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United Kingdom3482 Posts
I've been wanting to start writing about some of the interesting stuff I'm learning in my physics degree or stuff I've read around the subject for a while now. A kind of introduction to physics for people who didn't know much about it. I was planning on starting this week and then my PSU broke. Then the new one I bought was broken so while I wait for a replacement I'm stuck with only a phone and can't do the subject justice. So for now I'll just write a bit about why physics is so interesting. Also I haven't slept for 30 or so hours so this could be a bit rambling.
Everything, when you look closely enough, relies on physics. Even all the complex processes that make you who you are can be described by fundamental physical process. And we didn't even know some of what was going on even existed till the mid 20th century. In fact the last 100 years has seen a massive change in how we perceive the world and how nature works. We have gone from thinking the universe was euclidian and obeyed deterministic laws to one where space, on a small scale at least, is curved and intrinsically linked with time and that there is an inherent probabilistic nature to how everything interacts.
By far the most interesting thing is that this isn't the whole picture. We know that there are holes in our current theories. We know that quantum mechanics and relativity don't work well together when you have situations where you are dealing with large masses in a small area, for example black holes. We don't have a good understanding of how gravity works. There is the relativistic model of gravity where gravity is a by product of the curvature of space and not a force in the way electromagnetism and the strong and weak nuclear forces are or the proposed particle physics explanation where a particle, which has been dubbed the graviton, acts the force carrier for gravity. We know the standard model is incomplete in other ways as well. We don't have a definite candidate for dark matter which appears to be far more abundant in the universe than ordinary matter. We don't even have a definite understanding of the implications of quantum mechanics, a field of physics that has been around since the start of the 20th century.
It is all these unanswered questions that make physics, and all science for that matter, such an interesting subject.
 
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I absolutely agree. Everything relies on physics/fundamental physical processes. You realize that really quickly when you work in the medical field. I really enjoyed reading your blog! Seems like you found something that interests you and sparks a lot of questions - there's nothing better.
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Jesus answered those questions long ago, duh.
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I know that a lot of things in SC2 are implausible or inconsistent with physics, but can you name something that you feel is something that could happen in the future?
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United Kingdom3482 Posts
On January 25 2013 21:23 Grumbels wrote:
I know that a lot of things in SC2 are implausible or inconsistent with physics, but can you name something that you feel is something that could happen in the future?
I don't really understand what you are asking.
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On January 25 2013 21:29 imallinson wrote:Show nested quote +On January 25 2013 21:23 Grumbels wrote:
I know that a lot of things in SC2 are implausible or inconsistent with physics, but can you name something that you feel is something that could happen in the future? I don't really understand what you are asking.
yellow
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On January 25 2013 21:29 imallinson wrote:Show nested quote +On January 25 2013 21:23 Grumbels wrote:
I know that a lot of things in SC2 are implausible or inconsistent with physics, but can you name something that you feel is something that could happen in the future? I don't really understand what you are asking.
I think he wants to know whether some of the things in the Starcraft universe could be possible within the laws of physics in ours, i.e. blink stalkers or something. I think ^^
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United Kingdom3482 Posts
On January 25 2013 21:32 loazis wrote:Show nested quote +On January 25 2013 21:29 imallinson wrote:On January 25 2013 21:23 Grumbels wrote:
I know that a lot of things in SC2 are implausible or inconsistent with physics, but can you name something that you feel is something that could happen in the future? I don't really understand what you are asking. I think he wants to know whether some of the things in the Starcraft universe could be possible within the laws of physics in ours, i.e. blink stalkers or something. I think ^^
I'm not convinced teleportation is even possible. You basically have to decompose the matter and somehow rebuild it exactly as it was at the other end. Given how many atoms are in a person I can't see this actually being possible.
edit: even if it were possible it would require some very complex equipment. Not something you could fit on a stalker sized object.
edit: from a quick Google search the number of atoms in an average human is about 7,000,000,000,000,000,000,000,000,000. Figuring out how all of them are arranged is basically impossible never mind building a replica from scratch.
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i disagree with both of your statements^
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I have always found physics to be very interesting, although I'm rarely intelligent enough to truly understand what it is dem scientists are doing. I'd recommend the show "through the wormhole" for anyone like me that just needs a few more pretty pictures to understand all the theory 
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On January 25 2013 21:23 Grumbels wrote:
I know that a lot of things in SC2 are implausible or inconsistent with physics, but can you name something that you feel is something that could happen in the future?
