We have progressed far with space exploration, but there is still a lot we do not know. For example, no space company in UK or any other country can boast of will tell you exactly how many stars there are in space. Looking at the sky when there’s a clear night, you can distinguish thousands of them without having to use any telescope. If you have one, you will see hundreds of millions of stars. Still, scientists couldn’t give you a fair answer to the question how many stars are in space, even if it’s possible to see the stars in black space, too.

What we know about stars in space?

One thing is for sure, a few facts about stars in space have been well established for now. For example, we know there are red stars in space, which are the hottest stars in space. Stars aren’t randomly scattered throughout the Universe. They are gathered in galaxies. And, as you probably know, our Sun and planet are in the Milky Way Galaxy. According to astronomers, there are around 100,000 million stars here. The number of galaxies in the Universe is millions upon millions, so you can imagine how difficult it is to determine the number of bodies in space. Even so, there are some known stars in space that science has identified. On the other hand, the number of unknown stars in space is at the moment overwhelming.

What can we learn from galaxies?

There are around 1011 to 1012 stars in our Galaxy alone; the same numbers are estimated for the galaxies in the whole Universe. Making a simple calculation according to this data, we could suppose there are about 1022 to 1024 out there. But this number is by far rough since galaxies are not at all the same, just like sand is at different depths on a beach. Stars couldn’t be counted individually, but some of their integrated qualities can be measured. For example, the luminosity of a Galaxy could say a lot about the number of bodies in that Galaxy. This can be done in infrared, and this is what the ESA’s space observatory Herschel is doing at the moment.

Size is not relevant

In space, looks are more than often deceiving. For example, a star of a certain size doesn’t have a certain mass. Let’s take RMC 136a1, the most massive star in the Universe we know about. Surprisingly, RMC 136a1 has a very slim frame. Even if believed to have 300 times more in mass than our Sun, it’s only about 30 times wider than our star. There are a few other variables that can help with calculations. For example, knowing just how fast stars are forming can indicate their number out there. And once again, Herschel has charted their formation rates throughout the history of the Universe. From this data, estimation could be made about the number of stars in space. But once again, it would only be an estimation. Science has come up with exact and precise answers, but when it comes to space, we are still very far from knowing it all.

The Hubble Space Telescope (HST) transmitted in 1995 an image that indicated star formation got to a peak about 7,000 million years ago. But recently, astronomers have started to look into this again because the image is believed to be unclear and hiding evidence on early formation under dust clouds. When dust clouds are present, it becomes very difficult to view the stars and convert their light into infrared radiation for the HST to record it correctly. Besides, the HST took the image at optical wavelengths. Luckily, Herschel takes pictures at infrared wavelengths, meaning it can reveal much more about space than we have ever seen.

What the future holds when it comes to studying space?

Gaia is studying 1000 million Milky Way bodies, building on the Hipparchus mission’s legacy. At high precision, this mission is located in more than 100,000 stars, and, at lower precision, over 1,000,000 of them. Gaia is set to monitor each body in its 1 billion targets for five years. The project’s aim is to precisely chart the positions of the stars, their movements, changes in brightness, and distances. Measurements taken will tell a lot about how our Galaxy evolved and its structure.

Looking at what our space telescopes can do and trusting the Gaia mission will successfully come to an end, we can be optimistic that we will find an answer to the question “How many stars are in space?” at some point in the future. Yet, we shouldn’t expect this to happen soon.