows what a magnetic field is--yes, we know what a magnetic field does, but we don't know what it's made of.

If the strong interaction was a bit different and hydrogen was the only stable isotope, the only molecule capable of existing would be the H₂ molecule. And the only systems you could build with those would be a lot of hydrogen together. But even that would be quite dull, as no nuclear fusion would be possible and thus you would have no star but just a ball of hydrogen.

And you're sure hydrogen couldn't possibly do something you hadn't predicted....? (rhetorical question--the answer is no)

And your knowledge of the building blocks is quite limited as your statements are just wrong. The universe is not built from three building blocks, but there is a whole zoo of particles that we know of (and we do not even know what dark matter is made of).
And there is not just one quark, but there are twelve different types of quarks

Yeah. And twelve different types of quarks are still called quarks. Point remaining the same, whether it's one or three: you can still produce remarkable complexity from a very small number of fundamental particles. Conway's "Life" simulation uses only one. Yet it results in patterns that, paradoxically, always produce exactly the same outcome every time, but cannot be predicted without actually running the pattern.

 

[emzie]

Physics is weird.

 

[uppi]

Fine. So it changes the strength of interactions. Thereby bringing into play interactions that you hadn't predicted.

We know all the interactions of simple systems well enough, that there won't be any new interactions popping up if there was a small change in the physical constants as those would have been discovered by precision measurements a long time ago.

Have we....?

No but we could, if there actually was any doubt of what would happen. As there isn't nobody is interested in wasting valuable measurement time.

And here's another thought: suppose it's not possible for the physical constants of the universe to be anything else? "If they were" is currently only a thought exercise (that hasn't been tested), just as "what if rap music didn't suck". We can imagine it even though it's impossible.

Well, yes, if there was an explanation why the constants have the value they have there would be no argument. But currently there isn't and the entire premise of this discussion and this thread is that there might be no explanation for that (you know - the infinite universes thing)

Take gravity. Drop that bottle of Zima you're drinking and it will move towards the floor at a velocity that increases by 32 feet per second, every second. The physical constant known as gravitational acceleration is always the same. Whenever you're exactly 3,200 kilometers away from the center of mass of an object that has a mass of one Earth, the gravitational pull on you will always be the same.

No. Actual measurements show, that gravity varies quite a lot over the surface of the earth.

It cannot be any different. Because the property known as gravitational acceleration is completely dependent on other physical laws. The amount of light produced by a 100-watt light bulb is controlled entirely by movements in electron shells when propelled by electrical currents; electrical currents are controlled by the physical constants governing electrical and magnetic fields. And God only knows what a magnetic field is--yes, we know what a magnetic field does, but we don't know what it's made of.

Okay, so please tell me on which physical laws the gravitational constant depends on. (You might want to publish it somewhere first, so that nobody else gets the Nobel prize).

I won't bother correcting all the other mistakes of your explanation as that would lead nowhere. Except that armed with special relativity it is actually very easy to say what a magnetic field is.

And you're sure hydrogen couldn't possibly do something you hadn't predicted....? (rhetorical question--the answer is no)

Actually yes. Hydrogen is the one system we do understand almost perfectly.

Yeah. And twelve different types of quarks are still called quarks. Point remaining the same, whether it's one or three: you can still produce remarkable complexity from a very small number of fundamental particles. Conway's "Life" simulation uses only one. Yet it results in patterns that, paradoxically, always produce exactly the same outcome every time, but cannot be predicted without actually running the pattern.

But six quarks (with three different colors), six leptons and four gauge bosons and their antiparticles are quite a bit more than just one particle. And your "Life" example makes no sense: Why wouldn't a deterministic set of rules always produce the same outcome form the same initial pattern?

 

[Gamemaster77]

What exactly are you debating?

 

[warpus]

i have no idea what the universe actually looks like, but i love how basket case knows it exactly and beyond any doubt.

Silence! He knows everything

 

[BasketCase]

We know all the interactions of simple systems well enough, that there won't be any new interactions popping up if there was a small change in the physical constants as those would have been discovered by precision measurements a long time ago.

Unless (#1) we don't have any instruments with sufficient precision to measure them.
And, unless (#2) some of those previous interactions were zero and were therefore not interesting enough to notice.

No but we could, if there actually was any doubt of what would happen. As there isn't

Doesn't matter. A hypothesis must be tested before it can be accepted as fact. The argument "nobody cares if it's false, therefore it's true" doesn't cut the mustard. You think you know what would happen if the physical constants of the universe changed? Prove it.

No. Actual measurements show, that gravity varies quite a lot over the surface of the earth.

