Ran a FT combat and decided to try having asteroids on the board. We got into
a discussio on how dense an asteroid field should be. I had 1 asteroid about
every 12", they thought there should be a lot more (ie. Empire Strikes Back
scene with Mil. Falcon). How dense do other players on the list place them?
Does anyone know about the real life asteroid belt: how close are the big
asteroids to each other, how big, or small, would one have to be to be a
hazard, etc.
Hello
The asteroids should be spaced to create the desired tactical effect, if you
want a slight hazrd to navigation, scatter them, if you want a game where only
small ships can safely enter, pack them close. The only determinent is what
will produce the maximum dramatic effect!
Cheers
> At 12:20 AM 9/25/97 -0400, you wrote:
I cannot remember the source, but it pointed out that stellar distances being
what they are, a ship could fly through an asteroid belt, and never even know
it was there (come to think of it, I think it was 2001 the novel I read this
in...). Collision with an asteroid would be ludicrously unlikely unless, for
some reason, you were deliberately looking for it.
I suppose something like the rings of Saturn might be more dense, but I
wouldn't be surprised to find that even there collisions were unlikely.
To quote a famous source: Space is Big. Really Big...
The FT rules on the subject could be read to give the impression that the
'roid just represents a field - ie that why you can avoid damage by
moving through a 'roid slowly.
Thats how we play it. Also that means we have them pretty dense - like
ever 5" or 6". Jason Berman sigue@one.net.au
> Ran a FT combat and decided to try having asteroids on the board. We
Hollywood? SF? Dramatic Effect? It's a lot denser. And in NO way bears any
representation to reality (eg, Empire Strikes Back). It's purely for visual
effect.
Reality? Asteroids are really really reeeeaaally far apart from each other. If
the asteroid field were anywhere NEAR as dense as what you see in Hollywood,
you could actually SEE the thing as a ring in our solar system. Despite the
low albedos (light reflectivity) of individual asteroids, combined together in
such dense proportions would reflect plenty of light.
Want a fight in an Real Asteroid Field? Put one asteroid on the map. Voila'!
You are in the asteroid field. :-) (Okay, okay, so it depends on what
scale you're talking here; you might put in two)
How big/small are they to be a hazard? Okay, asteroid-education time.
;-)
To be a hazard, it again depends on your scale, and depends on how fast you're
travelling in RL. If fast enough, a basketball-sized asteroid could be a
real
bummer. ;-) How big? THere ain't too many 'big' asteroids out there.
There are only 18 that measure 125 kilometers across or larger (the largest is
only 512 km; the second largest is a whopping 277 km, and they go down from
there). Of those 18, only 4 are greater than 200 km. There are about 4000 or
so which are 50 km across or larger. You could probably feasibly guess that
there are 4 or more times as many which are only a few kilometers across.
So, now, let's say we're talking 20,000 asteroids here (just a rough number,
something to work with). That's really not very much in the grand scheme of
things. You see, it's like this...
The 'width' of the asteroid belt is quite large. Asteroids tend to range in
bands from ~1.8 AU to ~5.2 AU from the sun (side note: 1 AU
[Astronomical
Unit] is the distance from the sun to Earth; Mars is ~1.5 AU away from the
sun, and Jupiter is ~5.2 AU away). There are gaps between the bands, called
Kirkwood Gaps (I will leave it as an exercise for the student to explore the
Kirkwood Gap phenomenon). Most asteroids are 'concentrated' in a band that
ranges from 2.2 to 3.2 AU That's an area 93 million miles across. And from
186,000,000 to 270,000,000 miles from the sun. This will yield an area of
space that covers some 1.2 x 10**17 miles (that's 1.2 followed by 17 0's, btw
:).
To replicate, use this simple calculation:
pi x (270,000,000**2 - 186,000,000**2)
where 'pi' is ~3.14159
Now...toss 20,000 asteroids in an area measuring 1.2 x 10**17 miles. Oh, hell,
toss 20,000,000 asteroids in it. You only get 1 asteroid every 6,000,000,000
miles! And now we're talking stuff that's measuring meters across. And only 18
of them are larger than 125 km.
Okay, for the moment, go back to your map. Remove that one asteroid (or both
if you put down two). Now you have a blank map with ships. Declare this is an
asteroid field. You'll be just as right as not.
Now, mind you, I'm only talking 2 dimensions here. I haven't even tackled
the Z-coordinate (okay, yeah, it won't be *real* far above/below the
plane of the asteroid 'ring', but it'll be enough to really diffuse an already
tenuous 'field').
I hope this illustrates the point. WHich basically says: Hollywood is full of
it.
Trivia note: some of you may have noticed that Jupiter is ~5.2 AU from the
sun, and I indicated some asteroids range out as far as 5.2 AU from the sun;
these asteroids are part of the Kirkwood Gap phenomenon, and are called Trojan
Asteroids, something some of you may have heard of before, in some dim faint
distant memory from a basic astronomy class.
Thus endeth the lesson for today. :-)
Mk (ps: knowing the above, I did run a PBeM FT game last year that took place
in a hellaciously dense asteroid field - 30 or so asteroids in a 4900
square unit area. the purpose was mainly for terrain to force the players to
maneuver about the place, rather than fight in open space, but in reality this
field would not exist, unless it was from something recently broken up. i will
likely create fields just as dense in the future for gaming purposes, but not
to
reflect reality any - unless you want to call it an asteroid 'clump',
which might really occur in very localized areas, but again, 30 was a heck of
a dense field)
> Trivia note: some of you may have noticed that Jupiter is ~5.2 AU from
these
> asteroids are part of the Kirkwood Gap phenomenon, and are called
I think there are Trojan point asteroids described in the
Niven/Pournelle
"Mote" series. So for us non-physiscs guys what does this really mean ?
This info from the astronomer at the Planetarium, a couple of web sites too
> ----------
While on the topic of asteroid-ish starship hulls... If you're looking
for some great asteroids, pick up a bag of "lava rocks" in the gas grill dept.
I just set them on the table (I don't mount them or anything). If your
starship's mounting post comes into contact with the rocks... BOOM!
Pete
Yes, I have already constucted some asteriod ship hulls with the lava rocks.
We ran across this some months ago. Far superior to any foam or anything else.