1. Relativity Einstein versus Newton (what is the difference)

2. Einstein and Newton • Newtonian gravitational theory is based on forces acting on one another. • In Newtonian universal gravitation, gravitational effects propagate from place to place instantaneously. • This appears true to us due to the (short distances within our solar system – ex. The sun and its effect on Earth).

3. Einstein and Newton • Einstein, in 1905, pointed out that nothing is instantaneous. • He stated in special relativity that the fastest speed possible is the speed of light. • A photon travels at 186,000 mi / s • Therefore, the constraint of the speed of light indicates that instantaneous propagation is an impossibility. • This contradicts Newton’s law of universal gravitation and laws of motion.

4. Einstein and Newton • For Einstein, gravity wasn’t a question of force but of geometry. • In other words, one’s reference point has to be taken into account (on observer’s perspective is not going to be shared by another’s with a different reference point). • Einstein concluded that time is not linear and differs based on one’s reference point.

5. Gravitational Lensing • This is the eclipse experiment. Gravitational lensing is a prediction of relativity. Einstein's theory predicts that the direction of light propagation should be changed in a gravitational field.

6. Einstein and Newton • General relativity indicates that time and space are not linear and that instead of talking about time or space, the two are combined into space-time. • Space-time is a fabric and the manifestation of gravity is in the curvature of space-time.

7. Einstein and Newton • Relativity states that space and time are dependent on velocity. • So, at speeds near that of light, the fabric of space-time becomes contracted (warped) in the direction of motion and the passage of time slows.  • This is we talk hypothetically of wormholes.

9. Einstein and Newton • E=MC2 is at the heart of Relativity. • This equation heralded the arrival of the atomic age. • It demonstrated that energy and mass are related and that a little mass can produce A LOT OF ENERGY. • In order for this equation to be true, then light has to be particles, photons, that travel at the speed of light – not waves.

10. Einstein and Newton • Despite the contrast between General Relativity and Newtonian theory, Newton’s predictions for systems in which velocities are small compared to care accurate. • This is why we can discuss the structure of the Earth, planets, and other inhabitants our solar system using Newtonian theory.