From When Stars Explode

Part A

What are two main ideas of the articles by Ken Croswell?

• Supernovae are violent explosions of stars.

• Astronomers did not always use telescopes.

• Astronomers can see supernovae for months.

• Stars make energy through nuclear reactions.

• Stars produce light that travels across the universe.

Part B

Which two sentences from the articles best support the answer to Part A?

• The last time people saw a supernova in our galaxy was 1604

• That was before astronomers were using telescope

• Such a star is born with more than eight times the mass of the sun

• Its center makes energy the same way the Sun does: by changing hydrogen, the lightest element, into helium, the second-lightest element.

• If a supernova occurred within a few dozen light-years of Earth, we would be in trouble.

Read the following sentence from the text.

But as long as the star can make energy, it can fight the force of gravity and survive.

Which dictionary entry best defines energy?

• physical strength

• hydrogen and helium gas

• heavy metals that increase weight

• power that comes from heat

The last time people saw a supernova in our galaxy was

• 1604

• 1644

• 1804

• 1777

Most supernovae comes from

• The sun

• energy

• dense object

• massive stars