What is the lifespan of an asteroid? Find out what scientists say

Do you know about those rocky objects that orbit around the sun? Well, those objects are called asteroids and our scientists keep tracking their movements in order to save Earth from their impact.

According to NASA scientists, there are no known threats from asteroids but it is important to find them, before they find us. The question arises here that how long can these rock-like materials survive?

NASA's OSIRIS-REx spacecraft successfully approached the asteroid Bennu in October 2020, after nearly two years of orbiting. By deploying its robotic arm, the probe gathered approximately 4.4 pounds (2 kilograms) of dusty, rocky material from the asteroid's surface. This marks the first-ever sample of an asteroid collected by a U.S. mission. This material has the potential to shed light on intriguing questions about the age and lifespan of asteroids like Bennu.

To know about the lifespan of asteroids, understanding how they were formed is important. According to a report by LiveScience, these celestial bodies emerged from the protoplanetary disk around our sun about 4.5 billion years ago.Harold Connolly, an astronomer associated with OSIRIS-REx, explains that the process began with dust coagulating and gradually accumulating more material.

Through collisions and cohesion, some dust clusters evolved into planets like Earth, while others formed moons, comets, and asteroids. Asteroids are leftover material. Most asteroids now reside in the asteroid belt between Mars and Jupiter, although occasionally some are ejected and become near-Earth asteroids. The largest intact asteroids are approximately 4.5 billion years old, dating back to the solar system's origin. However, some asteroids can be considered younger, comprising smaller pieces that broke off from larger bodies.

How long can asteroids survive?

Asteroids can break up and be destroyed in a few ways. One is when they spin after a collision or being pushed by solar radiation, causing pieces to fly off. Another way is due to thermal stress, when materials expand and contract in the sun's heat for a long time, or when ice inside the asteroid turns into gas because of the sun's warmth. Sometimes, asteroids break up from collisions with other celestial objects, like a cosmic billiards game, as told by Connolly to LiveScience. The larger the asteroid, the longer it can survive before breaking up.

According to astronomer Kevin Walsh, a 1-kilometer asteroid can last around 440 million years in the asteroid belt without breaking up, while a larger 10-kilometer asteroid can survive for about 4 billion years before breaking apart.

Scientists are still studying the lifespan of the biggest asteroids. It's believed that some of them might last as long as the rocky inner planets in our solar system, which is around 8 to 10 billion years. In about 5 billion years, when the sun gets much older, it's expected to expand and consume nearby planets and asteroids.