According to a recent study, Mars faces a significantly higher risk of close encounters with potentially dangerous asteroids compared to Earth. Researchers discovered that around 52 large asteroids approach Mars annually, which is approximately 2.6 times more than the 20 or so asteroids that pass near Earth each year. These Mars-bound asteroids, known as ‘CAPHAs’ (close approach potentially hazardous asteroids), pose a potential threat to future exploratory missions and human settlements on the Red Planet.
The study highlights the importance of tracking PHAs (potentially hazardous asteroids) as part of planetary defense programs. While astronomers have identified around 33,000 space rocks that pass close to Earth during their orbit around the sun, only a fraction of them are classified as large enough to cause significant damage upon impact.
Researchers used computer models to simulate the movement of 11,000 randomly chosen asteroids over 100 million years. The simulations revealed that near-gap asteroids, or asteroids located near the gaps within the asteroid belt, are more likely to drift into the gaps due to the Yarkovsky effect (a force generated by the re-radiation of energy from sunlit surfaces). Once in the gaps, gravitational tugs from Jupiter or Saturn can alter the paths of these asteroids, sending them on potential collision courses with the inner planets.
The potential impact of these Mars-CAPHAs is not limited to mission safety concerns. Researchers also believe that studying these asteroids can provide valuable insights into the Martian environment, the interactions between asteroids and planets, and the evolutionary history of the inner solar system. Notably, two of these CAPHAs may be visible from Earth in early 2025, when Mars will be aligned with Earth and orbiting on the same side of the sun.
