Something Strange Happens on Mars During a Solar Eclipse

[gristy]

1. They figured it out

From the article:

This, the team believes, is the most likely cause of the strange reading.

"During an eclipse, the ground cools," said seismologist Martin van Driel of ETH Zurich. "It deforms unevenly, which tilts the instrument."

A similar effect was observed in 1997, at the Black Forest Observatory in Germany.

A technician forgot to turn off the light when leaving the seismometer vault, resulting in elevated noise in long-period data as the warmth from the bulb expanded the granite on which the seismometer rested.