Theory of Light

1
Theory of Light

• Imam Jafar Sadiq (as)
• Reference The Great Muslim Scientist
• and Philosopher,
• Jafar As-Sadiq

2
Why we cannot see distant objects clearly?

• Another great achievement of Imam Sadiq (as) is
  his theory of light.
• Imam Sadiq said that light reflected by different
  objects comes to us, but only a part of these
  rays enter our eyes.
• This is why we do not see distant objects very
  clearly.
• Distant objects would appear to be bigger to us
  if more and more rays from these objects entered
  our eyes.
• The Imam said If we make a device through which
  all the rays of light coming from camels grazing
  at a distance of 3000 zirah (1 zirah 40 inches)
  entered our eyes we would see the camels as if
  they were only 60 zirah away and all other
  objects would look 50 times closer to us.

3
The basis of many discoveries

• This spectacular theory was the basis of many
  inventions and discoveries.
• Lippershey of Flanders used this theory to make
  the first binoculars in 1608.
• Galileo made use of binoculars to invent the
  telescope in 1610.
• When Galileo used the telescope to see the moon
  he was surprised to see that there were
  mountains, plains and valleys on the moon just
  like the earth.
• It was through the telescope that Galileo
  realised that earth was not the only world.

4
Finally, man realises that earth rotates around
the sun, not vice versa!

• If Imam Sadiq had not formulated his theory of
  light, binoculars and telescopes may not have
  been invented and Galileo would not have
  confirmed that the all planets including the
  earth rotate around the sun.
• When Galileo was asked why his telescope made
  heavenly bodies look so near he repeated the
  words of Imam Sadiq and said
• This telescope collects all the rays of light
  coming from heavenly bodies. When all the rays
  are concentrated, the objects which are at a
  distance of 3000 feet away appear to us as if
  they were at a distance of only 60 feet.

5
Light travels from objects to our eyes, not vice
versa!

• Before the time of Imam Sadiq it was believed
  that light from our eyes fall upon different
  objects so that they could be seen.
• Imam Sadiq was the first scholar to reject this
  idea and said
• The rays of light from different objects come to
  our eyes and enable us to see them.
• The rays of light from our eyes do not go out
  and fall on other objects, otherwise we could
  have seen then in the darkness also!
• We see only those objects which are luminous
  (glowing).
• If they are not luminous themselves, they must
  reflect light from other luminous objects for us
  to see them.

6
The speed of light

• The Imam said Light is a kind of motion which
  is very fast.
• These words are in harmony with the modern theory
  of light and today we know that the speed of
  light is very fast.
• The speed of light has been measured to be
  300,000 kilometers per second.

7
The foundation of lasers

• During one of his lectures, the Imam said that a
  powerful beam of light could move heavy objects.
• The light which Moses saw at Mount Sinai was of
  that kind. It could have moved the mountain if
  God had so desired.
• The above statement laid the foundation of the
  theory of laser.

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Summary

• The Imams theories of light can be summarised as
  follows
• Rays of light are reflected by different objects
  and enter our eyes.
• We do not see distant objects clearly because the
  rays of light coming towards us are scattered.
• If the rays of light are concentrated by some
  device we can see distant objects distinctly.
• Light is a kind of motion which travels at a very
  high speed.
• A strong beam of light can move heavy objects.