How many potentially hazardous asteroids approach Earth?

Astronomers continue to discover new near-Earth objects, and according to the latest estimates, about 40,000 asteroids currently pass close to Earth. This figure was reported in an interview with RIA Novosti by Nikolai Zheleznov, a senior researcher at the Institute of Applied Astronomy of the Russian Academy of Sciences.

How Many Asteroids Exist in the Solar SystemTo date, astronomers have discovered more than 1 million asteroids in the Solar System. Most of them are located in the Main Asteroid Belt — the region between the orbits of Mars and Jupiter.

However, scientists pay special attention to a particular group known as Near-Earth Asteroids (NEAs), which periodically come close to our planet.

These objects are now detected relatively quickly thanks to modern sky-survey programs. They vary widely in size — from just a few meters across to several kilometers in diameter. The largest known near-Earth asteroids exceed 1 kilometer in size.

Potentially Hazardous AsteroidsWithin the population of near-Earth objects, scientists identify a special category known as Potentially Hazardous Asteroids (PHAs).

This classification includes asteroids that have either approached — or are predicted to approach — Earth within 7.5 million kilometers (about 4.6 million miles) at least once during their orbital history.

According to Nikolai Zheleznov, there are a significant number of such objects. In particular, astronomers have identified 154 potentially hazardous asteroids larger than 1 kilometer in diameter.

Why This MattersEven relatively small asteroids — those measuring 20–30 meters across — can cause substantial regional damage if they strike Earth. Larger objects, especially those exceeding 1 kilometer, could potentially trigger global-scale catastrophic consequences.

For this reason, all potentially hazardous asteroids are continuously tracked by international space-monitoring networks that focus on planetary defense and impact risk assessment.

In BriefAt present, about 40,000 asteroids periodically pass close to Earth. Among them, 154 objects larger than 1 kilometer are classified as potentially hazardous — meaning they have approached or are expected to approach Earth within 7.5 million kilometers.

More than 1 million asteroids have been discovered in total, with most located in the Main Asteroid Belt between Mars and Jupiter. Scientists continue to monitor near-Earth objects closely in order to detect any potential threats as early as possible.