Things I learned in physics class
POSTED BY: BadgersHat
UPDATED: Friday, August 12, 2005 15:00
VIEWED: 25158
PAGE 3 of 11
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Originally posted by thatweirdgirl:
No, I don't want to see it. Ack. Maybe he was high when he wrote that. Well crap.
So, anyone suggest a SANE physicist?
I may not be a physicist, but I'm into it! That good enough? Since all the others have proven there insanity, I would be proud to take his place
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"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show
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Quote:
Originally posted by TheGreyJedi:Quote:
Originally posted by SigmaNunki:
For example, the gun that the alliance uses does a lot to humans, but won't do a thing to a door.
The guns the alliance uses, to me at least, seem to be sonic based. Sound, no matter how focused, isn't going to do a whole lot to a heavy metal door with a solid lock. Not for a while at least. A human, however, with it's squishy fleshy bits is likely to catch the sonic wave like a sail and go flying back like a plastic bag in the breeze.
Seems to me that force is force no matter what it is projected against. Of course, if it was to shake or somesuch that wouldn't have any effect on a metal door, but a human wouldn't take to well to that. Same with micro-waves.
But, I seem to remember people reacting like they got hit, which means force against. This would make it such that the door would "feel" that same force.
That is unless the people reacting like they go hit is just my mistaken memory.
At any rate, I'm scheduled to re-watch the series over the next little while. *sigh* Way to long since I've watched them.
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"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show
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Quote:
Originally posted by fantasticlaughingfairy:
1. I don't quite understand the theory, but the closer an object gets to the speed of light, the more it weighs - which makes it even harder to pick up speed etc. Don't ask me why - it's true though apparently.
Be careful not to mix up weight with mass. As an object picks up speed it gains mass.
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2. Don't see how it'll help, but most of space is made up of dark matter - we can't see it - but it's there, and we know virtually nothing about it.
The existence of dark matter is far from certain. It's simply a way of making up the difference between the amount of matter/energy that we can see in the universe and the amount of matter/energy that there should be for our universe to behave the way it does. Fourskys would probably know more about this than I, seeing as his specialty is astronomy. (my focus is more towards quantum physics)
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3. It may be possible to travel through a wormhole (aparently space is curved or something). It may be impossible though, I don't know very much about them.
Who knows? The prevailing theory is that it would require far too much energy to create a decent sized wormhole and keep it open than is practical. Also, in order to keep the wormhole open you'd have to pump it with so much energy that anything you tried to shove through it would be vaporized. But that's all speculation. If the people from 'Sliders' say it's possible, then I'm inclined to believe them.
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Quote:
Originally posted by ColdFusion:
The existence of dark matter is far from certain. It's simply a way of making up the difference between the amount of matter/energy that we can see in the universe and the amount of matter/energy that there should be for our universe to behave the way it does. Fourskys would probably know more about this than I, seeing as his specialty is astronomy. (my focus is more towards quantum physics)
So (one of) the current theory(ies) about Dark Matter is that it likely would reside inside things with mass, but doesn't interact with things other than through the gravitation force (that is, you couldn't see it, that's an electromagnetic reaction). There are arguments for its existence through the rotation curves of galaxies (there appears to be more matter than is visible) and through observations of the cosmic microwave background. The cosmic microwave background is very convincing, and rules out 'normal' dark matter, such as cool stars and planets. This has to be a whole nother beastie all together. Something that, currently, we have no idea what it is.
As for it making up "All of space" that more along the lines of Dark Energy that you're thinking about. Which is completely different as well. Dark Energy makes up and permeates all of space, is EXPECTED (not shown or prooven, mind you) due to the accelerated expansion of the universe.
Both these problems are in the hands of cosmologists and particle physicists now.
Quote:
Originally posted by ColdFusion:
Who knows? The prevailing theory is that it would require far too much energy to create a decent sized wormhole and keep it open than is practical. Also, in order to keep the wormhole open you'd have to pump it with so much energy that anything you tried to shove through it would be vaporized. But that's all speculation. If the people from 'Sliders' say it's possible, then I'm inclined to believe them.
According to general relativity, the only way to get the curvature of spacetime required to create a wormhole is to have a particle with negative energy. Classically, there is no way to do this. Quantum mechanically, however, it is possible to have particles fluctuate to negative energies. But then you have the problem of making enough of them to stay in the negative energy superposition for a long enough time, and blah blah blah, pretty much impossible. On top of that, quantum mechanics and general relativity don't exactly see eye-to-eye, so there are plenty more vagueries where that comes in....
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Quote:
Originally posted by FourSkys:
According to general relativity, the only way to get the curvature of spacetime required to create a wormhole is to have a particle with negative energy. Classically, there is no way to do this. Quantum mechanically, however, it is possible to have particles fluctuate to negative energies. But then you have the problem of making enough of them to stay in the negative energy superposition for a long enough time, and blah blah blah, pretty much impossible. On top of that, quantum mechanics and general relativity don't exactly see eye-to-eye, so there are plenty more vagueries where that comes in....
It's been a while since I've done any general relativity, but if I remember correctly, the initial curvature can be created by normal energy/matter but it would need negative energy to hold it open. In either case, the main point of my comment was that this is one of those things that is on the fringe of physics. We don't have proven theories for such realms where both general relativity and quantum theory are applicable, so it's hard to predict what is beyond the next discovery. I certainly won't rule them out, it's good to keep an open mind.
Personally, I think that you can open a wormhole by pushing on a rope.
