Potentially Dangerous Asteroids – Annual Count of Close Approaches to Earth
Over the last year, our planet had some heart-pounding moments as it narrowly dodged more than 100 potentially dangerous asteroids (Photo: Newsweek)
Exploring Potentially Dangerous Asteroids – Cosmic Remnants That Ignite Public Imagination
According to an article from Space, Potentially dangerous asteroids are solid remnants originating from the early stages of our Solar System’s creation. There are approximately 500 million asteroids larger than four meters in diameter that orbit the Sun, traversing the Solar System at speeds approaching 30 kilometers per second, akin to Earth’s velocity.
Potentially dangerous asteroids often captivate public imagination, driven by Hollywood’s depictions of their potential to devastate Earth. Online headlines regularly highlight potentially dangerous asteroids of various sizes and ominous terms like “city killer” or “planet killer.” These fears aren’t unfounded, as history recalls the catastrophic impact of large potentially dangerous asteroids around 65 million years ago, which led to the extinction of most dinosaurs. Even a relatively modest four-meter potentially dangerous asteroids traveling at speeds of up to 60 kilometers per second can possess significant destructive potential.
So, how often do potentially dangerous asteroids collide with Earth, and how frequently do they come close to our planet?
Have you ever wondered how many asteroids fly past Earth each year?
According to Yahoo News, if you were to increase that surface area by a factor of two, the frequency would double to two occurrences each year. To illustrate, Earth’s radius spans 3,958 miles (6,400 km). When you consider a sphere with twice the surface area, its radius extends to 5,592 miles (9,000 km). Consequently, roughly once annually, a 4-meter asteroid would approach within 1,615 miles (2,600 km) of Earth’s surface, reflecting the difference between 3,958 and 5,592 miles (6,400 and 9,000 km). Doubling the surface area once more would result in an expectation of two such occurrences yearly, all within 3,958 miles (6,400 km) of Earth’s surface, and this pattern continues.
While this might seem substantial for small objects, most of the asteroids featured in media reports pass by Earth at much greater distances. Astronomers classify anything closer than the moon’s approximate distance (about 186,000 miles or 300,000 km) as a “close approach,” although this may not align with the public’s perception of “closeness.”
In 2022, there were 126 close approaches, and in 2023, there have been 50 so far. Now, let’s consider significantly larger asteroids, those exceeding one kilometer in diameter. Employing the same simplified logic as before, for each civilization-threatening impact event that occurs roughly once every half a million years, we can anticipate thousands of near misses (closer than the moon) within the same timeframe.
An example of such an event will transpire in 2029 when asteroid 153814 (2001 WN5) passes within 155,000 miles (248,700 km) of Earth.