Space cold atoms can weigh the Himalayas.

• Gravitational force on Earth’s surface is uneven due to mass distribution.

• Gravity gradiometers are sensitive instruments that measure the difference between different places.

• Newton’s second law states that force on a body is equal to its mass multiplied by its acceleration.

• Gravity gradiometers can measure the speed of a ball falling in different places.

• NASA scientists propose a quantum gravity gradiometer (QGG) on a satellite for studying changes in earth’s distribution of water, ice, and rocks.

• A QGG uses atoms cooled to near absolute zero and manipulated by lasers to experience a phase shift proportional to the gravitational force.

• A QGG can deduce a difference in acceleration lower than 10-15 m/s2 across a distance of 1 m on the earth’s surface.

• NASA’s QGG onboard a satellite could weigh around 125kg, have a volume of 250 litres, and consume 350 W.

• The team plans a technology demonstration and operational mission to validate the QGG’s feasibility.