|Gravity: A Property of All Massive Bodies
All massive bodies from atoms and subatomic particles to planets, stars and blackholes have
a property called gravity. Because your body is made up of matter you yourself have your own
personal gravitational field. Unfortunately though your field is too weak for you to visibly affect
Every massive body (and even non massive ones such as energy) finds itself drawn towards
other massive bodies. Not only do these objects find themselves pulled toward each other,
they actually accelerate toward each other, meaning that their attraction increases, even over
short time periods.
There are generally three ways for an object’s state to be acted upon by a gravitational force.
You can fall towards the source of gravity as you do when you fall from a jump. You can have
your trajectory altered by gravity as the light from distant stars is when they pass by the sun to
get to us. Or you can keep falling toward a source of gravity and continually miss it- traveling
in an oval or ellipse. This is seen in the highly elliptical orbits displayed by many of our Sun’s
comets and also by the flattened elliptical orbits displayed by our Sun’s planets.
Newton attributed the orbits of the planets around the sun to gravity, Einstein attributed the
curvature of the velocity of light to gravity, and the non-scientist attributes their attraction to
the earth to gravity. It is not just the earth’s gravity that attracts you to it. Your gravity attracts
the earth and the both of you accelerate (at far different magnitudes) toward each other
before your feet hit the ground.
So you might be thinking: “How far does my gravitational field reach before it loses its effects?”
Well…its force does decrease exponentially with distance but the fact is that your gravitational
field stretches as far as the earth’s. In fact all gravitational fields stretch in every direction in
our three dimensions indefinitely.
Gravity propagates at the speed of light, a fast yet finite speed of 186,000 miles per second. It
might interest you to know that when you move your body in any way you cause things all
around the world to move extremely small amounts within only fractions of a second. After
millions of years, the movements that you made today will cause whole galaxies, many light
years away to shift their location. The effects of your gravitational field (especially at these
distances) are imperceptible by human methods of measurement, but they are factual effects.
To find out more about Einstein's theory of gravity click here.
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