ASTEROID IMPACT
Extinction Level Event
66 million years ago, a large asteroid hit the Earth and caused an extinction event. Colossal shock waves burned countless animals alive, and triggered global earthquakes, volcanic eruptions and the largest mega-tsunamis in Earth's history. Three quarters of all species became extinct.
How it may look like (clip from the movie Deep Impact)
The key questions are:
- How often is the Earth hit by meteors?
INTERCEPTORS
It has to be the Nuclear Option
The Cretaceous-Tertiary (K-T) asteroid is estimated to weigh 1.5 trillion tons and have carried 310 zeta joule of kinetic energy. If we detonated our largest thermonuclear weapon on its surface, and 5% of the weapon's energy was converted to slow down the asteroid, it will slow down the asteroid only by 0.33 millimeter per second.
If we hit the K-T asteroid a hundred times with this nuke, 10 years prior to the projected impact day, the bombardment will slow down the asteroid by 3.3 cm per second and the impact to the Earth will be avoided. The issue is, currently we have no spacecraft which can deliver our largest nuke to the asteroid. Another issue is that we may not have enough time to discover the asteroid, build, launch and impact the asteroid 10 years before the projected impact day.
LUNAR STATION
Defense From the Moon
The spacecraft launched from the Earth must overcome atmospheric drag, aerodynamic heating, and the Earth's gravity to go to space. Saturn V burned 3,000 tons of fuel in order to send a 50-ton spacecraft to the Moon. In order to enter a heliocentric orbit, 98 percent of spacecraft of weight is spent as fuel or jettisoned structure to accelerate to 11 kilometer per second (km/s).
On the Moon, there is no atmospheric drag or aerodynamic heating to overcome. The spacecraft still has to accelerate to about 2.4 km/s to get out of both the Moon's and the Earth's gravity, but the energy requirement is only 1/20. Further more, the spacecraft can be accelerated by a electromagnetic catapult on the surface of the Moon, without consuming any on board fuel of the spacecraft. Continue...