/sci/ - Science & Math

[Anonymous No.2159275]

Discuss

[Anonymous No.2159288]

Travels at the speed of sound

[Anonymous No.2159292]

The speed of light should be infinite since it doesn't have any mass. The universe is broken.

[Anonymous No.2159299]

>>2159292
But it does have mass, I don't understand why it can pass through objects while still having mass but it is shown to have mass by being affected by gravity

[Anonymous No.2159319]

hurr

[Krakengineer !!5XY+x7grkpt No.2159329]

This thread is derp.

>>2159292
Infinity is not a number. Speed can no more be infinite than it can be cheeseburger.

>>2159299
Gravity is only the result of mass using Newtonian physics. Einsteinian gravity is a warp in space resulting from mass-energy, of which both mass and energy (light) are manifestations.

[Anonymous No.2159343]

>>2159329
So it has mass without really having mass?

[Anonymous No.2159346]

>>2159299
no. it. doesn't.

gravity dose not bother light...it bothers the path the light takes

two different things entirerly

[Austin No.2159369]

The stick is right next to the person, Meaning it only has to travel only a few inches or less, Light on the other hand has to travel 1 light year (A shitloada miles). So thats like a snail going 2cm vs a fighter jet going around the world 2 times, Whats going to get there first?

[Anonymous No.2159396]

>>2159369
First off think of the amount of energy it'll take to move a stick that long.
Second that energy can't travel faster than the speed of light.
If just look at it as a single line of molecules, the energy that is transferred to the first molecule at a speed slower then light, then the energy of that first molecule will transfer its energy (maybe elastically) at a speed slower than light and so forth.

[Anonymous No.2159410]

That would only work if you had a perfectly ridged material, which you don't. It would also require you to possess a material which wouldn't collapse under it's own weight, which you don't.

Also if you did have a material that fulfilled those requirements it still wouldn't be FTL in an actual sense since none of the atoms were moving faster then light. It would only be faster then light in a practical sense.

[Anonymous No.2159429]

Energy wouldn't propagate through the stick at nearly the speed of light.

[Anonymous No.2159439]

>>2159369
not so.

the stick is a light year long...not a few inches

when the goal is 2CM away, the snail obviously wins since a multi-ton aircraft weighs a hell of a lot more

the problem for you is one of scale.

have a friend hold what you would consider a good length of string, hold the other end, close your eyes, and simply have your friend start motion at the other end.
Your job is to say when you "feel" that motion.

this is your world. small. obviously it seems to be instant doesn't it?
move to a universal scale and redo the experiment on it's terms....not yours...
your string now is roughly 3 miles long.
will the motion still be "instantaneous"?

your a smart guy, so just think about it for a second kay?

[Anonymous No.2159470]

3 miles too big or unrealistic for you?

try a football field. End zone to end zone.

A spool of ordinary kite string aught to have enough in it for that too...

[Anonymous No.2159592]

[Austin No.2159614]

I'm just still a bit confused then, If you have the string (Supposed to be a solid stick) tight with no slack,how can the other person move because the stick wouldn't suddenly gain some extra inches when you pull it so it has to take it from the other end to respond to the other person pulling meaning it would move wouldn't it?

[Anonymous No.2159664]

correct.

However motion (while a poor one) is a nice way to see for ones own self how energy travels in matter.

a push or pull on either end needs a good amount of time to cover such large distances.
You simply have no frame of reference due to scale that there IS a time interval involved at all.
it seems instant...it isn't.

...it's the same for even what you may call a 'solid' object like a stick.

the exercise suggested is to give a peek how it works at that scale. Only continued higher education can answer these questions for you, not some random guy that sells fast food for a living.

[Anonymous No.2159699]

>>2159275
Um... by that logic, even the shortest of sticks move at the speed of light since moving my pencil by the eraser end moves the entire thing instantaneously. Its length had nothing to do with it.

[Anonymous No.2159859]

>>2159699
Sure seems like it doesn't it?
however, your sample is too small.

like i keep saying. you have to scale it up a hell of a lot more than you think to visually see it.

the motion still has a delay in even the pencil but you require some pretty expensive tech and or math to see it.

