The document discusses three physical models that attempt to explain time travel: classical mechanics, relativistic mechanics, and quantum mechanics. It describes Einstein's theory of relativity which adds time as a fourth dimension and shows how time is relative to velocity and acceleration. The document also considers whether time travel is possible based on theories of gravity affecting the flow of time and the twin paradox, but concludes it is unclear if traveling back in time could be achieved.

1. IS TIME TRAVEL POSSIBLE?

2. THE THREE PHYSICAL MODELS
• CLASSICAL MECHANICS
It can explain the phenomena occurring in our scale.
Isaac
Newton

3. • RELATIVISTIC MECHANICS
Time is not an absolute value, it varies with velocity and acceleration.
Used with big masses and velocities near light speed (300 000 km/s).
THE THREE PHYSICAL MODELS
Albert Einstein

4. • QUANTUM MECHANICS
Used for very small scales (atoms, photons, electrons, etc.)
THE THREE PHYSICAL MODELS
Erwin
Schrödinger

5. RELATIVITY: A WORLD IN 4D
• We have a 3D vision of our
world.
• For us, time is an absolute value.
It flows equally for everybody.
A 3D axis

6. • Relativity adds a new
dimension: time
• Time depends on velocity
and acceleration, higher
velocity/acceleration
implies slower time.
• Space-time “sheet” or net
is altered by the gravity of
each mass (planets, stars,
etc.)
RELATIVITY: A WORLD IN 4D
Space-time net altered by the gravity of the
Earth and the Sun.

7. IS IT REALLY POSSIBLE TO TRAVEL IN
TIME?
• Life expectancy: 79 years old.
• Life expectancy at the top of the Empire State (380
meters): 104 microseconds lower.
+ distance to Earth core = less gravity = time goes faster
Empire State Building

8. • Twin paradox:
IS IT REALLY POSSIBLE TO TRAVEL IN
TIME?

9. AND WHAT ABOUT TRAVELING BACK IN
TIME?