Galaxies avoid an early death because they have a 'heart and lungs' which effectively regulate their 'breathing' and prevent them growing out of control, a new study suggests. If they didn't, the universe would have aged much faster than it has and all we would see today is huge 'zombie' galaxies teeming with dead and dying stars. That's according to a new study that investigates one of the great mysteries of the Universe -- why galaxies are not as large as astronomers would expect.
