1.A supernova is the spectacular death of a star. The last time people saw a supernova in our galaxy was 1604. That was before astronomers were using telescopes. However, every year astronomers see supernova exploding in other galaxies. Astronomers can often observe such supernovae for months before they fade from view.
2.Most supernovae- that's the plural of supernova and pronounced SOO-per-Noo-vee- come from massive stars. Antares is a massive star. Such a star is born with more than either times the mass of the Sun.
What is the main idea of paragraphs 1 and 2 in the passage?