Society for Popular Astronomy

Thanks everyone. Stella I went back to basics and did it from first principles and now see how it works. I have much work to do

Thank you David

Yes I know that but 10 to the 12th is significantly less than 10 to the 9th and 10 tk the 10th combined. The book suggests that 2 components of the Milky Way have greater mass than the estimated total mss

I went to Maplin and got a 12v adaptor to plug the usual 'car socket' plug into and run it from the mains when at home. Gave up with rechargeble battery packs

I am guessing that this is the best place for this question and apologies if not. I am trying to learn the maths behind astronomy. I am told by the OU book 'Introduction to Galaxies and Cosmology' that the estimated mass of the Milky Way is 10 to the power 12 x the mass of the sun. It then goes on t...