On page 119 of Dangerous Voyage to Alpha Centauri Tasia witnessed from Siding Spring Observatory in Australia the effects of an impact thousands of miles away from her:
No one could ever have imagined an inferno like this happening. The speed of this tempest was unbelievable! It carried dirt, stones, branches, and trees. With a thundering noise, the debris crashed against the walls of our observatory. Hot, glowing meteors rained from the sky. We huddled under the dome, trembling with fear.
In this horror scenario Tasia was present to see how the Earth, as we know it, seized to exist. It isn’t a unique idea, because there have been other authors who wrote about impacts and it is still the plot of movies. My interest was not to frighten my readers, though the thread of a disastrous impact is apparent.
I rather want to draw attention of influential people on the fact that mankind probably is the sole intellectual species in our Milky Way. If Earth is hit by an asteroid of medium size intelligent life in this galaxy will be annihilated. Therefore we should use our means to protect Earth from an impact and we should also start to settle people on another celestial body to secure the survival of mankind.
If, as I described in the novel, almost all life on Earth has ended in a disastrous impact of a comet, mankind should have prepared for another home to live on.
Here are facts about threats from the space:
Up to one hundred tons of smaller interplanetary debris and dust fall on Earth each day. These meteorites heat up and burst in the atmosphere, which protects us from the bombardment as long as these meteorites are less than 30 ft in size.
Observing Earth’s atmosphere for nuclear blasts US Air Force would detect about ten explosions per year which proved to originate from the explosion of boulders from space. Even if they are objects with nimble 30 ft in diameter they release energies of about eight thousand tons of TNT as they travel with speeds about thirty times faster than sound. Compare this energy with that of the Hiroshima atom bomb which had the power of approximately fifteen thousand tons of TNT. The shock waves of meteorites of that size are also registered by stations on Hawaii, in Alaska, Canada and Germany.
If even these small boulders cause havoc in the atmosphere, what are the results of heavier objects? Billions of rocky objects are orbiting the Sun. If they live or lived between the orbits of the planets Mars and Jupiter they are called asteroids. If they come from the Kuiper Belt far behind the Planet Pluto, we call them comets.
As I said, asteroids or comets of less than 30 ft in diameter will detonate high above us when they enter the atmosphere. Yet if they contain metals as iron, they might penetrate the atmosphere and arrive at the surface. But these objects are rather rare, they make up less than 3% of those smaller meteorites.
Objects of 250 ft leave craters behind themselves if they contain iron, as the Winslow crater in Arizona. They will destroy an area of the size of Washington D.C., as did the Tunguska asteroid which exploded 8 kilometer above ground on June 30, 1908. The energy of this explosion was equivalent to fifteen megatons of TNT what means one thousand Hiroshima bombs. Remember, the hydrogen device on the Bikini-Atoll was 10 megatons of TNT.
Comets or asteroids with the target Earth on it with 500 ft in diameter produce significant tsunamis if they hit the ocean or annihilate a large urban area of the size of New York.
An object of the double in size would destroy an area the size of Delaware; ocean impacts would produce ocean wide tsunamis drowning all coastal areas.
Asteroids or comets measuring 2,000 ft reach hemispheric scales if they hit an ocean. Land impacts would destroy an area of a moderate state compared to the size of Virginia.
Measuring 5,000 ft the power of an impact would be the equivalent of one hundred thousand hydrogen devices. Land and ocean impacts would raise dust to affect climate and freeze crops. A thirty kilometer crater would penetrate through all but the deepest ocean depths.
A 10,000 ft impact would trigger wide-spread fires and destroy completely areas of the size of Mexico or India.
A 20,000 ft object hitting Earth with the power of ten million hydrogen bombs would provoke prolonged climate effects and global conflagration, probably mass extinction.
A 50,000 ft wide object would lead to large mass extinction as did the asteroid which hit Earth sixty-five million years ago when all dinosaurs among other species became extinct within days. Another impact of this size would threaten the survival of all advanced life forms on Earth.
Though there is a danger existing, at present an impact is quite improbable and you may have a good rest at night. We don’t know when a larger object will hit us, but we know it will hit Earth for sure, sometime.
Since 1998, funded by NASA and US Air Force, LINEAR, Lincoln Near Asteroid Research Project is surveying the sky for objects exceeding one thousand meter diameter which could come close to Earth. Similarly, LONEOS, Lowell Observatory Near-Earth Object Search is operating since the end of last century. Five hundred NEOs, Near Earth Objects of one thousand meter in diameter have been discovered in the last years. Twice as many have been catalogued being smaller than one thousand meter.
Let me name some of them which I regard as important.
1997 XF11 is a mile wide object which will come close to Earth on Oct 26, 2028. Its energy measures about 320,000 megatons of TNT.
2000 QW7 This 800 meter large object was first seen on Aug. 26, 2000, and approached Earth to less than five million kilometer six days later.
2001 CU11 is also 800 meter wide. It had been close to Earth Aug. 31, 1925, which wasn’t recognized then.
2001 YB5 is a 300 meter object which was discovered Dec. 27, 2001. It passed Earth ten days later only two times farther than the Moon.
2002 NY40 measures about 800 meters across. It was discovered July 14, 2002, and passed Earth in 1.3 lunar distances on August 18, 2002.
2004 MN4, named Apophis, is a 350 meter asteroid which is supposed to pass Earth on April 13, 2029, just 40,000 km distance from Earth’s surface. This is the distance in which our geo-stationary satellites for communication reside. Earth’s gravity will influence the orbit of Apophis. After it had passed Earth in 2029, we will be able to calculate its orbit and find out if it is on collision course with Earth in 2036.
1934 CT, named Toutatis, measures roughly 3,000 meters in diameter. It was lost for decades and re-discovered Jan.4, 1989. Toutatis passed Earth on Sept. 29, 2004, just four times farther than the Moon.
Money is well spent to find out approaching objects. But there is no sense just to look for hazardous asteroids if you do not know how to divert one of them in case an impact is feared.
No natural disaster we know of has global dimensions, except the impact of a well-sized asteroid. The collision, however, would induce an ecological catastrophe which would kill billions of people and destabilize our civilization. It would end the world as we know it. Even though disastrous impacts are extremely rare, impacts are a danger most people ignore. There lies the problem with statistical arguments, if you hear impacts are very rare. The weight we assign to threads from space determines how real they become in our collective mind.
Scientific American, Sept. 1993 pp. 52 – 62 and 65 – 71
More about this subject you can read in my thrilling novel, you can order here: ORDER