09/06/2026
The Sun feels unimaginably huge from our perspective. It contains about 99.8% of the mass of our entire solar system, is roughly 1.4 million kilometers across, and could hold about 1.3 million Earths by volume. Yet among stars, it is nowhere near the largest.
Betelgeuse is a red supergiant with an estimated radius hundreds of times larger than the Sun. NASA estimates it at roughly 724 solar radii. If you placed Betelgeuse where our Sun is, its enormous outer layers would extend beyond the orbit of Mars.
Antares is another red supergiant hundreds of times wider than our Sun. Rigel, despite appearing much smaller than those red supergiants, is still tens of times larger in radius than the Sun. Arcturus and Pollux are giants too, while even Sirius A is larger than our star.
But there is an important detail about images like this: stellar sizes are difficult to represent perfectly. Giant and supergiant stars have extended, diffuse atmospheres, and estimates of their radii can change as astronomers obtain better measurements. Betelgeuse itself also pulsates and changes over time.
And these aren’t even necessarily the biggest stars known. Astronomers have identified extreme supergiants with diameters approaching roughly a thousand times that of the Sun or more.
Our Sun is enormous compared with Earth, but the universe has a way of making almost everything look small once you change the scale.
