?

cthia wrote:Therefore, my notion upstream about SL missiles reaching .9C would be dependent on a breakthrough in particle screen technology.

tlb wrote:I did give you an answer to the particle shield problem some time ago. Simply add a buckler to the missile, which has the strength of a side-wall and does not limit maneuverability. It has the side benefit of making the missile harder to kill by energy weapons.

Jonathan_S wrote:Assuming this works, and assuming you can downsize it into a missile body, I still see a couple problems.

1) It does nothing to make the missile more survivable if intercepted by a CM (though, yes, a higher terminal velocity might reduce the odds of that interception a little)

2) It seemingly forces the missile to commit to a ramming attack.
If the buckler is all that's keeping it from being torn apart by the >0.9c particles then it can't drop it to engage with a laserhead or burn mode nuke. Nor can it slow down to a speed where conventional particle shielding can protect the laserhead as it goes through it's critical deployment phase -- to do that the missile would first have to perform a turnover flip; and giving the small diameter of a buckler (less than twice the diameter of the hull) attempting that would expose it to those destructive >0.9c particle -- destroying it before it can pitch more than a few degrees into its turnover.

So from an engineering standpoint this might someday be possible to build. But that doesn't seem to make it a practical weapon...

I grant some of that; but then I was only asked to provide something better than particle shielding by someone who wanted a missile (or ship) that could go faster.

I agree that it offers no protection against a counter missile and I never claimed that it did. I always limited that protection to energy weapons.

First as to the burn mode; I expect the nuclear blast to destroy the projector that created the buckler, so burn mode might operate as though it was not there. If there still is an unwanted residual field, you have to find the correct time interval to begin shutdown of the buckler and then trigger the explosion before its protection is completely gone.

Second as to the laser warhead; that is simpler because you rarely are shooting straight ahead. Since there are no sidewalls; at the proper time the wedge is rotated around the direction of travel so the rods can point through the open sides at the target, while still being protected from particles by the buckler.

What many avoid thinking about is the second law of thermodynamics along with relativity.
The equation E=MC2 can be rewritten as M=E/C2, so the weight gain that starts to become apparent at 0.9C is made up from enormous quantities of energy. Where does that energy come from? Apparently free from the wedge. My rationalisation is two fold. Firstly it is RFC's universe so he sets the rules, secondly the Honorverse is chronologically as far from us as we are from the ancient Greeks. When you think of all the things we take for granted, that the ancient Greeks would have declared to be magical, it isn't such a great stretch.

Daryl wrote:What many avoid thinking about is the second law of thermodynamics along with relativity.
The equation E=MC2 can be rewritten as M=E/C2, so the weight gain that starts to become apparent at 0.9C is made up from enormous quantities of energy. Where does that energy come from? Apparently free from the wedge. My rationalisation is two fold. Firstly it is RFC's universe so he sets the rules, secondly the Honorverse is chronologically as far from us as we are from the ancient Greeks. When you think of all the things we take for granted, that the ancient Greeks would have declared to be magical, it isn't such a great stretch.

I do not believe that we have avoided talking about relativity; indeed many have speculated that the author limited speeds to .8c specifically so that relativistic effects would be minimized.

Obviously it is the author's world to set the rules as he pleases. Obviously the wedge has seeming magical powers (to us, not just to the ancient Greeks), but there is no reason to expect the wedge would permit the approach to the speed of light without limit; since it does not offer endless power.

Possibly not endless power, but consider a 6 million ton SD (P) being under constant acceleration of 500 gravities for hours, versus a current moon rocket at maybe 8 gravities for a matter of minutes. Then consider that it is the compensator that is the limiting factor anyway.
Really an eternal motion machine.

tlb wrote:

Daryl wrote:What many avoid thinking about is the second law of thermodynamics along with relativity.
The equation E=MC2 can be rewritten as M=E/C2, so the weight gain that starts to become apparent at 0.9C is made up from enormous quantities of energy. Where does that energy come from? Apparently free from the wedge. My rationalisation is two fold. Firstly it is RFC's universe so he sets the rules, secondly the Honorverse is chronologically as far from us as we are from the ancient Greeks. When you think of all the things we take for granted, that the ancient Greeks would have declared to be magical, it isn't such a great stretch.

I do not believe that we have avoided talking about relativity; indeed many have speculated that the author limited speeds to .8c specifically so that relativistic effects would be minimized.

Obviously it is the author's world to set the rules as he pleases. Obviously the wedge has seeming magical powers (to us, not just to the ancient Greeks), but there is no reason to expect the wedge would permit the approach to the speed of light without limit; since it does not offer endless power.

Daryl wrote:Possibly not endless power, but consider a 6 million ton SD (P) being under constant acceleration of 500 gravities for hours, versus a current moon rocket at maybe 8 gravities for a matter of minutes. Then consider that it is the compensator that is the limiting factor anyway.
Really an eternal motion machine.

