A team of researchers has found a way to measure the subtle changes in the gravitational pull on the surface of Mars using scientific instruments that are already onboard Curiosity.
In a recent study, the team demonstrated how the rover's accelerometers can act as a gravimeter, an instrument that measures gravity, to reveal secrets about the red planet. They found that Mount Sharp, a peak in the middle of the Gale Crater, is much less dense than previously predicted, raising questions about the popular theory of how it developed.
The study was published in the journal Science.
Teaching Curiosity How To Measure Gravity
The idea stems from the Apollo 17 mission in 1972. Astronauts drove a buggy across the lunar surface using the gravimeter to track changes in the gravity of the Moon.
Unfortunately, Curiosity does not have the same instrument. It does, however, have accelerometers and gyroscopes, which are far more precise compared to the tools found in modern smartphones. The accelerometers of the rover, according to researchers, can detect gravity when it is standing still, allowing the team to measure and monitor changes in the gravitational pull.
They tested the technique during the rover's ascent to Mount Sharp. The research team expected the mountain to tug on the makeshift gravimeter, but they discovered that less additional gravity is exerted as the rover makes its way further up.
"The lower levels of Mount Sharp are surprisingly porous," shared Kevin Lewis of John Hopkins University, the study's lead author. "We know the bottom layers of the mountain were buried over time. That compacts them, making them denser. But this finding suggests they weren't buried by as much material as we thought."
The team analyzed more than 700 measurements from Curiosity's accelerometers from October 2012 to June 2017. They filtered out the influence of temperature and tilt of the rover as it climbs upward.
They also compared their data to existing models of Mars' gravity fields and mineral density from Curiosity's chemistry and mineralogy instruments.
The Mystery Of Mount Sharp Continues
Otherwise known as Aeolis Mons, Mount Sharp, which is about as tall as Denali in Alaska, sits at the center of Gale Crater. Some scientists believe that Gale Crater was once completely filled with sediments but over a billion years, it eroded, leaving the 5-kilometer high of layered materials in the middle.
However, based on the new findings by Curiosity, the theory that the crater was once completely filled to the brim is unlikely.