Comet Punch Threw Mars' Magnetism into Chaos

When Comet Siding Spring encountered Mars in 2014, it delivered a hefty magnetic punch.

Published On 03/10/2016
1:35 PM EST
The close encounter between comet Siding Spring and Mars flooded the planet with an invisible tide of charged particles from the comet's coma. The dense inner coma reached the surface of the planet, or nearly so. The comet's powerful magnetic field temporarily merged with, and overwhelmed, the planet's weak field, as shown in this artist's depiction. | NASA/Goddard