Earth evacuation

{{Date: 15 Sep 2003 12:29:07 -0700
From: (Doug Haxton)
In 2004, astronomers detect a *massive* body heading in the general
direction of the Earth. Let's go all out and make it a Kuiper Belt
200 miles in diameter.}}

So it's in an orbit very close to the plane of the planets and most of
the asteroids. See below for how we make use of that fact.

{{By 2015, the chance of actually hitting the Earth is 50%. By 2020,
it's 90%. ... Now what? A collision of this magnitude will sterilize
the planet. The only chance we have is to evacuate a self-sustaining
portion of the population. ... We have 80 years to do it.}}

There are tens of thousands of already-known asteroids in various
orbits with periods between one and ten years. These asteroids are in
all sorts of phases with respect to the trajectory of the KBO
Earth-killer when it crosses their orbit, so by chance several of them
will just barely miss (by less than 0.01 AU) striking the KBO as it
dives past the asteroid's orbit. We have 75+ years to pick three such
asteroids and divert all three of them to intercept the KBO, the second
and third as backups in case something goes wrong and the first misses.
75 years is plenty of time to develop a thermonuclear rocket system
such as Orion and test it and perform the three asteroid-nudging
missions. So then with all three looking like surely on collision
course with KBO, we sit and watch the fireworks of the first, as it
punches a hole through the center of the KBO and shock waves pulverize
most of the rest of the KBO, then the rubble pile collapses under
self-gravity and we slightly adjust the trajectory of the second
asteroid to intercept the slightly-different new orbit of the pile,
maybe detonating a bomb against the second asteroid shortly before
collision so we have a shotgun load of asteroid fragments striking the
KBO rubble pile so the entire KBO rubble pile is affected instead of
just a hole through the center, especially if the rubble pile hasn't
yet finished collapsing. By the time the million fragments of KBO reach
Earth orbit, each will be a full-fledged comet, but each so small that
it completely evaporates before reaching Earth. The few large chunks
remaining would miss Earth but come close. A few thousand small bits of
debris would actually arrive as meteors. What a sight! A million tiny
comets heading inward from Mars's orbit toward Earth's, and a few
surviving to pass right by before evaporating, and a small meteor
shower too!

Any reason, other than politics and motivation, why we couldn't protect
ourselves in that way, given 80-100 years lead time?

But with only 5 years warning, all we can do is arrange that most
people can get into underground bunkers to survive the initial blast,
and turn off all computers and other electric-using systems to avoid
damage during power surges and EMP, then come out when it's safe and
try to re-start electric service and agriculture. Unlike a
thermonuclear war, the KBO won't be deliberately targeting all large
cities and infrastructure centers such as nuclear power plants, so
bunkers in cities away from the impact point should be semi-safe, that
is by chance some won't collapse due to triggered earthquakes.

{{Date: Thu, 18 Sep 2003 00:10:19 GMT
From: Joann Evans
And there'd still be the lesser problem of evacuating what could be a
very large and densely popoulated area (if ground zero is, say, the
US east coast, or central Europe) to somewhere that any practical
shelter could hold up.}}

I'm sure there are enough motor vehicles (cars, busses, taxis, vans,
sport-utility vehicles) in the Eastern USA that we could evacuate the
entire population. It takes only a week or so to drive all the way from
ground zero to a safe distance. Under martial law, any vehicle driving
toward ground zero (to fetch a new passenger load) would be allowed to
have only one driver, no passenger, while any vehicle driving away from
ground zero would be required to be fully loaded, not just regular
loading with seat belts, but extra people (mostly children) lying
across the laps of the seated passengers.

Underdeveloped areas where hardly anybody has any transportation faster
than an elephant or water buffalo or ox might be harder to evacuate.
The really nice train system in India for example probably couldn't
move much of the population even given a year or two to do it.
Central Africa or China would probably be the hardest to evacuate.
How would Islands such as Japan fare? Assuming good weather, would
large numbers of rafts/ferries and fishing/whaling boats be available
and effective?

In article , wrote:
...we sit and watch the fireworks of the first, as it
punches a hole through the center of the KBO and shock waves pulverize
most of the rest of the KBO, then the rubble pile collapses under
self-gravity...

Uh, note that KBOs probably are not rubble piles.

The rubble-pile theory gets hyped too much. It is far from certain that
even the lighter asteroids are rubble piles -- there *are* other theories
for their low density. There is clear evidence that Eros in particular is
*not* a rubble pile; probably few or none of the denser asteroids are.

Furthermore, the KBOs almost certainly have a very different history than
inner-system asteroids, with far fewer collisions. And they probably have
very different compositions too.

And the proposed 320km object is, in any case, probably too large to be a
rubble pile -- it will have enough gravity to compact itself.

Oh yes, and an impactor won't "punch a hole through" an asteroid. At such
velocities, intuitive models of impact dynamics based on human experience
at low speed are simply wrong. The impact is primarily an *explosion*.
It will blow out a crater and throw out ejecta; if it is big enough, it
will break up the larger body entirely.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

wrote in message
...
{{Date: Thu, 18 Sep 2003 00:10:19 GMT
From: Joann Evans
And there'd still be the lesser problem of evacuating what could be a
very large and densely popoulated area (if ground zero is, say, the
US east coast, or central Europe) to somewhere that any practical
shelter could hold up.}}

I'm sure there are enough motor vehicles (cars, busses, taxis, vans,
sport-utility vehicles) in the Eastern USA that we could evacuate the
entire population. It takes only a week or so to drive all the way from
ground zero to a safe distance. Under martial law, any vehicle driving
toward ground zero (to fetch a new passenger load) would be allowed to
have only one driver, no passenger, while any vehicle driving away from
ground zero would be required to be fully loaded, not just regular
loading with seat belts, but extra people (mostly children) lying
across the laps of the seated passengers.

Most people would want to bring their stuff with them. I drive a Nissan
Sentra and the basic essentials would fill up my car. If I'm expecting a
major disaster, I wouldn't trust a moving company. U-Haul will run out of
trailers real fast. They could pay people to drive trailers towards the
disaster zone.

Underdeveloped areas where hardly anybody has any transportation faster
than an elephant or water buffalo or ox might be harder to evacuate.

Many people are capable of walking 3000 miles in a year. Finding food along
the way would be difficult. The government would have to set up free
restaurants along the road (or pay existing restaurants). If you only have
time to cover 200 miles, then people in the center of the blast zone will be
toast, but people farther away may have time to move to safer ground.

What happens if two countries build bomb shelters and then it is discovered
that one of them will be destroyed? People in that country will want to
move to the other country.