Re:If the universe is 13.8B years old, how can we see 46B li...
by wahern on Saturday December 07, 2019 @02:10PM
(#21731963)
Technically, galaxies do travel:
> In physical cosmology, peculiar velocity refers to the components of a galaxy's velocity that deviate from the Hubble flow. ....
> Galaxies are not distributed evenly throughout observable space, but are typically found in groups or clusters, where they have a significant gravitational effect on each other. Velocity dispersions of galaxies arising from this gravitational attraction are usually in the hundreds of kilometers per second, but they can rise to over 1000 km/s in rich clusters.
Re:If the universe is 13.8B years old, how can we see 46B li...
by lmilcin on Saturday December 07, 2019 @03:52PM
(#21732475)
That's why I wrote "more or less stationary", which is describing 1000km/s compared to double the speed of light that would come from naive calculation.
> In physical cosmology, peculiar velocity refers to the components of a galaxy's velocity that deviate from the Hubble flow. ....
> Galaxies are not distributed evenly throughout observable space, but are typically found in groups or clusters, where they have a significant gravitational effect on each other. Velocity dispersions of galaxies arising from this gravitational attraction are usually in the hundreds of kilometers per second, but they can rise to over 1000 km/s in rich clusters.
-- https://en.wikipedia.org/wiki/Peculiar_velocity
Granted, 1000 km/s isn't even 1% of light speed, so clearly this motion couldn't contribute much to a distant object's recession.