Electromagnetic waves help catch Mercury’s hidden lithium fingerprint

Researchers have, for the first time, confirmed the presence of lithium on Mercury by detecting its unique electromagnetic signature rather than spotting lithium atoms directly. Using magnetic wave data from NASA’s MESSENGER mission, the team identified ion cyclotron waves (ICWs) specifically tuned to lithium ions, which are created when meteoroid impacts vaporize Mercury’s surface material. These impacts release neutral lithium atoms that quickly ionize under solar ultraviolet radiation, and as the solar wind interacts with these lithium ions, it generates detectable ICWs. The study found 12 distinct events over four years where these lithium-specific waves appeared, each lasting only minutes and linked to sudden meteoroid bombardments rather than slow processes like solar heating. This discovery provides crucial evidence that Mercury’s surface remains chemically active and is continuously reshaped by meteoroid impacts. The impacts, involving meteoroids up to 21 centimeters in radius traveling at speeds up to 110 km/s, create mini-explosions that vaporize large