A meteor shower is a celestial event, wherein it is observed that a group of meteors radiate from a point in the sky. This phenomenon is also sometimes referred to as a meteor storm or a outburst. The meteors that are present in the showers are actually cosmic debris that enter the Earth's atmosphere at very high speed and vaporize very quickly due to friction, leaving behind a streak of light which is known as the shower. An identified shower is usually an annual affair as the Earth will encounter the same meteors at approximately the same time and same speed every year.
Meteor showers are a result of the interaction that takes place between the planet Earth and a comet. Comets consist of ice and rocks (often termed dirty ice balls) that orbit around the sun in a similar fashion to planets. Every time the comet gets close to the sun, some of the ice present in the comet melts, which produces a large amount of debris. This debris moves away from the comet and becomes a part of its tail, which is visible.
The solid parts of the tail are the meteoroids and they spread along the entire orbit of the comet, which is termed as a stream. As the Earth orbits around the sun, its path may cross the stream and thus, a meteor shower follows. When the stream is particularly dense, then we get to witness the storm and having witnessed one myself, I can guarantee that the sight is truly spectacular.
People Behind the Concept
It is believed that Irish astronomer George Johnstone Clooney, collaborating with the British astronomer, Arthur Matthew Weld Downing, and Adolf Berberich, belonging to the Royal Astronomical Computation Institute in Berlin, Germany, offered the very first idea of the meteoroid stream in 1890. They were able to calculate as to how the meteoroids once freed from the comet would travel at lower speeds, when compared to the speed of the comet itself, and it would start drifting after completing one orbit. This effect was attributed to simple orbital, wherein the materials drift laterally away from the comet, as some particles make a wider orbit compared to other particles. The gravitational pull of the Earth's atmosphere would decide where the dust trails would pass the Earth's atmosphere. It is a fair possibility that some years, the dust particles can completely miss the Earth's orbit.
Major Meteor Showers
If you want to watch meteor showers, then the best time of the year is the night of January 3. The shower has been named Quadrantids and this particular shower can produce close to 140 meteors per hour. The source of this shower is not a comet but a minor planet, 2003 EH1 which suffered a catastrophic breakup in 1490. However, the showers are very faint and the peak hours last only for a limited time. Hence, you will have to be in a good spot to watch the shower in all its glory and in fact, the best place to watch this particular shower is from the Northern Hemisphere.
People in Southern Hemisphere need not be disappointed. As a matter of fact, they get to witness a shower termed Eta Aquarids, which consists of debris from the famous Halley's Comet. This shower peaks on the night of May 5, and the rate is about 30 per hour.
The meteor shower 'Geminids' is considered to be the best annual shower. It peaks around the night of December 13 and the rate is around 70 per hour. The source of this shower is also a minor planet, 3200 Phaethon. It is best visible from the Northern Hemisphere and it is believed that due to the extreme cold conditions, the air tends to be more transparent and this is the reason as to why this particular shower is spectacular.