Re: Space Geography

 On Fri, 23 Sep 2011 10:50:52 +0100, Roger Burton West 
 <roger@firedrake.org> wrote:
> On Fri, Sep 23, 2011 at 05:48:00AM -0400, Indy wrote:
>>But note that in general the background radiation is
>>pretty low to begin with. On the flip side, contemporary technology 
>> has
>>challenges just detecting Earth-crossing asteroids. It's pretty much 
>> all
>>passive and optical.
>
> Part of the problem when it comes to spaceship detection is that they
> aren't relatively cool planets - in a world with realistic physics, a
> ship with enough power plant to run a space-drive and weapons and so 
> on
> is seriously glowing, and will be obvious to anyone with an IR 
> detector
> at several AU range. (Ask Ken Burnside about this...)

 Some suggestions for stealth involve trying to shed your heat in one
 direction - e.g., you point a non-radiating side towards the enemy
 sensors, and radiate all your heat back in the opposite direction.

 Ignoring the difficulty in doing this, it is foiled by having multiple
 sensors in the system, which makes it difficult to radiate in a 
 direction
 which isn't being watched.

 As far as coming in from the poles is concerned, if most civilian 
 traffic
 tends to be on or near the ecliptic, then civilian sensors are probably
 going to be focused there, so such a technique might work against soft
 targets. Military sensors will undoubtedly scan the entire sky, despite
 the extra expense of doing this.

 Coming from a direction very close to the sun might make it hard to be
 detected - which is another reason for a system to have lots of sensors
 spread throughout the system. There may be regions which are less well
 scanned than others though, so though you may not be able to avoid
 detection, you might be able to delay it.

-- 
 Be seeing you,
 Sam.