SYDNEY (Australia), Jul 1 : Seventy years ago, Earth had only one satellite: the Moon. Now it has more than 15,000 — about 10,000 of which are owned by Elon Musk's SpaceX. The world's first trillionaire plans to launch one million more satellites, each roughly 70 metres long and 20 metres wide, that would form a data centre megaconstellation.But more satellites means more space junk, which is already threatening critical infrastructure we rely on every day.Addressing this problem effectively requires work across three fronts: technology, policy and philosophy.Advertisement 13 million cane toads worth of space junk————————————————-Space junk is everything in…