> If I understood correctly:
Yep, I am working on the assumption that you are trying to detects using IR
radiation emitted from the ship. If the ship does something (turns on reaction
drives, fires somethign) all of this goes out the window.
> So, this to me says that if I could drop my temp to 150 K (a long way
This would be again to Cloaking.
> Or am I missing something? I'd be interested to see some of the
> [quoted text omitted]
So the math is really simple. The luminosity of a blackbody is
L = 4PI Radius^2 Temp^4
The flux of received is
F = L/(4PI * Distance^2)
So, the flux then becomes:
F = (Radius^2 Temp^4)/(Distance^2)
So, any thing that keeps your temperature down (for a fixed radius) makes you
harded to detect in the IR. The other thing to look at the equation above (L =
4PI Radius^2 Temp^4), is if you make your radius bigger, you lower your
temperature. Your luminosity will not change, but the cooler you are the more
you blend into the background (most things in our galaxy are around 20 of
degrees Kelvin).
None of this talks about reflecting light, or any kind of active systems like
radar. This is just thermal radiation from a an object. The problem is you
ship will generate a certain amount of heat, and you will have to get rid of
it. However, something like the cloak from FT could be mimiced by having
something that you dump the heat into temporarily, ( a really big vat of
Liguid Helium) which lets you "hide" as long as you don't turn on the engines
or shoot at people.
Is that clearer?
cheers
> Brad wrote:
Essentially, in FT if you fire up your drive, you've been detected from
ANYWHERE in the solar system. Why do I say that? Well, we have as canon (and
rules) that the interference from the drive prevents you from targetting ships
in your aft arc. Therefore, there's got to be a fair amount in the way of
emmissions REGARDLESS of how the drive works (for a reaction drive, anything
that'll do that is pretty bright. If you have decided to junk all the
conservation laws and allow a reactionless drive (why not allow magic while
you're at it, but that's another subject entirely), ANYTHING that'll screw up
targetting is undoubtedly detectable by passive means). Therefore, you can
stay hidden (for awhile) until you thrust, or get too close.
> On 19-Apr-00 at 15:40, Brian Quirt (baqrt@mta.ca) wrote:
> If you have
Tachyon drive?:)
> Roger Books wrote:
Not that I understand the Physics or if would be even practical, but some
think the use of Mach's principle could be use to produce a reaction less
drive.
http://www.inetarena.com/~noetic/pls/woodward.html
Tim
> At 01:51 PM 4/19/00 -0500, you wrote:
As an aside, did anyone (in ConUs or otherwise in PBS' broadcast footprint)
happen to see this week's Nova? In the discussion of CO2 as a nasty evil
greenhouse gas, they did a rather interesting demonstration in which a FLIR
camera had its vision occluded by nothing more than CO2 of a certain density.
This would suggest a simple stealth device for ships coasting into a
system: exude a mini-atmosphere of carbon dioxide to mask IR signatures.
This assumes that a) either screens could contain the gas to keep it with the
ship or b) once the CO2 cloud is out, any course change would move the ship
out of its protection.
Granted this is a knee-jerk idea without any consideration of real
physical issues (how dense does the CO2 need to be? How much would it take?
How much heat can it absorb before it too begins radiating IR?) but does
provide a
PSB justification for a low-mass, charge-based stealth system.
Random thoughts from a sleepless, suddenly talkative lurker. YMMV.:)
> Jim 'Jiji' Foster wrote:
Well, there are a couple of problems with this. First, of course, there's a
vacuum, the CO2 would tend to disperse fairly quickly. If you have a screen
that can keep it in, it'll probably also keep particle beams OUT, giving you
perfect shields. I'd think that would be very
useful in the GZG-verse (barring the Kra'vak of course). If you don't
have a 'magic screen' the density effectively needs to be infinite, because it
keeps dispersing. Second, the CO2 will tend to REALLY screw up the
emmission/absorption
spectrum. You don't get a lot of free CO2 in space, and detecting THAT in the
spectrum is a dead giveaway that there's SOMETHING not entirely natural out
there. I'd say that overall, without 'magitech', it's not possible.