How far are other galaxies from earth?

Question

Asher Cohen · Accepted Answer

Between #25 xx 10^3# light years (nearest) and #13.3 xx 10^9# light years (farthest)

The closest would be a Milky Way satellite galaxy. There appear to be two potential contenders: (1) The overdensity of Canis Major and the dwarf galaxy Canis Major. This contested dwarf irregular galaxy is located approximately 25 million light years (kly) away from Earth. (2) Saggitarius Dwarf Spheroidal/Elliptical Galaxy about #70#kly from Earth. The closest major galaxy is the Andromeda Galaxy M31, which is located approximately 2.5 million light years (Mly) from Earth and has a diameter of about 220 million kly, making it larger than the Milky Way galaxy. The third largest spiral galaxy in the Local Group is the Triangulum Galaxy at a distance estimated to be somewhere between #2.38#Mly and #3.07#Mly, with a diameter of about #60#kly. The most distant known galaxy is MACS0647-JD at a distance of #13.3#Bly (billion light years), meaning that we see it as it was about #420# million years after the Big Bang. Given that a light year is about #5.8785 xx 10^12# miles, that means that our nearest neighbouring galaxy is about #1.5 xx 10^17# miles (Canis Major Dwarf Galaxy) or #4 xx 10^17# miles (Saggitarius Dwarf Spheroidal Galaxy) away and the most distant known galaxy is #7.8 xx 10^22# miles away. Actually the (comoving) distance to the farthest galaxy is considerably more than this due to the expansion of the universe, probably closer to #44.8 xx 10^9# ly or #2.6 xx 10^23# miles.

Christopher Ales · Answer

undefined Other galaxies are typically millions to billions of light-years away from Earth.