<snip>


Missiles still need massive power to run the wedge, even though it is siphoning off most of what it needs from the wall. The reactor used for a Manty MDM can power a MidWestern US city for days, but is exhausted in less than 13 minutes. It's not completely free.

In all the discussions we've had over how much the compensator cares (or rather doesn't seem to care) about ship's mass I don't recall us talking about the ship's relativistic mass.

But an 8 mton ships going 0.6c should have a relativistic mass of about 10 mtons (if the random online calculator I found is to be believed). But we don't hear about ships dramatically losing acceleration in hyper as relativity pushed their mass over the edge of the compensator capability 'plateau'.


So just one more way that compensators seem to care virtually exclusively about volume, not tonnage.

Jonathan_S wrote:In all the discussions we've had over how much the compensator cares (or rather doesn't seem to care) about ship's mass I don't recall us talking about the ship's relativistic mass.

But an 8 mton ships going 0.6c should have a relativistic mass of about 10 mtons (if the random online calculator I found is to be believed). But we don't hear about ships dramatically losing acceleration in hyper as relativity pushed their mass over the edge of the compensator capability 'plateau'.

So just one more way that compensators seem to care virtually exclusively about volume, not tonnage.

I am not ready to accept that the compensator cares more about volume, than mass; I think that it is simply that we do not have a relativistic formula for the behavior of the compensator.

Relativity is peculiar anyway: to an observer on the ship, it is the Universe that is changing, not the ship. The relativistic mass increase is seen in the increase in average mass with increased speed of whatever is hitting the particle shielding. So it is the strength of the particle shielding that sets an absolute limit on the speed of the ship.

Jonathan_S wrote:In all the discussions we've had over how much the compensator cares (or rather doesn't seem to care) about ship's mass I don't recall us talking about the ship's relativistic mass.

Because it shouldn't matter. Acceleration and force are local things. It doesn't matter what someone else measures the current speed to be.

However, if relativity did apply, we would see what you've just said:

But an 8 mton ships going 0.6c should have a relativistic mass of about 10 mtons (if the random online calculator I found is to be believed). But we don't hear about ships dramatically losing acceleration in hyper as relativity pushed their mass over the edge of the compensator capability 'plateau'.


So just one more way that compensators seem to care virtually exclusively about volume, not tonnage.

Not not for the reasons I understood from you, because they don't lead to that conclusion.

The relativistic mass is on the eye of the beholder because of time dilation and space contraction. On its own frame of reference, the ship can continue to accelerate at 500 gravities, but it gets no closer to the speed of light. But another observer would see it accelerating less and less. If the force is constant, then the reduction is acceleration is explained classically by an increase in mass.

This all assumes that the acceleration imparted by the wedge does not, after all, depend on some other, non-local frame of reference. Unfortunately, we do have evidence that there is another frame of reference that matters, because ships can't enter hyperspace at above 0.3c. That and the fact that the spider drive works by pulling on and pushing the hyperwall leads to the conclusion that the hyperwall is a physical thing. Since the impellers do draw energy from hyperspace through the hyperwall, the acceleration that they can impart may depend on the relative velocity of the wedge and the wall.

But if it did, we'd still see relativistic effects, just inverted. If a ship could maintain 500 gravities indefinitely from the point of view of an observer at rest relative to the hyperwall, then the observer aboard the ship should be seeing the acceleration increase as the speed goes up. This also leads to the theoretical possibility of going faster than light, if not a practical one.

Special Relativity mainly is a discussion of inertial frames of reference and only talks about acceleration tangentially, as in the Twin Paradox. I do not know enough about General Relativity, which does discuss acceleration, to know how to answer what you are saying.

But even when talking about inertial frames of reference, we know that they are not really all equivalent; because the background of the Universe provides a standard. If instead of the random pattern of lights provided by the stars; we see the star light shifted to the blue in one direction and to the red in the opposite, then we know we are the ones that are moving. I am not sure if that is a non-technical statement of Mach's Principle.

tlb wrote:But even when talking about inertial frames of reference, we know that they are not really all equivalent; because the background of the Universe provides a standard. If instead of the random pattern of lights provided by the stars; we see the star light shifted to the blue in one direction and to the red in the opposite, then we know we are the ones that are moving. I am not sure if that is a non-technical statement of Mach's Principle.

Indeed each thing can have its own inertial frame of reference, even the Cosmic Microwave Background does. So indeed you can tell whether you're in the same frame of reference as that one or not, if you can observe it. And spoiler alert: the Solar System is not at rest relative to the CMB.

The Sun is indeed in orbit around the centre of the Galaxy, so its frame of reference is not completely inertial (one Galactic Year is a quarter billion years and the orbital radius is about 8 kpc, so the acceleration is about 156 pm/s²). And neither is the Galaxy's, as we are accelerating towards Andromeda and it towards us.