How Many Stars Are In The Sky?

The only real answer to this is that no-one actually knows !   There are two reasons for this.  First of all it is estimated that there are thousands of millions of galaxies in the Universe.  Our galaxy alone, which is by no means the largest, has in the region of 100,000 million stars, so there are potentially numbers of stars, bigger than numbers we can sensibly comprehend.  


However, we do not even know if all the stars we see are actually there.  Our nearest star, the Proxima Centauri is over 4 light years away, so the light has taken over 4 years to reach us.  Other stars send out light and their light could take up to 10,000 million years to reach us... By which time, the stars themselves may have disappeared and become a black hole, but we are seeing the light from the star, down on Earth !  SO even though we can see stars, we do not know if they are still there.....