Time- history, scientists, developments, measuring devices, present scenario, time dilation, time travel, and everything related to time.

1. By: Neha Sharma
B.Sc. B.Ed. 7th semester
Roll:26

2. helped in understanding

3. Albert Einstein

4. Sir Issac Newton

5. AlberA.Michelson Eward W. Morley

6. Stephen hawkings

8. • The Vedas, the earliest texts on Indian
philosophy and Hindu philosophy, dating back
to the late 2nd millennium BC, describe
ancient Hindu cosmology, in which
the universe goes through repeated cycles of
creation, destruction, and rebirth, with each
cycle lasting 4,320,000 years.

9. • "Newton did for time what the Greek
geometers did for space, idealized it
into an exactly measurable dimension.“
• Oxford Dictionaries:Time"the
indefinite continued progress of
existence and events in the past,
present, and future regarded as a
whole"

10. OF
OF

13. Time is the fourth dimension and a measure in
which events can be ordered from
the past through the present into the future,
Time is one of the seven fundamental physical
quantities in both the International System of
Units and International System of Quantities

16. • In Albert Einstein's theories of relativity, time
dilation in these two circumstances can be
summarized:
• In special relativity, clocks that are moving with
respect to an inertial system of observation are
measured to be running more slowly.
• In general relativity, clocks at lower potentials in
a gravitational field

18. (a) Mavis measures (proper) Dto (= 2 d /c).
(b) Stanley measures Dt.
The path observed by Stanley is longer:
2 L = 2 [ (d2 + (u Dt / 2)2 ] ½
So c Dt = 2 L = 2 [ (c Dto / 2)2 + (u Dt / 2)2 ] ½
(Dt)2 = (2 L/c)2 = (2/c)2 [ (c Dto/2)2 + (u Dt/2)2]
(Dt)2 = [ (Dto)2 + (u Dt/c)2]
(Dt)2 - (u Dt/c)2 = [ (Dto) 2 ]
(Dt)2 { 1 - (u /c)2 } = [ (Dto) 2 ]
Time dilation: Dt = Dto / {1 – u2/c2} ½

20. • Many of the pridiction of relativity such as lenth
contraction, time dilation, mass variation with
velocity etc appears somewhat paradoxical
because the concepts are bafflinng to our daily
life………
• Twin paradox is one of the most controversial
predictions of special relativity…

21. 2 twins A and B
A B
v=βc

22. A finds B much older then himself

23. • For the return journey b has a certain reversal
in the direction of the velocity, magnitude
remaining same.
• This implies acceleration takes place and a
change from 1 inertial frame to another.
• Nothing to the equivalence of the frame A and
B- The basic postulate of special relativity….
• Hence the non semetrical of the result is real
and so called paradox gets resolved.

28. • WE MAY SAY FOR A PARTICLE TO TRAVEL
FASTER THAN LIGHT TO TRAVEL TIME…
• OR SOME THING HAVING MUCH GREATER
SPEED THAN LIGHT………
• 3* Light’s speed
• 50*Light’s speed or
• May be 99.9*light’s speed

29. • Neutrinos—ghostly subatomic particles—
may have been observed traveling faster than
the speed of light, scientists announced this
week.
• If confirmed, the astonishing claim would
upend a cardinal rule of physics established
by Albert Einstein nearly a century ago

30. Huge Observatory 1.5 Miles Deep in
Antarctic Ice
• Members of the Oscillation Project with Emulsion-
tRacking Apparatus, or OPERA, at the European
Center for Nuclear Research (CERN) described the
unusual neutrino detection in a paper published
this week on the research website arXiv.org.
• The team shot neutrinos out of a particle
accelerator near Geneva,Switzerland and measured
how long it took the particles to travel to a
neutrino detector in Gran Sasso, Italy, 450 miles
away.

31. Neutrinos are subatomic particles that have
almost no mass and can zip through entire
planets as if they are not there.
• Being nearly massless, neutrinos should travel
at nearly the speed of light, which is
approximately 186,000 miles (299,338
kilometers) a second.
• To the astonishment of the OPERA team, the
particles appear to have reached their
destination about 60 nanoseconds faster than
expected.
• A nanosecond may not sound like much, but
"the effect is quite large,"