What causes Shooting Stars

Falling stars and shooting stars, while related, are actually mutually exclusive phenomena. The subtle yet distinct difference relates to the origins and  velocity of the object, its visual effect when encountering Earth’s atmosphere and its ultimate disposition. In both cases, these objects begin as meteorites or micrometeorites, but a falling star could also include space junk of human origin falling out of orbit while in the case of a shooting star it could not.

With respect to  “falling stars,” although these objects are obviously not really stars, the object actually enters the atmosphere and is set ablaze by friction with air molecules. In most cases, the falling star objects will be vaporized completely before impacting the Earth. On rarer occasion, impact will occur and result in a crater on land, but since 75 percent of the earths surface is covered with water, most falling objects end up splashing into the oceans. In contrast to falling stars, shooting stars, which are not stars either, exhibit a different characteristic envelope of cause and effect.   

Shooting stars never enter Earth’s atmosphere, but instead skip off of it in the same way a flat rock bounces across the calm surface of a pond or lake. It’s all a matter of velocity and trajectory. Shooting stars begin as meteorites or micrometeorites traveling through the solar system at very high velocities. When one of these objects comes within the gravitational field of a planet or other space object, the two objects are drawn towards each other and an acceleration of the closing velocities takes place. In the case of meteorites and micrometeorites approaching Earth, all of the velocity increase occurs with the smaller objects. Keep in mind also, that Earth is traveling through space at 66,000 miles per hour in its orbital trajectory around the Sun.

As the velocity of a meteorite or micrometeorite approaching Earth is increased, the possibility of a collision and resulting “falling star” phenomenon decreases. In fact, the window of opportunity for a falling star becomes quite small as the velocity of the approaching object increases. In contrast, most meteorites and micrometeorites approaching it will never even get close to Earth’s atmosphere, instead whisking by, far out in space. A very small fraction of these will be on a collision trajectory with Earth, but due to their approach angle and extreme velocity, will simply bounce off the Earths Atmosphere. From our earthly perspective we see these kind of objects as streaks of light across the night sky, usually quite faint, although on rarer occasion, when larger meteorites are involved, they can create quite a spectacular visual display and even be seen in daylight.

So, in summary, a falling star would be a meteorite that enters the Earth’s atmosphere and burns up or crashes into the Earth, while a shooting star is one moving at greater velocity causing it to bounce off the Earth’s atmosphere. If you’ve ever seen one, the quickness of a shooting star is its most obvious clue. In the time it takes to blink an eye, they have usually come and gone.