## Dinner With a Black Hole

1 May 2010, 20:10 UTCA number of people have asked: If Earth contained a tiny Black Hole, wouldn't we be sucked up? This shows a common misconception, even among PhD's. A Black Hole, even nearby, would not swallow you. We can illustrate this around the dinner table.Suppose you are seated at the dinner table, about one meter from the table's centre. The hostess surprises you by placing a primordial Black Hole on the table. The Universe is thought to contain billions and billions of these tiny holes. They were formed from tiny quantum fluctuations grown large by the rapid expansion of the Universe. Typical mass of a primordial Black Hole is about 10^11 kg.This Black Hole with the mass of Diamond Head, would have a Schwarzhild radius of:2GM/c^2The 10^11 kg hole has a diameter of just 10^(-16) meters, less than the size of a proton!Sitting at the table, the gravitational acceleration you would feel is given by:GM/r^2Where G is Newton's gravitational constant, M is Mass of the Black Hole and r is your distance.This is easy to calculate. G = 6.67 x 10^(-11), M is 10^11 kg and r = 1 meter. The acceleration you would feel is just 6.67 m/sec^2, barely 2/3 that ...