Time dilation

Today, I have learnt about time dilation. Time dilation is slowing down of a clock as determined by an observer who is in relative motion with respect to the clock in theory of relativity. It was first found out from Albert Einstein because of special relativity in accelerated frames of reference. In relation to clocks, effect concerns the nature of time and the first to point out its reciprocity or symmetry. Minkowski then discovered the concept of proper time and equation. This is observed from the constancy of the speed of light in all reference frames dictated by the second hypothesis of special relativity . Gravitational time dilation occurs because objects with a lot of mass create a strong gravitational field. It is a curving of spacetime. The stronger the gravity, the more it curves and time will be slower.

Examples

1. Twin Paradox. The elapsed time on the rocket ship will be smaller to that of the inertial observer twin. Non inertial twin would have aged less than inertial observer when they rejoin

2. When the train moves at a constant speed along the track. Person in the train still considers that the light has gone from the torch straight across and returns/ It still goes a distance to 2d and if the speed of light is c the time int has taken is 2d/c

The speed of light is constant and you have to alter the time such that light takes longer to travel the greater distance so more time has passed for the person at the bank than the carriage.

Media

Velocity and gravitational time dilation are subjects of science fiction works in a variety of media. Like interstellar and planet of the apes. A planet near the black hole one hour is equivalent to 7 years on Earth because of time dilation.

Time inversion

Time reversal, replacing the expression of time with negative formulas or equations so that they describe an event which time runs backwards and every motion is reversed.

The basics is that someone invented something in the future that allows time to flow backwards so certain elements flow backwards through time and the trajectory becomes inverted.

Overall, I felt this this presentation was fine in general and went by pretty smoothly without much conflict although I do see some disagreements. The concepts from this lesson were also quite comprehensive and a bit difficult to understand because I didn't study much about space-time. I sometimes wish that the presenters could be a little louder when they are presenting important points and they are also referring to the slides a lot and reading off it but I guess that this is their first time so its ok but they shouldn't directly read off the slides.