How many stars in a galaxy

A gorgeous panorama of the Milky Way. Read more. Why is this? To make an estimate, we have to calculate the mass of our galaxy, and then the percentage of that mass that is made up of stars. Then we have to decide what the mass of an average star is so we can calculate the number of stars in the galaxy. This is not trivial either — you could say our Sun is an average sized star, which would give you one estimate for the number of stars in the galaxy. So we know how much star stuff is floating around the galaxy.

And we know roughly how much of that mass should be big stars, and how much should belong to small stars. That means we should know how many stars there are in total, right? Well, kind of. Depending on whom you ask, there may be anywhere between billion and 1 trillion stars out there. Perseverance is having a blast collecting specimens on the Red Planet. Using the Milky Way as our model, we can multiply the number of stars in a typical galaxy billion by the number of galaxies in the universe 2 trillion.

The answer is an absolutely astounding number. There are approximately billion trillion stars in the universe. Or, to put it another way, sextillion.

Hello, curious kids! Ask an adult to send your question to CuriousKidsUS theconversation. Please tell us your name, age and the city where you live. But Herschel could peer into this previously hidden Universe at infrared wavelengths, revealing many more stars then ever seen before.

Soon Gaia will launch, which will study one thousand million stars in our Milky Way. It will build on the legacy of the Hipparchus mission, which pinpointed the positions of more than one hundred thousand stars to high precision, and more than one million stars to lesser precision. Gaia will monitor each of its one billion target stars 70 times during a five-year period, precisely charting their positions, distances, movements, and changes in brightness.

Combined, these measurements will build an unprecedented picture of the structure and evolution of our Galaxy. Thanks to missions like these, we are one step closer to providing a more reliable estimate to that question asked so often: "How many stars are there in the Universe? You have already liked this page, you can only like it once!

Hipparcos mapped millions of stars in our galaxy, but how many more are there?