The 'planetary defenders' prepared to protect Earth from asteroids | 7.30

Key Concepts

• International Asteroid Warning Network
• Planetary Defense
• Near-Earth Asteroids (NEAs)
• Optical Telescopes
• Radio Telescopes
• Radar Observations
• Impact Probability
• City Destroyers
• DART Mission (Double Asteroid Redirection Test)

Asteroid Tracking Drill: An International Effort

The video documents a planetary defense drill led by NASA, involving international teams, including Australian astronomers, to simulate the response to a potentially hazardous asteroid. The goal is to test the speed and efficiency of the global network in identifying, tracking, and characterizing a near-Earth asteroid.

Australian Involvement

Australia plays a crucial role in the International Asteroid Warning Network due to its geographical location, allowing it to be among the first to observe asteroids approaching from the southern hemisphere.

• Zadko Observatory (Western Australia): Equipped with a robotic optical telescope, it is used to track the simulated asteroid, designated FA22. The observatory is part of the Australian arm of the International Asteroid Warning Network.
• Canberra Optical Telescope: Ed Kruzens uses another optical telescope in Canberra to track the asteroid. He uses a sky map and telescope controller to point the telescope.
• CSIRO's Deep Space Communication Complex (operated for NASA): Utilizes radio telescopes to gather additional data on the asteroid's location, path, speed, and composition. This facility uses large antennas to bounce radio signals off the asteroid.

The Simulated Asteroid and Threat Assessment

The drill focuses on a simulated asteroid with a low but significant impact probability.

• Impact Probability: The scenario involves an asteroid with a 0.00001 (1 in 100,000) probability of impact, which is described as 300,000 times more probable than winning the lottery.
• Asteroid Size: Asteroids range in size from hundreds of kilometers in diameter to less than 10 meters. The focus is on smaller, undiscovered objects that pose a greater concern.
• "City Destroyers": Asteroids large enough to cause significant regional damage upon impact. NASA is tasked by the US Congress to find and track near-Earth asteroids larger than 140 meters.

Tracking Methods and Technologies

The video highlights the use of both optical and radio telescopes in tracking asteroids.

• Optical Telescopes: Act as the "eyes" of space surveillance, providing initial observations and data on the asteroid's position and movement.
• Radio Telescopes: Function as the "ears," providing more accurate data on the asteroid's location, path, speed, and composition through radar observations. Radar uses the speed of light to calculate the distance to the asteroid. The closer the asteroid, the shorter the time for the radio signal to transmit and receive.
• Speed of Asteroid: The asteroid is moving at 38,000 km/h, which is 10 times the speed of a rifle bullet.

Data Collection and Analysis

The exercise emphasizes the importance of rapid data collection and sharing.

• Data Flow: Optical telescopes provide initial data to NASA, which is then supplemented by radar observations from radio telescopes.
• Importance of Early Data: Early information is vital for calculating the asteroid's path and determining the level of risk it poses to Earth.

Planetary Defense Strategies

The video touches upon strategies for planetary defense, including asteroid deflection.

• Finding and Tracking: Dr. Kelly Fast from NASA's planetary defense office states that "planetary defense is finding asteroids before they find us."
• Asteroid Deflection: NASA's DART mission (Double Asteroid Redirection Test) successfully demonstrated the possibility of deflecting an asteroid by crashing a spacecraft into it. "And we have impact."

Statistics and Facts

• Near-Earth Asteroids (NEAs): Approximately 40,000 known NEAs are being tracked.
• Potentially Hazardous Asteroids: About 11,000 of these NEAs are over 140 meters in size, capable of causing regional damage upon impact.
• Chelyabinsk Event (2013): In 2013, an asteroid around 20 meters in diameter exploded in the atmosphere over Russia, injuring more than 1,600 people.

Conclusion

The asteroid tracking drill demonstrates the collaborative, international effort to protect Earth from potential asteroid impacts. The use of optical and radio telescopes, combined with data analysis and potential deflection strategies, highlights the ongoing work of "planetary defenders" in mitigating this natural hazard. The video emphasizes the importance of continued vigilance and preparation to safeguard the planet.