A question about life, the universe and everything.

[c_dug]

This is something I ponder occasionally, it might be a bunch of bollocks but I figure somebody more sciencey than me might be able to answer.

My impression of physics and chemistry is that if you know all of the parameters of something then you can work out with 100% accuracy the result. There is no element of random to it. So for instance two chemicals combined under exactly the same conditions will give the same result time after time after time.

Assuming I am not wrong with that, does that mean that everything that ever happened and will ever happen is a forgone conclusion?

So for instance if you had an impossibly smart computer and you input every single atom or particle of the big bang, and all of the parameters, you could map everything that happened after and everything that will happen?
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Snorty]

Ha, I once thought about this and came to the same conclusion as you.

https://en.wikipedia.org/wiki/Determinism

Have a read
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[Howling TerrorOutOfOffice]

Dunno guv.

Read this?
https://upload.wikimedia.org/wikipedia/en/e/ed/Bill_bryson_a_short_history.jpg
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[syl]

But you can never have all of the parameters. Measuring them causes them to change.
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[The Artist]

[stinkwheel]

[CaNsA]

[Ariel Badger]

Quantum Physics is so weird that it makes God look a more viable explanation for the universe.
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[Lord Percy]

Yeah you can't control 'everything' at the moment because of the uncertainty in measurement of the properties of subatomic particles (or are they waves? ).

A brief explanation because I have an exam on this in a couple of weeks:

Heisenberg's uncertainty principle (which has been verified many times) states:

https://upload.wikimedia.org/math/0/a/1/0a1c02498125a255a2f5b0e58908a8ae.png

Where ħ is a fixed value called Planck's constant. Essentially it's just a big number with a letter assigned to it.

Δx ("Delta x") is the uncertainty in the measurement of an object's position. eg if you use a ruler to measure a bouncy ball, you'll have an uncertainty of Δx = 0.5mm because the ruler only goes in 1mm intervals, so you need to account for the fact that the measurement might be at some point in between.

Δp is the uncertainty in measurement of an object's momentum (or velocity, kind of).

So ΔxΔp is always greater than this fixed value ħ/2 .

ΔxΔp>ħ/2

This immediately limits the accuracy with which we can know anything about an object. To illustrate this, imagine you were able to measure the momentum of something with such accuracy that the uncertainty was absolutely tiny. Then imagine measuring it even more accurately, and more accurately, and more and more and more until it's so accurate that Δp is so vanishingly small that you could almost say Δp=0 . But for this to be the case, it would mean Δx is absolutely huge, or infinite! Because the product ΔxΔp must always amount to ħ/2 .

So, the more accurately you know about an object's momentum, the less you know about its position, and vice versa. This is why you can't ever make absolute predictions about subatomic particles.

However for large objects it's different because the uncertainty in measuring them is negligible compared to their actual sizes. eg when launching a spaceship the uncertainty in its launch position will be so tiny when compared with the scale of the whole thing, and so the uncertainty can be ignored. So for dealings with large objects - eg sending probes to deep space to orbit Saturn - we certainly do have the ability to plan, predict, control and foresee what will happen.

Big Bang stuff isn't possible though because of the uncertainty in position, momentum and energy of each 'thing'.

String theory's trying to fix it though.

Physicists like to think they can predict absolutely everything, so here's a joke about them: "It only works in the case of spherical cows in a vacuum."

[Suntan Sid]

42!
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[CaNsA]

[Llama-Farmer]

Heisenberg's Uncertainty Principle and the Observer's Effect.

Not all parameters can be known or measured because if they are they are affected and thus render the principle invalid.


I do love all the paradoxes and thought experiments. I used to "waste" hours of physics lessons by drawing the physics teacher into discussions about quantum and theoretical physics amongst other things, that were more interesting that the stuff we were supposed to be learning.
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[dydey90]

Physics and calculations aside, as soon as living creatures evolve, all predictability goes out of the window. How can you predict which blade of grass a rabbit will eat? Where it will take a dump and fertilise the soil?
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[c_dug]

Because in the end an animal, be it a rabbit or a human is all just a bunch of elements interacting in a specific way?
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[GhostRider]

[The Artist]

[GhostRider]

I don't believe I have ever heard/read the term "watching" used for the measurement of anything in a scientific setting, be that in the lab itself or in any science papers/journals.

You might say "we determined the concentration of the protein via measurement of optical density at 280nm with the relevant extinction coefficient".

You wouldn't say "we watched the protein to determine its concentration". Hell you wouldn't even say "we watched the A280nm measurement" Unless you wanted to be regarded as a retarded cunt of course.

The trouble is semantics is important in this instance, since so many people get it very wrong and start drawing all sorts of bizarre conclusions about the nature of the universe and how it works as they believe that watching things, as in looking at them directly, alters their behaviour as a direct result of them having been looked at (thus being aware of their observation).

GhostRider
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[The Artist]

Fair enough but explaining fairly complex experiments to non scientists, I think most people will get the whole watching = measuring thing.

[c_dug]

As a non scientist I prefer the way GR explained it, to me watching involves no interaction so if watching something makes it do something else it creates far more questions than it answers.



None of this really explains much though, there must be a rule of some kind that particles follow, even if we don't know it yet, so for instance if you measure a particle in a particular way it reacts in a predictable manner?
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[GhostRider]

[GhostRider]

[DrSnoosnoo]

It's just one of those things, we can't know everything at the same time but as our understanding develops our predictive models can evolve to become more predictive.

I've done a design of experiments which was once used to predict the ability to remove grease from textiles. I had 6 variables, 3 concentrations each and carried each experiment out. The model which was developed still wasn't very accurate when I tested some optimised systems.
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[Rogerborg]

Leave aside Heisenberg and pretend that you could know position and velocity at the same time. You'd need to do that to make a Star Trek transporter, which as we know are factual, because we saw them in the Documentary Series.

But...

[stinkwheel]

[Llama-Farmer]