Gravitational fluctuations  

NASA launched two new satellites from the Vandenberg Air Force Base in California on Tuesday.

The twin satellites, collectively named “Gravity Recovery and Climate Experiment Follow-On” (GRACE-FO), will continue collecting data about the Earth’s gravitational pull, just as its forerunners (the original GRACE satellites) did.

Why is information about the Earth’s gravitational field useful? Precise gravitational data can indicate changes in conditions or reveal unusual phenomena on Earth. For example, tracking changes in gravity on a month-by-month basis can give valuable data about the movement of liquid and frozen water. Water represents a tiny fraction of the Earth’s mass, and therefore exerts a gravitational force, which can be detected by the GRACE-FO satellites. As snow accumulates on mountains in the winter or glaciers melt in the summer, the pull of gravity changes in those regions. These effects can be big enough to shift the Earth’s centre of mass and cause Australia to “seesaw” up and down each year by 2-3mm.

Past GRACE data has also measured strange fluctuations in the Earth’s crust months before a major earthquake hit Tohoku, Japan. Although researchers have not identified the definitive link between the two, they hope further information from GRACE-FO can give them valuable insight.

Read more: NPR / NASA: GRACE / NASA: GRACE-FO

Image: NASA – Twin satellites taking off

This story is taken from the 25 May 2018 edition of The Warren Centre’s Prototype newsletter. Sign up for the Prototype here.