A recent study found that the asteroid belt between Mars and Jupiter is gradually shedding mass over time. This region was previously predicted to form a planet during the Solar System's birth 4.6 billion years ago, but it never occurred, owing to Jupiter's tremendous gravity. Instead of allowing material to come together, Jupiter generated collisions that separated things.

The asteroid belt now contains just around 3 per cent of the Moon's mass, which is spread out over a large area. Jupiter, Saturn, and Mars continue to influence the orbits of these space rocks, drawing some into the inner Solar System and others out towards the outer Solar System, including the vicinity of Jupiter. Others merely turn to dust after colliding with each other.

A team of scientists led by Julio Fernandez of the Universidad de la República in Uruguay investigated how quickly the asteroid belt is losing material. According to Universe Today, they discovered that it is shrinking by around 0.0088 per cent every year, just from the half of the belt that still collides.

While this appears to be a minor amount, it becomes significant when spread over billions of years. Of the material lost, approximately 20 per cent escapes as bigger bits, which can occasionally hit Earth's orbit and form meteors. The remaining 80 per cent is converted into fine dust, which contributes to the zodiacal light —a faint glow in the night sky visible after sunset or before sunrise.

The study excludes the largest and most stable asteroids, such as Ceres, Vesta, and Pallas, which are no longer part of the primary depletion process.

Understanding the continuing loss allows scientists to examine Earth's past. Around 3.5 billion years ago, the asteroid belt could have been 50 per cent larger, with a far higher rate of impact on Earth and the moon. This is consistent with what we know from ancient rock layers that reveal evidence of previous meteor strikes.

Though the asteroid belt appears to be a permanent feature of our Solar System, the recent study indicates that it is gradually fading. Its past and destiny are inextricably related to the evolution and safety of our planet.