What causes meteor showers? To understand this we must first look at other orbiting bodies in our solar system.
There are many, many comets held by the gravitational pull of our sun, Sol. These comets spend many years in the outer reaches of the solar system, their icy and dusty bulk held together in a solid mass in the freezing temperatures of deep space. However, at some point all of these comets are pulled back toward the sun, where they complete a kind of slingshot around the sun, speeding up as they approach and round the sun, then being flung by the slingshot back out to the outer reaches.
During their approach to the sun, these comets gradually heat up, feeling the full strength of the sun as they draw ever nearer. As the surface of the icy, dusty body of the comet heats, some of the ices melt, releasing a trail of gas and dust particles behind the main body. This forms the classic shape of the comet that we on Earth have come to know, a ball of ice followed by a trailing tail.
As noted previously, there are many of these comets, all coming toward the sun and moving away again over the years in many different orbits and at many different times. Each individual comet leaves a dust trail behind it that takes many, many years to disperse, and is in a slightly different orbit each time it rounds the sun. As you can imagine, there are a myriad of comet trails in space at any one time. The trails are left behind each comet until the comet finally loses all of its main body to the heat of the sun and is gone, leaving behind only the dust trails as the clue to its previous existence.
During the Earth’s own orbit of the sun over the course of an Earth year, we pass through many of these dust trails left behind by comets. As the Earth ploughs through these trails of dust and fragments, they are burned up in the Earth’s atmosphere. Even a particle the size of a grain of sand can pass through our atmosphere so quickly that it heats up immensely, producing a streak of light in the night sky as it burns up. The bigger the particles, the more spectacular the burn up.
There are countless dust particles in normal space, and as the Earth encounters these, or they themselves hit the Earth’s atmosphere and burn up, they are commonly known as shooting stars, but when we travel through the trail or tail of a comet, these shooting stars can be many and spectacular, this is when they are normally described as meteor showers.
There are many meteor showers that occur throughout the year as the Earth passes through particular comet trails. The Geminids, Orionids and Perseids are just some of the more spectacular. They are so named, because as the Earth encounters the particular dust trails that cause them, the meteor showers appear to emanate from particular areas of the sky. For instance, the Geminid meteor shower appears to emanate from the constellation Gemini, the Orionids from Orion, and the Perseids from Persius.
Meteor showers are fascinating and spectacular phenomena that can be viewed easily without the aid of a telescope. The naked eye, a clear sky away from the glare of car, street and house lights (known as ‘light polution’) and warm clothing are all that is normally needed to enjoy them, oh and perhaps a garden lounger or similar to save a sore neck in the morning…