HOMEWORK # 6
2(A) We know that
Sun is roughly in the center of the disk because the galaxy’s dust lane bisects
the Milky Way.
redshift due to the Doppler effect is due to the motion pf the object with
some reference point, for example, the Doppler shift in a binary star
system may be measured with respect to the center of mass of the binary
stars. In the case of redshift due to the expansion of the universe, the
redshift is not due the galaxy’s motion through space, but rather due to
the galaxy being carried along due to the expansion of space itself.
- (a) We
would conculed that we lived in a static universe, and that the observed
redshifts were due to the random motion of the galaxies in the universe.
(b) This would suggest that we
lived in a collapsing universe, and that the blueshifts of galaxies was
primarily to the contraction of the space in which the galaxies are embedded.
(c) From this we can conclude that
our galaxy were moving through a static universe.
didtribution of the galaxies on large scales resembles a network of soap
bubbles, where galaxies are distributed along the surfaces of the bubbles,
which surround large voids that are largely free of galaxies. The universe
begines to look featureless and smooth on scales of 300 Mpc and greater.
6. If the Hubble constant were 65 km/s/Mpc and density parameter
were 1, such high values of the
constant and density parameter would imply that an age of the universe using the big bang model of significantly
less than 14 billion years measured for the oldest known stars.