38 SOME CAN BE TINY

The smallest theoretical mass for a black hole is around 22 micrograms, a value known as Planck mass.

39 THE CLOSEST KNOWN BLACK HOLE IS 1,560 LIGHT YEARS AWAY FROM EARTH

The closest black hole to Earth is Gaia BH1 in Ophiuchus. It has the mass of about 9.6 Suns.

40 BLACK HOLES HAVE NO HAIR

This famous statement made by scientist John Wheeler describes the simplicity of black holes. Typically, they can be described by just three quantities: their mass, angular momentum and electric charge.

41 THEY HALT LOCAL STAR FORMATION

The largest and most active supermassive black holes often occur in the quietest galaxies. The radiation released as they feed stops the gas around them condensing to form stars.

42 THE SUN COULD NEVER BECOME A BLACK HOLE

To become a black hole, a star must be so massive that it completely collapses under its own gravitational pull. The Sun is much too small, and instead it will end its life as a white dwarf.

43 BLACK HOLES COME IN DIFFERENT SIZES

Stellar-mass black holes can measure just a few kilometres in diameter, whereas supermassive black holes can be the size of our Solar System.