WEBVTT

00:00:00.000 --> 00:00:02.000
Hi, this is Najib,

00:00:02.000 --> 00:00:03.350
this video is about a Cheikh

00:00:03.350 --> 00:00:05.800
claiming that the Earth is fix and not moving.

NOTE Paragraph

00:00:05.800 --> 00:00:07.000
Why, because,

00:00:07.000 --> 00:00:09.000
if the Earth was moving,

00:00:09.000 --> 00:00:11.000
and a plane wanted to go from Ashariqa (KSA) to China;

00:00:11.000 --> 00:00:12.000
if this plane kept static in the sky,

00:00:12.000 --> 00:00:14.000
it is China that would come to it ! 
(as earth is turning)

00:00:14.000 --> 00:00:16.000
let’s watch the video:

00:00:16.000 --> 00:00:18.000
(Cheikh) “So the earth is static, 
not moving

00:00:18.000 --> 00:00:19.000
The logical arguments, God bless you,

NOTE Paragraph

00:00:19.000 --> 00:00:21.000
we go to the Ashariqa airport,

00:00:21.000 --> 00:00:23.000
we want to go to China,

00:00:23.000 --> 00:00:24.000
on the plane,

00:00:24.000 --> 00:00:24.000
clear?

00:00:24.000 --> 00:00:27.000
stay focused:

00:00:27.000 --> 00:00:29.000
this is earth, if you say that it is spinning,

00:00:29.000 --> 00:00:32.000
if we take off from Ashariqa,

00:00:32.000 --> 00:00:34.000
in an international frlight to China,

00:00:34.000 --> 00:00:36.000
the earth is spinning, right?

00:00:36.000 --> 00:00:37.000
Ok, if the plane stopped in the sky,

00:00:37.000 --> 00:00:40.000
wouldn’t China come to it !?

00:00:40.000 --> 00:00:41.000
Right or not,

00:00:41.000 --> 00:00:43.000
China would come or not !?

00:00:43.000 --> 00:00:46.000
Now if earth is spinning this way 
(like the cup of water in his hands),

00:00:46.000 --> 00:00:49.000
whatever the plane is doing to reach china 
it will never catch it,

00:00:49.000 --> 00:00:53.000
as China would be also following the earth 
in its spinning movement.

00:00:53.000 --> 00:00:56.000
So how would you reach China !?

00:00:56.000 --> 00:00:57.000
(Najib) The video is longer than that,

00:00:57.000 --> 00:00:59.000
and contained another type of arguments,

00:00:59.000 --> 00:01:01.640
mixing up Science and religious texts.

00:01:01.640 --> 00:01:04.440
And this is a whole issue,

00:01:04.440 --> 00:01:05.420
but in this video,

00:01:05.420 --> 00:01:07.000
I would like to tackle this particular part of his video.

00:01:07.000 --> 00:01:11.000
And by the way I take the opportunity to 
congratulate the Cheikh for his methodology !

00:01:11.000 --> 00:01:13.000
The cheikh is using Nature observation,

00:01:13.000 --> 00:01:16.000
to extract general rules of Nature.

00:01:16.000 --> 00:01:19.000
This is at the core of Natural Sciences.

00:01:19.000 --> 00:01:23.000
The idea this Cheikh is putting here 
belongs the greek scientist Aristotle,

00:01:23.000 --> 00:01:25.000
who lived in the fourth century BC,

00:01:25.000 --> 00:01:30.000
and was among the natural scientist and philosophers 
with the highest influence on the old world.

00:01:30.000 --> 00:01:34.000
(map showing Alexander The great empire, 
Aristotle’s student, expanding)

00:01:34.000 --> 00:01:39.000
And it is completely normal that his ideas end up 
in muslim scholars’ texts in the middle ages,

00:01:39.000 --> 00:01:43.000
which have probably been used by our Cheikh.

00:01:43.000 --> 00:01:46.000
Aristotle said that it is impossible 
for the Earth to be spinning,

00:01:46.000 --> 00:01:47.000
Why ?

