Are Light rays Always Straight?
Light rays are subject to the effects of gravity. If a ray passes close to a star or galaxy its path is curved by an effect known as ‘Gravitational lensing’. This can produce some interesting effects. For example, scientists can observe Quasars which would otherwise be hidden from us behind a much closer galaxy. The light curves around the intervening object, allowing us to see it. Depending on how objects are situated in relation to one another, the light from distant bodies can even be broken up into spectacular arc or ring. The diversion of light also causes variations in brightness. If a star visible from Earth passes in front of another star is also being orbited by a planet this can lead to a further increase in brightness thanks to this phenomenon, astronomers have discovered several planets orbiting other stars.