Use the drop-down menu to select whether the underlined text is a cause or an effect.

As the nuclei meld, a smidgen of their matter vaporizes into energy.

Soon the pressure in the center is so high, it ignites a booming nuclear reaction.

As the star material rushes outward, the star grows and grows until it is a supernova, or super star.

In the star's center, the gas is so energized that it has become a sort of super gas, called plasma.