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How to use EinsteinYouAre

Start screen
 1 Newtonian mechanics
 2 The speed of light is the same
 3 Simultaneity depends on observer
   1 Train and photon -- system on the earth
   2 Train and photon -- system on the train
   3 Simultaneity depends on observer
   4 Space-time diagram--train and light
   5 Space-time diagram--simultaneity line
   6 Space-time diagram--time axis, space axis
 4 Phenomena of special relativity
   1 Length contraction
   2 Time dilation
   3 Cause and effect
   4 Redshift
   5 Lifetime of muon
 5 Phenomena of general relativity
   1 Light deflection
   2 Perihelion advance of Mercury
   3 Gravitational redshift
   4 Clock at GPS ticks faster
   5 Accelerating universe
   6 Garavitational wave
   7 Gravitational lens

Start screen

The screen is main contents.
Screens are displayed by Touching the lines.

Newtonian mechanics

- In Newtonian mechanics the velocity is added to the speed of the ball when the ball is thrown from the train.
- The speed of ball changes by the direction the ball is thrown to.
- By the menu button you can change the direction of ball.

The speed of light is the same

- The speed of light is the same for all inertial observers regardless of the state of motion of the source. This is experimentally verified. This is a principle of special relativity.
- By the menu button you can change the direction of the source.

Simultaneity depends on observer

- When two events occurred at the same location, we can judge easily whether they occurred simultaneously.
- When events occurred at the different locations, we can judge by adding the time for the movement of light whether they occurred simultaneously. The time for the movement of light varies by the location of the observer. Therefore, whether the events occurred simultaneously varies by the observer location.
- When the location of the event is moving or the observer is moving, we can judge by adding the time for the movement of light whether they occurred simultaneously.
- We show the movement of the train and the photon from the earth(the system of the earth), and then from the train(the system of the train).
- We also show the space-time diagram with which we can analyse briefly the phenomena.

Train and photon -- system on the earth

- The train is running at half of the speed of light.
- Just when the center of the train come to the observer on the earth, the photons are lauched from the front end and the back end of the train.
- We see the movement of the train and the photons from the earth.
       = the system on the earth
- How the observer at the center of the train see the movement of the photons? And how the observer on the earth see the movement of the photons?
- The movement of the trains , the photons and the observers are displayed.
- We can see clearly both photons arrive at the observer on the earth simultaneously, but they don't arrive simultaneously at the observer at the center of the train. - In the system on the earth we see the observer on the earth doesn't move , but the train moves.
- Using the menu button we can launch the photon , display the measure, and make slower the speed of the photon in the screen.

Simultaneity depends on observer

- The time of the event varies by the location of the observer.
- As seen at Train and photon -- system on earth and Train and photon -- system on train, the time of the event arriving at the observer varies by the location and the movement of the observer. Therefore the time of event occurring varies by the location and the movement of the observer.
- In order to analyse the events we need to combine space and time. Then, we use Space-time diagram.
- Using the menu button we can launch the photons to the moving star in the screen.

Phenomena of special relativity

- We display phenomena of relativity.
- Length contraction, time dilation, cause and result, redshift and lifetime of muon are phenomena of special relativity.

Cause and effect

- The train is running at half speed of light. The sytem on the train is displayed by .
- Then throw the ball from the train. The sytem of the ball is displayed by .
- In the system of the ball, point P corresponds to R and point Q to S.
- Suppose the arrow was thrown at point P and arrived at point Q.
- In the system on the earth the event at P occurred before the event at Q. That is normal.
- In the system on the train the event at P occurred at the same time the event occurred at Q. That is normal.
- In the system of the ball the event at Q is observed to have occurred before the event at P occur. That is inconsistent because the result is observed before the cause.
- How to solve the inconsistency?
- Using the menu button you can change the speed of the train, ball and arrow in the screen.

Phenomena of general relativity

- We display phenomena of general relativity.
- Light deflection, Perihelion advance of Mercury, Gravitational redshift, Clock at GPS ticks faster, Accelerating universe, Garavitational wave, and Gravitational lens are phenomena of general relativity.

Gravitational redshift

- The wire snapped and the elevator is falling.
- The elevator becomes weightless.
- Observing in the coordinate system moving with the elevator, the ground is rising with accelerative speed.
- This means all bodies accelerate up in a gravitational field when observed in a weightless field.
- Suppose the light comes to the earth.
  -- The heavy star has heavy gravitation, and that is the same thing the heavy star is rising with accelerative speed.
  -- The light launched from the star rising upward is observed with redshift on the earth.
  -- Therefore, the light from the heavy star is observed with redshift on the earth.

Gravitational lens

  --Gravitational lens and microlens are shown.