Bush Cancels trip to Pluto.

[TCO]

Interesting.

3000m/s is very slow. Are you sure, Krazy? a bullet moves at 3000 m/s. And 4% energy loss would be noticeable as a color shift. That implies I could easily construct some sort of apparatus at home to show light dopplering. Should we make it a design project for physics freshmen?

Does the energy transfer approach 50% or 100% as I move towards c? If I'm at 300,000 m/s what percent of photon energy is transferred?

[KrazyHorse]

Crap! I mixed up meters and kilometers!

F*ck, why didn't anybody point it out?

I'd require 3000 km/s to do what I said.

So, assuming (more realistically) a speed of ~30 000 m/s, we'd get 0.04% power loss on each bounce. Therefore, it takes...

720 bounces for 25% power loss.

And yes, given v = 3*10^8, we get 100% loss on a single bounce.

[TCO]

Krazy, it doesn't add up.

You said within the clasical range the energy transfer is proportional to v. If I go to 300,000m/s (still well in the classical regime) I should get 400% energy transfer.

[KrazyHorse]

Classical = non-relativistic.

I already mentioned this earlier in the thread

Note that we can see why the constraints are necessary, since for v/c > 0.25 we have that the photon descends into a negative energy state with this approximation, and for v=0 we get "something for nothing" as the photon does not lose energy in the process

[TCO]

errr...I think I did.

(nice editing by the way.)

I had this really nice college physics demonstration figured out using a revolver, silver tipped bullets, a laser and a highspeed camera. You set it all up on a table to make sure that the laser beam intersects the bullet path and that the camera can get the bounce. Then You have the students look at the images colors to see visible doppler shift of light.

[Dauphin]

Crap! I mixed up meters and kilometers!

KH, I'm dissapointed in you.

[KrazyHorse]

Originally posted by GP
errr...I think I did.

(nice editing by the way.)

I had this really nice college physics demonstration figured out using a revolver, silver tipped bullets, a laser and a highspeed camera. You set it all up on a table to make sure that the laser beam intersects the bullet path and that the camera can get the bounce. Then You have the students look at the images colors to see visible doppler shift of light.

Are you sure you aren't just trying to kill werewolves?

[TCO]

Originally posted by KrazyHorse
Classical = non-relativistic.

I already mentioned this earlier in the thread

Gotcha...my comment was made before you editted in the correction.

[KrazyHorse]

DP

[KrazyHorse]

Huh? I didn't edit anything.

Unless you're trying to cover up your lack of reading skills...

[TCO]

I thought you had a post in the 1453 slot that said "all of it". That you then edited to put in the correction.

Anyway. My comments were made using your earlier 3000m/s. The new figures seem to make more sense. If 3 *10^6 gives 4% than 100 times that is light speed and is 400%. So you start climbing up the wall, where you'd expect.

[KrazyHorse]

Oh, that...

The "all of it" referred to your question regarding what happened at c

[TCO]

Anyways....moving along now.

Let's say that the craft is moving at KH's speed that gives us 720 bounces to get 25% energy conversion.

And lets say that the craft is the distance from the moon to the Earth. (could be a lot farther, right?) That is 3 light-seconds right. That means that the photon takes 36 minutes to do its work.

I really wonder if you can keep that kind of optical precision given: The changing geometry, keeping the mirrors rigid (especially the one on the craft), and physical imperfections on the mirror surfaces (even at the atomic level).

[KrazyHorse]

Why does the geometry of the craft's mirrors have to be non-dynamic?

[TCO]

looking at it another way:

Assume the geometry issues (with keeping the beam "trained") are overcome (big ass assumption):

You just have problems of absorption and scattering. Let's assume space is a perfect vacuum (it's not) but let's say close enough so that the photon can cycle back and forth 720+ times without appreciable scatter on dust/hydrogen. (Needs to be checked but maybe a fair assumption.)

Then you just have the issue of mirror surface effects. If this is the major loss source than, you figure that means1440 bounces (two mirrors) gives you a loss of 75% of your photons. So about .5% of the energy is lost at each bounce. Or 99.5% is kept.

I think you can get a top-notch optical mirror may give you <.5% for diffuse scattering and absorption (need to check though...Krazy you cold ask some laser jocks what the loss factors are per mirror on their optical tables.) There's another form of loss that occurs becasue of beam spread after hitting the mirrors. You could ask the jocks about this, too Krazy. You need to keep that beam tight for a long ways...current laser would have issues there (without any mirrors...)