the Mathematics of the Milky Way
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the Mathematics of the Milky Way
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 to say that the estimated mass of the central bulge is 10 to the power 10 x the mass of the sun. Further the mass of the stellar halo is ONLY 10 to the power 9 x the mass of the sun. Surely the bulge and halo estimates exceed the total estimated mass? Sorry if the answer is obvious but I have spent my life dealing with words and O Level Maths is where I stopped. Could it be the book is just wrong?

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Re: the Mathematics of the Milky Way
Hi Alan, welcome.
10 to 12th is more than 10 to 9th or 10th.
Regards, David
10 to 12th is more than 10 to 9th or 10th.
Regards, David

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Re: the Mathematics of the Milky Way
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
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
Re: the Mathematics of the Milky Way
No, combining those two gives 1.1x 10^10, which is less than 10^12.
Re: the Mathematics of the Milky Way
This Wiki may give you more of a feel for the 'powers of ten' https://en.wikipedia.org/wiki/Power_of_10 .Hope this is a help

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Re: the Mathematics of the Milky Way
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