Recent content by damasgate

It's somehow relating it to the CMB, What I'm not understanding is the procedure to solve the question. Do I use Friedmann equations? full text Gas temperature and star formation. Gas, immersed in the CMB photon bath continuously, behaves like the Earth in problem 1 and is heated up to a...

If gas has to be cooled below, say, 100 K, in order for stars to form, what is the highest redshift for star formation? What would be the necessary equations to solve this problem??

CMB hot spots have a physical size that corresponds to the size of the horizon at age 300; 000 yrs. Assume one such hot spot region has been expanding together with the universe, how big in physical size (express in unit of light-year) has it become today? For this exercise, use a model of...

I know that H(t) = 1/a(t) x da/dt I know that a(t) is proportional to t^2/3 and da/dt is proportional to a^-1/2 now H(t) should equal H(t) = a(t)^-1 x a(t)^-1/2 = a(t)^-3/2 = (t^2/3)^-3/2 = t^-1 However where is the constant 2/3 coming from? I can't find it anywhere in my...

Now I'm using p=3H^2/8piG and I have H=70 km/s/Mpc, what is the critical density of the universe? now I'm plugging in all the values and I can never ever get something close to the densities calculated in the theories (something like 1.06x10^-28 g/m^3) in fact I can never get anything...

Homework Statement IT IS POSTED IN THE ATTACHMENT BELOW Homework Equations everything is in static equilibrium The Attempt at a Solution well I know how to follow up to solution on these types of problems quite easily, however..on this one I can't seem to get started because I...

um...should it be 2/3 of the distance...i.e 5x(2/3)?

thanks a lot, but I still don't understand exactly the 5/3m distance from the y-axis for the force of the gate...

THE QUESTION IS POSTED ON THE ATTACHMENT FILE BELOWHomework Statement density of the gates is 4000 kg/m^3 width of the gate is 6mHomework Equations Static Equilibrium : every equation that sums up forces or moments equals zero You also must find the force of the weight going down F=mg but...