Since light has no mass, how can it be trapped by the gravitational pull of a black hole?
Newton thought that only objects with mass could produce a gravitational force on each other. According to Newton’s theory, the force of gravity should not affect light. Einstein discovered that the situation is a bit more complicated than that. First he discovered that gravity is produced by a curved space-time. Then Einstein theorized that the mass of an object actually curves space-time. Mass is linked to space in a way that physicists today still do not completely understand. However, we know that the stronger the gravitational field of an object, the more the space around the object is warped. In other words, straight lines are no longer straight if exposed to a strong gravitational field; instead, they are curved. Since light ordinarily travels on a straight-line path, light follows a curved path if it passes through a strong gravitational field. This is what is meant by “curved space,” and this is why light becomes trapped in a black hole. In 1919, a team led by Sir Arthur Eddin
