Asteroids range in size from Vesta—the largest at about 329 miles (530 kilometers) in diameter – to bodies that are less than 33 feet (10 meters) across. The total mass of all the asteroids combined is less than that of Earth’s Moon.

What is MOST useful to scientists in measuring the size of asteroids? The gravitational effect when spacecraft flies close to the asteroid.

But how do scientists track an asteroid’s path? Telescopes and math. Observations of asteroids and other near-Earth objects are made optically; in the case of this week’s flyby, researchers at Spain’s La Sagra Observatory discovered the asteroid (called 2012 DA14), in February of last year.

layer of volcanic ash. layer of burned organic matter. change in average global temperature. mass extinctions.

Typically, though, a meteoroid would have to be about the size of a marble for a portion of it to reach the Earth’s surface. Smaller particles burn up in the atmosphere about 50 to 75 miles (80 to 120 kilometers) above the Earth.

Hoba

As stated above, humans have only survived ice ages which means there is no accurate reference to compare with global warming. The true effects of modern day climate change is relatively unknown. Many people believe animals and plants can adapt to modern day climate change because they did so during the Ice Age.

The variation of sunlight reaching Earth is one cause of ice ages. When less sunlight reaches the northern latitudes, temperatures drop and more water freezes into ice, starting an ice age. When more sunlight reaches the northern latitudes, temperatures rise, ice sheets melt, and the ice age ends.