Can someone explain to me why this wouldn't work?

5/31/2009 3:47:06 AM

wait for it...

5/31/2009 3:48:24 AM

your message would travel down the rod at the speed of light, or something

or probably be completely absorbed by compression within the rod

[Edited on May 31, 2009 at 3:51 AM. Reason : lol]

5/31/2009 3:50:00 AM

Quote :

"A STEEL ROD FIVE LIGHT YEARS AWAY"

whos gonna manufature that and where are they gonna do it.

5/31/2009 3:51:56 AM

also, steel is made up of atoms. the force has to be transmitted. this does not happen instantaneously.

but aside from all that. where are you going to get a steel rod that is five light years long? how are you going to move it? and assuming you can move it, how would you not just destroy the ends of it with the amount of force it would require to move something so massive?

5/31/2009 3:54:44 AM

what exactly is the scenario being given here?

5/31/2009 3:55:04 AM

If you ignore the inertia and assume the rod is perfectly rigid...is this hypothetically possible? What at the atomic level would prevent this from working?

5/31/2009 4:00:50 AM

I suppose it's hypothetically possible, but there are so many things wrong with it in terms of real world physics that the hypothetical point is beyond moot.

5/31/2009 4:04:55 AM

wtf. it's not hypothetically possible. Atoms that make up the rod are held together by the electromagnetic force. The electromagnetic force travels at the speed of light.


i see this being the new plane on a treadmill

5/31/2009 4:14:10 AM

i see it being a thread where i comment on things i have no fucking clue about

to rectify that situation, this thread is now about the pixies

5/31/2009 4:46:02 AM

haha, I thought of this in like, third grade. I thought I was a genius.

turns out ^^. You would see transverse waves traveling down the rod, like a slinky.

5/31/2009 5:10:19 AM

Quote :

"wtf. it's not hypothetically possible. Atoms that make up the rod are held together by the electromagnetic force. The electromagnetic force travels at the speed of light. i see this being the new plane on a treadmill"

You, sir, are incorrect. Pressure waves travel at the speed of sound, not light. Of course, the speed of sound in steel is much faster the the speed of sound in air, but nowhere remotely close to the speed of light.

For steel:

v = sqrt(B/rho)=sqrt( (160E9 N/m^2)/(7860 kg/m^3) ) ~ 4512 m/s or 0.00001504 times the speed of light.

[Edited on May 31, 2009 at 5:16 AM. Reason : ]

[Edited on May 31, 2009 at 5:17 AM. Reason : P.S. The speed of sound is faster in aluminum]

5/31/2009 5:13:13 AM

Congratulations on refuting an argument I didn't make! Internet nerd fag points go to you.


(For reference: the actual topic of the thread is whether the rod will travel *faster* than the speed of light, not slower)

5/31/2009 5:21:08 AM

Except you said that it would travel at the speed of light, which is as ridiculous as the original post.

[Edited on May 31, 2009 at 5:27 AM. Reason : +3 internet nerd fag points]

5/31/2009 5:26:46 AM

Are you sure I didn't say that the electromagnetic force moves at the speed of light? I may have been unclear about that. Maybe the words that I actually wrote can shed some light on this mystery.

In case my point was unclear to you: no rod will transmit force faster that the speed of light, even a magical material that transmits the force as fast as possible, because the speed of the electromagnetic force is the upper limit.

Who the fuck cares that the actual speed through steel or aluminum is? It's irrelevant.

In any case, some helpful advice about the real world: learn to shut your mouth when what you want to say adds nothing of value to the discussion. This is one of the biggest problems socially dysfunctional nerds have when they try to function in the real world. It makes you look like a dumbass rather than a smart person.

5/31/2009 5:41:56 AM

this guy isn't the first to think jerkin his huge rod back and forth is somehow significant and he won't be the last

[Edited on May 31, 2009 at 7:03 AM. Reason : and anyways, if you wanna send information faster than c, that's what quantum entanglement is for]

5/31/2009 7:01:40 AM

^^ Go eat a bowl of dick.

5/31/2009 7:06:06 AM

Quote :

"You, sir, are incorrect. Pressure waves travel at the speed of sound, not light. Of course, the speed of sound in steel is much faster the the speed of sound in air, but nowhere remotely close to the speed of light."

I'm sure I'm confused, but wouldn't this be implying that no object can travel faster than the speed of sound through it's material?

Maybe that's true and not really that amazing of a point, but I am curious.

In any case, the fallacy here is that the opposite end of the rod will move immediately.

5/31/2009 7:20:55 AM

or will it?

5/31/2009 7:24:21 AM

5/31/2009 7:25:17 AM

This will work. Someone refute this:

Some of you are [apparently] thinking about banging the rod on one end (with a rubber hammer, for eg) and waiting for the vibrations/waves to reach the other end. Of course, that would take practically forever, far far longer than 5 years (~300,000 years). If you send any EM radiation through it, that will take 5 years. (for eg fiber optics)

But I don't see the picture saying that. You just move the rod back and forth. In that case, the opposite end DOES respond immediately. Imagine someone sitting 2 cm away from the other end, on some planet. You move the rod towards him (away from you), and it only has to travel 2 cm before it touches him. You can transmit a whole paragraph in morse code like that in a few minutes. A message sent by EM radiation would take 5 years.

