The Perseids meteor shower

  Aug 17, 2020

The Perseids meteor shower

The Perseids meteor shower is going to be active from August 17-26. The annual celestial event is considered the best meteor shower because of many bright meteors and fireballs shooting through the sky making it easy for people to watch it from Earth.

Q. What are meteor showers?

A. Meteors are bits of rock and ice that are ejected from comets as they manoeuvre around their orbits around the sun. Meteor showers, on the other hand, are witnessed when Earth passes through the trail of debris left behind 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. According to NASA, over 30 meteor showers occur annually and are observable from the Earth.

As meteors fall towards the Earth, the resistance makes the space rocks extremely hot and, as meteorites pass through the atmosphere, they leave behind streaks of glowing gas that are visible to the observers and not the rock itself.

Q. What is the Perseids meteor shower?

A. The Perseids meteor shower peaks every year in mid-August. It was first observed over 2,000 years ago. The Perseids occur as the Earth runs into pieces of cosmic debris left behind by the comet Swift-Tuttle. The cloud of debris is about 27 km wide, and at the peak of the display, between 160 and 200 meteors streak through the Earth’s atmosphere every hour as the pieces of debris, travelling at some 2.14 lakh km per hour, burn up a little less than 100 km above the Earth’s surface.

Q. Where do the Perseids meteor showers come from?

A. The comet Swift-Tuttle, which was discovered in 1862 by Lewis Swift and Horace Tuttle, takes 133 years to complete one rotation around the sun. The last time it reached its closest approach to the sun was in 1992 and will do so again in 2125. Every time comets come close to the sun, they leave behind dust that is essentially the debris trail, which the Earth passes through every year as it orbits around the Sun.

Q. How can one view the Perseids meteor shower?

A. According to NASA, these meteor showers are best viewed from areas in the Northern Hemisphere in pre-dawn hours. However, at times, it may be possible to view the meteor showers as early as 10 pm. Further, meteors are best visible on a cloudless night, when the sky is visible and when the Moon is not extremely bright.

But this year, the showers are coinciding with the last quarter of the moon phase, which it reached on August 11 (the last quarter moon is half-lit by sunshine and its own shadow, it rises during midnight and sets at noon) due to which, the view of the showers may be restricted as a result of the Moon’s brightness, reducing the visible meteors from about 60 per hour to 15-20 per hour, NASA has said.

Chances of a successful viewing are higher from locations far away from the lights of cities. Pollution and monsoon clouds make the Perseids difficult to view from India. But in areas where there is no light or air pollution, viewers do not need to use any special equipment to view the showers and one should make sure to give enough time to let the eyes adjust to the darkness, which can take about 30 minutes. Additionally, viewers should try to stay away from their phones as looking at bright screens affects night vision.