Tiny specks of dust from a “giant space cushion” almost as old as the solar system can provide new clues about how to avoid catastrophic asteroid collisions with Earth, research suggests.

Three tiny particles of dust – smaller than the diameter of a hair – collected from a 500-metre-long asteroid known as Itokawa show some of these space rocks are much older and tougher than previously thought.

The peanut-shaped Itokawa is classified as a potentially hazardous asteroid, one that could veer perilously close to Earth and could cause significant damage if it collided.

A study, published in the Proceedings of the National Academy of Sciences, has found that Itokawa formed more than 4.2bn years ago, making it 10 times older than solid asteroids of a similar size.

“We were really surprised,” said Prof Fred Jourdan of Curtin University’s school of earth and planetary sciences, the study’s first author.

Nasa’s recent Dart test showed asteroids like Itokawa can be nudged off course, but that would probably require a lead time of several years.