An appeal by IUA and UNESCO: “… the citizens of the world rediscover their place in the Universe through the day- and night-time sky observation, and thereby.

400 YEARS OF THE ASTRONOMICAL

OBSERVATION BY TELESCOPE

An appeal by IUA and UNESCO: “… the citizens of the world rediscover their place in the Universe through the day- and night-time sky observation, and thereby engage a personal sense of wonder and discovery… .”

GALILEO : FATHER OF MODERN SCIENCE

(END OF PAPAL DOCTRINE)

Talk by:

Surajit Sen

Physics Department

G C College

SilcharGALILEO GELILEI (1564

-1642)

1. `Papal Doctrine’ in medieval age

2. Galileo: Biographical Timeline 3. Power of equation

i) Evolution of Mechanicsii) Law of Falling Bodiesiii) Laws of Kinematics iv) How Galileo’s was an inch away from

Newton’s laws of motion.

Contents

4. Other major discoveries 5. Power of Telescope

i) Galilean Telescope

ii) Momentous astronomical discoveries

6. Telescope versus Church 7. End of Papal Doctrine 8. Why Galileo is regarded as the

`Father of Modern Science’?

Contents

Papal Doctrine

Aristotelian Thought Ptolemaic Thought

Papal Doctrine in Medieval Age

The Vatican considered `Ptolemaic and Aristotelian Thought’ as a `Papal Doctrine’ and the civic society accepted it without any experimental demonstration.

“Heavier bodies fall faster than the lighter bodies”, i.e., “Objects falling under gravity is proportional to their mass”.

Aristotelian Thought(384 - 322 B.C.)

1 1

2 2

1 1

2 2

t M

t M

t M

t M

M1>M2 t1<t2

M1

ARISTOTLIAN `THOUGHT’

M2

Galileo asked:

Is it correct ?

(1589)

Copernicus asked:

Is it correct ? (1514)

“Sun, moon and all planets (up to Saturn) move around the Earth in circular path in the backdrop of fixed stars”.

Ptolemaic Thought (2nd Century A.D.)

EARTH

SUN

Planet

GALILEO GELILEI established the pivotal role of `EXPERIMENT’ as the `SCIENTIFIC METHOD’ which is essential to validate of any scientific proposal or thought.

Using `TELESCOPE’ he further established Copernicus’ `HELIOCENTRIC THEORY’ which compels the Vatican to correct its stand on the `GEOCENTRIC THEORY’.

Why to Celebrate the Discovery of Telescope

1564February 15

•Born at Pisa, Italy•Father: Vincenzo Galilei •Mother: Giulia Ammannati

1581• Entered University of Pisa to

study Medical Science, but left because of poor economic condition

1583• Discover isochronous

character of pendulum watching the lamp of the cathedral of Pisa.

Galileo: Biographical Timeline

1586 • Discovered Hydrostatic Balance

1588• Obtained position of

Professor of Mathematics at University of Pisa

1589-92 • Conducted some experiments `On Motion’

Galileo: Biographical Timeline

1592• Obtained position of

Professor of Mathematics at University of Padua

1604• Conducted famous `Inclined

Plane Experiment’ to obtain `Law of Falling Bodies’.

1604-07• Discovered Pump to lift

water, Military compass, Thermoscope etc.

Galileo: Biographical Timeline

1608• The Dutchman, Hans

Lipperhey discovered socalled `spyglass’ to see distant object.

1609• Built up the replica of

Telescope started observing sky.

Galileo: Biographical Timeline

Newton

Einstein

Mechanics: Queen of Physical Sciences

Other Major Players

Lagrange Hamiltonian Jacobi De Alembert

Galileo

MECHANICS(Science of objects in motion)

KINEMATICS(Galileo)

DYNAMICS(Newton)

F =/= 0F = 0

Power of Equation

Experiment with Uniform Motion

V=L/T V=L/T V=L/T V=L/T V=L/T

Uniform Motion =>No Acceleration

Equal DistanceUniform velocity=

Equal Time

Experiment with Non-Uniform Motion

Non-uniform Motion => Uniform Acceleration

VelocityAcceleration=

Time

V3= L3 / T

V2= L2 / T

V1= L1 / T

V1=

L1 / T

V2= L2 / T

Galileo’s Inclined Plane Experiment in Kinematics

VelocityAcceleration=

Time

1 1

2 2

1 1

2 2

t M

t M

t M

t M

1

2

1 2

Absurd!

t M

t M

M M

Galileo’s famous experiment from the Leaning Tower of Pisa demonstrates that, `The time of fall of different bodies is independent of their mass’.

