/sci/ - Science & Math

What is this implying? That you could build a really long pole?

Yeah that's fine.

No. Burden of proof is on you to show that your pole has unbounded rigidity. Which is impossible. Whoops, guess I proved you wrong anyway.

this would work in theory, but the pole would break.

if you are touching it it can't move at the speed of light
/thread

> HOW TO COMMUNICATE ACROSS SPACE AT LIGHT SPEED
How about by using light?

What the fuck no

Even if you had a magic bar made of pure unobtanium
You would push one end, which would send an impulse through the length of the pole which would be fast, but much slower than the speed of light.

>>1699097
Why do people bring out burden of proof out of the blue for absolutely no reason? Is it from reading too much Dawkins?

Old failed idea is old.

>>1699115

YOU ARE A SUPER GENIUS.

How'd you post "prove me wrong" without getting b&?

protip: earth and the moon are not stationary.

>>1699115
I fucking lol'd

You wouldn't be communicating at the speed of light unless you could move the pole at the speed of light. You're only communicating at the speed that you can move the pole.

>>1699137

I thought the OP was stupid, but now,

>> A challenger appears

>>1699144

U mad cause I'm right.

How to communicate at the speed of light:

Radio waves

>>1699153

Nah, just lolling at how wrong the answer is.

my personal favorite

>>1699174

wat

>>1699165

How is it wrong? I push pole. Pole moves at speed which it has been pushed. Ignoring the movement of planets and shit and the impracticality of making a pole that long, the fact is still that the pole isn't moving at the speed of light.

>>1699174

what?

>>1699091
wow so no one proved him wrong.

If you touch the pole you create a mechanical wavelength that travels through the pole, so any information sent will be forced to travel at mechanical wavelength speeds, aka the speed of sound, but in this case it is traveling in a solid object.

In all cases the stupid thing is slower than shit.

>>1699184

The speed of moment of an object isn't the speed at which you move it. It propagates down the object at around the speed of sound in that object.

How fast you move the object is nothing to do with information transmission speed, in this case.

>>1699187
>>1699183
I know, isn't it wonderful? It doesn't even claim to be explaining anything. Note the "v=c" touch.

>>1699184

OP is talking about the information that is send. Let's say the pole is as long as the distance from the earth to the sun.

For a light beam it takes 8 minutes to travel that distance.

In OP's mind the movement of one side of the pole will result in an instantaneous movement of the pole on the other side. If that were true (and such a long pole possible etc.) then you could send information even faster than light.

You get it?

>>1699191

I did not know that.

>>1699184
Maybe you should try an experiment. Get a mile long pole. Get a friend (hire one) to stand at one end of the pole. You stand at the other end. Push your end of the pole at a speed of 1 mile per hour.

Your friend feels the pole move
1) almost instantaneously
2) an hour later

Think carefully, now.

>>1699197

Except wouldn't relativity prevent the rod from moving faster than light?

>>1699203

His end of the pole would instantly begin moving at one mile per hour. Not at the speed of light.

>>1699206
the rods speed is the same as sound through a solid object.

the rod is massive, it will collapse on itself and create an object

also think how much energy is required to get a reasonable push out of it, ever try pushing a skyscraper over with your hands?

>>1699206
Many things would prevent the impulse from traveling faster than the speed of light.

The pole is held together by electrostatic fields. Changes in those fields will propagate at the speed of light, but each time it needs to move a mass, it will slow down the speed of propagation. The tightness of the bonds together with the mass of the particles will define how fast the impulse will travel. This speed is referred to as the speed of sound through the material.

>>1699211

>>1699211
Right, but NOT instantly. It would start moving 1 mile / (speed of sound in material) later. It seems so close to instant that we think of it as instant. If it really were instant, then we'd be sending information faster than light.

Even if you take a rod a meter long in your hand, and push it forward. The far end doesn't move instantaneously as you push the near end. There's a delay, even tough it's incredibly small. The movement actually travels as a wave although it gives the appearance of a uniform rigid object on the macroscopic scale.

>>1699211
okay now...... lets try another experiment. increase the distance to 2 miles. and your friend pushes the pole still at 1 mph. you still feel it instantly right?
now increase the distance to 1 light year, friend pushes pole AGAIN. you still feel it instantly right?

>>1699215
It wouldn't take much energy to send the signal. The "push" would just entail tapping it with a hammer. The person on the other end would just listen for the ping.

>>1699236
No, you do not. Information CANNOT propagate faster than the speed of light, and neither can movement.

>>1699249

but then when I call someone on the telephone why do I hear them right away

>>1699249
Bitches don't know about my quantum entanglement.

>>1699285

The furthest you can be away from someone on earth is half it's radius, which is about 3000km. speed of light is 300000km/s

My face when I see no one mentioning the wave that would be created by pushing the rod in the 10 first posts (didnt bother reading).

Pushing the rod would create a wave deforming the rod that wouldn't travel faster than light.

>>1699236
Think of it this way. Let's say I tap the 2-mile-long stick with a hammer. It vibrates - the pulse moves through the material at the speed of sound in that material.

Now I hit it REALLY FUCKING HARD with the hammer. But it's still an impulse in a solid. It can't move through the stick (without breaking it) any faster than the speed of sound in the stick.

But how can you keep the pole connected? the moon rotates...the earth rotates.....for the pole to stay connected it not only has to pivot and turn but it also has to travel across the surface of the earth......WOOHOOO lets make a giant traintrack.

>>1699293
No YOU don't know about quantum entanglement if you think you can use it to transmit signals.

>>1699311
Im sorry...the moon REVOLVES but does not rotate...but the earth does

>>1699285
You don't. Electrical signals travel near light speed but less than light speed.

>>1699314

The moon does rotate. It just rotates slowly enough that the same side is always facing the earth.

>>1699315
I'm just saying that information can travel faster than the speed of light. As the spin changes, the information about it is "sent" to the entangled particle, which also changes it's spin instantaneously, ignoring the distance between them. Thus information "travels" faster than light.

sage goes in email field

>>1699314

Fail. It just rotates at such a speed that only one side ever faces us.

>>1699328
Except it doesn't, because it travels at the speed of sound in the medium. The speed of sound is lower than the speed of light.

Unless you're now talking about quantum entanglement, in which case there is an entirely different reason why it doesn't work.

>>1699294
What? HALF it's radius? If the Earth is a (rough) sphere, then the furthest away from it you can be is it's diameter.

>>1699374
You didn't bother to actually read my post, did you? I didn't say anything about communicating through use of quantum entanglement, but about the phenomenon itself.

>>1699392
>the furthest away from another person you can be is it's diameter
fix'd
The largest distance there can be between two points on the surphace of a sphere is the sphere's diameter.

>>1699328

Quantum Entanglement CANNOT be used to transmit information.

Information is not being transmitted between the two particles.

>>1699404

Can you change the spin of one particle causing the other to also change it's spin? If so then you could send a message with it.

>>1699294
What? You mean half it's circumference 20.000 km (Germany - New Zealand), if we assume that the information is transported accross the surface and not directly through earths core.

>>1699328
No. Nothing is sent from one particle to the other, and the spin of one doesn't change when you measure the other. You don't understand entanglement.

>>1699408
No, you can't. There's no way to know when you measure one particle if the other particle has even been measured or not.

The pole would have to be PERFECTLY rigid. This is impossible. End of story.