Question

Some astronomers have suggested that cooled white dwarf are made of diamond. Why might it be impractical to mine them?

Answer 1

The surface gravity of a white dwarf is very high, of the order of `200,000` times stronger than Earth's surface gravity, and its density in similar proportion.

Explanation:

A typical white dwarf with mass approximately `0.6` times our sun but the size of the Earth would have `200,000` times the mass of the Earth, but the surface at the same distance from the centre. Therefore the surface gravity would be `200,000` times greater than Earth's.

The high surface gravity makes it very difficult to escape from the gravitational pull of the white dwarf, even if you were able to collect some material from it - which brings me to the second point...

The material you are attempting to collect from the white dwarf is on average `200,000` times denser than similar material on Earth. So for a given volume of material, its mass would be `200,000` greater, but its weight in that gravity would be a staggering `200,000 xx 200,000 = 4 xx 10^10` times the weight of the corresponding volume of material on Earth.

It's probably easier to make diamonds at home.