The Royal Institution - How to stop a killer asteroid from hitting Earth - with Robin George Andrews
The speaker, a science journalist, explains the importance of asteroid defense, a concept popularized by movies like Armageddon. He discusses the real threat of asteroid impacts, citing historical events like the Tunguska event in 1908 and the Chelyabinsk meteor in 2013. These events demonstrate the potential devastation asteroids can cause, even if they are relatively small. The speaker emphasizes the need for proactive measures to detect and deflect asteroids, highlighting NASA's efforts to track 'planet killers' and 'city killers.' He describes the Dart mission, which successfully demonstrated the ability to deflect an asteroid by crashing a spacecraft into it, proving that such threats can be mitigated. The presentation underscores the importance of international cooperation and continued investment in planetary defense to protect Earth from future asteroid impacts.
Key Points:
- Asteroid impacts are real threats, with historical examples like the Tunguska event and Chelyabinsk meteor demonstrating their potential devastation.
- NASA is actively tracking large asteroids ('planet killers') and smaller ones ('city killers') to prevent potential impacts.
- The Dart mission successfully demonstrated the ability to deflect an asteroid, proving that proactive measures can mitigate these threats.
- International cooperation and investment in planetary defense are crucial for protecting Earth from future asteroid impacts.
- Public awareness and support for asteroid defense are growing, with surveys showing strong public interest in monitoring and preventing asteroid impacts.
Details:
1. Welcome to Asteroid Defense 🌌
- Asteroid defense is a real and significant scientific field, contrary to its portrayal as science fiction.
- The aim is to prevent catastrophic impacts on Earth from space rocks, emphasizing the importance of planetary defense.
- The speaker transitioned from being a scientist to a science journalist, focusing on storytelling within scientific contexts.
2. Asteroid Impacts: Fact vs. Fiction 🌍
- Movies like Armageddon exaggerate asteroid sizes for dramatic effect; asteroids as large as Texas are unrealistic.
- The possibility of discovering an asteroid only 18 days before impact highlights the necessity for improved early detection systems in planetary defense.
- The portrayal of training oil drillers as astronauts in films is criticized for its impracticality and lack of realism.
- Asteroid impacts are a genuine threat, evidenced by Earth's history, underscoring the importance of ongoing scientific efforts in planetary defense to mitigate such risks.
3. Exploring Historical Impacts 📜
- Asteroid impacts are catastrophic natural disasters, comparable to other natural disasters in terms of potential destruction.
- NASA has identified and monitored real asteroids, highlighting the importance of preventive measures against potential impacts.
- A small asteroid of 140 meters in length can create a massive crater and cause substantial destruction, equivalent to 68 million tons of TNT.
- The energy release from such an asteroid impact would surpass that of the 1883 Krakatoa eruption, which is historically significant.
- An impact could result in the vaporization of approximately 7,000 people, underscoring the severe human toll of such events.
4. Asteroids in Culture and Policy 🎬
- Anyone within 8 km of an asteroid impact would receive lung damage due to the air being forced into lungs with extreme pressure, potentially causing them to explode.
- Those within 10 km would suffer ruptured eardrums due to the blast.
- Structures within 24 km would collapse from the impact's force.
- Trees within 26 km would be knocked down, similar to experiencing a tornado over 16 km.
- The area surrounding the impact would experience a magnitude 5 earthquake.
- Meteor Crater, an actual impact site in Arizona, was initially discovered by the US Army, who underestimated its significance.
- Iron from the meteorite that created Meteor Crater was used to build railroads in Arizona, demonstrating the meteor's cultural and practical impact.
- The crater was formed by a 30 m wide object, illustrating the potential devastation caused by relatively small asteroids.
- The energy of the impact was sufficient to liquefy and flip the ground, highlighting the catastrophic power of asteroid impacts.
- A small asteroid impact on a populated area could result in one of the worst natural disasters in history, emphasizing the importance of monitoring and mitigating such threats.
5. The Chelabinsk Meteor Incident 🚀
- In 1908, a meteor explosion in Siberia caused a forest the size of Greater London to disappear, yet only three people died, showcasing the potential localized impact of such events.
- The meteor was only 40 meters long but unleashed a 12-megaton explosion, comparable to a large nuclear bomb, illustrating the significant energy release from relatively small space objects.
- Had the meteor struck an hour later, it would have hit Moscow with the force of a thousand atomic bombs, demonstrating the potential for catastrophic urban impact.
- The incident faded from memory until a US Air Force major, inspired by science fiction, highlighted the need for planetary defense, bringing attention to the potential threat of near-Earth objects.
- In the 1990s, reports stressed the importance of preparing for planetary defense, advocating for proactive measures to identify and mitigate asteroid threats.
- Modern planetary defense strategies have evolved to include global cooperation, advanced tracking technologies, and strategic planning to mitigate impacts from space objects.
- The Chelabinsk Meteor Incident serves as a historical example driving the development of these strategies, emphasizing the importance of readiness against natural space threats.
6. NASA's Tracking Systems: A Safety Net 🔭
- NASA's tracking systems were prompted by the discovery of Shoemaker-Levy 9, a comet that broke into 21 pieces and impacted Jupiter with a force equivalent to 300 million atomic weapons.
- The potential threat of such celestial objects impacting Earth led to NASA receiving funding to track these objects, highlighting the importance of planetary defense.
- Movies about asteroid impacts have influenced lawmakers by making them aware of the potential catastrophic effects, leading to legislation requiring NASA to find 'planet killers,' asteroids about one kilometer or bigger.
- By a legal mandate, NASA was given 10 years to identify all 'planet killers,' and they discovered most of them quickly. By 2005, NASA was also required to find 'city killers,' which are smaller asteroids capable of destroying cities.
- The large size of 'planet killers' makes them easier to detect as they reflect a significant amount of sunlight. NASA has found nearly all of the estimated 950 near-Earth 'planet killers,' with about 900 identified.
7. Asteroids and Comets: Separate Threats 🌠
7.1. Asteroid Impact: Chelabinsk, Russia
7.2. Planetary Defense and Public Perception
7.3. Comets: A Distant Threat
8. DART Mission: A Milestone in Defense 🛰️
- Asteroids have historically contributed to life on Earth but also pose potential threats; the one that killed the dinosaurs was 10 km long, and its impact sent Earth matter to the moon.
- NASA is concerned about 140 m wide 'city killer' asteroids, which could destroy entire cities; statistically, these occur once every 20,000 years, and there are about 25,000 in near-Earth orbit.
- NASA has identified only 40% of these city killers, leaving 60% undetected, highlighting a significant risk.
- The DART mission aims to prevent asteroid impacts by deflecting them; it's the only natural disaster that can be entirely prevented.
- The DART mission involves a spacecraft crashing into a small asteroid orbiting a larger one to test deflection strategies.
- The spacecraft uses ballistic missile technology to autonomously pilot into the asteroid at 14,000 mph, testing its ability to alter the asteroid's course.
- The mission's success depends on precise targeting akin to throwing a dart from JFK Airport to hit a bullseye in Dallas Airport.
- If unsuccessful, a second attempt would take two years, demonstrating the challenges in asteroid deflection.
- The DART mission launched in November 2021 on a SpaceX rocket, marking a significant step towards planetary defense.