Asteroids and Their Threat to Earth

Introduction

• Date: 13th April 2029
• Asteroid Apophis: 1000 feet diameter, potential devastation if it collides with Earth.
• Energy release: 1 million times more than Hiroshima bomb.
• Potential tsunami waves of hundreds of meters; entire cities at risk.

Upcoming Threats

• Another asteroid may collide on 12th July 2038 with a 72% chance.
• NASA and ISRO are raising alarms and preparing for planetary defense.
• Query on the truth behind such news and the current state of asteroid threats.

Understanding Asteroids

• Definition: Asteroids (Planetoids) are rocky bodies in space, sizes vary from 10-20 meters to 940 kilometers (largest: Ceres).
• Location: Most asteroids in the Asteroid Belt between Mars and Jupiter.
• NEOs (Near Earth Objects): Includes asteroids, comets, meteors, meteorites, and meteoroids.

Differences Between Space Objects

• Asteroids: Made of rock and metal.
• Comets: Made of ice, rock, and dust (known as dirty snowballs); have tails when close to the sun.
• Meteoroids: Small pieces of asteroids or comets.
  • Meteor: Enters atmosphere, seen as a shooting star.
  • Meteorite: Survives impact with Earth.

Risks from Asteroids and Comets

• Comets pose more danger than asteroids due to higher speeds and shorter warning times.
• Historical extinction event of dinosaurs linked to asteroid impact.

Importance of Reliable News Sources

• Warning against following unreliable social media news.
• Reputable sources: The Hindu, Indian Express, etc.

NASA's Hypothetical Exercise

• Recent reports claim a 72% chance of an asteroid collision in 2038.
• This figure came from a mock test by NASA and other agencies assessing readiness against hypothetical impacts.
• Apophis: Now confirmed to have a 0% chance of actual collision with Earth due to further observations.

Current Risk List for Asteroids

• NASA’s risk list: Monitors potentially dangerous asteroids.
• Identified current threats include:
  • 2023VD3: 11-24 meters, potential collision on 8th November 2034 (0.25% chance).
  • 1979XB: 400-900 meters, potential collision on 12th December 2056 (0.00002% chance).
  • 2008JL3: 23-50 meters, potential collision on 1st May 2027 (0.01% chance).

Detection Systems

• LINEAR: Discovers 65% of asteroids; collaboration started in 1996.
• CSS: Notable for accurately predicting asteroid falls.
• PAN-STARRS: Uses large digital cameras for asteroid detection.
• ATLAS: Last-minute warning system for asteroid impacts.

Strategies for Asteroid Defense

1. Kinetic Methods: Direct collision with spacecraft to change asteroid's orbit (successfully tested with DART).
2. Slow Push/Pull: Gradual orbit change using solar energy.
3. Nuclear Methods: Deploying nuclear explosives, complicated by political and technical challenges.

Conclusion

• No significant threats from asteroids for the next 100 years.
• Enhanced detection systems being developed (e.g., Near Earth Object Surveyor).
• Preparation measures in place for potential asteroid impacts.
• Encouragement to rely on credible sources for space-related news.