I know it's disturbing, but a lot of things we take for granted are wrong on grand scales and totally counter intuitive to what we would expect.
Nature and physics has no respect for our comfort and piece of mind...that's the way it works even if a life time of experience says other wise.
Higher learning makes it not so scary and frustrating...but requires a significant effort and many years on your end.

not much more to say

[Anonymous No.2159916]

Velocity is change in position over change in time so
If that stick moves to that guy with the anime face from rest in t amount of time, it's not moving at the speed of light because the trollface cannot propel it at a force to give it that velocity

NOW IF THAT STICK WAS A LASER
but it isn't, it's just a stick, so fuck that picture

[Anonymous No.2159941]

Actually the force of acceleration that the stick experiences is transmitted through the stick at about the speed of sound in the material the stick is made out of.

[Austin No.2159951]

Ah, I get what your saying.

[Anonymous No.2159960]

from pure guessing

as the stick's length increases, the force required to move it forward increases also, as the length tends towards infinity so do the force

[Anonymous No.2159989]

This annoyed the shit out of me for years. The answer (according to relativity) is that the movement of the stick or string or whatever is at the speed of light. The stick doesn't really change length, it's the correct length in any given frame of reference.

There are newtonian factors like the compression/expansion any realistic material would undergo in a practical experiment, but for thought, the problem is one of spacetime.

[Figgy No.2159998]

Wrong. Nothing can be totally rigid. Pretend you have an extremely long slinky on a frictionless table, then you push but the motion moves in a series of compressions. Just like particles. (thanks to a friend of mine)

[Anonymous No.2160007]

See "superluminal scissors" problem

[Anonymous No.2160009]

>>2159998
I specifically said for a hypotheical non-Newtonian perfectly rigid body.

[Boomer !!bcdVCSUmpgT No.2160033]

>>2159275
The dudes trying to explain why the stick thing is wrong are using a terrible analogy, as is common among scientists. Stop using analogies and just explain shit, geez.

Look, the kinetic energy in an object is going to travel through it at the speed of sound, no faster. To impart noticeable velocity to an object requires delivering it energy sufficient for it's mass to change its velocity. Therefore, transferring energy through a one light year long stick will take a damn, damn long time. attempting to poke with a light year stick will take so much energy you might as well just fly your ass the whole distance.

[Anonymous No.2160093]

Newton PWNS Einstein once again ...

Also, this proves that you can transfer information faster that the speed of light

[Anonymous No.2160299]

>>2159346

How are those two different things entirely?

[Anonymous No.2160345]

>>2160033
my analogy worked fine.
the longer the string is the more your friend has to do to even get you to feel anything at the end.
i said it was a poor example...what do you want?

big whoop...big old science terms and knowledge is not required to understand it
same reasoning applies even...just simpler....and with things and words anyone is capable of actually seeing, acquiring, and using to understand the very basics for them selves

[Anonymous No.2160385]

The stick would move at the speed at which it was struck, not the length of the stick.

[Anonymous No.2160417]

>>2160385
it wasn't struck...it was a jab along the length

forget your education and try to relate to those you speak to for heavens sake man.
your petty details mean nothing to our simple way of seeing things

[Anonymous No.2160428]

if you could make a stick that long with all the difficulties implied and you could actually exert enough energy on it to make it move...

big ifs but lets just pretend.

It would work, nothing moves faster than light, the stick changes relative position at a sublight speed. The guy at the other end would feel it as soon as you moved the stick far enough to touch him.

Nothing has moved the speed of light, no laws are broken.

But you'd never get a stick that long or be able to move it

[Anonymous No.2160436]

Do you guys not see the mother fucking trollface?

[Anonymous No.2160477]

>>2160436
no. what are you talking about?

[Anonymous No.2160486]

>>2160428
exactly....that's why string is a good choice.
we can actually see with our own eyes what gibberish you are speaking of.

[Anonymous No.2160498]

Incorrect. The object has a high kinetic energy, but that's due to its extraordinary mass.

[Anonymous No.2160561]

>>2160498
we don't understand what that means...do you not know what the term "energy" means to a simple person like me?
Do you have the time to educate everyone of us the years you spent learning it all?
Cause that's what that kind of understanding takes.

...and don't expect me to believe you were not taught by analogy at some point...

you crawl before you walk. you walk before you run.
OP clearly has just discovered his legs and you want him to go half way through a marathon.
what's wrong with you academic types anyways?
asking for basic understanding of something complex does not require your level of sophistication and nit picking to explain in basic terms.
Some people need to see things for them selves and can not simply take your word for it.

