Gravity is a fundamental force of nature that has been studied extensively by scientists for centuries. While our understanding of gravity has evolved over time, it is not accurate to say that scientists don't know what gravity is.
Gravity was first described by Sir Isaac Newton in the late 17th century with his law of universal gravitation, which provided a mathematical framework to understand the force of gravity between objects. Newton's laws of motion and gravitation were highly successful in explaining and predicting the motion of celestial bodies and objects on Earth.
In the early 20th century, Albert Einstein developed the theory of general relativity, which provided a more comprehensive and refined understanding of gravity. According to general relativity, gravity is not a force transmitted between objects but rather the curvature of spacetime caused by mass and energy. This theory has been extensively tested and has successfully explained a wide range of phenomena, including the bending of light, the precession of Mercury's orbit, and the existence of black holes.
Despite the success of general relativity, there are still open questions and areas where our understanding of gravity is incomplete. One major challenge is reconciling general relativity with quantum mechanics, the theory that describes the behavior of particles on very small scales. The quantum nature of gravity and how it interacts with other fundamental forces remain active areas of research.
Scientists are actively exploring various approaches, such as string theory, loop quantum gravity, and other quantum gravity theories, to develop a more complete understanding of gravity at the quantum level. While these theories are still under development and not yet experimentally confirmed, they represent ongoing efforts to deepen our understanding of gravity.
In summary, while there are aspects of gravity that are still being explored and understood, scientists have made significant progress in comprehending the phenomenon and have developed successful theories to describe and predict its behavior.