I have formulated a plan on how to destroy the world.

Remember in the Sydney 2000 Olympics, when some swimmers used body suits designed to reduce friction? Well, that material, which is called something like ny-lex or lato-ribex or something has been virtually perfected. It combines a special friction-reducing fabric (reducing friction much like Teflon), with ribulets, small V-shaped grooves in the fabric which help reduce resistance a further 10-15%, making friction effectively zero.

So what you do is this:

Take a large male adult African elephant, and dress him from head to toes in the friction-reducing fabric. Put him on the spaceship, and fly to about 150 miles up (about 240 kilometers). This will put you in the thermosphere, at about the maximum height where the elephant won't catch fire. Push the elephant out of the spaceship.

A large male adult African elephant weighs about 7 tons. According to my quick calculations, an elephant free-falling for 150 miles without friction, should reach the ground (at sea-level) at a velocity of approximately 50,000 metres/second. Using the simple momentum calculation we all know from physics class (p = mv), the elephant's momentum should be about 7,000 * 50,000 = 350,000,000 kg m/s.

An elephant hitting the ground with such a momentum will deliver the equivalent of about 10,000 atomic bombs. This will create a crater 50 miles wide, and send enough dust into the atmosphere to block the sun's light for 200 years, killing all life forms on the planet.

```

```
I have been asked why not just drop the spaceship if you're already up there. Well, that's just silly. What would you drop it out of?

(v = velocity, vbar = average velocity, t = time, d = distance, e = energy, 241350 = 150 miles in meters, 10 = acceleration due to gravity, gbar = average force exerted by gravity during the drop, 5.98E24 = Mass of earch in KGs)

```   v = at
vbar = at/2
t = d/vbar

vbar = at/2
vbar = 5t

t = d/5t
5t^2 = 241350
t^2 = 48270
t = 219.7

v = at
v = 10*219.7
v = 2197 m/s
```

The elephant impacts at just under 3.5 times the speed of sound. I am sure it may smart a bit, but not enough to destroy all living things on the earth.

Now, if e = 1/2 mv^2 and we use The Custodian's figure of 4.184E12 Joules per kiloton. If you want to aim for 10,000 atomic bombs worth of energy, then we need to drop the elephant from a little higher up.

I am assuming for the purposes of argument that an atomic bomb is 1 Megaton (forget about the bomb that totalled Hiroshima, technology has moved on since then).

First, lets calculate the total energy required:

```e = (total number of bombs) * (power of each bomb in kilotons) * (joules per kiloton)
e = 10,000 x 1,000 x 4.184E12
e = 4.184E19
```

We can now work out how fast this elephant needs to be going:

```e = 1/2mv^2
4.184E19 = 1/2 x 7000 x v^2
v^2 = 4.184E19 / 3500
v = 1.093E8 m/s```

Now we are getting to the point, all we need to do is accellerate our elephant to just over 1/3 of the speed of light.

The next part is trickier, we need to find the altitude required to drop the elephant. Assuming a steady accelleration of 10m/s/s, this would be easy, but gravity is inversly proportional to the square of distance, and I have a feeling that this will come into play with these figures.

```                           f = ma
v = at => t = v/a
t = d/vbar

vbar = 1.093E8 ^ 0.5
= 1.045E4

v/a = d/1.045E4
1.093E8/a = d/1.045E4
a/1.093E8 = 1.045E4/d
a = 1.142E12/d

a = 6.672E-11 * 5.98E24 / ((6.38E6+d)*(6.38E6+d)) (stolen from gsu.edu)
a = 3.99E14 / (4.07E12 + 1.276E7d + d^2)
a = 9.80 + 3.12E7/d + 3.99E14/(d^2)

1.142E12/d = 9.80 + 3.12E7/d + 3.99E14/(d^2)
1.142E12 = 9.80d + 3.12E7 + 3.99E14/d
9.80d + 3.99E14/d = 1.142E12
9.80d - 1.142E12 + 3.99E14/d = 0```

Solve as a quadratic equation and d = 116524244548.55304

This works out at just over 116 million kilometers. Note, for this to work properly, you will have to remove all matter in the Solar System which is not part of the Earth, but this is left as an exercise for the reader.

Hmm. Well, a kiloton of TNT releases (AFAIK) approximately 4.184 x 1012 joules of energy. Furthermore, calculations performed to study asteroid impact indicate that an object travelling at approximately 3 km/sec will strike with an equivalent energy of its weight in TNT. Ergo, a 7-ton elephant moving at 50 km/sec would strike with the energy of approximately (7 ton) * (50km/sec / 3km/sec) tons of TNT. Worked out, I get something around 16.66*7 tons, or around 116 tons...leading me to state that said elephant would hit with a force equivalent to just about one-one-hundredth the energy release of the Hiroshima explosion (~11-12kt).

Nasty if you're under it, but not really an extinction-level impact. Plus, think of all the crispy heffalump you'd have scattered about. Now, for a tactical, conventional use this might have merit; said explosion would be perfect for whacking a bunker, or tank group, or large structure (dams, bridges, airfields, etc.) without concomitant release of radiation and thus fallout! This is at least a good idea as those morons in Washington, D.C. who seem to think you can make a 'small and safe nuclear bunker buster.' Unfortunately, the elephant is an endangered species, no? Thus, any attempts to weaponize pachyderms would probably result (at the very least) in one being branded an eco-terrorist.

For that matter, so would dropping them around the landscape. Ever smelled an elephant up close? Wheeeeee-yooo!

Update: Anark says Look at it this way: if your elephant's energy equals 7 tons of TNT when it's traveling at v = 3 km/s, then at 50 km/s = 16.7v its energy will be 7*(16.7)^2 = about 2 kilotons.

Anark is absolutely right and caught me with my physics pants down 'round me ankles whilst bending over for a fresh beer. Okay, so I had confused momentum and kinetic energy. The former is a vector; the latter a scalar, and the formula for KE is:

KE = 1/2 * mv2

...so, okay, as noted above, a 50 km/sec incoming ballistic heffalump contains within its fragrant hide KE equivalent to around 2 kilotons of TNT. That's still not enough to be a global problem; given that it doesn't release any ionizing radiation on impact unless you've force-fed the elephant in question some form of radioactive material in advance of the shot. This, however, would likely violate several strategic trunks reduction treaties as well as cause all your Mahouts to lose their hair and grow extra toes.

Heh. Never get a semi-pro nuclear targeter started on impact energies.

In fact, this magic fabric cannot eliminate air resistance. If it did, the swimmers would not need to put in any effort beyond diving in at the start, because in the absence of resistance, objects keep moving at a constant velocity, like the planets do. They could also not stop until they hit the wall at the other end, at rather dangerous speeds.

If there is any air resistance, which there must be, the elephant will eventually reach what is known as terminal velocity. This is where the upward force of air resistance, which increases with velocity, balances the downward pull of gravity, and so the elephant stops accelerating. Its impact velocity is therefore limited to a certain maximum determined by how aerodynamic the elephant is; and elephants were not designed to be aerodynamic!

Sorry to be such a spoil-sport! Great idea though ;)

Log in or register to write something here or to contact authors.