The possibility of an asteroid hitting the Earth is real, but unlikely. In fact, scientists have spotted over 500 asteroids whose orbits cross the Earth’s. However, they have lost sight of most of these asteroids over time.
In 1908, an asteroid weighing about 100,000 tons exploded over Russia and destroyed thousands of square miles of forest. The asteroid caused 2,000 times the damage of an atomic bomb. Other asteroids have caused extensive destruction, too, but most of them occurred over 65 million years ago.
Some scientists also believe that asteroids are responsible for the death of dinosaur populations. This theory indicates that upon hitting Earth, a ten-mile-wide asteroid raised enough smoke and dust to block out the sun. Ultimately, this caused the death of all vegetation, one of the main food sources for dinosaurs. If an asteroid of this size hit Earth today, you likely would not even have time to turn around and see it because of its speed.
When it comes to asteroids, there is much more to worry about than their immediate impact. Those who live near coastlines face the risk of asteroids landing in nearby oceans and causing tsunamis, which could potentially destroy everything in their path. Even relatively small asteroids, about 200 yards in diameter, could lead to small yet deadly tsunamis. Small asteroids like these are not big enough to kill all life on Earth, but they could create big enough craters to destroy entire states.
Though a person is more likely to be killed by an asteroid than in a plane crash, no one has been hit in 1,000 years. So, while it may be helpful to be aware of them, asteroids likely do not pose a threat to the common person!
[Source: Secrets Of The Universe]