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At Multiverse Impasse, a New Theory of Scale

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Re: At Multiverse Impasse, a New Theory of Scale

#51

Post by lifeisstillgood »

lutusp wrote: post #19
lifeisstillgood wrote: post #16

Earlier quoted context omitted.

Well, I don't think I understand entropy - even after Wikipedia. So is there somewhere in universe some energy that is not available to do anything at all? How does that work? Is it too diffuse such that the energy needed to pull it together to perform a unit of work is greater than the energy available ? If so how did it get to that state?

> Well, I don't think I understand entropy - even after Wikipedia. Okay, here's a commonly used explanation. Entropy and time are bound together -- as time passes, overall entropy increases (with local violations like us). This is one idea about why time "moves" in the direction it does -- if time were to reverse, we could tell because some classic entropy results would run in reverse, violating common sense. Imagine…

Thank you

Re: At Multiverse Impasse, a New Theory of Scale

#52

Post by snowwrestler »

lutusp wrote: post #19
lifeisstillgood wrote: post #16

Earlier quoted context omitted.

Well, I don't think I understand entropy - even after Wikipedia. So is there somewhere in universe some energy that is not available to do anything at all? How does that work? Is it too diffuse such that the energy needed to pull it together to perform a unit of work is greater than the energy available ? If so how did it get to that state?

> Well, I don't think I understand entropy - even after Wikipedia. Okay, here's a commonly used explanation. Entropy and time are bound together -- as time passes, overall entropy increases (with local violations like us). This is one idea about why time "moves" in the direction it does -- if time were to reverse, we could tell because some classic entropy results would run in reverse, violating common sense. Imagine…

> Entropy and time are bound together -- as time passes, overall entropy increases (with local violations like us). This is one idea about why time "moves" in the direction it does -- if time were to reverse, we could tell because some classic entropy results would run in reverse, violating common sense.

As an aside, this is my own pet theory as to why some actions of living beings seem to resist scientific prediction. Observed within its own boundaries, a living being appears to be a system that locally decreases entropy; therefore within those boundaries it does not appear to operate causally.

So for example we can predict a human being who is deprived of food will die (basic energy balance), but we can't use science to predict what color shirt they will choose to wear next Tuesday.

Re: At Multiverse Impasse, a New Theory of Scale

#53

Post by snarfy »

danbruc wrote: post #44
givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

For the moment it seems to me that there is no chance to ever know what something REALLY is. There is obviously stuff out there that behaves exactly like mathematical models we made up - there are things called electrons behaving like our model of electrons interacting with things called photons behaving like our models of photons. But what does this tell you about the nature of electrons and photons? Is a electron j…

Why are all electrons the same? It's because they are all manifestations of the same electric field. But then what is the electric field? Yep, it's a rabbit hole.

Re: At Multiverse Impasse, a New Theory of Scale

#54

Post by Ono-Sendai »

lifeisstillgood wrote: post #16
lutusp wrote: post #4

Earlier quoted context omitted.

Entropy = the inverse of available energy to do anything at all. EDIT: Look -- if you don't understand physics, don't compound your ignorance by downvoting the posts of people who do. Instead, post a written objection, and I will explain why you're wrong.

Well, I don't think I understand entropy - even after Wikipedia. So is there somewhere in universe some energy that is not available to do anything at all? How does that work? Is it too diffuse such that the energy needed to pull it together to perform a unit of work is greater than the energy available ? If so how did it get to that state?

Entropy = disorder/randomness.

Re: At Multiverse Impasse, a New Theory of Scale

#55

Post by antimagic »

JackC wrote: post #50

For a heroic attempt to explain this article to laypeople, check out physicsmatt's comments over at Metafilter: "First, for maximum sense-making, read my previous comments here, here, here, and here. I realize that's a lot, sorry. The Universe is complicated. Then, for what follows, recall that to a particle physicist such as myself, there is no difference between lengths and energies (or indeed, any other dimensiona…

Or don't - it's incredibly badly written, in the sense that it often descends into grammatical gibberish, even without worrying about the physics the gibberish is trying to describe.

Re: At Multiverse Impasse, a New Theory of Scale

#56

Post by mSparks »

calinet6 wrote: post #41
mSparks wrote: post #11

I don't see why this kills the multi verse theory. Which is a basic conclusion of a 10 dimensional space-time environment that doesn't include mass anyway.

It "kills it" because it's only really appealing if the universe we're in appears extremely unlikely, like it's the "just right" goldilocks balance of cosmic variables that we can't explain, that happened to be the stable ones that resulted in life evolving eventually. If the universe is actually very likely to occur in the state that it's in, then we don't need to use this "vast multiverse where our universe was the…

But the whole point of the multi verse model is that universe also exists. Multi verse theory afaik is just a mathematical construct of the various dimensions we can observe in a space time framework.

The whole http://en.m.wikipedia.org/wiki/Flatland Idea.

Re: At Multiverse Impasse, a New Theory of Scale

#57

Post by thibauts »

danbruc wrote: post #44
givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

For the moment it seems to me that there is no chance to ever know what something REALLY is. There is obviously stuff out there that behaves exactly like mathematical models we made up - there are things called electrons behaving like our model of electrons interacting with things called photons behaving like our models of photons. But what does this tell you about the nature of electrons and photons? Is a electron j…

Maybe asking what things REALLY are has no meaning. Do objects have characteristics apart from what we can (physically) interact with and measure ? If thoses characteristics exist but aren't measurable can we say they are real ? Does it make any sense ?

I often use this line of thought to talk about God with open-minded believers. If there is a God that created our reality and acts on it, then the effects of these actions are real in our sense and thus measurable. It then follows that God isn't separate from the natural world and can be observed like many other natural phenomena we don't look at directly. Without a chain of interactions this wouldn't be possible.

What I mean is our reality is one of interactions. What is real to us, and what can be called "existing" is what interacts directly or indirectly with our senses and our minds. What we mean by "nature" on a large scale is ultimately internal structure. Once we hit a level where internal structure doesn't make sense anymore, I'm not sure what we are looking at and what the word "nature" can be made to encompass.

Re: At Multiverse Impasse, a New Theory of Scale

#58

Post by macspoofing »

givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

Only one way to find out.

Re: At Multiverse Impasse, a New Theory of Scale

#59

Post by macspoofing »

axilmar wrote: post #45
givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

I do not think that it is possible. Any physical system that can be described by a set of mathematical laws is bound to have some axioms that simply cannot be proven within its context. Godel's incompleteness theorems prove that. Hence, we will never get to the bottom of the reality of our universe.

What if we live in a universe/reality where anything that can happen, does happen. And the reason for this state is because it just is.

Re: At Multiverse Impasse, a New Theory of Scale

#60

Post by protonfish »

givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

There is this belief propagated among physicists that smaller scales somehow have more to do with reality. I have never been presented with logic or evidence that convinced me that an electron is somehow more "real" than a molecule or a person or the solar system or the observable universe.

I wish the word "reality" would stop being thrown around without justification. "Fundamental" might be a more appropriate term.

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