
v = H x d
where v is
the galaxy's radial outward velocity, d is the galaxy's distance from Earth,
and H is the constant of proportionality called the Hubble constant.
The exact
value of the Hubble constant is still somewhat uncertain, but is generally
believed to be around 65 kilometers per second for every megaparsec in
distance. (A megaparsec is given by 1 Mpc = 3 x 106 light-years). This means
that a galaxy 1 megaparsec away will be moving away from us at a speed of 65
km/sec, while another galaxy 100 megaparsecs away will be receding at 100 times
this speed. So essentially, the Hubble constant reflects the rate at which the
universe is expanding.
So to
determine an object's distance, we only need to know its velocity. Velocity is
measurable thanks to the Doppler shift. By taking the spectrum of a distant
object, such as a galaxy, astronomers can see a shift in the lines of its
spectrum and from this shift determine its velocity. Putting this velocity into
the Hubble equation, they determine the distance. Note that this method of
determining distances is based on observation (the shift in the spectrum) and
on a theory (Hubble's Law). If the theory is not correct, the distances
determined in this wa

Black holes are composed of many oceans, numerous star constellation, cyclones, storms, chemical interactions, magnetic, and electrolytic waves, light beams dust which are sucked through its funnel-shaped mouth superior Black Hole are responsible for the creation of the earth-like planet harboring life