692
THIn 1798, Henry Cavendish “weighed the Earth” using two lead spheres and a torsion balance.
The force he measured was 100 billion times weaker than your body weight.
That experiment never ended.
More than 200 years later, physicists in Vienna measured gravity between gold spheres weighing just 100 milligrams. So sensitive that passing city trams had to stop.
At the scale of a grain of sand, gravity still behaves exactly as predicted.
But we are approaching the Planck mass — the boundary where spacetime may stop being smooth and start behaving like a quantum object.
We’re not just measuring gravity anymore.
We’re closing in on the scale where physics itself could break.
And it all started with weighing the Earth.
#physics
#gravity
#quantumgravity
#scienceshorts
#planckscale
@thearcivium