Galileo’s Experiment of Falling Bodies

M1>M2 t1<t2

M1

ARISTOTLE `THOUGHT’

M2

M1>M2 t1=t2

GALILEO `EXPERIMENTED’

M1 M2

21 1

22 2

s t

s t

Theorem of Uniform Motion: “If a moving particle, carried uniformly at constant speed, traverses two distances, the time intervals required are to each other in the ratio of these distances.”

1 1 1 2

2 2 1 2

t s s s s

vt s t t t

Galileo and Laws of Kinematics(Concept of Uniform Motion)

Theorem of Non-uniform Motion: “If two particles are moved at a uniform rate, but with unequal speeds, through unequal distances, then the ratio of time intervals occupied will be the product of the ratio of the distances by the

inverse ratio of the speeds.” Uniform rate means the Uniform Acceleration:

(1)

Galileo and Laws of Kinematics(Concept of Accelerated Motion)

1 2 1 1

1 2 2 2

and v v t v

a at t t v

For non-uniform velocity we obtain from the law,

(2)

Eliminating velocities from Eqs.(1) and (2) gives most important Law of Kinematics; same as the law of falling bodies:

21 1

22 2

s t

s t

Galileo and Laws of Kinematics (Concept of Accelerated Motion)

2 s t

1 2 1

2 1 2

t v s

t v s

“The spaces described by the bodies falling from rest with a uniformly accelerated motion is equal to the ratio of the squares of the time

intervals employed in traversing these distances.”

Thus we obtain famous `Law of Falling Bodies’:

2s t

21 1

22 2

s t

s t

Galileo’s Law of Falling Bodies

2 21 1 2 2 and s t s t

Distance Velocity AccelerationTime

0 Sec

2 Sec

3 Sec

0 meter

-19.6 meter

44.1 meter

0m/sec

-19.6m/sec

-29.4m/sec

-9.8 m/Sec^2

-9.8 m/Sec^2

-9.8m/Sec^2

1 Sec -4.9 meter -9.8 m/sec -9.8 m/Sec^2

22

s4.9m /sec

( t)

An Experiment with Free-Fall

Acc

eler

atio

n

(m/s

ec^

2)

Time (In Sec)

Vel

oci

ty (

m/s

ec)

Dis

tan

ce (

m)

Plots for `Free-Fall’ Experiment

i) Concept of uniform motion:

ii) Concept of acceleration for non-uniform motion:

iii) Law followed by the accelerated bodies:

iv) Eliminating time one obtains an auxiliary relation:

v u at

0s s ut

2 2 2v u a s

21

2s u t a t

Modernized Laws of Kinematics

Galileo’s Law of Inertia: “Imagine any particle projected along a horizontal plane without friction; then we know . . . that this particle will move along this plane with a motion which is uniform and perpetual, provided the plane has no limits.” “A body at rest remains at rest and a body in motion continues to move at constant velocity along a straight line unless acted upon by an external force”

Newton’s Law of Inertia: “Every body continues in its state of rest, or of uniform motion in a right [straight] line, unless it is compelled to change that state by forces impressed upon it.”.

How Galileo was a few inch away from Newton

Galileo : “Acceleration is directly proportional to the motive force and inversely proportional to the volume of the body”.

Newton’s second law: “The change of motion is proportional to the motive force impressed and is made in the direction of the force”.

