Assume you had a long rod or pole that was so long that one end was near the surface of the moon and the other on the earth. It’s an inch in diameter, made of some super-strong titanium alloy and doesn’t compress. If a buddy on the moon gave it a push, wouldn’t you feel the motion immediately on the other end and therefore wouldn’t the force of the push have transcended the speed of light? Remember, it takes 30 seconds to go from the moon’s surface to the earth’s surface at lightspeed.

Okay, first off, yes we cannot do this. No material exists that could support itself at that size, mass, and under the tidal stresses it would endure. Even if it could, if it was conducive at all, it would draw enormous amounts of static electricity from the passage through such a length of atmosphere. Also, the relative motions of the two bodies (earth, moon) would not allow for a person on either end to seize hold and actually do this. Even if they could, it would mass so much, it would weigh as much as New Hampshire and no one could actually push it hard enough to make it move appreciably. Even if you had that strength, the ground under the pusher wouldn’t offer enough resistance to his feet and he’d push himself into the ground rather than move the much more massive rod. Kinda like the ancient mathematician who said he could move the world by hand if he had a long enough lever. So….that being said, acknowledging this to be an impossible test, the theory is still interesting.

Tugging a string that distance and you’d not see it exceed the speed of light, since there’d be compression as the string tensed from the pull. Think tapping an extended slinky. But our imaginary rod is more solid, totally non-flexible. A movement on one end should manifest instantly on the other. But wouldn’t that break the light barrier?

I’m wondering if a smaller-scale test could be done, but the instrumentation would have to be terribly precise.

Food for thought.


:confused:

I think the issue is that nothing can really be uncompressable...To our eyes it may be, but that is the method of transmission...I think...

Think in the smaller scale. Take a pencil. Push one end. Movement is transferred instantaneously (seemingly...this may be the sticking point) and compression really doesn't play into it.

One of those things you wish you could try. Again, maybe someone will do it with a 100-meter rod and really sensitive equipment.

I've read the whole annoyingly-long argument before, here (http://www.everything2.com/index.pl?node_id=715671&lastnode_id=0).

Ribbit.

Hmm. Wasn't aware anyone else had discussed that before. I thought that up on my own, so I guess some folks do think alike.

I figure, if they can make a photon break lightspeed by a factor of 10 or more by sending it through a chamber of cesium gas (they've done that) that maybe some of our assumptions regarding lightspeed are lacking info.

Seems we've had a lot of things proven wrong in recent years. Look at the probe that just took a dive into Jupiter a couple of years back. We had these intricate layers of atmosphere all worked out, then the probe drops in for a firsthand look and the data indicates we were way off. Specifically, I believe the initial layer was horendously deeper and more consistant than we thought, and it contained more water vapour too.

*croak*

Frog, ya sure about the cesium gas? Last I heard there was a fatal miscalculation in their results...

Hmm.. read the article in Newsweek, CNN, and FoxNews and hadn't seen a retraction yet.

Originally posted by TheFrog
Hmm.. read the article in Newsweek, CNN, and FoxNews and hadn't seen a retraction yet.

How recently?

I know one of the experiments where a team was sending photons through a gas ended with them later finding an erorr of calculation...

The "rod" doesn't work.

Becuase, the same particles on one end does not reach from the moon to earth, if it was a coin, and could travel from one side of the pole to the other as quickly as the rod moved, then it would move faster than light. But the rod only pushes other sections of the rod...etc. See what I mean?

Good analysis, Chaotic. (Any relation to Chaotica, the dark ruler in the Captain Proton Holodeck serials?)

I was hoping the transition would mean the force of the push produced results that exceeded lightspeed. Then the universe would have a rip in it where the physical laws got violated, a quantum singularity would form sucking up the rod and the International Space Station, and then I'd have to quit playing with physics 'cause Mom said it's dinner time and I have to go in now.

...maybe I should have had that Scotch after I wrote this.


*croak*

:p

It takes energy to accelerate mass. If you pushed on a rod of that length it wouldn't move immediately unless enough energy was applied. E=mc^2 is still valid.

I take it nobody read my link. It wouldn't work. It would require *infinite* energy to accelerate anything to the speed of light, thanks to Einstein's theory. No matter how fast you pushed the rod, each particle would only respond at or below the speed of light, thus the chain would have to expand and compress to some degree before the entirety could be said to move.