Question

How many stars exist in the universe?

Answer 1

Hint : Counting stars is impossible because it will take a lot of time. the simplest way to find how many turn planets are in the universe is finding average stars in galaxies. and how many galaxies are there in the universe. By applying this concept we are going to find the answer to this question.

Complete step by step solution:
Simplest way to find how many stars and planets are in the universe is to find how many stars are in a typical Galaxy and multiply it with the number of galaxies in the universe. According to an article in science, there are about 2 trillion galaxies in the observable universe. According to the Gaia mission, there are about one billion stars in the Milky Way Galaxy.
 From some estimates the milky way’s star mass is 100 billion solar masses or 100 billion times the mass of the sun. So according to this answer there are about 100 billion stars in the Galaxy.
 According to Kornreich, he roughly estimated 10 trillion galaxies in the universe. After multiplying it with the milky way’s 100 billion stars we get one with 24 zeros after it which is one septillion in the American numbering system.
 You may have read that there are at least 100 to 200 billion planets in our Milky Way Galaxy. But considering at least 200 billion galaxies we can say that their universe is filled with around \[{10^{25}}\] planets.

Note: Stars are actually huge clusters of gases which are constantly undergoing nuclear fission and nuclear fusion reactions, and these reactions are the reason for the energy that is stored in these stars. Mainly hydrogen and helium are the two gases which undergo nuclear fission and fusion reactions, interchanging into one another.
$_1{H^1}{ + _1}{H^1} + 2{ _0}{n^1}{ \to _2}H{e^4}$
$_2H{e^4}{ \to _1}{H^1}{ + _1}{H^1} + {2_0}{n^1}$