Econintersect: Scientists have confirmed approximately 35,000 meteorites have impacted the surface of the earth over the past 4,600 years, but the estimated number is much larger. Just since 861 AD the estimate is that there have been more than 45,000 such impacts, but only 1,017 have eye-witness reports. The confirmed 35,000 meteorites since 2,500 BC have been identified through meteor fragments recovered.
Click on picture for larger close-ups of Barrington Crater, AZ at Experimental Graffiti.
The following graphic shows the geographic distribution of known meteorite impacts over the past 4,600 years. The map does not show any sites where meteorites may have fallen but have not been discovered.
Click on map for larger image.
The timeline of meteorite impacts since 861 AD is shown in the following graphic from Bolides via The Guardian. Of the estimated more than 45,ooo meteorites only 1,107 shown in the graphic had eye-witnesses.
Click on map for larger image.Click here for interactive, animated version at The Guardian.
The following table contains the largest recovered meteorite fragments.
*1 tonne =1,000 kilograms = 2,204.6 pounds = 1.102 ton
Not included on the list above are larger impacts attributed to asteroids, which are larger than meteors. Some are so large that they are classified as dwarf planets. Some planetary moons may be captured asteroids.
A longer table (50 entries) is available at Wikipedia. The same source has the following table on large unconfirmed craters.
Click on table for larger image.
Periodically earth has close encounters with asteroids which could produce very large craters like the ones experienced over the planet’s history. The two most recent occurred in February and May. On February 15 an asteroid about 50 yards wide passed within 17,100 miles of earth. At the end of May a much larger asteroid (1.6 miles wide) passed within 3.4 million miles. If the February asteroid had impacted earth the force would have been sufficient to level a major city. The one that went by May 31 would have created a major disruption of the planet and have created an extinction event such as the one that created the end of the age of the dinosaurs.
Scientists believe that we have the technology available that could be used to develop an asteroid deflection system but there is no serious effort to try to develop such a system. The odds of a major asteroid impact are almost incalculable small but the odds of life as we know it surviving are also incalculably small. So doing nothing is like playing a game of Russian roulette with the odds very much in our favor. But the odds in our favor are not 100.000…% sure.
Sources:
- Meteorites seen falling since 2500BC visualized (Flowing Data, 22 May 2013)
- Every meteorite fall on earth mapped (Simon Rogers, The Guardian, 15 February 2013)
- Every meteorite since 861 AD: watch them fall (Mona Chalabi, The Guardian, 08 May 2013)
- Meteors and Asteroids (Dept. of Astronomy and Astrophysics, Penn State University)
- 10 Greatest Major-Impact Craters on Earth (Environmental Graffiti)
- 7 Most Massive Single Meteorites on Earth (Environmental Graffiti)
- List of impact craters on Earth (Wikipedia)
- Close call? Kind of, as asteroid hurtles past Earth (Gary Strauss, Dan Vergano and Todd Halvorson, USA Today, 15 February 2013)
- Giant asteroid with its own moon safely passes Earth (CTV News, 31 May 2013)