#### Transcript 幻灯片 1

```Space and Time
From infinite singularity to infinite galaxy
Time is…
• A independent variable in our lab
• A period of a football game
•
∆𝑑
𝑣
?
.
.
.
Let’s see what Einstein's special
•
•
•
•
Time begin with the big bang
End with the black hole
Get faster if we travel faster
May go to the future of future if we are in the future
You may confuse about some of the above, before the
understanding of Einstein's special relativity.
Special relativity
Different Frames of Reference
View from the sailor
Same scenario
View from the other ship
So, motions are relative. You can run 500m/s but only 10m/s
relative to the ground.
Special relativity
The time is different relative to 2 observers who has
different motion relative to each other.
Time Dilation
3 atomic clock is put on a east-going
plane, origin place and a west-going
plane. After they went around the
earth, one clock is quicker than the
origin and another is slower.
Time Dilation
In the experiment, the time dilation on each plane is exactly
what Einstein’s equation predicted
∆𝑡𝑚 =
∆𝑡𝑠
𝑣2
1− 2
𝑐
• ∆𝑡𝑚 - time interval of a
moving observer
• ∆𝑡𝑠 - time interval of a
stationary observer
• v
- speed of the moving
observer.
• c
- speed of light.
Relativistic Momentum
𝑝=
𝑚𝑣
𝑣2
1− 2
𝑐
Based on the conservation
of momentum and the time
dilation equation, Einstein
came up with the equation
of momentum in different
velocity relative to the
stationary.
Special relativity
• Nothing can travel faster than light
• Light has the speed of 3 × 108 m/s
with all observers
Einstein 1905
Speed of Light
Nothing can get faster than the speed of light
It’s experiment proved again!!
Protons are accelerate to
0.99999999 speed of light
Fermilab accelerator
Time Travel
Review the time dilation equation
What if we travel at almost the speed
of light?
Then while we travel 1 seconds on the
spaceship, the earth might has gone
through many years.
∆𝑡𝑚 =
But only in the future, we can have the
technology to travel at high speed and
go to the future of future.
∆𝑡𝑠
𝑣2
1− 2
𝑐
Mass–energy equivalence
Do you still remember
the nuclear bomb in
Japan?
How can such a big
amount of energy was
released by a small
mass bomb?
Mass–energy equivalence
Einstein came up with one of the most important
equation in physics.
𝐸 = 𝑚𝑐 2
Because of the huge value of c, small amount of mass can
have huge amount of energy.
Space-time relationship
Space-time can be seen as a
inverse proportion relationship
The car stand still, the time
goes at normal speed
The car tar to move in space,
the time gets slower
General Relativity
Newton’s theory works, but he never find the reason of
gravity, because …
There is no gravity
General Relativity
Einstein’s ideas:
Einstein’s space view:
Space is a fabric and
matters make it warp
The reason why the earth go
around the sun is because
the curve made by the sun.
And if sun disappear, earth still
remain its motion until the wave
come, which is exactly the speed
of light.
This again, proved the theory of
special relativity.
General Relativity
So, we can say that the thing we called Gravity is
just the object's reaction to the bends on spacetime fabric.
Although there is no gravity, since that we have use the term for
many years and the awesome job done by newton, we will keep
using it reluctantly…
General Relativity
Not only space, light also, is bend by gravity.
It’s easy to try and
demonstrate also, when
eclipse happens, the
stars place change a little
bit when the moon
completely hide the sun.
General Relativity
Visualization of black hole
• Time stand still near
black hole because
the bend of it.
• Even light is trapped
forever and we can’t
see it.
• Every galaxy has a
enormous blackhole
General Relativity
Time might begin at the
big bang , or before our
big bang, there is another
big big bang.
Einstein 1923
General Relativity
• Relativity can not
explain every thing
and break down at
Singularity.
Singularity
String Theory
After the discover of
quarks, we believe that
there is a smaller particle
and try to find it.
And here comes the
string theory
Which try to define
everything in the
universe
String Theory
The idea is that, at all the end
of smaller particle finding, it is
actually similar type of string
that form this particles.