Your way of doing things does not allow an ordinary person to SEE IT for themselves...it requires ever deepening levels of understanding and faith.

[Anonymous No.2160857]

The energy would travel at the speed of sound in the object. The speed of sound increases with the stiffness of the material and since this stick is infinitly "stiff" the energy travels at an infinite speed.

If you were to just use a regular stick that was not perfectly rigid though then the energy would move slower than the speed of light.

[Anonymous No.2160941]

How do you plan to determine exactly when serious-faced-person feels the stick poke? It isn't like he can simply yell across the field that he felt it, he's a lightyear away. Even if he brought and synchronized, with mathematical precision, a clock and knew that troll-face would jab him at a specific time the quantum effects of having a rigid object a lightyear long (the compression of molecules into each other imparting objects, while not significant to objects that exist on this earth, would be incredibly significant in a lightyear long stick) would impact the amount of time it takes.

Also, as many people have said before, the propagation of energy of the particles in the stick is at the speed of sound of the material. So, without breaking into extra-dimensionality once again physics confounds us.

[Anonymous No.2161204]

i took physics in high school and now im an econ major blah blah but.. wouldnt it just travel at the speed of sound >_>? or just slightly above it? i dont see how the stick has actually traveled faster than light since.. you cant move it faster than the speed of light.

[Anonymous No.2161219]

ITT: Derp.

[Anonymous No.2161252]

The end of the stick is only a few inches from the person. The end of the stick is not starting from a light year away and being hurtled across space. Of course the stick will reach the person faster than the light at the other end of the stick.

[Anonymous No.2161282]

Since the stick is, I assume, solid and is no more than a few inches away from the one to be poked, at best, I'd say that the stick would move as fast as the holder moves it. The stick is one entity, therefore, it does not have more than a few inches to travel. It moves at one speed, which is whatever it was to start with. The issue that worries people is the distance. The distance, theoretically, shouldn't matter. It moves as one entity, not as anything else. It simply doesn't have to cross such a vast distance. Technically, the stick would never be breaking the universal light-speed barrier, as nothing can move anything else at that speed. "But how does it poke them instantly, Anon?" you may ask. Well, it's because there isn't anything distance for the stick to move. There's a simple gap a few inches wide. Some may complain that, "The energy in the stick has to travel through it Anon. You can't forget that." They'd be right. Unfortunately for their argument, the stick is all one thing, and therefore the energy moving it moves it all simultaneously. To those of you who would denounce me, I'm studying to be an astrophysicist. Note, studying. I haven't gotten there yet. In fact, just so you know, I'm an eighteen year old college freshman. Just out of high school as of June 2010. Thank you for your time.

[Anonymous No.2161323]

It would still take 1 year. You would see a 'bulging' pressure wave affect travel through the stick at the speed of light.

[Anonymous No.2161335]

>>2161219
ITBoard: derp

[Anonymous No.2161344]

>>2161323
>pressure wave
>speed of light
Oh u

[­­­­­­ !BatMaN77/A No.2161353]

I had this theory when I was 13. Mine was very similar to OPs.

>It's been proven that force travels at no faster than the speed of light (just as gravitational force between the earth and sun travels at the speed of light). The force of the poke would propagate down the length of the rod at the speed of light.

[Anonymous No.2161355]

>>2161335
>treating pi like a variable

[Anonymous No.2161356]

>>2161282
>studying to be an astrophysicist
Better study harder champ

[Anonymous No.2161359]

>>2161355
That's not the flaw in that image but thanks for trying. Good luck with high school

[Anonymous No.2161362]

For the poke to travel the atoms inside have to push against each other. This is exactly the same as sound, the poke would travel the speed that sound travels through the object.

everyone see
>>2159288

[Anonymous No.2161364]

>>2161359
>implying I was trying to point out the flaw

[Anonymous No.2161374]

WHAT IF

pi = 3.2

[Anonymous No.2161376]

that giant stick is gonna be so hard to move

[Anonymous No.2161380]

>>2161282
You sir, entertain me. Such A statement you do pose. You best be trollin'.

>>2161356
I agree with you.