The solar system is crowded with small objects like asteroids and comets, and most have stable orbits which keep them out of harm’s way, but a small proportion of them are in orbits that risk collision with planets.

Smaller objects are more numerous and therefore result in more frequent collisions. The recent meteor seen over Chelyabinsk, Russia, in February 2013, was rare because the object was relatively large, around 17 meters across. However, the giant planet Jupiter is a much bigger target due to its tremendous gravitational attraction -- and it gets hit far more often than the Earth. The collisions are also much faster, happening at a minimum speed of 60 kilometers per second.

Citizen scientist astronomers observing Jupiter with video cameras have been able to observe three of these collisions in the last 3 years and a detailed report of these collisions has been presented at the European Planetary Science Congress, held at University College London a week ago, by Ricardo Hueso from the University of the Basque Country, Spain. “Our analysis shows that Jupiter could be impacted by objects around 10 meters across between 12 and 60 times per year. That is around 100 times more often than the Earth.”

The first of these collisions was observed by A. Wesley from Australia and C. Go from Philippines on June, 3 2010. The second object was observed by three Japanese amateur observers (M. Tachikawa, K. Aoki and M. Ichimaru) on August, 20 that year and a third collision was observed by G. Hall from USA on September, 10 2012 after a report of a visual observation from D. Petersen from USA. Credit: Hueso/Wesley/Go/Tachikawa/Aoki/Ichimaru/Petersen

The work was a broad collaboration between professional and amateur astronomers and also includes detailed simulations of objects entering Jupiter’s atmosphere and disintegrating at temperatures above 10,000 °C and observations from telescopes such as the Hubble Space Telescope or the Very Large Telescope of the impact area taken only tens of hours after the impact.

Despite observing the planet soon after the impact, Hubble and the VLT saw no signature of the disintegrated objects, showing that such impacts are very brief events.

Simulations of object entering Jupiter’s atmosphere. Credit: Jarrad Pond/South Florida University

Because the glow of these impacts is so short-lived, and they happen at unpredictable times, major observatories like Hubble and the VLT cannot reliably observe them -- these telescopes have packed observing schedules and cannot be dedicated to long-term monitoring of a planet.

Amateur astronomers, who can dedicate night after night to observing a planet, have a far better chance of spotting these impacts, even if the government is not buying them expensive equipment.