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View Full Version : High Accelerations: Or how to make chunky soup.

wedgebert
2003-Jul-28, 04:56 AM
Ok I have a question. If you have a device that can apply a force to a given volume, and do it in such a manner so that every inside that volume is affected equally, what would it feel like to be inside?

Or put another way, say you have a "warp bubble" that can accerlerate everything inside at 100 km/sec. What affects would that have on a person?

Would you go "splat" or would you not feel a thing since every part of your body is experiencing the same acceleration?

The Supreme Canuck
2003-Jul-28, 05:02 AM
I think you wouldn't feel it. You are being accelerated at the same rate as everything else.

ToSeek
2003-Jul-28, 02:46 PM
I think you wouldn't feel it. You are being accelerated at the same rate as everything else.

Exactly. Imagine being in an enclosed, free-falling elevator. Whether you're in the Earth's gravity, the Moon's gravity, or a black hole's gravity, you wouldn't notice.

kucharek
2003-Jul-28, 02:48 PM
But in the black hole you'd reach some point where you recognize the gradient of the field...

wedgebert
2003-Jul-28, 03:28 PM
Ok, the reason I asked was because I'm currently re-reading the Honor Harrington series (waiting for War of Honor to come out on paperback) and I'm trying to figure out how the propulsion works.

At first I just figured the gravity wedges "push" on the alpha and beta nodes of the starship, thus the need for compensators.

But, then the missile pods come into play. It's mentioned that missile pods that are tractored inside the wedge do no affect the ships accleration. This leads me to believe that the gravity wedges apply their force on everything between them. If this is true then there are no need for compensators.

ToSeek
2003-Jul-28, 04:43 PM
But in the black hole you'd reach some point where you recognize the gradient of the field...

Well, yes, the general relativity equivalence rule between acceleration and gravity only works at a point. Assuming one has instruments of unlimited accuracy and precision inside the elevator/enclosure, I can think of at least two ways to tell the difference. Can you? ;)

daver
2003-Jul-28, 04:59 PM
But in the black hole you'd reach some point where you recognize the gradient of the field...

Well, yes, the general relativity equivalence rule between acceleration and gravity only works at a point. Assuming one has instruments of unlimited accuracy and precision inside the elevator/enclosure, I can think of at least two ways to tell the difference. Can you? ;)

Yes, but they probably don't count. One of them i got from an A. C. Clarke story, the other is essentially a modification of the first setup.

I assume "waiting for the elevator to reach the top floor" doesn't count.

kucharek
2003-Jul-28, 05:29 PM
But in the black hole you'd reach some point where you recognize the gradient of the field...

Well, yes, the general relativity equivalence rule between acceleration and gravity only works at a point. Assuming one has instruments of unlimited accuracy and precision inside the elevator/enclosure, I can think of at least two ways to tell the difference. Can you? ;)

In a real gravity field, the filed is stronger on the bottom than on the top of the cabin. And because it is a radial ield, you will find divergence. When you let drop two things in the cabin, they will also get closer to each other while falling.

Geo3gh
2003-Jul-28, 06:03 PM
Ok, the reason I asked was because I'm currently re-reading the Honor Harrington series (waiting for War of Honor to come out on paperback) and I'm trying to figure out how the propulsion works.

At first I just figured the gravity wedges "push" on the alpha and beta nodes of the starship, thus the need for compensators.

But, then the missile pods come into play. It's mentioned that missile pods that are tractored inside the wedge do no affect the ships accleration. This leads me to believe that the gravity wedges apply their force on everything between them. If this is true then there are no need for compensators.

OK, I had to go re-read parts of More Than Honor, which has Weber's essay on the technology of the Honorverse.

As far as I can understand, the two wedges created by an impeller drive make a localized pseudo hyperspace field, in which is suspended a bubble of normal space. The ship rides in that bubble.

Unfortunately, the normal-space "pocket" had to deal with the conservation of inertia, which meant that the effective acceleration of a manned ship was limited to that which produced a g force the crew could survive.

What seems to happen with the towed pods is that they are tractored so they are in the peudo-hyperspace.

Geo3gh
2003-Jul-28, 06:15 PM

After reading more, I think I am wrong.

Here's the salient part of the description of how impeller drive works:

The impeller drive used a series of nodal generators to create a pair of stressed bands in normal-space, one "above" and one "below" the mounting ship. Inclined towards one another, these produced a sort of wedge-shaped quasi-hyper-space in those regions, having no direct effect upon the generating vessel but creating what might be called a "tame grav wave" which was capable of attaining near-light speeds very quickly. Because of the angle at which the bands were generated relative to one another, the vessel rode a small pocket of normal-space (open ahead of the vessel and closing in astern) trapped between the grav waves, much as a surfboard rides the crest or curl of a wave, which was driven along between the stress bands. Since the stress bands were waves and not particles, the "impeller wedge" was able, theoretically, at least, to attain an instantaneous light-speed velocity. Unfortunately, the normal-space "pocket" had to deal with the conservation of inertia, which meant that the effective acceleration of a manned ship was limited to that which produced a g force the crew could survive. Nonetheless, these higher rates of acceleration could be maintained indefinitely, and no reaction mass was required; so long as the generators had power, the drive's endurance was effectively unlimited.

So now I am in the position of trying to re-digest this.

What it looks like to me, is that the wedge itself is what accelerates, and whatever is inside the wedge just hitches a ride. Apparently, being inside the wedge does not affect the wedge's acceleration (does not add mass to the wedge).

I'll ponder this more, but I do have to return to actual work (blech!!).

ToSeek
2003-Jul-28, 08:56 PM
But in the black hole you'd reach some point where you recognize the gradient of the field...

Well, yes, the general relativity equivalence rule between acceleration and gravity only works at a point. Assuming one has instruments of unlimited accuracy and precision inside the elevator/enclosure, I can think of at least two ways to tell the difference. Can you? ;)

In a real gravity field, the filed is stronger on the bottom than on the top of the cabin. And because it is a radial ield, you will find divergence. When you let drop two things in the cabin, they will also get closer to each other while falling.

Yes, those were the same two I came up with.