Yes, almost all of it is. (Source: physics degree)
Teleportation, (mechanical) telepathy, (theoretical) time travel, wormholes (warp gates), laser weapons, cloaking, Zerg-scale genetic engineering and shields should all be possible.
I agree physics is beautiful but I think the way it is currently taught succeeds in killing one's interest in it rapidly.
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On January 25 2013 21:39 imallinson wrote:Show nested quote +On January 25 2013 21:32 loazis wrote:On January 25 2013 21:29 imallinson wrote:On January 25 2013 21:23 Grumbels wrote:
I know that a lot of things in SC2 are implausible or inconsistent with physics, but can you name something that you feel is something that could happen in the future? I don't really understand what you are asking. I think he wants to know whether some of the things in the Starcraft universe could be possible within the laws of physics in ours, i.e. blink stalkers or something. I think ^^ I'm not convinced teleportation is even possible. You basically have to decompose the matter and somehow rebuild it exactly as it was at the other end. Given how many atoms are in a person I can't see this actually being possible. edit: even if it were possible it would require some very complex equipment. Not something you could fit on a stalker sized object. edit: from a quick Google search the number of atoms in an average human is about 7,000,000,000,000,000,000,000,000,000. Figuring out how all of them are arranged is basically impossible never mind building a replica from scratch.
And teleportation will kill you every time you do it (by disintegration. You will literally stop to exist, save your atoms.) An old argument, but still gold.
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I agree that the universe is awesome. When I say awesome, I mean it. Awe inspiring. Worthy of awe.
I want to get in to quantum computing. :D I've seen documentaries that touch on it briefly, but those aren't enough for me, because they don't give me a deep understanding of the subject, which I want.
However, you didn't explain WHY physics is fucking awesome. Just saying.
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I have a Question for you:
How can the universe be Finite? What is there at the "end" ?
So, we know that the most remote objects we can see are Quartz some 15 bilion light years aqay from us. But how is it possible that space is limited? like quantified i mean. So i heard talk about the Theory of infinite parallel universes, but i don' t believe in that. Infinite does not exist. Nothing material can be infinite. One day, (if the nature persues its course) the Sun will implode and all life as we know it on earth will come to an end.
An example of why i do not believe in this theory. If i stand on my street, i see up to a certain point. Lets assume i never moved from where i stand, and therefore i do not know what is beyond from where i can see. Now, thanks to technology, i can access google maps and see what is beyond my street, and i see another street. However, many years ago (say 2000) i could not do this. The only way i could this was by actually travelling to that other street i could not see. Or i could just stand where i was and assume, try to imagine what was there. And maybe someone would come and tell me that beyond my road there where infinite roads, when in fact they are many roads in the world but they are Finite definable number.
The same with our universe. We were able to map it because we developed the technology to do it. But we still don' t have the technology to see beyond a certain point. Thats my opinion. Like we don' t have the technology to truly see what is at the center of our earth.
So, the question that has always bugged me, was what is there beyond what we can see and how is it possible that "space" is limited?
I' d like to hear your opinion on the subject
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On January 26 2013 01:02 pebble444 wrote:
I have a Question for you:
How can the universe be Finite? What is there at the "end" ?
So, we know that the most remote objects we can see are Quartz some 15 bilion light years aqay from us. But how is it possible that space is limited? like quantified i mean. So i heard talk about the Theory of infinite parallel universes, but i don' t believe in that. Infinite does not exist. Nothing material can be infinite. One day, (if the nature persues its course) the Sun will implode and all life as we know it on earth will come to an end.
An example of why i do not believe in this theory. If i stand on my street, i see up to a certain point. Lets assume i never moved from where i stand, and therefore i do not know what is beyond from where i can see. Now, thanks to technology, i can access google maps and see what is beyond my street, and i see another street. However, many years ago (say 2000) i could not do this. The only way i could this was by actually travelling to that other street i could not see. Or i could just stand where i was and assume, try to imagine what was there. And maybe someone would come and tell me that beyond my road there where infinite roads, when in fact they are many roads in the world but they are Finite definable number.
The same with our universe. We were able to map it because we developed the technology to do it. But we still don' t have the technology to see beyond a certain point. Thats my opinion. Like we don' t have the technology to truly see what is at the center of our earth.
So, the question that has always bugged me, was what is there beyond what we can see and how is it possible that "space" is limited?
