Top 20 Near-Earth Objects at Greatest Risk of Impact 🌎

65 million years ago, an asteroid with an estimated diameter of 10 km struck the Earth with an explosive force equivalent to 72 teratonnes of TNT. The impact left a crater 200 km in diameter and caused the mass extinction of three-quarters of the planet's plant and animal species, dinosaurs included.

While asteroids of this size that cross Earth's orbit are rare, there are many more smaller asteroids that could still cause significant and possibly civilization-ending damage up there. Here are the top 20 Near-Earth Objects (NEO) most likely to impact the Earth according to the European Space Agency's Risk and Special Risk Lists.

Key Takeaways

• Two NEOs in particular are considered of special risk: 101955 Bennu (484 m) and 29075 1950DA (1300 m), both for their size and how close their orbits approach Earth. But we have time. 29075 1950DA isn't predicted to be a risk until 2056, while we have until 2880 to wait for Bennu's most likely impact.
• While velocity and impact location (surface vs. atmosphere) are important contributors to potential damage, size is perhaps the most important. NEOs as small as 140 meters can level a city, while objects between 2,000 and 3,000 meters have the potential to cause the end of human civilization.
• Even relatively small asteroids can cause significant damage. In 1908, an asteroid between 50–100 meters in diameter exploded in the atmosphere above sparsely-populated Siberia, flattening 80 million trees over 2,000 square kilometer area.
• Knowing about NEOs is one thing, but then what? On Sept. 26, 2022, NASA's Double Asteroid Redirection Test (DART) spacecraft intercepted the asteroid moonlet Dimorphos (160 m) and successfully redirected it's course, akin to cosmic billiards.