How many galaxies are there estimated to be in the known universe? Some say about 100 billion, and others even say up to 1 trillion. Which estimate would be closer to the actual number?

Feb 3, 2017

See explanation.

Explanation:

Firstly, these are scientific $s u r m i s e s$.

Approximations to a few significant digits (2-sd or 3-sd), in great

unit like billion, are based on other scientific surmises.

Different sources might use different models.

The estimating process is based on surmises on the extent of $o u r$

universe and average density of population of galaxies, taking unit

area as great as $1 m i l l i o n {\left(l i g h t y e a r\right)}^{2}$.

Despite all these reasons that give relative error in the estimates as

1 in 10, it is possible to have a consensus estimate, if a specialist,

who is conversant in Numerical analysis and Statistics, is included in

the team of astronomers in the observatories.