Off Interstate 40 in Arizona, large asteroids do hit Earth.
The 600-foot “Meteor Crater,” which landed 50,000 years ago, is there. Kansas City was destroyed by a 100- to 170-foot-wide bomb. The space rock wasn’t little, but it wasn’t a “planet-killer” like the six-mile-wide giant that killed most dinosaurs.
Though another major crash from an asteroid 200 feet or 2,000 feet across is imminent, astronomers are optimistic.
A new census(opens in a new tab) of many of the largest asteroids that pass through our solar system neighborhood found no known threat of collision for the next century, and the likelihood of an impact in the next thousand years is extremely low, though researchers will keep an eye on 20 huge cosmic rocks whose distant future trajectories are unknown.
This kilometer-wide or bigger asteroids pose no threat. However, the latest research showed that certain paths remain unclear a thousand years from now, and additional observation is needed to rule out an influence.
“We need more information about these asteroids, although the probability [for an impact] is still very low,” Oscar Fuentes-Muñoz, a researcher at the University of Colorado Boulder who led the new census, told Mashable.
The peer-reviewed Astronomical Journal will publish this planetary defense study from Arxiv.
Why asteroid collisions are unlikely
NASA and other scientists are vigilantly searching for “near-Earth objects,” sometimes known as “asteroids.”
As of May 2023, astronomers have detected almost 10,000 nearby space rocks over 460 feet large, with 500 more found each year. “Nearby” might imply millions of kilometers distant. Undiscovered 15,000 of these can unleash massive area harm. Fortunately, over 90% of the biggest behemoths—over a half-mile across—have been located.
Two factors reduce future impact risk: The frequency of asteroids hitting Earth now and in the past, and no known upcoming asteroid attacks. (Asteroid-sleuthing telescopes are used nightly.)
Every day, 100 tons of dust and sand burn up in Earth’s atmosphere. NASA(opens in a new tab) says a “automobile-sized asteroid” erupts every year. Every 10,000 to 20,000 years, objects roughly 460 feet in diameter crash, while “dinosaur-killing” impacts from rocks a half-mile or greater occur on 100-million-year periods.
Astronomers think a major impact in our lifetimes is unlikely.
This newest count examined 851 big asteroids that circle Earth and spend more time near us.
The researchers investigated what the asteroids would do after a thousand years after being touched by other planets’ gravity and the sun’s heat, even if they pose little threat in the next century.
New orbit models showed most asteroids are harmless. However, 20 asteroids with uncertain sun orbits were less predictable. Observe more.
The two-thirds-mile-long asteroid 7482 (1994 PC1) was simulated to travel through Earth’s orbit around the sun many times during the next thousand years. 7482 (1994 PC1)’s effect risk is uncertain.
Scientists locate close asteroids
Sky scans often discover new asteroids.
Asteroid-watching projects include NASA’s Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) on Maui, the Catalina Sky Survey in Arizona’s Santa Catalina Mountains, and the Asteroid Terrestrial-impact Last Alert System (ATLAS) with telescopes worldwide.