How big does the asteroid have to be?
You will be surprised with the size of the asteroid that could be life-ending. The asteroid only has to be a couple of kilometres to wipe out the majority of the earth. For example, the asteroid that was predicted to wipe out the the dinosaur was only estimated to be between 5 to 15 kilometers in diameter and look at what it was able to do.
This is a table of the damage different sizes of asteroids can cause to the Earth:
Sizes: Effect:
75 m Land impacts destroy area the size of Washington or Paris)
160 m Destroys large urban areas
350 m Destroys area the size of a small state. Ocean impacts produce tsunamis.
700 m Land impact destroys Virginia, Tiawan and ocean impact causes major tsunami.
1.7 km Land impacts affect climate, global destruction of ozone, tsunamis destroy coastal communities
3.0 km Large nations destroyed, widespread fires from ejecta, climate change.
7.0 km Mass extinction, global conflagration, long term climate change.
16 km Large mass extinction.
This is a table of the damage different sizes of asteroids can cause to the Earth:
Sizes: Effect:
75 m Land impacts destroy area the size of Washington or Paris)
160 m Destroys large urban areas
350 m Destroys area the size of a small state. Ocean impacts produce tsunamis.
700 m Land impact destroys Virginia, Tiawan and ocean impact causes major tsunami.
1.7 km Land impacts affect climate, global destruction of ozone, tsunamis destroy coastal communities
3.0 km Large nations destroyed, widespread fires from ejecta, climate change.
7.0 km Mass extinction, global conflagration, long term climate change.
16 km Large mass extinction.
How to prevent this from happening?
The astronomers of the world are planning to prevent the world ever having an issue with an asteroid hitting and destroying life as we know it by using a survey that NASA created called the Spaceguard Survey. This survey's main purpose is to locate and track any asteroid that come near the Earth. The calculated odds of an asteroid smashing into the earth decrease each time an astronomer finds an asteroid that isn't on course to collide into Earth. The odds of an asteroid colliding with the earth decreases by a factor of 10 when the survey is all said and done. So for example, if the chances of an asteroid colliding with the earth are 1 in 70,000, they will go down to 1 in 700,000 when the survey is done. This is only assuming that astronomers don't find an asteroid that is actually on a collision course with the Earth of course. Spaceguard Surveys are done one a year and are are done by doing a detailed search of the solar system to search for any asteroids that are on course colliding with the Earth and researching and analyzing the orbits of these asteroids.
What are the odds of this happening?
The earth is constantly being hit with small rocks rather than big ones. In fact it's over 100 tons of matter that Earth is being exposed to every day. However, most of these "small rocks" are nothing but dust or tiny sand-grained meteors that come from the shooting stars that appear in our atmosphere time from time. These rocks are all way too small to actually do any damage to Earth, but over time it is possible for a bigger size astroid to collide with the Earth. For example a bus sized asteroid is predicted to come around about every 1,000 years and a 300 meter asteroid is predicted to come around about every 50,000 years. An asteroid that has a chance of wiping out all of life comes around about every billion years. These are all estimations of course, but astronomers are lowering these numbers by using methods like the Spaceguard Survey.
Possible asteroids that could be a problem for earth
Asteroid - The name of the asteroid that may have a chance of colliding with the Earth.
Mass - A measure of how much matter is in an object
Megatons - 1 megaton = 1,000,000 tons, so about 1,000,000,000 pounds = 1,000,000 tons
Velocity (km/s) - The amount of kilometres per second the asteroid is moving through space
Approach Date - The date that the asteroid is predicted to collide with the Earth, or pass by the Earth
Mass - A measure of how much matter is in an object
Megatons - 1 megaton = 1,000,000 tons, so about 1,000,000,000 pounds = 1,000,000 tons
Velocity (km/s) - The amount of kilometres per second the asteroid is moving through space
Approach Date - The date that the asteroid is predicted to collide with the Earth, or pass by the Earth