What's wrong here? (I am serious, not fooling around)

The rod doesn't have to be that long for this, just long enough that it would take less time for it to travel 2 cm with your push than for light to travel its length. If you cover the 2 cm in 1 second, it only has to be > 300,000 km in length, not 50,000,000,000,000 km (5 light years).

This scenario is similar to this:

Imagine you have a car/ship/rocket that is 5 light years long (or even just half a million kms), and it is at the start line of a race, with its BACK end at the start line, i.e., the front of the vehicle extends 5 light years beyond the start line. The other contestant is a flashlight/laser beam, that is to be shone from the start line. The finish line is just 2 cm beyond the front of the vehicle.

Who will win?

Of course, the vehicle, because it is already there, practically at the finish line (just 2 cm away from it). It will reach the finish line in a second or so, while the beam of light will take 5 years. Similarly, the rod is already there, next to your friend. You just have to nudge it, and it will touch him within a second.

5/31/2009 7:44:17 AM

the rocket is cheating and would be disqualified so it doesn't matter anyways

5/31/2009 8:13:28 AM

well if the steal rod was on a treadmill going at the exact speed the vibrations were traveling would it ever take off?

5/31/2009 8:26:03 AM

No, this won't work.

IF the rod was perfectly rigid then it would work. But of course the rod can't be perfectly rigid, because it's not really a single object, but a bunch of atoms stuck together with electromagnetic forces.

5/31/2009 8:40:25 AM

why even argue it if it's not realistic - if you are going to argue non-realistic possibilities of how to transfer information faster than the speed of light then this is low on the totem pole

5/31/2009 10:12:31 AM

5/31/2009 10:36:58 AM

Quote :

"What's wrong here? (I am serious, not fooling around)"

[facepalm]

5/31/2009 10:37:52 AM

maybe transmitting of information in this situation is "move one side and cause the other side to move"? maybe

5/31/2009 10:43:42 AM

what kinda troll thread is this?

5/31/2009 10:44:57 AM

What if a wizard cast a spell that made the rod completely rigid? TAKE THAT, SCIENCE!!!

5/31/2009 10:45:44 AM

you'd have to be a pretty powerful wizard to cast that spell

5/31/2009 11:06:58 AM

do spells travel at the speed of light?

5/31/2009 11:17:59 AM

Depends on the transmission medium. Were you thinking wands?

5/31/2009 11:23:23 AM

They travel at the speed of magic.

Unicorns travel at the speed of rainbows, btw.

5/31/2009 11:23:55 AM

:nods:

5/31/2009 11:27:24 AM

Quote :

"No, this won't work. IF the rod was perfectly rigid then it would work. But of course the rod can't be perfectly rigid, because it's not really a single object, but a bunch of atoms stuck together with electromagnetic forces."

I'm not sure I buy that, but fine -- let's say the rod is chilled to absolute zero so the atoms are motionless.
Then what?

5/31/2009 11:51:06 AM

5/31/2009 12:00:37 PM

spacetime will bend the rod.

can't happen.

5/31/2009 12:09:39 PM

the plane won't take off.

5/31/2009 12:10:04 PM

BUT WHAT IF YOU PAINTED SOME SWEET FLAMES 'N' SHIT ON THE ROD? THEN WOULD IT WORK?

5/31/2009 12:11:22 PM

would this 5yl rod have more bandwidth than a 5" penis?

http://everything2.com/index.pl?node_id=973934

5/31/2009 12:13:19 PM

^ downloading porn would be an infinite loop in that case

[Edited on May 31, 2009 at 12:15 PM. Reason : haha internet shananigans.]

5/31/2009 12:15:17 PM

the lunar module will not levitate.

5/31/2009 12:17:06 PM

Quote :

"TO SEND SIGNALS BUMP THE ROD FORWARD AND BACK"

5/31/2009 1:07:14 PM

you just have to have a native american at the other end of the rod listening to the vibrations

5/31/2009 1:17:12 PM

Quote :

"BUT WHAT IF YOU PAINTED SOME SWEET FLAMES 'N' SHIT ON THE ROD? THEN WOULD IT WORK?"

absolutely

trust me, I'm an engineer

5/31/2009 1:19:11 PM

Quote :

"I'm not sure I buy that, but fine -- let's say the rod is chilled to absolute zero so the atoms are motionless. Then what?"

Then you've built a very huge, very nice freezer to cool the whole rod down. And you're probably too busy picking up all the Noble prizes to do any rod bumping.

5/31/2009 1:26:10 PM

how do you plan on nudging this rod?

5/31/2009 1:26:31 PM

Quote :

"Noble prizes"

5/31/2009 1:27:44 PM

You could also rotate it instead of nudging it...

[Edited on May 31, 2009 at 1:28 PM. Reason : ]

5/31/2009 1:27:52 PM