CONTENTS
1.        Nature of time
2.        What causes Time?
3.        Why Time slows in gravity and with motion?
4.        Is time a dimension?
5.        How gravity works
6.        Why gravity is only attractive?
7.        Acceleration and Twin paradox
8         The beautiful mechanism of length contraction?
9.        What causes inertia?
10.      Why speed of light remains constant?
11.      Why black holes cannot have singularity?
12.      Is the universal expansion accelerating or time is slowing down?
13       Arrow of time
14       Summary
15       Philosophy In A Cup Of Tea
16       Links to other sites
17       Time Quotes
By
mkhan@timephysics.com

Writer and physicist Paul Davies has called time Einstein’s unfinished revolution. Despite tremendous advancement in science and
technology and the precision with which time can be measured there is very little known about true nature of time. There are many
questions about nature of time. What is time? What causes time? Why time slows in gravity? Why time slows in motion? Is time a
dimension?

Aristotle may have came closest to understanding time when he speculated that time may be motion. Aristotle however said that time may
not be motion as motion could be slower or faster but not time. Aristotle did not have the privilege of knowing about Einstein’s relativity
in which time also becomes amenable to change. Similarly when Einstein was working to develop theory of general relativity and
proposed the revolutionary idea that mass curves space he did not know that universe was expanding. It is still remarkable that despite
lack of this knowledge he developed the concept of curved space-time.

The discovery that universe is expanding came 13 years after Einstein published his general relativity. By that time his concepts had
already gained popularity. Had Einstein known of this great discovery his work may have been far simpler and knowing his brilliance he
may have incorporated these ideas into his theories.  Conceptually it is easier to derive space curvature in an expanding universe as an
area of slower expansion under the influence of gravitons.

The most dramatic aspect of the universe is that it is expanding and the presence of motion, forces and curved space-time just does not
happen in any space but in the expanding space. In general relativity matter produces curvature in space-time, this concept can also be
extended to moving objects and it can be shown that moving objects can also curve space-time.  

In this article time is defined as the presence of motion and forces. It is proposed that the motion and forces are due to expansion of the
universe. Slower expansion of space around large masses like earth and sun could be considered as the cause of slower time linking time
to the expansion of space. Gravity can be explained on basis of tendency of matter composed of billions of particles orbiting at
tremendous velocities to move from faster to slower time when placed in a time differential. This explains why gravity is so weak yet
extends to great distances and why it is always attractive.  This new approach towards understanding time eliminates the infinite gravity or
singularity of black holes.  It also shows us that not only gravity of large masses but also motion of objects can curve space which leads to
the beautiful mechanism of length contraction for moving bodies.  It leads to a deeper understanding of why time slows with motion and
in gravity.  It also provides a clear explanation of why there cannot be a twin paradox.

This new interpretation of time linking it with expansion of space may have been already confirmed by the discovery that the universal
expansion appears to be accelerating. If time is indeed related to the expansion of space and our time is slowing down then as we make
measurements of light emitted by distant supernova (when time was faster) we will be measuring their frequency changes from our slower
time. This will give an illusion that the universal expansion is accelerating. Similarly the pioneer anomaly can be explained by slowing of
our time during the period the signal travels from earth to pioneer space craft and back. These predictions are not based on any exotic
phenomenon but on Einstein’s relativity and can be easily tested. This new approach in understanding of time, motion, and gravity could
bring about a revolution in physics.
WHAT IS TIME?

NATURE OF TIME
More powerful than all the armies of the
world, is an idea whose time has come.
                        .............Victor Hugo
MOVING OBJECTS ALSO CURVE SPACETIME
Rotating buckets and twin paradox reveal
the reality of motion through space.
FASTER EXPANSION OF SPACE
FASTER TIME
SLOWER EXPANSION OF SPACE
SLOWER TIME