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Quote:Always a good practice. But things like negative energy, exotic matter, wormholes and faster then light travel always seem to be bounded by the requirement of some ridiculously insurmountable wall that ultimately requires some amount of energy equal to or larger then the universe itself. The laws of physics might allow a wormhole to be opened, but any wormhole large enough to serve human practice would, based on the quantum inequalities, require more energy then exists in the known universe.
Originally posted by ColdFusion:
I certainly won't rule them out, it's good to keep an open mind.
There are basically two schools of thought here, either the energy requirement is a product of an incomplete model or it’s real. There are lots of people who accept the incomplete model theory, diligently searching for some new discovery that will usher in the days when we can see past the event horizon. But I think it’s real. Although the model may be incomplete as well, and certainly the failure of quantum theory and relativity to get along may be demonstrative of that, but there is a broader philosophical point here. I think it says that the universe can’t be broken without destroying it. The universe is like a balloon, and you can’t punch a whole through the fabric of space without destroying it.
If you'll allow me to speculate (more then I already have): as our knowledge of the universe grows, I think we will come to understand some day that faster then light travel, whether through wormholes or space-time bubbles may indeed be possible, and maybe, someday even within our grasp. But the universe may not be without a since of irony, because it is entirely possible that if indeed we can someday engineer some monstrous device to manipulate negative energy and create a usable wormhole to wherever, we may do so only once.
Because what we may have created is the ultimate doomsday device.
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Qui desiderat pacem praeparet bellum.
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Quote:
Originally posted by thatweirdgirl:
....and everything else is magic.
I have a confession. I didn't take physics. It conflicted with something, I don't remember what. It's more of a hobby. Wish I had taken it. When I have trouble understanding an equation or theory, I ask my dad. He's also a hobbyist. Two amateurs with no formal training sit around and talk about physics. I can only imagine how wrong we are! I'm monitoring this thread in hopes of learning something. So be smart!
thatweirdgirl with a crush on Michio Kaku
www.thatweirdgirl.com
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"...turn right at the corner then skip two blocks...no, SKIP, the hopping-like thing kids do...Why? Why not?"
God I love thatweirdgirl
I bet Physics conflicted with Cheerleading Practice
Are you really Cordelia Chase?Or perhaps Harmony?
Remember what LOUIS VUITTON said: "It's in the bag!"
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To the physicists/cosmologists kicking around:
I am currently reading Brian Greene's, "The Fabric of the Cosmos: Space, Time, and the Texture of Reality". I'd like to toss out some topics for your commentary, in order to compare them to 'popular' works like Greene's.
I won't comment on them, because I know there's at least one 'science troll' hereabouts who's just waiting to tell me I'm not a scientist (which I readily admit) and that my opinions and interests on the subject are 'wrong' because I'm not a scientist and could not possibly understand (which I will not concede).
Here are the subjects I'd like some perspective on, if you'd be so kind:
1. String theory and its variants (Greene's a proponent, as is the previously imprecated Kaku).
2. Bohmian 'implicate and explicate orders'.
3. Higgs' fields and energy. (Greene goes to great length describing a non-zero Higgs' field that coalesced during the first 10 to the -36 seconds of the universe to drive the inflationary phase (what he calls an 'inflaton') and the remnant non-zero "Higgs' ocean" that continues to drive the universe's accelerating expansion against the force of gravity (which becomes weaker as the matter becomes increasingly 'spread out'). My question: Are you familiar with this notion? He cites references; but is this a widely held viewpoint? Any other input you may have on the topic.)
4. Do you believe the universe is ultimately holographic and/or n-dimensional?
5. Do you hold to the idea that any 'theory of everything' must invariably be incomplete because we are a part of the system being observed; that is, in order to completely understand a system we would have to be outside of the system under investigation? (It is my understanding that this concept is part of the core concepts of quantum mechanics, particularly the 'Copenhagen' interpretation. Do you believe this tenet to be true?)
I've got other burning questions I'd like to hear from y'all on -- for a more well-rounded informational base, if nothing else -- but, I suspect I've given y'all more than enough to chew on already.
Respectfully,
zoid
P.S.
Do the sheepskinned scientists hereabouts share Sigmanunki's opinion that Kaku is literally a madman? Just wondering. I mean, I know Sagan experimented with LSD and hid that fact for years; but isn't a little craziness just another descriptor for 'human'?
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"Study your math, kids. Key to the Universe." -Gabriel, The Prophecy
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Quote:
Originally posted by SimonSays:
God I love thatweirdgirl
I bet Physics conflicted with Cheerleading Practice
Or perhaps Harmony?
Cheerleader? Maybe band or AP French...It was a while ago. Um, no. Never ever been a cheerleader. Geek. Nerd. Dork. Or perhaps weirdo would better explain it. I have A Brief History of Time on my clie...I read it whenever I'm bored. I admit, I struggled through the third chapter. Bet it gets easier as you go.
www.thatweirdgirl.com
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"...turn right at the corner then skip two blocks...no, SKIP, the hopping-like thing kids do...Why? Why not?"
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Interesting thing that...
Jayne gets hit and goes flying back a few metres. Looking at it from a conservation of momentum point of view, the guy who fired it should have flown back about the same distance to conserve momentum. Basically, when the alliance guy fired the weapon, it should have pushed him back with the same force that hit Jayne.
Imagine the sonic gun as being like a cannon. You remember what happens to cannons that arent tied down? hehe...
Something like this was on mythbusters a few weeks ago.
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The Speed of Dark is faster than the speed of light.
Anyone read that book, Speed of Dark? Elizabeth Moon. Its quite nice, about these autistic people that think, well, autistically.
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