In 1828, the Scottish botanist Robert Brown published his observation that tiny particles in suspension were in constant motion ... contemporary “caloric” theory of heat, and took a while ...

For gravity, Einstein expanded on this work a decade later with his 1915 theory of general relativity. As objects approach ... s speed is constant, regardless of Earth's motion, suggesting the ...

When physicists announced last week that they had detected subatomic particles ... turn out to involve accelerating motion, something that is not really an object" — like the bright spot ...

Here we explore what the theory ... that two objects exert on one another. Sir Isaac Newton quantified gravity in the same text in which he formulated his three laws of motion, the "Principia." ...