Cue exasperated sigh. What did I say last post?? That if you're exactly 6,300 kilometers away from Earth's center of mass, Earth's gravitational pull on you will always be the same. Of course that pull changes elsewhere on the Earth because you're different distances away from the center of mass.

I re-iterate: the same amount of mass always exerts exactly the same amount of gravitational pull.

Okay, so please tell me on which physical laws the gravitational constant depends on.

Covered by general relativity. The gravitational constant is determined by the curvature of space produced by an object of a given mass. A bowling ball that weighs exactly fifteen pounds and is exactly ten inches across will always curve spacetime by exactly the same amount.

And your "Life" example makes no sense: Why wouldn't a deterministic set of rules always produce the same outcome form the same initial pattern?

That wasn't what I was aiming at. The fascinating thing about Conway's Life is, we can't predict it. Even though it is deterministic. There is no mathematical formula anywhere that will tell us what this or that Life pattern will do; there is no way to predict the outcome until we actually see it.

Based on that, I think you're assuming much that you shouldn't.

What exactly are you debating?

uppi and I are somewhere between quantum physics and Creation Science. Scary neighborhood. Full of wierd people and strange quarks.

 

[Gamemaster77]

uppi and I are somewhere between quantum physics and Creation Science. Scary neighborhood. Full of wierd people and strange quarks.

Haha i see what you did there, physics humour, haha. Also Im not sure whis on what side but I dont see why you can't have both. Imagine you create a computer simulation that simulates life (I know Im being overly simplistic here), you would effectivly be the god of all those creations. Just like i believe God can, you can make things happen in your simulation because you made it, and have backdoors allowing you to temporarily bend the laws you have set in place.

 

[BasketCase]

Yes, Conway's Life is a bit like that. But Conway's Life also proves something near-opposite, and more subtle. The "Life" universe does require an initial Creation--the gameboard itself, the ruleset, and the initial setup of Life cells. But after that, depending on the pattern you start with.....

.....utter simplicity can evolve into marvelous complexity--sometimes infinite complexity--with no divine intervention at all.

In other words: Conway's Life proves that all the life we see on Earth can indeed evolve without God. It doesn't prove that it did, only that it can.

 

[uppi]

Unless (#1) we don't have any instruments with sufficient precision to measure them.
And, unless (#2) some of those previous interactions were zero and were therefore not interesting enough to notice.

Doesn't matter. A hypothesis must be tested before it can be accepted as fact. The argument "nobody cares if it's false, therefore it's true" doesn't cut the mustard. You think you know what would happen if the physical constants of the universe changed? Prove it.

#1, our instruments are extremely precise. We talking a rather small change here, any effect should be already measurable.

#2, If interactions would cancel out, these would have to be new interactions which we have no knowledge of yet. And then we are already outside of the "just the physical constants change" scenario and you are postulating new physics. And for new physics you have to make testable predictions instead of "uhh...something could be different"

#3, you seem to fundamentally misunderstand the scientific method: There is no way you can prove a hypothesis.

Cue exasperated sigh. What did I say last post?? That if you're exactly 3,200 kilometers away from Earth's center of mass, Earth's gravitational pull on you will always be the same. Of course that pull changes elsewhere on the Earth because you're different distances away from the center of mass.

I re-iterate: the same amount of mass always exerts exactly the same amount of gravitational pull.

(Btw: If you're 3200km away from earth's center you would feel other forces than earths gravity. Being inside the earth's outer core and all that)

You might want to read that article again. And unless you totally fail at reading comprehension, you should notice that this is earth's gravity measured from a satellite. Which is at constant height from the center of the earth. Yet it measures different gravity, depending on location. Fascinating, isn't it? And no, this is not dependent on height. Or else the Himalaya would not be the same color as the ocean, although the former is clearly farther away form the center as the latter.

Covered by general relativity. The gravitational constant is determined by the curvature of space produced by an object of a given mass. A bowling ball that weighs exactly fifteen pounds and is exactly ten inches across will always curve spacetime by exactly the same amount.

If you had taken even a quick look at Wikipedia instead of talking about things you don't know about, you would have noticed: The gravitational constant is explicitly a part of the Einstein equation. So the gravitational constant has the same reason for its value in General Relativity as in Newtonian gravity: None.

That wasn't what I was aiming at. The fascinating thing about Conway's Life is, we can't predict it. Even though it is deterministic. There is no mathematical formula anywhere that will tell us what this or that Life pattern will do; there is no way to predict the outcome until we actually see it.

