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Explore the Minor Planets (Part-2): Comets, Meteoroids, Meteorites, and Meteors

Introduction: Exploring Space through Comets, Meteoroids, and More #

Comets, meteoroids, meteorites, and meteors are amazing things in space that really grab our attention. Comets are like space travelers with shiny tails that we can see at night. Meteoroids are small space rocks that sometimes come close to Earth and turn into meteors, making bright, sparkly shows in the sky. If a meteor doesn’t burn up, it becomes a meteorite, and these are like space treasures that help us learn about our solar system.

All of these things in space make the night sky fascinating and help scientists discover new things about the universe.

Comets: Cosmic  Celestial Nomads with Icy Tails      #

Comets are small solar bodies primarily composed of ice. They follow elliptical orbits around the Sun. They are known for their distinctive appearance and unpredictable appearances in the night sky. 

Comet

  • Composition:  At the heart of a comet is a solid core called the nucleus, primarily composed of water ice, frozen gasses, dust, and rocky material
    • This nucleus can vary in size from a few kilometers to tens of kilometers in diameter.
  • Coma: As a comet approaches the Sun, the heat causes the nucleus to release gas and dust, forming a glowing cloud around the nucleus called the coma. 
    • The coma can expand to many thousands of kilometers in size.
  • Tails: Comets are famous for their tails, which are composed of gas and dust particles pushed away from the Sun by the solar wind and radiation pressure. 
  • There are two types of tails:
    • Ion Tail: Composed of ionized gas (plasma) and points away from the Sun.
      •  It appears bluish and can be very long.
    • Dust Tail: Made up of fine dust particles and follows the comet’s path, appearing white or yellowish. 
      • It can be curved due to the comet’s motion.
  • Types of Comets Based on Origin – Understanding their Diversity

Comets exhibit diverse origins and orbital characteristics, classified as short period, long period, periodic, and non-periodic.

    • Comets can be classified into two main types based on their origin and orbital characteristics:
      • Short Period Comets
        • Originates from the Kuiper Belt, a region of the solar system.
        • These comets complete their orbits around the Sun in less than 200 years.
      • Long Period Comets
        • Originate from the Oort Cloud, a distant region of icy bodies beyond the heliopause.
        • These comets have much longer orbital periods and can take thousands of years to complete one orbit.
      • Periodic and Non-Periodic Comets
        • Some comets, like Halley’s Comet, have predictable and periodic orbits, returning to the inner solar system at regular intervals.
        • Others are non-periodic and may visit the inner solar system only once.
    • Example: Halley’s Comet is a well-known periodic comet that appears every 76 years
The Oort Cloud is a theoretical and hypothetical region of space located far beyond the outermost planets of our solar system, including the Kuiper Belt and the scattered disk.

  • Distance: These are believed to extend from about 2,000 to 100,000 astronomical units (AU) from the Sun.
  • Composition: These are thought to be composed of icy objects, including comets and other small, icy bodies, which are remnants from the early solar system.
  • Origin: Objects in the Oort Cloud are believed to be remnants from the formation of the solar system, representing material that never coalesced into planets or was ejected from the inner regions.
  • Comet Reservoir: These are considered the source of long-period comets.

Understanding Meteoroids: Celestial Particles and Hazard to Earth #

Term Description
Meteoroid
  • Small celestial objects that range in size from a grain of sand to several meters in diameter.
Composition
  • Meteoroids can be composed of various materials, including rock, metal, or a combination of both.
Origin
  • Meteoroids can originate from various sources, such as comets, asteroids, or even lunar and Martian impacts that eject debris into space.
Impact on Earth
  • When a meteoroid enters Earth’s atmosphere and produces a bright streak of light, it’s called a meteor or “shooting star.” 
  • If a meteoroid survives its passage through the atmosphere and reaches the Earth’s surface, it’s called a meteorite.
Hazards
  • Larger meteoroids can pose a risk if they collide with Earth, potentially causing damage upon impact. 
  • However, most meteoroids burn up in the atmosphere and do not reach the surface.

Decoding Meteorites: Survivors of Celestial Journeys and Earthly Impacts #

Term Description
Meteorite
  • A meteoroid that survives its passage through Earth’s atmosphere and lands on the surface.
Composition
  • It  can be composed of various materials, including rock, metal, or a combination of both.
Types
  • They are categorized into three main types: iron meteorites, stony meteorites, and stony-iron meteorites, based on their composition.
Origin
  • Meteorites originate from meteoroids that enter Earth’s atmosphere and withstand the intense heat and pressure during their descent.
Impact on Earth
  • Meteorite impacts, although rare, can cause localized damage and are studied to understand the potential hazards they pose.
Examples
  • Lonar crater, Maharashtra, India and Chicxulub crater, Mexico.

