[0812.4491v1] Strange Quark stars: Observations & Speculations.
Love compact objects – they’re massive embodiments of quantum mechanics and general relativity. Neither white-dwarfs or neutron-stars or quark stars would exist if it wasn’t for the Pauli Exclusion principle causing particles to push each other apart. About 90 years ago Arthur Eddington wondered aloud what is stopping stars from collapsing forever? Eventually they figured it out – quantum mechanics.
But “neutron stars” might be overly simplistic, because nucleons – protons and neutrons – are composed of 3 quarks joined together in a complex dance of forces. When quarks get close enough together the old distinction between the separate triads of quarks gets broken-down and ‘free’ quarks can now join together as much larger stable systems of indefinite numbers of quarks.
One possibility – which neutron stars can’t do, contra Larry Niven’s “There is a Tide” – is the formation of ‘quark planets’… ejected fragments of a quark star now orbitting their parent body. Just how big would a ‘quark earth’ be? With a density over 1017 kg/m3 our Earth would fit in a sphere less than 300 metres across. It’s gravity would be over 400 million times its present day value, making it rather deadly if you got too close.