1,

Fa F a a

V V

, (m=constant)dp F

F adt m

How Galileo was a few inch away from Newton

i) Isochronous character of Simple Pendulum ii) Pendulum based clock iii) Parabolic Path of Projectile iv) Determination of specific gravity by

Hydrostatic Balance (1586) v) Water lifting pump vi) Thermoscope (Earlier version of

Thermometer) vii) Military compass viii) Improved Microscope

Other Major Scientific Contributions

“Philosophy is written in this grand book the universe, which stands continually open to our gaze. But the book cannot be understood unless one first learns to comprehend the language and to read the alphabet in which it is composed. It is written in the language of mathematics, and its characters are triangles, circles and other geometric figures, without which it is humanly impossible to understand a single word of it; without these, one wanders about in a dark labyrinth.” – Galileo (1622)

From his treatise `The Assayer’

Telescope (Device that brings distant objects

closer)Momentous Astronomical Discoveries

Win of Rational Thought

over Authoritarian

ism

Power of Telescope

. .

.

How Modern Observation revalidated Galileo’s Discoveries

Galileo was the first person to use the refracting telescope, now known as Galilean Telescope, for astronomical observation.

Galilean Telescope

Galileo’s Telescope Hubble space Telescope

Galileoscope and A Modern Telescope

Galileo’s diagram Modern observation

Phases of Venus

Galileo’s diagram Modern observation

Sunspots & their Movement

Galileo’s diagram Modern observation

Lunar Mountains & Craters

Starry Milky Way

Galileo’s diagram Modern observation

Satellites of Jupiter

Galileo’s diagram Modern observation

Strange Feature of Saturn

Galileo and Modern Astronomy

1. Developed and improved Telescope for astronomical observation (1609)

2. Phases of Venus

3. Satellites of Jupiter

4. Mountain in the moon

5. Stars as the composition of the Milky Way

6. Sunspot and its movement

7. Strange feature of Saturn

8. Established the Copernican thought of heliocentric universe.

Telescope versus Church

Effect of Papal Doctrine

Vatican endorsed Ptolemaic Model of Universe

Galileo advocated Copernican Model of Universe

Telescope versus Church

Discovered the Sunspots and noted their movements. Established of the Sun and the Moon as the imperfect bodies contrast to Church’s belief.

Discovered of the phases of the Venus, mountains in the Moon and the satellites of Jupiter and starry composition of Milky Way.

In 1609, Galileo developed and refined `Telescope’ and make it suitable for astronomical observation

Telescope versus Church

Galileo visited Rome for first time to meet Pope and explain him about `Power of Telescope’.

In `Letter on the Sunspots’, Galileo unequivocally mentioned that Copernicus is correct and Ptolemy was wrong.

All these discoveries convinced Galileo to become an ardent proponent of the Copernican theory.

Galileo meets Pope

Telescope versus Church

Galileo emphasized, “in disputes about natural phenomena, one must not begin with the authority of scriptural passages, but with sensory experience and necessary demonstrations.”

Galileo argued, “The primary purpose of the Holy Writ is to worship God and save souls. …The Bible tells us how to go to Heaven, not how the heavens go… ”.

Church ordered the heliocentric theory of Copernicus as a “foolish and absurd and formally heretical” and asked Galileo to give up the theory.

Telescope versus Church

Vatican from Rome summoned him for second time and ordered to accept Ptolemaic doctrine renouncing the Copernican theory publicly.

Published masterpiece `Dialogues concerning Two Chief World Systems’ to establish the Copernican theory. It was later banned by Vatican.

Galileo declined to accept Papal Order and continued his support to the Copernican theory.

Galileo facing Inquisition

Telescope versus Church

Galileo became gradually blind, his health deteriorated and finally he died on 8th January, 1942.

Behind the grill Galileo wrote `Dialogues of Two New Sciences’ which summarizes his all great discoveries.

Galileo declined again and faced `Inquisition’. After the trial he was kept house arrest for disobeying the Vatican.

End of Papal Doctrine

In October 2, 1992, Pope John Pal II has withdrawn `Papal Order’ on Galileo.

Galileo and Modern Science

Established prime role of

Experiment in

Science

Rescued physics

from metaphys

ics

Any natural

phenomena is

comprehensible as a Laws of

Nature

Established

Copernican theory

“Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experiment and ends in it... Galileo saw this, and particularly because he drummed it into the scientific world, he is the father of modern physics - indeed, of modern science altogether”… . - Albert Einstein

Why Galileo is regarded as the Father of Modern Science?

Thank You for Patient Listening