There is no specific size threshold at which an asteroid becomes a problem for Earth. It depends on a number of factors, including the asteroid’s size, composition, impact velocity, and impact angle.
Asteroids that are less than about 50 meters (164 feet) in diameter are generally not considered a threat to Earth, as they are small enough to burn up in the Earth’s atmosphere upon entry and do not typically survive to reach the surface. However, even smaller asteroids can cause significant damage if they impact a populated area.
But what about the big “wise guys” in space? Luckily, NASA astronomers always look for ways to overcome such threats.
NASA’s NEO Surveyor will scan the sky in infrared
NASA’s NEO Surveyor is the space agency’s idea for spotting dangerous asteroids that could approach our planet one day. It has passed its technical review, which means that we don’t have too long to wait to hear about its launch in space.
Construction Begins On NEO Surveyor https://t.co/ZT9DJpgpSm #NASA #asteroid pic.twitter.com/1hfmiwFsMD
— SpaceRef (@SpaceRef) December 28, 2022
Lindley Johnson, who’s the NASA Planetary Defense Officer at PDCO, explained as the space agency’s website quotes:
NEO Surveyor represents the next generation for NASA’s ability to quickly detect, track, and characterize potentially hazardous near-Earth objects,
Ground-based telescopes remain essential for us to continually watch the skies, but a space-based infrared observatory is the ultimate high ground that will enable NASA’s planetary defense strategy.
The asteroid that is believed to have caused the mass extinction event that wiped out the dinosaurs and many other species 66 million years ago was likely about 10 to 15 kilometers (6 to 9 miles) in diameter. This asteroid would have been significantly larger than most asteroids that pose a potential threat to Earth.
Of course, a Chicxulub 2.0 asteroid hitting our planet today would cause an apocalyptic scenario if the world is not prepared for it.