A presentation of Time Travelling. Contents:- Introduction Theory History Time Machine Relativity

1. Click Me

2. TIME TRAVEL: the concept of
movement
between
certain points in
time

3. INTRODUCTION
Time Traveling: How much Real this Science Fiction Is ?

4.  Time travel is a recognized concept in philosophy and
fiction, but traveling to an arbitrary point in time has a
very limited support in theoretical physics, and usually
only in conjunction with quantum mechanics.
The concept was touched upon in various earlier works
of fiction, but was popularized by H.G.Wells‘ 1895
novel ”TheTime Machine”, which moved the concept of
time travel into the public imagination.

5. HISTORYOF
THETIMETRAVEL
CONCEPT
Some ancient myths depict moving in time .

6. • InHindumythology,theMahabharatamentionsthestory
ofKingRaivataKakudmi,whotravelstoheaventomeet
thecreatorBrahmaandisshockedtolearnwhenhe
returnstoEarththatmanyageshavepassed.
TheBuddhistPāliCanonmentionstherelativityof
time."IntheHeavenoftheThirtyThreeDevas,timepasses
atadifferentpace,andpeoplelivemuchlonger.“ Inthe
periodofourcentury;Onehundredyears,onlyasingle
day;Twentyfourhourswouldhavepassedforthem.
TheJapanesetaleof “UrashimaTarō“,ayoungfisherman
namedUrashimaTarovisitsanunderseapalace.After
threedays,hereturnshometohisvillageandfinds
himself300yearsinthefuture,wherehehasbeen
forgotten,hishouseisruins,andhisfamilyhasdied.

7. Washington Irving's "Rip
Van Winkle" (1819)
depicts a man who takes
a twenty-year nap on a
mountain, waking up in a
future where he has been
forgotten, his wife has
died, and his daughter
has grown.Sleep is also
used as a means of time
travel in H.G.Wells' The
Sleeper Awakes, in which
a man wakes up after a
two-hundred year
hibernation.

8. THEORY
*The Boring Part*

9. Some theories, most notably special and general
relativity, suggest that suitable geometries of spacetime
or specific types of motion in space might allow time
travel into the past and future if these geometries or
motions were possible.
C O N C E P T O F
SPECIAL &
GENERAL
REALTIVITY
Quite Boring… Right???

11. CONCEPT OF REALATIVITYANDTIMETRAVEL
Einstein's theory of special relativity says that time
slows down or speeds up depending on how fast you
move relative to something else. Approaching the
speed of light, a person inside a spaceship would age
much slower than his twin at home. Also, under
Einstein's theory of general relativity, gravity can bend
time.

12. TOURISM INTIME
Stephen Hawking has suggested that the absence of
tourists from the future is an argument against the
existence of time travel.
TIME
MACHI
NE
1990 2000 2010 2016 2020 2030
Hey!!! We are from
the Future.
In all time
travel theories
allowed by real
science, there
is no way a traveler
can go back
in time to before
the time machine
was built.
POSSIBLE OR NOT?

13. TIMETRAVELTOTHE
PAST IN PHYSICS
Time travel to the past is theoretically allowed using the
following methods:

14.  Traveling faster than the speed of light.
According to the theory of relativity, a signal or matter
moving faster than light from one point to another would
appear in some inertial frame of reference as moving
backwards in time.
 The use of cosmic strings and black holes.
The general theory of relativity extends the special theory to
cover gravity, illustrating it in terms of curvature in spacetime
caused by mass-energy and the flow of momentum.

15. TIMETRAVELTOTHE
FUTURE IN PHYSICS
There are various ways in which a person could “Travel into
the future" in a limited sense.

16.  Time dilation
* Using velocity-based time dilation under the theory
of special relativity.
* Using gravitational time dilation under the theory
of general relativity.
 Time perception
Time perception can be apparently sped up for living
organisms through hibernation, where the body
temperature and metabolic rate of the creature is reduced.A
more extreme version of this is suspended animation,
where the rates of chemical processes in the subject would
be severely reduced.

17. TIMETRAVEL &TIME
MACHINE
A scene from the movie “TheTime Machine” is a 2002
American science fiction film loosely adapted from the 1895 novel of
the same name by H. G.Wells

19. An OBJECTION that is sometimes raised against the
concept of time machines in science fiction is that they
ignore the motion of the Earth between the date the
time machine departs and the date it returns.The idea
that a traveler can go into a machine that sends him or
her to 1865 and step out into exactly the same spot on
Earth might be said to ignore the issue that Earth is
moving through space around the Sun, which is moving
in the galaxy, and so on, so that advocates of this
argument imagine that "realistically" the time machine
should actually reappear in space far away from the
Earth's position at that date.