Asteroid To Give Earth a Close Shave
February 14, 2013
An asteroid barreling through space will pass Earth tomorrow by only about 17,200 miles (27,700 kilometers), the closest encounter with such a large space rock that researchers have ever known about in advance. Earth’s nearest neighbor in space, the moon, is 225,000 miles (362,000 kilometers) from Earth, and even some artificial satellites are farther away from Earth. Traveling at the rate of 68,800 miles (110,700 kilometers) per hour, the asteroid–named 2012 DA14–will miss Earth by only 15 minutes. Scientist and educator Bill Nye, “the science guy,” estimates that the diameter of 2012 DA14 is from 130 to 400 feet (40 to 90 meters). Asteroids of similar size created Arizona’s Meteor Crater and caused the 1908 Tunguska explosion in Siberia.
Scientists believe that asteroids are chunks of material left over from the formation of the solar system. Most asteroids orbit the sun between the orbits of the planets Mars and Jupiter, in a region known as the Main Belt. The gravitational pull of Jupiter probably prevented these pieces from coming together to form a full-sized planet. Some asteroids may represent the nuclei (cores) of comets that are no longer active.
The atmosphere protects Earth from most asteroid strikes. Air friction causes an asteroid smaller than about 160 feet (50 meters) in diameter to disintegrate before it can reach the surface and cause damage. Larger asteroids can impact the environment of the entire globe. The impact of an asteroid with a diameter of around 0.6 mile (1 kilometer) would kick large amounts of dust into the atmosphere. The dust would block sunlight, which would cool the air for many months. One such strike occurred 65 million years ago on what is now Mexico’s Yucatan Peninsula. Many scientists think environmental damage caused by the collision led to a mass extinction. The extinction eliminated huge numbers of species, including the dinosaurs.
Additional World Book articles:
- Dawn
- Eros
- Vesta
- When Worlds and Comets Collide (a special report)
- What Has Caused Mass Extinctions (a special report)