Asteroid Bennu, a near-Earth object currently 186,000 miles (299,000 km) from Earth, has a 1 in 2,700 chance of colliding with our planet on September 24, 2182, according to astronomers. While this probability is low, the potential consequences of an impact would be catastrophic.
Immediate Effects of a Bennu Impact
If Bennu, which is about 500 meters (1,640 feet) in diameter, were to strike Earth, the initial destruction would include:
- A powerful shockwave that would flatten everything within hundreds of kilometers.
- Severe earthquakes and thermal radiation, sparking massive wildfires.
- A crater several kilometers wide, throwing enormous amounts of debris into the atmosphere.
Long-Term Global Impact
According to a recent study published in Science Advances, the impact would inject 100-400 million tonnes of dust into the atmosphere, triggering a multi-year “impact winter” similar to the aftermath of massive volcanic eruptions.
Climate Consequences
- Global temperatures could drop by 4°C (7°F), disrupting weather patterns.
- Rainfall would decrease by 15%, leading to droughts.
- Severe ozone depletion (32%), increasing exposure to harmful UV radiation.
Impact on Food Production
- Land plants would see a 20-30% decline in photosynthesis, reducing crop yields.
- Ocean plankton, however, would recover within six months, and diatoms (a type of algae) could experience a boom due to iron-rich dust entering the oceans.
Risk to Human Civilization
While the death toll would depend on the impact location, an event of this magnitude could cause widespread destruction, food shortages, and long-term disruptions to global ecosystems.
Can We Prevent It?
NASA has already taken steps in planetary defense:
- In 2022, NASA’s DART mission successfully altered the trajectory of the asteroid Dimorphos, proving that asteroid deflection is possible.
- If Bennu were to pose an imminent threat, similar deflection techniques could be used to change its orbit and avoid a collision.
Conclusion
Although the probability of a Bennu impact is extremely low (0.037%), the potential consequences would be devastating. Continued advancements in asteroid tracking and deflection technology are crucial to ensuring that future generations are prepared for such cosmic threats.
