Ever tried to count the grains of sand on the beach? It is unlikely that you will succeed in such an experiment. Now imagine that there are more stars in space than there are grains of sand on all the beaches of the Earth … Do you want more accurate numbers? Unfortunately, none of the existing telescopes will be able to look into the farthest corners of the universe (if at all something in it can be called a "corner"). Yes, even not in the most distant ones – he can’t. What science can see today is only a small part. The rest she can only guess. Although this is by no means bad, because empiricism has long ceased to be the main driving force of scientific knowledge.
In addition, light, or rather, its speed, is of particular difficulty in such calculations. If the light from the Sun takes a little more than 8 minutes to reach us, and from the next closest star, after our luminary, for more than four years, then how “fresh" can the information that reaches our planet for millions of years be? Who knows what the star looks like at the moment, the brilliance of which we see – maybe it has already spent most of its “fuel” and is now burning sadly in anticipation of the end, which earthlings are destined to learn about very soon? So, if you suddenly want to look into the past, then just fix your eyes on the starry sky.
Well, how did you manage to find out that there are so many stars, and not just 3000, which a resident of one of the hemispheres can observe with the naked eye (while a resident of the other hemisphere sees completely different three thousand)? The approximate number of stars can be judged by the number of galaxies that scientists see in the Universe accessible for review. And the approximate number of stars in these galaxies can be judged by the number of stars in galaxies of this type closer to us. For example, our Milky Way galaxy contains about three hundred billion (300,000,000,000) stars. At the same time, its diameter is 20 times smaller than the diameter of the largest galaxy known by 2012 (IC 1101).
In fact, it is difficult for us earthlings, accustomed to the comfortable small size of our planet, to imagine that all these zeros represent real sizes and distances. Wow! Directly breathtaking!