The temperature of the CMB today is T=2.725 K. Calculate the temperature of the CMB at redshift z=2000

5) The recessional velocity of a galaxy is found to be 0.52c. Calculate the redshift. (2

Give examples of nonbaryonic matter.

In 1999, scientists discovered a new class of black holes with masses 100 to 10,000 times the mass of our sun that occupy less space than our moon. Suppose that one of these black holes has a mass of 1x10^3 suns and a radius equal to one-half the radius of our moon. What is the density of the black hole in g/cm^3? The radius of our sun is 7.0x10^5 km, and it has an average density of 1.4x10^3 kg/m^3. The diameter of the moon is 2.16x10^3 miles.

What happens on the surface of a neutron star to produce bursts of X rays?

Why is there an upper limit to the mass of neutron stars?

The critical density of a universe is around 5×10-27 kg/m³. Estimate the Hubble constant for this universe.

The life average of stable muon is 2.2*10^-6 s , while the life average of moving muon in Cosmic ray is 1.5*10^-5 s. Calculate the velocity of the cosmic ray muon.

What is the total energy of all the radiation in the current Hubble Radius? H0 = 70 km/s/Mps omega(radation) 0 = 9.0 x 10^-5

Calculate the gravitational redshift of radiation of wavelength 550 nm that is emitted from a neutron star having a mass of 5.8 x 1030 kg and a radius of 10 km. Assume that the radiation is being detected far from the neutron star.