A hypothetical question/thought about distance with an example...

Hi,

For some months every know and then this pops up in my mind.

Ok

Lets say there is a planet like 1.000.000.000.000.000.000.000 kilometers away from here. And I like to pull over an egg on that other planet.

1.
With the speed of ligth it would last a lot of time to get there and pull that egg over
2.
But what if I got a real long stick, like 1.000.000.000.000.000.000.000 kilometers long. When I hit it here it would pull the egg on the other planet over at once. That would be strange

Ok, besides you would need a tremendous source of energy and of course a very long straight stick (the stick does not bend or deform in anyway), this is possible???
Or am I going wrong somewhere.
I mean, for some reason I guess, if you have the right material for the stick, the movement goes way beyond the speed of light?

I am not a scientist so I like to hear some other thoughts about it

greetings Lunica

The problem, of course, is that the stick in this hypothetical is a physically impossible object. Nothing is perfectly rigid. how quickly motion propagates down a rod is determined by the speed of sound in the substance it's made of. Now the speed of sound in a solid is much higher than the speed of sound in air, but it's still a very far cry from the speed of light.

So it would take double digit billion seconds minimum to poke an egg 1.000.000.000.000.000.000.000 kilometers away with a rod.

There does not, and, indeed, physically cannot exist "the right material for the stick".

[edit on 24-5-2008 by mdiinican]

Hypothetically, this is a really good question. I can't think of an answer.
If you made a rod one lightyear long out of solid diamond, and then hit one end with a sledgehammer, how long would it take for the shock to be felt at the other end? I get the feeling the shock wave would be faster than sound. In my head it seems instantaneous. This is of course impossible, given that C is absolutely constant in all frames of reference . . . but perhaps you could think that the rod, or any part of the rod, isn't moving at light speed, it's just conducting a pressure wave. Like the ocean. Waves are not moving water until they break; they are merely a travelling hump in the water.

The question is, how fast would that shockwave travel? I guess you could argue that it travels only at the speed of sound in that particular medium, which logically seems true. I can't seem to find any information on that.

reply to post by Lunica


An Action always gets a reaction (remember?),so I figure your egg is cut in half,velocity goes through egg,egg goes with velocity at velocity off impact,the energy is Nearly half each per half egg,now the stick has wastered all its velocity now it's up too the Two parts off the Egg(which are less than Half off the Full velocity). These two parts will go 45degree each(lets just say)

I reckon your thinking that because your stick went very close ,your hoping of a Drag effect,sorry man were in space right?

What I feel your asking is Can I poke this planet with a pool que (stick)yes you can (I say) but than you have to stop it where you need it.
Great thought you triper.
Regards
Zelong.

Originally posted by watch_the_rocks
In my head it seems instantaneous.

Make your equation out off what you have,density off diamond rod(diamonds are though to be solid) ,Hammer weight and length off swing( force) = answer
The verlossity off the hammer would became part of the atoms off the Diamond rod,hance pretty dam quick. Almost instant Reaction given the length well it's gota take some sort of time.

Travels at the speed off Force,in space,not much resistance.
I love this thought.
Regards
Zelong.

I didn't know the speed of a "pressure wave" in a "stick" is connected to the speed of sound. (on earth ) But then again. like watch_the_rocks and Zelong also say.

I make a synthetic medium where all atoms are exactly connected to each other, like diamond but better. (we cannot make this, but in theory its possible)
Then I hit one atom at one end. How can a shock/pressure wave proceed if there is no room between the atoms for it.

Originally posted by Lunica
I didn't know the speed of a "pressure wave" in a "stick" is connected to the speed of sound. (on earth

) But then again. like watch_the_rocks and Zelong also say.

I make a synthetic medium where all atoms are exactly connected to each other, like diamond but better. (we cannot make this, but in theory its possible)
Then I hit one atom at one end. How can a shock/pressure wave proceed if there is no room between the atoms for it.

It isn't just the speed of sound on earth, it's the speed of sound everywhere *in that medium.* Diamond has a speed of sound of about 12000 meters per second, which is pretty dang fast (the speed of sound in air at sea level is like 342 meters per second). But light travels 300000000 meters per second. Therefore, the speed that motion travels down a diamond rod is 25000 times slower than light.

You aren't going to get much better than diamond, even in theory. diamond atoms are already connected to surrounding diamond atoms with four covalent double bonds, which seems to be the maximum possible. Other interesting nanotech rearrangements of carbon might do better or worse.

assuming stable neutronium can exist, it might have a higher speed of sound. But even that would assuredly fall far short of the speed of light.