Back in the Apollo mission days to the moon in 1972, the moon rover that the astronauts drove around had instruments on board to measure the gravity of the surface. Scientists wanted to measure the gravity on the surface of Mars, but the Curiosity rover lacks sensors for such measurements. That didn’t stop researchers from figuring out a way to measure gravity with what Curiosity does have on board.
Researchers were able to repurpose sensors that Curiosity used to drive the rover and turn them into gravimeters. A gravimeter can measure changes in gravitational pull. With the sensors reconfigured, the team was able to measure the tug on the rover from rock layers on lower Mount Sharp.
Mount Sharp towers three miles from the base of Gale Crater; Curiosity has been climbing that mountain since it landed in 2014. The rover’s accelerometers can measure the gravitational pull on the rover from Mars. Scientists have found that as the rover ascends Mount Sharp, the gravitational pull exerted on it increases.
While the increased gravity as Curiosity climbs was expected, scientists are saying that the gain in gravitational pull is less than they expected. This is important because scientists say that they knew the bottom layers of the mountain had been buried over time. The act of burying the mountain compacted the rock layers and made them denser.
However, the team now says that their findings suggest the mountain wasn’t buried as much as they had thought. That might throw cold water on one theory of how Mount Sharp was able to grow inside Gale Crater. The theory was that sediment had once filled the crater and millions of years of wind erosion blew the sediment away leaving the mountain. Scientists now think the rock would have compacted more if that was the case.