2006-10-14 04:07:54 · 5 answers · asked by loni 2 in Science & Mathematics ➔ Physics
First, its more common to give galactic masses in multiples of solar masses , according to
http://en.wikipedia.org/wiki/Milky_Way
secondly 10^35 kg is about 5 orders of magnitude too small.
It does seem very picky and arbitrary to insist on mass units so I expect that it's the 10^35 figure as an order of magnitude estimate for galactic mass being very small.
It's just possible that someone would like you to mention dark matter and dark energy but that seems rather picky too to be honest particularly as the dark energy part of the universal mass doesn't seem to be associated with galactic masses.
http://aa.springer.de/papers/8330003/2300953.pdf#search='dark%20mass%20galactic%20mass'
http://www.shef.ac.uk/physics/research/pppa/research/dm/darkMatter.php
http://www.journals.uchicago.edu/ApJ/journal/issues/ApJS/v148n1/57713/57713.html
is a fabulous read.
Best of Luck - Mike
2006-10-14 04:29:48 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Well, maybe because you should use 1 * 10^35, and it should be the MASS of the galaxy is 1 * 10^35 kg.
2006-10-14 11:54:42 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Who says it's wrong? What you gave is certainly in units of mass (i.e., kg). You may have the wrong value (i.e., 10^35), but that would depend on the galaxy, and you didn't give that.
Although it is true that the mass of a galaxy is frequently given in Msun, the mass of our sun, if you are using the kg-m-sec metric system to calculate things in physics, you will eventually have to convert solar mass (Msun) into kilograms (kg) for consistency.
One solar mass (Msun) = 1.98 X 10^30 kg/Msun. Thus, with the number you gave (i.e., 10^35 kg), you are talking about a small galaxy with approximately Nsun = Mgal/Msun = 10^35 kg/(2 X 10^30 kg/Msun) ~ .5 X 10^5 Msun sized suns. That's 50,000 suns, which is way below the millions of stars in most galaxies.
2006-10-14 11:48:14 · answer #3 · answered by oldprof 7 · 0⤊ 0⤋
Nothing wrong. But it convenient to use solar masses. This is in analogous to kg ( weight) and tons.
2006-10-14 11:50:59 · answer #4 · answered by Dr M 5 · 0⤊ 0⤋
You might be thinking of order of magnitude. That would be 35. It's basically how big your number is. If something is an order of magnitude bigger than something else, that means it's about ten times bigger.
2006-10-14 11:30:05 · answer #5 · answered by Alan J 3 · 0⤊ 0⤋