Glimpsing Meteors: Understanding Celestial Light Shows #

A meteor is a bright streak of light produced when a meteoroid, a small celestial object, enters Earth’s atmosphere.

  • Appearance: Meteors are often referred to as “shooting stars” because of their rapid and luminous appearance.
  • Cause: Meteors are caused by the friction and heating of the meteoroid as it rapidly descends through Earth’s atmosphere.
  • Brightness: Meteors can vary in brightness, with some being faint and others exceptionally bright, known as fireballs or bolides.
  • Duration: A typical meteor streak lasts only a few seconds, but they are memorable and visible from the ground.
  • Abundance: Meteors are quite common, and numerous meteors can be seen during meteor showers, which occur when the Earth passes through the debris left by a comet.
  • Safety: Meteors do not pose any danger to Earth as they are usually small and disintegrate in the atmosphere.
  • Scientific Study: Meteors are studied by scientists to better understand the composition of meteoroids and the dynamics of Earth’s atmosphere.

Understanding the Cosmic Trio: Meteoroids, Meteors, and Meteorites #

The distinction among a meteor, meteorite, and meteoroid primarily depends on where these objects are located:

  • Meteoroids are objects in space, varying in size from tiny dust grains to small asteroids. 
    • They can be thought of as “space rocks.”
  • When meteoroids enter Earth’s atmosphere, they become meteors, creating bright streaks of light as they heat up and burn during their descent.
  • If a meteoroid successfully traverses Earth’s atmosphere and lands on the ground, it is then referred to as a meteorite, making it a tangible piece of cosmic material to study.

Fireballs in the Sky: Exploring Brilliant Celestial Phenomena #

A fireball is an exceptionally bright and luminous meteor, often much brighter than the average meteor.

  • Cause: They are produced when a relatively large meteoroid, typically several centimeters to meters in size, enters Earth’s atmosphere and rapidly heats up due to atmospheric friction.
  • Duration: They can last longer than regular meteors, sometimes visible for several seconds, which allows more people to witness them.
  • Frequency: While less common than ordinary meteors, fireballs are still regularly observed around the world.
  • Scientific Value: They  are of great interest to scientists as they can provide information about the composition, size, and speed of the meteoroids that produce them, helping to better understand the population of space objects in our solar system.
  • Impact: Fireballs typically disintegrate high in the atmosphere and do not pose a threat to the surface.

Conclusion: #

  • In the vastness of space, comets, meteoroids, meteorites, and meteors provide inspiring celestial displays, offering valuable insights into the workings of our universe and posing minimal danger to Earth. 

Previous Year Question (Prelims) #

Q. A meteor is:(UPSC CSE 1995)

  1. a rapidly moving star
  2. a piece of matter which has entered the earth’s atmosphere from outer space
  3. part of a constellation
  4. a comet without a tail

Ans: b

 

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 Final Result – CIVIL SERVICES EXAMINATION, 2023.   Udaan-Prelims Wallah ( Static ) booklets 2024 released both in english and hindi : Download from Here!     Download UPSC Mains 2023 Question Papers PDF  Free Initiative links -1) Download Prahaar 3.0 for Mains Current Affairs PDF both in English and Hindi 2) Daily Main Answer Writing  , 3) Daily Current Affairs , Editorial Analysis and quiz ,  4) PDF Downloads  UPSC Prelims 2023 Trend Analysis cut-off and answer key

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 Final Result – CIVIL SERVICES EXAMINATION, 2023.   Udaan-Prelims Wallah ( Static ) booklets 2024 released both in english and hindi : Download from Here!     Download UPSC Mains 2023 Question Papers PDF  Free Initiative links -1) Download Prahaar 3.0 for Mains Current Affairs PDF both in English and Hindi 2) Daily Main Answer Writing  , 3) Daily Current Affairs , Editorial Analysis and quiz ,  4) PDF Downloads  UPSC Prelims 2023 Trend Analysis cut-off and answer key

Quick Revise Now !
AVAILABLE FOR DOWNLOAD SOON
UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
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Quick Revise Now !
UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
हिंदी में भी उपलब्ध

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