The only difference between
them is the different
vibrations they make.
String Theory
Strings are everywhere, but we just can’t see it,
because it has several more dimensions.
When we see a line far away, it’s a
1d shape line
When we go closer and inside, we
found out that it’s actually a tube
and has 3 dimension on it.
String Theory
Right now, when we think back, string may exist
in our world and we didn’t notice, or we may
exist in string’s world and didn’t notice neither.
String Theory
Singularity
Singularity has the infinite density, infinite mass
and infinite gravity.
It is a point and doesn’t really has a volume.
Because of this special chrematistics, space and
time get trapped in it and end.
Quezt
This is a multiple choice question.
Jobs sold out all his iPhones and built a spaceship in case of 2012.
Right now he is on the beautiful spaceship and traveling at 0.5c
away from the earth.
Another ship from Bill Gates is traveling toward Jobs at a lower
speed of 0.4c
Jobs throw a stone to Gates' spaceship at a speed of 3m/s
What’s the speed of the message?
A.B.0.1c
D.0.7c
c
Constant box:
B.Because
c
g=9.8m/𝑠 2
speed ofE.0.3c
light is constant
8 m/s
c=3×
10
C.relative
0.4c to all observer.
11
G=6.67× 10 @?!&*\$%@
Quezt
This is a multiple choice question.
Jobs sold out all his iPhones again and built a spaceship in case of 2012.
Right now he is on the beautiful spaceship and traveling at 0.5c
away from the earth.
Another ship from Bill Gates is traveling toward Jobs at a lower
speed of 0.4c
Jobs sent a hello message to Bill gates.
What’s the speed of the message?
A. 0.1c
D.0.7c
Constant box:
All
of
them
are
correct.
B. c
E.0.3c
g=9.8m/𝑠 2
Because the speed is relative to different frame of
8 m/s
c=3×
10
C.reference.
0.4c
11
G=6.67× 10 @?!&*\$%@
Quezt
This is a multiple choice question.
Jobs sold out all his iPhones again!!!!! and built a spaceship in case of Oct
2011. why is it Oct?... Siri tells him that bad things happens to him at 8 Oct,
and good things happens in earth at 12 Oct, but time always has a sequence,
so…
He decided to launch the spaceship at 2 Oct and come back to
meet good thing first.
What speed relative to earth should him travel to make
everything work?
0.8c
A. 0.8c
D.0.7c
Constant box:
Jobs'
time
interval
is
maximum
7
days
B. 0.6c
E.0.5c
g=9.8m/𝑠 2
Good thing’s time interval is minimum 11 days
c=3× 108 m/s
C. 0.4c
F. c
G=6.67×
1011 @?!&*\$%@
Since we know each variables in time dilation
equation,
we can
calculate the most suitable solution
Quezt
This is a multiple choice question.
Jobs failed eventually, because you didn’t send the answer to him as the
speed of light..
Finally, 2012 came and the sun disappear, what will happen?
A. As soon as it happen, gravity of the sun disappear and earth start to do
uniform motion.
B. After several minutes, earth start to go along a line.
C. After several minutes, earth start its circular motion, just like JJ Thomson
Experiment, is affected by the electric field in the solar system.
D. As soon as it happen, gravity of the sun disappear and earth slowly
stopped its spinning.
Constant box:
B
Gravity can not be faster than light.
g=9.8m/𝑠 2
c=3× 108 m/s
G=6.67× 1011 @?!&*\$%@
Quezt
This is a multiple choice question.
Based on string theory and it’s dimensions Choose the right one.
A. String is the basic of particles, vibration differentiate them.
B. Particles form different materials by the vibration of strings which is not
only man-made string, but also anything that can vibrate.
C. String theory explained singularity and the beginning of time, and
illustrate how singularity is massless before the big bang.
D. String is in extra dimensions because when we see a string, we may
think it’s a line, but actually it may consist a bunch of string , it just too
thin that we can not find out about it.
A
Review the notes.
Constant box:
g=9.8m/𝑠 2
c=3× 108 m/s
G=6.67× 1011 @?!&*\$%@
Bibliography