Science need help ?????///

posted by .

An astronomer observes two galaxies, A and B, which have redshifts of:

Galaxy A = 0.020 and Galaxy B = 0.010.

Which galaxy is closest to us and what is its distance away from us?

You may assume that the Hubble constant is H0 = 75 km s–1 Mpc−1 and that the speed of light is
c = 3.0 × 105 km s–1.

The closest galaxy is: Galaxy a?? or galaxy b??
It is at a distance of ????? Mpc.?


Assuming that Galaxy A is intrinsically of identical luminosity to Galaxy B, how does its apparent brightness on the night sky compare to that of Galaxy B?

Galaxy A is ???? times BRIGHTER or FAINTER??? than Galaxy B.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Astronomy - help!

    Imagine that you have obtained spectra for several galaxies and have measured the observed wavelength of the H emission line of atomic hydrogen. The rest wavelength of H is 656.3 nanometers (nm). Your results are as follows: • …
  2. Astronomy

    The apparent brightness of a Cepheid variable star in a far-away galaxy is measured to be 640,000 times fainter compared to an equivalent star 2,000 light years away from the Sun in our Galaxy. Assuming that there is no light absorption …
  3. Physics

    Our Milky Way galaxy is very similar to our neighboring galaxy Andromeda. Consider that each galaxy contains approximately 4.0 x 10^11 stars each star having an average mass of 2.0 x 10^30 kg. a. If the gravitational pull of Andromeda …
  4. Cosmology

    What observations were used by Edwin Hubble to show that the universe is expanding?
  5. Cosmology

    magine you look through a really strong telescope and see a rich cluster. Your telescope is so good that you can see a single galaxy at the center of the cluster. What can you say about that galaxy and be pretty confident that you …
  6. Cosmology

    What explains the observation that galaxy clustering is stronger at higher redshifts, which is an apparent reversal of the trend out to about z ~ 1?
  7. astronomy

    Imagine that you live in a distant galaxy far far away. This galaxy is in a different universe, and so may have different cosmology. It seems that in this distant universe, all galaxies have the same luminosity, which you have worked …
  8. unsolved mysteries astrophysics

    Q3.2 COLLAPSE TIMESCALE (5 points possible) Imagine that you live in a distant galaxy far far away. This galaxy is in a different universe, and so may have different cosmology. It seems that in this distant universe, all galaxies have …
  9. Astronomy

    A galaxy is receding away from us with a recession velocity of 100,000 km/s. What is the distance to this galaxy?
  10. Physics

    The diameter of our disk-shaped galaxy, the Milky Way, is about 1.7E+5 light-years (ly). The distance to the Andromeda galaxy, which is the spiral galaxy nearest to the Milky Way, is about 1.9E+6 ly. If a scale model represents the …

More Similar Questions