Transcript Our Picture of The Universe

Our Picture of The Universe
Eng. Mohamed Salah Ebeida
Teaching Training Course for Future Professors
Alexandria University
9 / 26 / 2002
Important Questions!!

What do we know about the universe?
 Where did the universe come from, and where is
it going?
 Did the universe have a beginning, and if so what
happened before then?
 What is the nature of time? Will it ever come to
an end?
Development of Human
Thoughts Toward Universe!

340 BC, the Greek philosopher, Aristotle put
two arguments that the earth was rather a round
sphere rather than a flat plate:
1. The Earth Shadow on the Moon was always round
during its eclipse
2. The North Star appeared lower in the sky when viewed
in the south than it did in more northerly region

The Greeks had a third argument that one first see the
sails of a ship coming over the horizon, and only later
see the hull

In the 2nd Century A.D. “Anno Domini” Ptolemy
elaborated the idea of Aristotle that the earth was the
center of the Universe into a complete cosmological
model

Ptolemy Model provided accurate system for
predicting the positions of heavenly bodies in the
sky.
 What lay beyond the last sphere was Never made
Clear!!

This Model was Adopted by the Christian Church as
the picture of the Universe, Guess
Why?!!
Lots of Room for
Heaven & Hell!!
The Earth is not the center!

In 1514, Nicholas Copernicus proposed that the sun
was stationary and all planets move in circular orbits
around it. But he didn’t say a word about that!

In 1609, Death blow to the old theory came as Galileo
started observing the night sky with a telescope, he
found that there are several moon that orbit around the
planet Jupiter.

At the same time, Kepler modified Copernicus’s
theory into elliptical orbit, finally the prediction
matched the Observation!!
Newton Enters the Race!

In 1687, Sir Isaac Newton postulated a law of
universal gravitation.
Earth
M
Moon
m
r
Object Should Rotate
To avoid Collapse!
Earth
M
Moon
m
Centrifugal
Force
So What about Fixed Stars!

Newton said, that would happen only in a finite world
which is now obvious to be infinite!!

Others tried to make the gravitational force repulsive
at very large distances!!

It has been generally accepted that either:
The universe had existed forever unchanged, or
2. It has been created at a finite time in the past.
1.
The Universe Can’t be Static!

In 1823, Heinrich Olbers noticed that in an infinite
static universe the sky would be as bright as the sun

Since that doesn’t happen, he deduced that not all
stars went on together.
 What
did God do before he created
the Universe?!
The Universe is Expanding!

In 1929, Edwin Hubble made the landmark
observation that wherever you look, distant galaxies
are moving rapidly away from us.

And that brings us to the Big Bang!

An expanding universe does not preclude a creator!

Working to find out the unified theory!
‫!‪One Question remains‬‬
‫?‪Why are we here‬‬
‫(وما خلقت الجن و اإلنس إال ليعبدون)‬
‫اآلية ‪ 56‬من سورة الذاريات‬
Thank you
for your
time 