From UPSC perspective, the following things are important :
Prelims level : Meteor shower
Mains level : Not Much
- The Orionids meteor showers will make their yearly appearance this and the next weekend, reaching their peak on October 22.
Orionids meteor showers
- These meteor showers are known for their brightness and speed, travelling at about 66 km/s into the Earth’s atmosphere.
- Orionids meteor shower is believed to originate from the constellation Orion The Hunter. This point of origination is referred to as the radiant.
- Even so, this does not mean that the meteor showers originate from a particular constellation, but the name is given only for the purposes of identification.
- The Orionids meteor shower is not the only one that occurs annually. For instance, the Perseid meteor shower occurs every year in August and was first observed over 2000 years ago.
- Other meteor showers include Quadrantis, that happen between December-January, Lyrids in April, Leonids in November and Geminids in December.
What are meteor showers?
- Meteors are bits of rock and ice that are ejected from comets as they manoeuvre around their orbits around the sun. The Orionids meteors emerge from the comet 1P/Halley.
- Meteor showers, on the other hand, are witnessed when Earth passes through the trail of debris left by a comet or an asteroid.
- When a meteor reaches the Earth, it is called a meteorite and a series of meteorites when encountered at once, is termed as a meteor shower.
- As it falls towards the Earth, the resistance makes the space rock extremely hot and as the meteorite passes through the atmosphere, it leaves behind a streak of hot glowing gas that is visible to the observers and not the rock itself.
Why do meteor showers happen on an annual basis?
- Like the Earth orbits around the Sun, comets orbit around it as well. Although they may not be as circular as Earth but maybe lop-sided.
- Therefore, when comets come closer to the Sun, their icy parts melt and break off, forming the debris that the Earth may encounter around the same time every year as it makes way around its own orbit.
- In the case of the Orionids, each time the Halley comet, that takes 76 years to orbit around the Sun, reaches the inner solar system the icy and rocky dust is released into space.