how was the Number of galaxies calculated or counterd?

Answer 1

You ask an interesting question, actuallly. The techniques used to answer this question keep getting refined and the equipment keeps improving, which allows scientists to make better estimates on this number. Current estimates have it at roughly 125 billion. Now, new technolgies may change this estimate - as knowledge improves, scientists reserve the right to change their minds. :)

Answer 2

The number of galaxies may be infinite, because the Universe may be infinite.

Within our event horizon, the 40-billion-lightyear sphere centered on us, we can make a good estimate of the number of galaxies. Essentially all the galaxies within 100 million lightyears are known, and can be counted. We also know that all the other 200-million-lightyear diameter spheres within the event horizon are about the same in their average properties, in particular the various amounts of the various constituents of the Universe. So then it becomes a matter of multiplying the known density of nearby galaxies with the volume of known space.

One complication is that we see distant parts of the Universe as they were long ago. The number of galaxies in a volume evolves with time---new galaxies form out of the intergalactic matter, and galaxies merge, making one galaxy where there once were two. So when you ask, "how many galaxies are there?" you have to specify: (1) within what volume, that is, do you only count galaxies within our current event horizon and (2) do you want to know how many galaxies we see, or how many there are "now"?

Answer 3

....................... its only a very wild guess .................... honey .............