All galaxies farther away than about 50×106 ly exhibit a red shift in their emitted light that is proportional to distance, with those farther and farther away having progressively greater red shifts. What does this imply, assuming that the only source of red shift is relative motion? (Hint: At these large distances, it is space itself that is expanding, but the effect on light is the same.)

The hypervelocity star S5HVS1 has a redshifted Hβ line (rest wavelength of486.135 nm) observed at 487.784 nm. How fast is it traveling radially awayfrom the Earth?

why is it reasonable to suspect that travel between stars is nearly impossible?

Looking for  km/s/Mpc:            Years: Years:

Why do we think that nothing, other than light, can travel faster than the speed of light?

If a galaxy is 9.0 Mpc away from Earth and recedes at 488 km/s, what is H, (in km/s/Mpc)? | km/s/Mpc What is the Hubble time (in yr)? | years How old (in yr) would the universe be, assuming space-time is flat and the expansion of the universe has not been accelerating? years How would acceleration change your answer? O If the expansion of the Universe has been accelerating, the Universe could be substantially younger than the value entered above. O If the expansion of the Universe has been accelerating, the Universe could be substantially older than the value entered above. Need Help? Read It

One of our closest stars is our Sun, duh. If the distance from Earth to our Sun is 1.56e-05 light-years, how quickly is that star travelling away from us? [Note that Hubble's Constant is roughly 70 km/s/Mpc and 1 light-year is roughly 3.07E-7 Mpc.] m/s

According to the tiny world experiment, there are only 5.2 intermediates between any two people on Earth (thus 6-degree of separation). This is a remark that has been made for well over half a century. The Internet may be useful in this regard. Let's pretend that everyone on Earth doubles their friend count on Facebook, Twitter, and every other social network they participate in (2x). Calculate the relative distance between us now. What do you think it is?

How does Hubble’s Constant depend on time? How about distance? (In what sense is it constant?

When astronomers observe far away galaxies they see the light being redshifted (i.e. the frequency of the observed light waves is lower – more towards the red – than expected). That is an indication that far away galaxies are moving away from us. not moving. moving towards us.