I' d like to hear your opinion on the subject
There is no end or boundary to space but it is finite. Imagine standing on a spherical surface and trying to run around it and find the "edge". You can't yet it's still finite in size. That is like the 2D analog to the 3D universe.
The universe is constantly growing in size at a rate faster than the speed of light. At the moment of the big bang there was no space or time. What the big bang really signifies is the expansion of space-time from point like to a finite size. It's helpful to imagine space and time as physical entities that can expand, bend etc rather than just being concepts.
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United States115 Posts
You're so close to the truth, yet so far.
Clearly everything is explained by Math, the language of physics. I mean, after all, God created the integers. And the rest is just abstraction from there. All of physics, and by extension the universe (and all possible universes, as well as the completely abstract) relies on Mathematics.
xkcd Purity
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On January 26 2013 01:02 pebble444 wrote:
So, the question that has always bugged me, was what is there beyond what we can see and how is it possible that "space" is limited?
Here's an easy analogy to conceptualize a finite universe. Imagine that we lived in a one-dimensional universe, like a number line. Possible universes:
1. The entire real line. This is what most people imagine; space stretching on forever in all (both) directions. Plausible.
2. A finite but really really really large interval around zero, say [-a,a] for some obscenely large number a. This is what you're imagining as a finite universe, where there's a sudden end at a point too far away for us to observe. You're right to think this is implausible, unless there's more to the story. Not likely.
3. Same as before, but an open interval (-a,a). Basically just as implausible, but now there is no location which is literally "the edge of space". Not likely.
Here's where it gets interesting.
4. A finite interval, say [-1,1], but with the endpoints identified, so just when you would fly off the left end of the universe, you reappear on the right end heading back to your start point. Note that this is the same as replacing the number line with a circle. This works just as well in higher dimensions -- think of Asteroids, where if you fly off the edge of the screen you reappear on the opposite edge. You're actually flying around on the surface of a sphere in Asteroids. This is the same as what L3gendary said. Very plausible. #topologyfuckyeah
5. A finite open interval, say (-1,1), but with the laws of physics rigged up so that the closer you are to the boundary, the more energy it takes to move towards it. There's an "end" to space in that there is a maximum distance two objects can be from each other, but it's still sensible because you cannot fly off the edge without using infinitely large quantities of energy, which you do not have. Plausible.
6. More exotic stuff. Take the real line and delete zero. In each half, rig physics so it takes arbitrarily large amounts of energy to approach the zero point. You now have two mirror universes. Why stop there? Take the real line and delete all the integers, making each subinterval (n,n+1) its own universe like those in 4 or 5 above. You now have infinitely many parallel universes. Go nuts. Perhaps less plausible, but cool.
Side note: physicists talk about "open" and "closed" universes to mean ones with positive or negative curvature, not ones whose shape is an open (without boundary) or closed manifold. Also, each spatial dimension need not have the same topology as the others... For example, imagine playing Asteroids where the top/bottom edges of the screen teleport you as usual, but otherwise it's a side-scroller; the left/right edges pan infinitely. Now you're flying on the surface of a cylinder.
Generalize this up to three spatial dimensions (intervals -> circles -> spheres) and there you go. Or however many spatial dimensions our universe actually has...
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United Kingdom3482 Posts
On January 26 2013 02:01 Artisian wrote:You're so close to the truth, yet so far. Clearly everything is explained by Math, the language of physics. I mean, after all, God created the integers. And the rest is just abstraction from there. All of physics, and by extension the universe (and all possible universes, as well as the completely abstract) relies on Mathematics. xkcd Purity
While maths is really interesting and physics is exceptionally reliant on it you need an interpretation of the maths to have a full understanding of how the universe works. But yes physics is mostly applied maths.
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United Kingdom3482 Posts
On January 26 2013 00:52 vOdToasT wrote:
I agree that the universe is awesome. When I say awesome, I mean it. Awe inspiring. Worthy of awe.
I want to get in to quantum computing. :D I've seen documentaries that touch on it briefly, but those aren't enough for me, because they don't give me a deep understanding of the subject, which I want.
However, you didn't explain WHY physics is fucking awesome. Just saying.
Quantum information and computation is a fascinating subject that I really don't know enough about 
Yeah I was a bit incoherent but I was trying to convey how much enjoyment I derive from learning how the universe works on a fundamental level.
edit: also that it's fascinating that even though we have figured out so much there is so much we still don't know.
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EPT
