1. Newton conceived of space and time as absolute and unaffected by events within them. Einstein later developed the theory of relativity which holds that space and time are relative and can be affected by motion and gravity. 2. According to Einstein, the speed of light is constant for all observers, and time and length can change relative to the observer's frame of reference and motion. 3. General relativity explains gravity as a curvature of spacetime caused by mass and energy, and predicts effects like gravitational time dilation near massive objects.

1. Presented by Sumera Saleem
SPACE AND TIME

2. WHAT IS SPACE?
• Space is the boundless three-dimensional extent in which objects and
events have relative position and direction.

3. WHAT IS TIME?
• Time is a measure in which events can be ordered from the past through the
present into the future, and also the measure of durations of events and the
intervals between them.

4. NEWTON CONCEPT OF SPACE AND TIME
• According to Newton space and time is real but not genuine.
• Space and time are unaffected by events occurred in it.
• Space is rigid and nonflexible.
• Space behave like a stage for event , action and motion.
• Time is constant.
• Space and time are absolute.

5. ABSOLUTE SPACE
• Absolute space, in its own nature, without regard to anything external,
remains always similar and immovable

6. ABSOLUTE TIME
• Absolute time (which is also sometimes known as “Newtonian time”) exists
independently of any perceiver, progresses at a consistent pace throughout
the universe, is measurable but invisible, and can only be truly understood
mathematically.

7. From late 19th century concept of space
and time change
“BUT”

8. EINSTEIN CONCEPT OF SPACE AND TIME
• Space and time are genuine and real.
• Space and time are affected by events, motion and action occurred in it.
• Space is flexible.
• Time is changeable.
• Space and time are relative.
• Space behave like a stage but it is not rigid.
• Space and time should be considered together and
in relation to each other.

9. RELATIVE SPACE
• Relative space means space that is defined by relative units.
• Relative units are units whose magnitude may vary in different locations.

10. RELATIVE TIME
• Time between two events as measured by observers either moving
relative to each other or differently situated from a gravitational mass or
masses.

11. THEORY OF RELATIVITY
• Einstein proposed “theory of relativity” in 20th century.
• Theory of relativity is actually two separate theories.
• First one is special theory of relativity.
• Second one is general theory of relativity.

12. SPECIAL THEORY OF RELATIVITY
Special theory of relativity presented by Einstein in 1905. This theory based on
following points:
• Speed of light is same for all observers.
• Observers moves with constant speed obey the same physics laws.
• Time must change with the speed of object relative to the frame of reference
of the object.
• Space and time relative.
• This theory is true in the absence of gravity.
• E=mc2 show that mass is equal to energy, single particle of matter converted
into the huge amount of energy.

13. Speed of light is 300,000 km/s.
According to Einstein speed of light is same for every observer.
SPEED OF LIGHT

14. “HOW”

15. SPEED OF LIGHT
• Speed= distance/ time.
• When object move with speed of light.
• Time dilate.
• Distance of length contract.

16. TIME DILATION
• Time slow down for object which is move close to the speed of light.

17. LENGTH CONTRACTION
• Length of distance contract when object move close to the speed of light.

18. TIME TRAVEL
• Time slows for the object which moves close to the speed of light.
• Time stops for the object which moves with speed of light.
• Time must go backward if object moves faster than the speed of light.

19. NEWTON CONCEPT OF GRAVITY
• Newton's law of universal gravitation states that every mass attracts every
other mass in the universe, and that the gravitational force between two
bodies is proportional to the product of their masses, and inversely
proportional to the square of the distance between them.
• Newton only defined gravity.
• He fails to explain how gravity works.

20. GENERAL THEORY OF RELATIVITY
• Einstein worked further 11 years to explain gravity in his equation. In 1916 he
presented general theory of relativity.
• He considered space-time together and in relation to each other.
• According to theory gravitation is not a force as understood by the Newton
but a curved field (an area of space under influence of a force) in the space-
time fabric that is actually created by the presences of mass of matter.

24. GENERAL THEORY OF RELATIVITY
• This theory also predicts that time should appear to run slower near massive
body like earth. This because of there is a relation between energy of light
and its frequency.
• Light upward in the earth’s gravitational field, it loses energy and so its
frequency goes down.
• In 1962, using a pair of very accurate clocks mounted at top and bottom of
water tower, the clock at bottom which was nearer the earth was found to run
slower, in exact agreement with general relativity.

25. SPACE IS EMPTY??

26. NO EMPTY SPACE IN UNIVERSE
• Empty space, is actually not empty at all. Quantum effects constantly
produce particles and antiparticles "out of nothing," only to have them
disappear few moments later. And space itself can either be almost flat or
curved, depending on the amount of matter it contains.

27. NO EMPTY SPACE IN UNIVERSE
• Space contains 3 things atoms, dark matter and dark energy in it.

28. “Dark matter is an invisible, mysterious substance that makes up
about 26.8 percent of all matter and energy in the universe”
DARK MATTER

29. DARK ENERGY DISCOVERY
• Scientists a period ago while observing distant exploding stars. The
explosions revealed a universe expanding at an ever-faster rate, a finding at
odds with previous expectations that the expansion of the cosmos should be
slowing down, braked by the collective gravitational pull of all the matter out
there.

30. Dark energy is that it is a new kind of dynamical energy field,
something that fills all of space but something whose effect on
the expansion of the Universe is the opposite of that of matter
and normal energy.
It makes up the 68.3% of the space mass
DARK ENERGY