Why in news?

NASA and the European Space Agency are monitoring asteroid 2024 YR4, which has a 1.2% chance of hitting Earth on December 22, 2032.

The director of NASA’s Center for Near-Earth Object Studies stated there is a 99% chance it will miss but acknowledged it warrants attention. Further observations will refine the impact probability.

What’s in today’s article?

• Asteroid
• Asteroid Deflection: Strategies to Prevent Potential Collisions
• 2024 YR4
• Potential Destruction from 2024 YR4

Asteroid

• An asteroid is a small, rocky object that orbits the Sun, primarily found in the asteroid belt between Mars and Jupiter.
• Unlike planets, asteroids are irregularly shaped and much smaller.
• They are remnants from the early solar system, formed about 4.6 billion years ago.
• Some asteroids cross Earth's orbit and are classified as Near-Earth Objects (NEOs), which are closely monitored for potential collisions.
• Frequency of Asteroid Collisions
  • Thousands of asteroids enter Earth’s atmosphere daily, but most burn up due to friction.
  • Some larger ones appear as fireballs, and small fragments may reach the surface without causing significant damage.
• Impact of Large Asteroids
  • Asteroids over a kilometer wide, like the Chicxulub asteroid that caused the dinosaur extinction, strike Earth very rarely—approximately once every 260 million years.
  • The vastness of the Solar System makes such impacts unlikely.
• Threat from Smaller Asteroids
  • Smaller asteroids can still cause regional damage. For instance, the Chelyabinsk meteor caused widespread destruction.
  • A 40-meter-wide asteroid could devastate an entire city, depending on its speed and angle of entry.

Asteroid Deflection: Strategies to Prevent Potential Collisions

• Space agencies like NASA are developing planetary defense strategies to prevent catastrophic asteroid collisions with Earth.
• The DART Mission
  • NASA’s Double Asteroid Redirection Test (DART), in collaboration with the Johns Hopkins Applied Physics Laboratory, was the first planetary defense mission.
• Successful Asteroid Deflection
  • In 2022, the DART spacecraft crashed into the asteroid Dimorphos, altering its shape and trajectory.
  • Though Dimorphos was not a threat to Earth, this mission demonstrated the feasibility of asteroid deflection.

2024 YR4

• Discovery and Characteristics of 2024 YR4
  • Asteroid 2024 YR4 was discovered in December by a telescope in Chile.
  • It is a near-Earth asteroid measuring 40 to 100 meters, roughly the size of a football field.
• Close Approach to Earth
  • The asteroid passed 800,000 km from Earth on Christmas Day 2023, about twice the distance of the Moon.
  • It will fade from view in the coming months and reappear in 2028.
• Current Observations and Challenges
  • Scientists are using powerful telescopes to study 2024 YR4’s path and size before it becomes too faint by mid-April.
  • Determining its exact size is challenging because brightness depends on reflectivity, making it hard to distinguish between a large dark asteroid and a small reflective one.

Potential Destruction from 2024 YR4

• While 2024 YR4 is not as large as the asteroid that caused the dinosaur extinction, it could cause significant localized damage if it impacts a populated area.
• Destruction Potential: Torino Scale Rating
  • NASA’s Center for Near-Earth Object Studies (CNEOS) has rated 2024 YR4 a 3 on the Torino Scale (0 to 10), indicating a moderate risk.
    • The Torino Scale is a risk assessment tool that categorizes the potential impact of asteroids on Earth. 
    • It uses a scale of 0 to 10, with higher numbers indicating a greater likelihood of impact and more severe consequences. 
  • In comparison, the Apophis asteroid was initially rated 4 but later downgraded after further observations.
• Energy Release and Impact Comparison
  • If 2024 YR4 crashes into Earth, it is expected to release 8 to 10 megatons of energy.
  • By comparison, the Chelyabinsk meteor (February 2013) released 500 kilotons, injuring 1,500 people and damaging thousands of buildings.
  • 2024 YR4 is about twice its size, meaning its impact could be significantly more powerful.