Based on that, I think you're assuming much that you shouldn't.

It's a highly nonlinear chaotic system, so it's no wonder that it is hard to predict. Hydrogen isn't.

uppi and I are somewhere between quantum physics and Creation Science. Scary neighborhood. Full of wierd people and strange quarks.

Well, yeah, I am the quantum physicist. Who are you, then?

 

[ParadigmShifter]

I'm sure the same amount of mass exerts the same amount of pull if you assume that everything is a point mass and can't do integral calculus.

 

[Earthling]

The fascinating thing about Conway's Life is, we can't predict it. Even though it is deterministic. There is no mathematical formula anywhere that will tell us what this or that Life pattern will do; there is no way to predict the outcome until we actually see it.

You're actually wrong and don't know seem to understand how Conway's Game of Life works. Not that it probably matters as I'm not sure anyone else sees this as pertinent or evidence towards another point you're making rather than a nonsense tangent not even using terms correctly. But anyway it's not accurate. A cursory overview would show someone else the truth about structures like gliders but just to make it clear to everyone in thread without having to waste further time.

 

[BasketCase]

#1, our instruments are extremely precise.

Are they infinitely precise? No.

And then we are already outside of the "just the physical constants change" scenario and you are postulating new physics.

And you're posulating that we already know everything there is to know about the physical constants of the universe. We don't. The simple fact that you said that calls your obedience to the scientific method into question.

All things science need to be tested under controlled conditions. No exceptions. Testing different values of universal constants is not a waste of time; science never is. Though there might be an extremely small risk of blowing up the Earth if our test chamber flips a constant too far the wrong way.....

you seem to fundamentally misunderstand the scientific method: There is no way you can prove a hypothesis.

Hypothesis: if the physical constants of the universe were different, the universe itself would be different in ways uppi cannot predict.

Way to prove the above hypothesis: change the constants of the universe (and uppi himself said we can, in laboratory conditions) and see what happens.

There. I posted a hypothesis and a way to prove it. Therefore it is possible to prove a hypothesis. Of course, at that point it stops being a hypothesis.....

You might want to read that article again. And unless you totally fail at reading comprehension, you should notice that this is earth's gravity measured from a satellite. Which is at constant height from the center of the earth. Yet it measures different gravity, depending on location. Fascinating, isn't it?

Nope. Easily explained, and therefore boring. The satellite isn't measuring gravity with perfect accuracy (see my very first sentence up top) and the satellite's altitude is not actually constant because it's being pulled around by the gravity from the Sun, the Moon, other objects in orbit, etc.

(Btw: If you're 3200km away from earth's center you would feel other forces than earths gravity. Being inside the earth's outer core and all that)

Oh yeah. That was supposed to be 6,300. I'll correct that straightaway. The concept still got across to everybody just fine.

It's a highly nonlinear chaotic system, so it's no wonder that it is hard to predict. Hydrogen isn't.

No. A conglomeration of hydrogen atoms is a good deal more complicated than Conway's Life.

 

[ParadigmShifter]

Do you think the Earth's matter is evenly distributed with respect to density or something? Isn't it a bit weird that certain things float on water? You do know that some things float on water, don't you? You do know that water is like 70% of the Earth's surface, do you not? How do you think that affects the gravitational formula?

 

[B-29 Bomber]

I believe it's possible and I think time travel has something to do with it. Let's say you travel back to December 5, 1941. You have brought with you a carrier task force armed with the latest aircraft. You go to the military higher ups with the warning that Imperial Japan is planning a sneak attack on Pearl Harbor. Assuming you can convince them of the threat, you've just entered into an alternate universe.

 

[uppi]

Are they infinitely precise? No.

But precise enough that we can do calculations with it. You know, math and that stuff.

And you're posulating that we already know everything there is to know about the physical constants of the universe. We don't. The simple fact that you said that calls your obedience to the scientific method into question.

I seriously begin to doubt your reading comprehension. I never said we know everything. I said, if we take our current theories and randomly change the constants we would very likely end up in a very dull universe unable to support life. I have said, and I say it again, there might be ways to explain why the constants are what they are. But despite your misguided attempts to support this, we do not know anything in this direction. With new physics we might find an explanation, but we will have to discover and find evidence for this new physics first.

All things science need to be tested under controlled conditions. No exceptions. Testing different values of universal constants is not a waste of time; science never is. Though there might be an extremely small risk of blowing up the Earth if our test chamber flips a constant too far the wrong way.....

Hypothesis: if the physical constants of the universe were different, the universe itself would be different in ways uppi cannot predict.

