Comet Siding Spring’s close shave by Mars last year provided a rare glimpse into how Oort Cloud comets behave, according to new research.
The comet flew by Mars at a range of just 83,900 miles (135,000 kilometers) — close enough for the outer ridges of its tenuous atmosphere to pummel the planet with gas and dust.
In just a short flyby, the comet dumped about 2,200 to 4,410 lbs. (1,000 to 2,000 kg) of dust made of magnesium, silicon, calcium and potassium — all of which are rock-forming elements — into the upper atmosphere, the new study found.