Here's why:
* Supernovas happen to massive stars. Our Sun is a medium-sized star, not a massive one. To become a supernova, a star needs to be at least 8 times the mass of our Sun.
* The Sun will become a red giant. In about 5 billion years, the Sun will exhaust its hydrogen fuel and expand into a red giant, engulfing the inner planets (including Earth). It will then shed its outer layers, becoming a white dwarf. This is a much less dramatic event than a supernova.
In short, the Sun will have a relatively peaceful end compared to the explosive demise of massive stars.
