| Probability of an Asteroid Impact |
|
The largest asteroids will cause the most damage but there are less of them. Astronomers have used mathematical models and historical data to estimate the probability of an asteroid hitting the earth. |
|
Size
|
Number near Earth
|
Frequency of impacts
|
Last impact
|
Annual probability of impact
|
|
10 - 50m |
|
1 in every 5 years |
Siberia, 1908: area not populated. |
0.2 |
|
100m |
2 hundred thousand |
1 in every thousand years |
China, 1490: 10,000 deaths |
0.001 |
|
1-2km |
2 thousand |
1 in every 100,000 to 1 million years |
Argentina, 3 million years ago: local extinctions and global cooling |
0.00001 |
|
15km |
50 |
1 in every 65 million years |
Mexico, 65 million years ago: dinosaur extinction |
0.00000002 |
|
Even though the largest asteroids could cause mass extinctions, the likelihood of one hitting the earth is almost negligible. Smaller asteroids are more likely to impact and so are more of a risk. |