This slide is about time travel

1. Md. Mahbub Hasan
ID: 151012
Dept: EEE

2. “Time travel is the concept of moving
between different points in time in a
manner analogous to moving between
different points in space, generally
using a theoretical invention known as
a time machine .Nature also allowed
us Time Travel through
Wormhole,Blackhole,Crossing speed
of light(theoretically).”
 What is Time Travel

3. What Exactly is Time?
 Most people think time is constant.
 Physicist Albert Einstein showed that
it was merely an illusion.
 Time depending on one’s speed
through space.
 Einstein declared time as the fourth
dimension.
 Time only provides the coordinate
direction, which only moves forward.

4. • Einstein's theory of special relativity describes that the speed of time
depends on how fast you are moving relative to something else
• Ex. If someone in a spaceship flies around the earth at the speed of
light, that person would age much slower than a person back on earth
• Theory of general relativity states that gravity can bend time.
Einstein's Theory of Special & General
Relativity

5. One possibility of traveling
back in time would be to
travel even faster than the
speed of light, but even then
it is shown in Einstein's
equations that one's mass &
length must infinitely be 0.
However, other scientists are
optimistic about that it may
be done .
Possibilities of Time Travel

6. Through Wormholes
WORMHOLE a shortcut connecting
two separate points in spacetime that
could connect extremely far distances
such as a billion light years or more, in
theory, different points in time.
• Create a wormhole between
different points in space time
- Space-time is a four-dimensional
fabric that when bent, causes
gravity .
• But wormholes collapse fairly
quickly & would only work for tiny
particles.
• Technology to even create a
wormhole goes beyond anything
we have today.

7. • A black hole is a large amount of matter
squeezed into a small area; its gravitational pull is
so strong that even light can’t escape it
• Fly a spaceship quickly around the black hole to
make the big rotating structure
• Would have to travel at the speed of light for this
method to work
Black Holes

8. But some physicist claimed that the machine used for time travel
can fall apart for the gravitational pull of the blackhole.
This picture shows that how light bend near a blackhole for
strong gravitational pool.
Black Hole from movie- INTERESTELLAR

9. Time Machine
A machine in which people or objects can be transported into
the past or the future. Though, at present it’s only exists in
science fiction stories & movies. If a true time machine would
ever invented, it can only travel forward not backward.
Because if it is capable to travel back in past, it may create
some inconsistent loop(paradox). Which physics doesn’t
allowed.
Time Machine from movie- Back to The Future

10. Grandfather Paradox
The main problem with Time Travel is the time
travel theory is unable to answer some
paradoxes. paradox is a statement or concept
that contains conflicting ideas. The grandfather
paradox is a proposed paradox of time travel.
Considering this paradox time travel can not
be possible.
Grandfather Paradox: If the time traveller goes
back in time and kills his grandfather before he
meets his grandmother. As a result, the time
traveller is never born. But, if he was never
born, then he is unable to travel through time
and kill his grandfather.
This creates inconsistent a loop. That can never
be answered by our theoretical physics.

11. References
Websites-
 https://en.wikipedia.org/wiki/Time_trave
www.space.com/21675-time-travel.html
http://www.dailymail.co.uk/home/moslive/article-
1269288/STEPHEN-HAWKING-How-build-time-
machine.html
Image Courtesy-
 www.google.com/images
Movies-
INTERESTELLAR(2014)
Predestination(2014)
Back to the future Trilogy(1985,1989,1990)

12. Any Query?!

13. Thank You!