Einstein's General Relativity Theory.pptx

In this ppt, you will find a way to present a topic on General Theory of Relativity. And the topics of discussions include: Introduction, The incompatibility of Einstein’s STR and Newton’s Gravity, Einstein’s Happiest Thought, Equivalence Principle, Einstein’s Geometric Gravity, Predictions of General Relativity.

1. GENERAL THEORY OF RELATIVITY PRESENTED BY: RANJITH.K.S SASTRA DEEMED UNIVERSITY

2. 03-10-2024 2 -:Topics of Discussion:- Introduction The incompatibility of Einstein’s STR and Newton’s Gravity Einstein’s Happiest Thought Equivalence Principle Einstein’s Geometric Gravity Predictions of General Relativity

3. INTRODUCTION: When the word "physics" is pronounced, suddenly two names will strike our mind. They are  Sir Isaac Newton and Albert Einstein WHY…………? Because they made a great impact on the field of physics. Newton is famous for his gravitational laws. Einstein is famous for his relativity theories. They two are non-negligible in physics . 03-10-2024 3

4. What is the relation between them? 03-10-2024 4

5. How? Universal Law of Gravitation Any two bodies in the universe attracts each other with a force directly proportional to the product of the masses and inversely as the square of the distance b/w them. 03-10-2024 5

6. The incompatibility of Einstein’s STR and Newton’s Gravity: Changes in gravitational fields instantaneously transmitted across arbitrary stretches of space. But according to STR, a physical law has to respect Lorentz invariance. Therefore instantaneous transmission is impossible. 03-10-2024 6

7. Einstein’s Happiest Thought: There is no way for an observer in a closed laboratory to distinguish between the effects produced by a gravitational field and those produced by an acceleration of the laboratory. In Freefall In Anti-Gravity In Acceleration At Rest 03-10-2024 7

8. Equivalence Principle: Gravity ≡ Constant Acceleration Is equivalent to 03-10-2024 8

9. Einstein’s Geometric Gravity: But still, Einstein has been confused. How is gravity attracting the particle instantly, and how is the sun attracting both the nearest planet Mercury and the farthest planet Neptune at the same time? If we draw a parallel line in the earth and ask two people to walk on it from the equator, due to the earth's curvature, they will eventually meet in the pole. 03-10-2024 9

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11. Predictions of General Relativity: 1.Bending\Deflection of light in spacetime 2.The Einstein Field Equations 3.Gravitational frequency shift 4.Geodesics 5.Black Holes and Singularities 6.Gravitational Waves 03-10-2024 11

12. 03-10-2024 12 Bending\Deflection of light in spacetime: In May 1919, British Astronomer Arthur Eddington sailed to Africa. During a solar eclipse of the sun, most of the sun's light is blocked on Earth by the moon, which afforded the opportunity to view starlight passing close to the sun. The starlight was bent as it passed near the sun which caused the star to appear displaced. Einstein's general theory predicted a deflection of 1.75 seconds of arc, and the two measurements found 1.98 ± 0.16 and 1.61 ± 0.40 seconds. Since the eclipse of 1919, many experiments, using both starlight and radio waves have confirmed Einstein's predictions about the bending of light with increasingly good accuracy.

13. 03-10-2024 13 The Einstein Field Equations : These are the mathematical equations that describe how matter and energy in space affect the curvature of spacetime. They can be expressed as: where Gμν ​ represents the curvature of spacetime and Tμν ​ represents the matter and energy within it. Gravitational frequency shift : In physics and general relativity, gravitational redshift is the phenomenon that electromagnetic waves or photons travelling out of a gravitational well lose energy. This loss of energy corresponds to a decrease in the wave frequency and increase in the wavelength, known generally as a gravitational redshift. The opposite effect, in which photons gain energy when travelling into a gravitational well, is known as a gravitational blueshift. The relative frequency change is  

14. 03-10-2024 14 Geodesics: Objects move along the shortest paths in curved spacetime, called geodesics. In the absence of other forces, objects in freefall follow these geodesic paths. For instance, a planet orbiting a star is following a curved geodesic around the star due to the star's mass bending spacetime. Black Holes and Singularities: Einstein's theory predicts the existence of black holes, regions of spacetime with such extreme curvature that nothing, not even light, can escape which means light also gets deflected due to the spacetime curvature. At the center of a black hole lies a singularity, a point of infinite density and curvature where the known laws of physics break down. Gravitational Waves: Ripples in spacetime caused by accelerating massive objects (like merging black holes or neutron stars) are known as gravitational waves. These waves were first directly detected in 2015 and provide further evidence for Einstein’s theory of geometric gravity.

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