Learn about gravity, stars, and really big lumps.
Plasma, created in a lab by heating gas, constitutes the fourth state of matter.
Beyond our atmosphere flies a lot of debris. Some fragments can be larger than mountains, but most is space-dust.
Here’s a physics classic. Suppose you drop a golf ball and a bowling ball from the Empire State Building. Which hits first? Answer? They hit at the same time. Learn more on this Moment of Science.