Gravity is the reason things with mass or energy are attracted to each other. It is why apples fall toward the ground and planets orbit stars. Magnets attract some types of metals, but they can also ...

Astronomers suggest that an alternative concept of gravity, known as modified Newtonian dynamics, could explain orbital inconsistencies that have previously pointed to the existence of a ninth planet ...

Astrophysicists have observed some puzzling behavior in star clusters that seem to defy our current understanding of gravity at cosmic scales. Intriguingly, the observations fit with an alternative ...