00:01:47.000 --> 00:01:49.000
because if it was doing so,

00:01:49.000 --> 00:01:52.000
and if we consider someone throwing an arrow vertically,

00:01:52.000 --> 00:02:01.000
than the arrow wouldn't be back to the same place because, 
Earth would have moved in between.

00:02:01.000 --> 00:02:02.000
The idea sounds reasonable,

00:02:02.000 --> 00:02:04.000
and we can’t blame aristotle,

00:02:04.000 --> 00:02:05.000
nor the old muslim scholars

00:02:05.000 --> 00:02:08.000
or not even this Cheikh to think about it.

00:02:08.000 --> 00:02:09.000
But the question is:

00:02:09.000 --> 00:02:14.000
is this idea corresponding to the reality of our world?

00:02:14.000 --> 00:02:18.000
Aristotle ideas remained accepted for 
centuries all around the region,

00:02:18.000 --> 00:02:24.000
and the first one to challenge it 
and verify it was Galileo.

00:02:24.000 --> 00:02:28.000
Galileo lived in the 17th century, in Italy.

00:02:28.000 --> 00:02:31.000
He explained the error done by Aristotle in 
a book he wrote in the late days of his life,

00:02:31.000 --> 00:02:34.000
the book sparked a revolution in natural science.

00:02:34.000 --> 00:02:40.000
The book was named “Discourses and Mathematical Demonstrations 
Relating to Two New Sciences”.

00:02:40.000 --> 00:02:43.000
Or simply put: “Two New Sciences”.

00:02:43.000 --> 00:02:45.000
In this book, Galileo described the following experiment:

00:02:45.000 --> 00:02:47.000
if we are on a moving ship

00:02:47.000 --> 00:02:48.000
and went up to the top of the mast

00:02:48.000 --> 00:02:51.000
to let down a pebble from above.

00:02:51.000 --> 00:02:52.000
If Aristotle was right,

00:02:52.000 --> 00:02:55.000
the pebble shouldn’t fall vertically to the bottom of the mast,

00:02:55.000 --> 00:02:59.000
but should be left behind while the boat is moving forward.

00:02:59.000 --> 00:03:00.000
Let’s figure out this by ourselves !

00:03:00.000 --> 00:03:07.000
Today we have a ship that moves way faster 
than boats of Italy in that period.

00:03:07.000 --> 00:03:08.000
This ship is named:

00:03:08.000 --> 00:03:09.000
...

00:03:09.000 --> 00:03:10.000
the car !

00:03:10.000 --> 00:03:14.000
I’m on the highway now driving at 120km/h,

00:03:14.000 --> 00:03:15.000
if Aristotle was right,

00:03:15.000 --> 00:03:18.000
this pebble, if thrown from the roof of the car,

00:03:18.000 --> 00:03:21.000
while falling, the back of the car should “catch up with it”.

00:03:21.000 --> 00:03:25.000
The pebble should either end up on the back seats, 
or even break the rear windows of the car.

00:03:25.000 --> 00:03:30.000
Let’s try !

00:03:30.000 --> 00:03:34.000
The pebble is falling vertically in the car,

00:03:34.000 --> 00:03:36.000
this proves that Aristotle was wrong.

00:03:36.000 --> 00:03:40.000
Galileo proved this in detail using the concept of reference frame.

00:03:40.000 --> 00:03:43.000
The reference frame is the place where we situate rigorously 
a phenomenon before studying its mechanics.

00:03:43.000 --> 00:03:45.000
In the reference frame of the car,

00:03:45.000 --> 00:03:47.000
this pebble is static,

00:03:47.000 --> 00:03:48.000
its speed is zero,

00:03:48.000 --> 00:03:55.000
while earth and the trees outside are moving 
with the speed of 120km/h in the opposite way.

