### Re: Do the magnetic lines around Earth contain any light?

Date: Sat May 19 20:41:50 2001
Posted By: Gary Treistman, Undergraduate, Gen. Knowl. Dept., Programming Technologies
Area of science: Physics
ID: 988957344.Ph
Message:
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Ann:

You will probably consider this answer very dry and not very
glamorous.

There is a relationship between magnetism, electricity and light.

The whole set of phenomena is called electromagnetism, because
they are all
intertwined with each other.
The major differences are that the first two can exist in static fields,
whereas light is always moving at, can you guess, the speed of light
(186,282 miles per second).

Magnetic and electric fields can be static in time, meaning they can
act
like stationary fixtures, not changing in shape/size or strength, and
extending through space like a fluid.
Also, magnetic fields can give rise to electric fields if they are not
static, that is if they are moving in position or in strength. This is also
true vice-versa, electric can make magnetic fields.
There are two flavors of each - positive and negative (for electrics), &
north and south for magnetics. They are kind of like a beginning of
the
fields, and a end.

Another thing to know about these fields is that they have big
difference
between the two, is that an electrically charged object will not react to
a
static magnetic field, and a magnetically charged object will not react
to a
static electric field. However if either is changing, then they will react
as if pushed or pulled by a force.

Now, light is created whenever you have a (magnetically or
electrically)
charged object accelerating - that is, going faster and faster or faster
and
slower, as long as the speed is changing.

What happens is, every time the charged object accelerates, a part of
the
field it generates cannot catch up to the object, and is left behind. The
thing is when a piece of electric or magnetic fields is left on its own, it
never hangs around very long. In fact it takes off at the speed of light
and
rapidly disappears. That piece of a left-behind field is in fact light.

Now to your question, can magnetic fields/lines contain light, the
no. A magnetic field does not contain light any more than a pond
contains a
rushing river.

It is only when you accelerate the thing that makes the magnetic line
that
light is created, and then the light flies away very fast. Static magnetic
lines (which are the things that surround our planet) do not direct light
either.

```

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