I recently viewed the galaxy UGC10151 and I got to thinking about distance. People always ask me and I always say I don't know because I never really cared before. I'm a voracious reader. I found the following formula on a website called teachastronomy dot com. d=zc/h. In this equation d is distance, z is the observed redshift, c is the speed of light, h is the Hubble constant. This is not truly d equals, it is an approximation which is more than good enough for me.

For UGC 10151, according the Simbad site, the spectroscopic redshift is z=.03249, the same teachastronomy article has the Hubble constant at h=70.8 km/second/MegaParsec (This value for h is approximate). Since h is km/second then I must use km/second for c, therefore c=300,000 (it is slightly less than this but it's all an approximation anyway). All this junk leads to: d=0.03249 * 300,000 / 70.8 or d=137.669492. This number is in MegaParsecs, since the Parsec (per Wikipedia) is 3.26 lightyears we have to take 137.669492 and multiply it by 3.26 Million which yields d=448,802,542 light years.

Does this sound right?

Sources:

http://simbad.u-stra...t=SIMBAD search

https://www.teachast...t-and-Distance/

https://en.wikipedia...ec#cite_note-14