00:03:55.000 --> 00:03:58.000
While for a tree outside:

00:03:58.000 --> 00:04:03.000
BOTH the car and the pebble are moving with a speed of 120km/h

00:04:03.000 --> 00:04:05.000
If my car was convertible,

00:04:05.000 --> 00:04:08.000
I would have been able to throw my pebble up higher in the air,

00:04:08.000 --> 00:04:13.000
the movement of the pebble in the reference frame 
of the car would still be vertical,

00:04:13.000 --> 00:04:15.000
while in the reference frame of the tree,

00:04:15.000 --> 00:04:23.000
the pebble would have a horizontale movement with a 120km/h velocity,

00:04:23.000 --> 00:04:25.000
Seem from the latter reference frame,

00:04:25.000 --> 00:04:27.000
its movement resembles that of a projectile,

00:04:27.000 --> 00:04:32.000
going up and then reaching the car back.

00:04:32.000 --> 00:04:33.000
The error made by Aristotle,

00:04:33.000 --> 00:04:37.000
is that he was not fixing the reference frame 
where he was studying the movement.

00:04:37.000 --> 00:04:40.000
As soon as we have a clear idea 
in which reference frame we are talking,

00:04:40.000 --> 00:04:42.000
things become clear.

00:04:42.000 --> 00:04:44.000
The plane of our Cheikh is like a butterfly,

00:04:44.000 --> 00:04:46.000
going from the front seat (Ashariqa),

00:04:46.000 --> 00:04:48.000
to the back seat (China).

00:04:48.000 --> 00:04:50.000
In the reference frame of the car,

00:04:50.000 --> 00:04:53.000
the rear seat is fix,

00:04:53.000 --> 00:04:55.000
it is not “coming” to the butterfly.

00:04:55.000 --> 00:04:56.000
In the reference frame of the tree,

00:04:56.000 --> 00:05:00.000
the butterfly has already a velocity of 120km/h,

00:05:00.000 --> 00:05:07.000
decreasing a little bit while the butterfly os going to the rear seat.

00:05:07.000 --> 00:05:10.000
All of this is true since the car has a constant velocity.

00:05:10.000 --> 00:05:15.000
In this case, we say that the reference frame 
of the car is a Galilean reference frame.

00:05:15.000 --> 00:05:16.000
If the velocity of the car suddenly changed,

00:05:16.000 --> 00:05:19.000
for example if I push on my breaks,

00:05:19.000 --> 00:05:20.000
it is no longer a Galilean reference frame,

00:05:20.000 --> 00:05:23.000
and the poor butterfly will hit the front window.

00:05:23.000 --> 00:05:24.000
If Earth did the same (suddenly stopped rotating),

00:05:24.000 --> 00:05:28.000
the american scientist Neil deGrasse Tyson 
explains in this video what would happen.

00:05:28.000 --> 00:05:31.000
I can tell you that it wouldn’t be a happy event.

00:05:31.000 --> 00:05:34.000
Now the conclusion I can draw from this story,

00:05:34.000 --> 00:05:38.000
is that our intuition can sometimes lead us in mistake,

00:05:38.000 --> 00:05:39.000
just like it did to Aristotle.

00:05:39.000 --> 00:05:42.000
Intuition sometimes works, sometimes not.

00:05:42.000 --> 00:05:47.000
The only way to figure out is to do the experiment,

00:05:47.000 --> 00:05:49.000
just like Galileo did.

00:05:49.000 --> 00:05:53.000
If the experimental result is not agreeing 
with our initial idea,

00:05:53.000 --> 00:05:55.000
we should accept changing our point view.

00:05:55.000 --> 00:05:57.000
This is the scientific method !

00:05:57.000 --> 00:05:59.000
The scientific method,

00:05:59.000 --> 00:06:02.000
with readiness to change one’s mind in its core principles,

00:06:02.000 --> 00:06:08.000
in which Arab scholars and philosophers played 
a key role to make it precise and rigorous,

00:06:08.000 --> 00:06:12.000
would later spark the scientific revolution in Europe,

00:06:12.000 --> 00:06:16.000
the same scientific revolution that is still 
happening all over the world.

00:06:16.000 --> 00:06:19.000
This is it, happy experimenting, and good bye.