Leonids Meteor Shower

• 10 Nov 2021

Why in News

The annual Leonids Meteor Shower has begun and will be active between 6^th and 30^th November, with peak activity expected on 17^th November.

Key Points

• Meteor: It is a space rock or meteoroid that enters Earth's atmosphere.
  
  • Meteoroids are objects in space that range in size from dust grains to small asteroids.
    
    • Most are pieces of other, larger bodies that have been broken or blasted off. These come from comets, asteroids, planets and the Moon.
  • When meteoroids enter Earth’s atmosphere (or that of another planet, like Mars) at high speed and burn up, the fireballs or “shooting stars” are called meteors.
    
    • Fireballs are larger explosions of light and color that can persist longer than an average meteor streak. This is due to the fact that fireballs originate from larger particles of cometary material.
  • When a meteoroid survives its journey through the atmosphere and hits the ground, it’s called a meteorite.
• Meteor Shower:
  
  • When Earth encounters many meteoroids at once, it is called a meteor shower.
    
    • Comets, like Earth and the other planets, also orbit the sun. Unlike the nearly circular orbits of the planets, the orbits of comets are usually quite lop-sided.
    • As a comet gets closer to the sun, some of its icy surface boils off, releasing lots of particles of dust and rock (meteoroids).
    • This comet debris gets scattered along the comet's path, especially in the inner solar system (including planets Mercury, Venus, Earth and Mars).
    • Then, several times each year as Earth makes its journey around the sun, its orbit crosses the orbit of a comet, which means Earth encounters a bunch of comet debris.
  • Meteor showers are named for the constellation where the meteors appear to be coming from. So, for example, the Orionids Meteor Shower, which occurs in October each year, appears to be originating near the constellation ‘Orion the Hunter’.
• Leonids Shower:
  
  • The debris that forms this meteor shower originates from a small comet called 55P/Tempel-Tuttle in the constellation Leo, which takes 33 years to orbit the sun.
  • The Leonids are considered to be a major shower that features the fastest meteors which typically travel at speeds of 71 km per second, although the rates are often as low as 15 meteors per hour.
  • The Leonids are also called fireballs and earthgrazer meteors.
    
    • Fireballs, because of their bright colours, and earthgazer, because they streak close to the horizon.
  • A Leonid shower turns into a meteor storm every 33 years and when it happens hundreds to thousands of meteors can be seen every hour. The last Leonid meteor storm took place in 2002.
    
    • A meteor storm should have at least 1,000 meteors per hour.

Source: IE