And some stars die spectacularly in a supernova explosion, leaving remnants like that.

This would be about one million years a second, because you have about roughly one supernova every century or so.

When the Sun begins to go nova, everything is on schedule, but most of the spaceships turn out to be defective, and fail en route to Mars.

And they certainly didn't intend to describe the mechanics of supernova explosions, which eventually told us where the building blocks of life were synthesized in the universe.