Here's why:

* Red supergiants are formed by stars much larger than our Sun. They are typically 8 to 40 times the mass of our Sun.

* Our Sun is a yellow dwarf star. It's not massive enough to become a red supergiant. Instead, it will evolve into a red giant and eventually become a white dwarf.

Here's a breakdown of the Sun's future:

1. Red Giant Phase: In about 5 billion years, the Sun will run out of hydrogen fuel in its core. It will start to burn helium, causing it to expand dramatically and become a red giant. At this stage, the Sun will engulf Mercury and Venus and potentially even Earth.

2. Planetary Nebula: The Sun will then shed its outer layers, creating a beautiful planetary nebula.

3. White Dwarf: The remaining core will become a dense, hot, and small white dwarf, slowly cooling over billions of years.

So, while the Sun will change dramatically in the future, it will never become a red supergiant like the much larger stars in the universe.