What is the hottest star in the Universe? The straightforward answer to this question might be the blue hypergiants, like Eta Carinae - probably the hottest stars in the universe.

But it needs a little explanation.

You may be thinking that the answer to the hottest star is quite apparent, that it is the sun. But you should remember there are billions of stars in the galaxy; some of them are more than ten times hotter than the sun.

How to identify the hottest stars by their colors?

There is an effortless way to roughly tell how hot a star is by merely looking at its color. Stars of the same color will emit about the same amount of heat.

The coolest stars are the red stars, with yellow stars down the line being hotter than red. Then, the white stars are hotter than both red and yellow. The hottest stars in the galaxy are the blue stars.

In outer space, the sun has a white appearance; therefore, it is classified as a relatively hotter star, but not the hottest out there in the galaxy.

As explained above, the hottest discovered star in the universe is Eta Carinae. It is a blue hypergiant star that weighs 100 times more than the sun's mass and spans 180 times more than the radius of the sun.

What is the hottest star?

These hot stars shine the brightest since they are stars that have more power. However, to the human eye, the brightness would also depend on the proximity of the star.

A red star close to earth may appear to have the same brightness as a blue star that is actually thousands of light-years away. Therefore, the sun may appear to be the hottest, but this is only because it is closer to earth than other stars.