Questions and answers from my astronomy shows





14-Aug-19



Q: What is Space expanding into?

A: The universe is not expanding into anything. What cosmologist theorize and what observational evidence supports is that space is stretching over time or should I say spacetime is stretching. It appears galaxies are rushing away from us but what is happening is that the space between the galaxies is stretching so it appears that galaxies are moving away from us. Think of 2 dots on a rubber band and the rubber band is space and the 2 points are galaxies. Stretch the rubber band and the 2 points move apart. So space is being created. Current thinking is that space contains Dark Energy and this makes up 66% of the mass/energy of the universe. It is the Dark Energy that is stretching space like an antigravity. Our local group of galaxies will not disperse though and the stars within them will not either. Mass bends space and time which we perceive as gravity. Space tells matter how to move by its shape which is why the Moon keeps orbiting the Earth, and the Earth orbits the Sun, The Sun orbits the Galaxy and galaxies close enough can overcome the stretching of space.