Sorry I'm not sure what the density is
Homework Statement
Suppose that the halo, assumed spherical, of non-baryonic dark matter surrounding our galaxy has mass ~ 5 x10^12 M solar and radius 0.1 Mpc. What it its average density in Kg m-3?
Homework Equations
M= r v^2/ G
The Attempt at a...
Sorry I'm not sure what the density is as that's what I'm trying to find. I have previously found the average density of non-baryonic dark matter in the Universe by dividing it's percentage into the critical density. Should I be using that?
Sorry I'm very new to this site. I did look in the homework forum but I could not find a cosmology homework thread.
Also I'm a mature student and I haven't done this level of mathematics in years so I'm trying to re-learn as I go. The second equation was my best effort to re-work the first. :(
I've got a homework question that I'm particularly stuck on:
Suppose that the halo, assumed spherical, of non-baryonic dark matter surrounding our galaxy has mass ~ 5 x10^12 M solar and radius 0.1 Mpc. What it its average density in Kg m-3?
I think that I need to use the formula...
I'm using the the Doppler formula to calculate the relative velocity between the approaching and receding filaments of the crab nebula: Δλ/λnaught = v/c Change in wavelength/ wavelength = velocity/ speed of light
I have reworked the formula as v= c(Δλ/λnaught)
When I plug in the values I get...
Homework Statement
A binary star system at a distance of 85pc consists of two stars of equal luminosity that are so close together that they are observed in a telescope as a single image. If the apparent magnitude of the two stars combined is 10.7 what would be the apparent magnitude of just...