At first glance when you see the title of this article, you are surely tempted to say that it’s impossible to say for sure how many stars are there in the entire Universe. Well, that’s indeed true, but it doesn’t mean that we can’t have a pretty approximate number of the number of stars that exist out there in the vast ocean of space based on scientific observations and conclusions.
First of all, we all need to understand that our Universe doesn’t necessarily mean the total amount of matter, time, and space that exists in physical reality. Scientists are pretty sure now, based on math calculations and other pieces of evidence, that we actually live in a Multiverse and that our Universe is just a small portion of it. The bad news is that there’s no possible way to ever escape our Universe to know for sure what boundaries it has and if anything exists beyond.
However, based on what astronomers and astrophysicists know so far about the Universe we live in, based on scientific insights, we’ll try to find out an estimated amount of stars that exist.
10^24 (a 1 followed by 24 zeros)
You got the idea by now: the Universe is incredibly large, so large that nobody would ever be able to even imagine how large it is. But thanks to telescopes, calculations, and other scientific data, the world is able to understand a lot of what’s happening out there in the vastness of space.
Scientists are only able to see what’s happening in what they call the observable Universe. Each of the 100 to 200 billion estimated galaxies contains hundreds of billions to trillions of stars. Our Milky Way galaxy, for instance, contains about 200 billion stars, including our Sun. The Sun is also a star, a middle-sized one. There are stars thousands of times larger out there.
If we multiply the number of galaxies by the average number of stars per galaxy, we can have an approximate estimate of the total number of stars that exist in the observable Universe, which is on the order of 10^24 (a 1 followed by 24 zeros). Of course, this number is only an estimate, as nobody can provide an exact number at the moment.
Where are the Universe’s boundaries?
To figure out just many stars are there in the Universe, knowing exactly where the boundaries of our totality of spacetime are is crucial. While nobody can observe beyond the boundaries of the observable Universe, which is why they call it “observable” in the first place, we can only stick to what we know so far. Therefore, the diameter of the observable Universe is 93 billion light-years if we consider the observable Universe as a sphere.
But what if even the observable Universe, without including a possible Multiverse, is a lot larger than what scientists were able to measure? This scenario is also very plausible, considering that the light emanated by the stars might not have gotten enough time during the 13.8 billion years since the Big Bang to reach us. Therefore, the true size of our Universe, without counting the Multiverse, could even be millions of times bigger than the known diameter that measures 93 billion light-years.
You got the idea: our Universe is way too large and diverse even for the scientific knowledge that exists today. Nobody can say for sure how many stars there are in the Universe, but even so, the good news is that astronomers still don’t stop searching for answers.