1 upvotes, 1 direct replies (showing 1)
View submission: Ask Anything Wednesday - Engineering, Mathematics, Computer Science
Years ago, I remember reading an article that suggested that a Forward mass detector could be built sensitive enough to detect the gravitational force of a hand near the detector or a car in the driveway. Is this true and practical, and if so, how far from DIYable is it?
Comment by mfb- at 25/07/2024 at 06:36 UTC
4 upvotes, 0 direct replies
Superconducting gravimeters can do this.
A classic story here is the snow removal from the roof[1] picked up by the gravimeter in the building. It didn't just register that snow was removed (effectively increasing the gravitational acceleration felt below), it even saw when people took a break from work. And that was 25 years ago.
A human hand has a mass of about 500 g, at a distance of 50 cm this leads to a gravitational acceleration of 1.3*10^(-10) m/s^(2), which is easy to detect by good gravimeters. The arm next to the hand will only increase the signal even more.
You can't build this yourself, however.