The Heat Death of the universe refers to a time in the distant future when the whole universe...

A) runs out of energy

B) gets too hot

C) gets too cold

D) gets just right

E) none of the above

Solution: E. The heat death refers to a time when the whole universe comes to the same temperature (and therefore runs out of useful energy, not energy as a whole). It might be hot or it might be cold or it might be just right. It doesn't matter what it is as long as it is the same all over.

The universe is now separated into hot and cold places. The stars are hot; the space between the stars is cold. But each day the stars get a little cooler as they radiate their energy, and each day the place the energy goes to gets a little warmer. Sooner or later the temperature difference must vanish. Too bad.