Tag: GS 1||Geography||Geomorphology || Universe

Why In News?

• 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

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.

Perseid Meteor Shower

When does Perseid Meteor Shower occur?

• Several meteor showers can be seen around the year.
• Among the brightest and best known of them is the Perseid Meteor Shower, which has been active from July 17 onward, and can be seen until August 26.
• The showers peaked on the night of Monday-Tuesday.
• 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 14 lakh kmph.

When to see them?

• Meteors are best seen on a cloudless night, when the entire sky is visible, and when the Moon is not extremely bright.
• 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.
• The showers peak when the Earth passes through the most dense part of the debris cloud.
• Peaks can last for a few hours or several nights. They tend to be most visible after midnight and before dawn.
• The showers should be seen with naked eyes; binoculars and telescopes narrow the field of vision.

The Swift-Tuttle Comet

• The Perseids currently visible in the night sky are not due to the debris left behind by the comet Swift-Tuttle during its most recent pass, which happened in 1992.
• This particular comet goes around the Sun once in 133 years, and the meteors now visible were left behind by the pass before the last one — or perhaps even earlier.

Geminid Meteor Shower 

• Geminid Meteor Shower Share Share Tweet Email First Published: April 7, 2018. Last Updated: April 7, 2018 The Geminids are a meteor shower caused be seen in December and usually peak around December 13–14, with the date of highest intensity being the morning of December 14 Geminid meteor shower is so named because the meteors appear to originate from the constellation of Gemini in the night sky.
• It is not a comet but an unusual asteroid called 3200 Phaethon, discovered in 1983, that is the origin of the meteors.

Additional Info  

• An asteroid is a large, irregularly shaped object in space that orbits our Sun. If one of these giant rocks ends up on a collision course with Earth, we are in for big trouble. An asteroid is like a comet. … Around a million asteroids are located between Mars and Jupiter in an area called the “asteroid belt.”

• https://indianexpress.com/article/explained/orionid-meteor-shower-northern-hemisphere-constellations-sky-6077877/

 Mains  Question

What are meteor showers?