The graviton is a theorized boson intended to include the gravitational force in the Standard Model. No graviton has ever been experimentally observed and its theoretical underpinnings remain uncertain.
The photon is a boson in the Standard Model responsible for mediating the electromagnetic force. Photons can have different energy levels ranging from low-energy x-rays to high-energy gamma rays. A particular range of photons within the visible light spectrum can be seen by humans as the colors of the rainbow.
One fascinating consequence of quantum mechanics is the strange phenomenon of entanglement, in which observing the state of one entangled particle determines the state of another in a completely different location. This effect can be harnessed by quantum computers to perform powerful calculations.
The theory of quantum mechanics was constructed in response to the surprising results of many experiments, including the famous double slit experiment. Quantum mechanics is currently the most accurate theory for describing the motions and interactions of fundamental particles. Among the many surprising predictions of quantum mechanics are wave-particle duality and quantum entanglement.
Our everyday experiences are varied and complex, and yet we would like to understand them all in terms of simpler components. Everything we see and interact with on a daily basis is constructed of atoms from the periodic table; atoms are themselves made of smaller particles.
The principle of relative motion is the intuitive idea, originally proposed by Galileo Galilei, that there is no “universal reference frame.” It is meaningless to describe an object as traveling at some speed without reference to some background frame of reference.