Way to prove the above hypothesis: change the constants of the universe (and uppi himself said we can, in laboratory conditions) and see what happens.

There. I posted a hypothesis and a way to prove it. Therefore it is possible to prove a hypothesis. Of course, at that point it stops being a hypothesis.....

Oh, you could try to falsify my assertion by simulating a universe with just hydrogen and discovering life in that. But within the scientific method, there would be no way to prove that no such things exists, as there would be an infinite amount of possible constant combinations to test. One can only ever find proof against a (positive) hypothesis, never full proof for one. (Of course it's the other way around with a negative hypothesis)

Nope. Easily explained, and therefore boring. The satellite isn't measuring gravity with perfect accuracy (see my very first sentence up top) and the satellite's altitude is not actually constant because it's being pulled around by the gravity from the Sun, the Moon, other objects in orbit, etc.

So, you are insinuating that the scientists are unable to control the flight path of their satellite and the fluctuations are so periodic that instead of washing everything out they actually lead to a pattern? And all this despite your apparent lack of understanding for Newton's gravity law and the calculus surrounding it?

No. A conglomeration of hydrogen atoms is a good deal more complicated than Conway's Life.

But because these are totally different systems and problems we have way better methods to calculate what is happening with hydrogen. The great minds of the last two centuries did not develop thermodynamics for fun but to solve exactly these kinds of problems.

 

[BasketCase]

Do you think the Earth's matter is evenly distributed with respect to density or something?

No. You guys are just nitpicking. Any given chunk of matter, of a particular shape and size, always exerts precisely the same gravitational field. You know that.

I believe it's possible and I think time travel has something to do with it. Let's say you travel back to December 5, 1941. You have brought with you a carrier task force armed with the latest aircraft. You go to the military higher ups with the warning that Imperial Japan is planning a sneak attack on Pearl Harbor. Assuming you can convince them of the threat, you've just entered into an alternate universe.

Are you sure? Have you moved to another universe, or changed the current one....?

<uncalled-for insult snipped> I never said we know everything. I said, if we take our current theories and randomly change the constants we would very likely end up in a very dull universe unable to support life.

Aha.....so, from the underlined part, I gather you're not sure what we would end up with? Good. You get what I was driving at.

Oh, you could try to falsify my assertion by simulating a universe with just hydrogen and discovering life in that. But within the scientific method, there would be no way to prove that no such things exists

Not with 100% accuracy, no. But by doing several iterations, we can make a guess at what the odds are.

In the meantime, keep this in mind: from what we've observed of the universe so far, intelligent life is an extremely rare thing. Yet.....here we are. I'm not a Creationist, but the fact is, we humans appear to be the physical embodiment of beating extremely long odds. It can happen, because it has at least once.

So, you are insinuating that the scientists are unable to control the flight path of their satellite and the fluctuations are so periodic that instead of washing everything out they actually lead to a pattern?

Not specifically. Could simply be other nearby satellites and space junk mucking up the sensors.

 

[Perfection]

Aren't there regimes where hydrogen behavior isn't perfectly understood, such as extreme pressure or ultra-low temperatures?

It also occurs to me there will be a brand new regime for hydrogen to behave in under the conditions of hydrogen only, the regimes in which now it fuses.

 

[emzie]

I believe it's possible and I think time travel has something to do with it. Let's say you travel back to December 5, 1941. You have brought with you a carrier task force armed with the latest aircraft. You go to the military higher ups with the warning that Imperial Japan is planning a sneak attack on Pearl Harbor. Assuming you can convince them of the threat, you've just entered into an alternate universe.

I seem to recall that being in a movie.

 

[uppi]

Aren't there regimes where hydrogen behavior isn't perfectly understood, such as extreme pressure or ultra-low temperatures?

It also occurs to me there will be a brand new regime for hydrogen to behave in under the conditions of hydrogen only, the regimes in which now it fuses.

At ultra-low temperatures hydrogen is pretty well understood. Although there is still exciting research in the field of ultra-cold quantum gases, the research has mostly shifted from "what happens?" to "What cool things can we do with it?"

The regime where it now fuses is also pretty well explored, because the effects of fusion are actually quite small (or otherwise the sum would have used up all hydrogen long ago). A large part of doing fusion research is understanding how an ultra-hot hydrogen plasma behaves and how to control it. Fusion complicates things a bit, but most of the research has to be concerned with the effects of "just" a very hot hydrogen plasma.

There are parameter regimes that are less explored or less accessible, but although a ball of hydrogen might behave a bit strangely at those, it really hasn't enough degrees of freedom to form a complex internal structure.