Meteors appear as streaks of light that are popularly referred to as “shooting stars” or “falling stars,” though they are not really stars at all. In reality they are grains of dust, which have been gliding for countless thousands of years in the spaces between the planets. When one of them happens to impact the Earth’s atmosphere, the flaming flash that is ultimately created is not what you might think, for the meteoroid itself is not what lights up at all; it is the incandescence of the air ahead of it that could not get out of the way fast enough!
Entering the atmosphere at speeds as high as 45 miles (72 km) per second, atmospheric friction releases the kinetic energy of the object in a short-lived streak of light that we momentarily see about 60 miles (100 km) above the ground. The energy released per gram of the meteoroid’s weight far exceeds the energy efficiency of the most powerful man-made explosives. Thus, a pea-sized object can blaze across the sky with a brilliance rivaling Jupiter or Venus.
Some meteors leave bright trails that remain in the sky for a few seconds or more, but most appear as just faint streaks. So, if your sky is somewhat hazy, or there are bright lights in your vicinity, or if you’re not alert, you won’t see many. A few have noticeable colors, in part caused by the chemicals in them, but chiefly due to their speed as they move through the upper atmosphere. Slow meteors usually appear orange or red, while fast meteors appear white, occasionally tinged with hues of blue or green.
