What is the biggest star in the universe?

When we think about the size of planet Earth, it is almost impossible for our mind to get a sense of how big it is. However, when compared to Jupiter, the largest planet in the solar system, we realize that it is a very small planet, fitting 1000 Earths in the gas giant! What if we take the full size of Jupiter and compare it to the Sun ? Well, in that case, 1000 Jupiters fit inside the Sun. Despite this, it is far from the biggest star in the universe.

 As we said above, the Sun itself is gigantic, being the largest object present in our solar system. However, when compared to the scale of the universe, it barely ranks in the top 1000 largest stars ever seen.

Thus, the largest body of its kind ever discovered was Stephenson 2-18, a red supergiant. In this way, it is in the constellation of Scutum, at a distance of 18,900 light years from our planet.

Your size? Stephenson 2-18 is a whopping 1.50 × 10^9 km, or 1.50 x 1000000000 radius. It is so gigantic that it is actually part of a special category: hypergiant stars.

Despite this, upon verifying that it is a red supergiant, it is already possible to gather some data. For example, stars of this type are the largest in terms of volume, but not in terms of mass or luminosity. They are also stars in the final phase of their life, with not so high temperatures.

Eventually, by consuming all the hydrogen present in its core, Stephenson 2-18 will collapse, causing an explosion called a supernova, large enough to shine throughout the galaxy and, in some cases, create a black hole.

The biggest star in the universe compared to the Sun

And when compared to the Sun, how big is Stephenson 2-18? Despite the size of our star, it doesn't even come close to the absurdity that this giant is.

So the first hint of your size is in your category. Hypergiants are a very exclusive group, comprising only those stars that have more than 1 million times the luminosity of the Sun and at least 50 times its mass.

In that alone, we already realize that it greatly surpasses the central body of the Solar System. But only by comparing directly can we get a real sense of their superiority.

It is at least 2158 times larger than the Sun. Its rays are, on average, 1708 times greater than the sun's rays. Its volume is also unbelievable: 10 billion times the volume of our star.

It is unimaginable how big this star is and how small the Sun becomes next to it. Practically a grain of sand on a huge beach!

If it were in our solar system, its outer layer, the photosphere, would be somewhere close to Jupiter.