The Journey of Flight.pdf - Valkyrie Cadet

magnetic field—that is, they align with the field of force. The filings sweep toward the magnet’s North
and South Poles, concentrating more or less at the poles and leaving relatively few filings toward the
Equator of the magnetic force field.
If the bar magnet and the iron filings could be suspended in three dimensions, instead of the paper’s
two dimensions, the iron filings would probably, at least for a short time, form a sort of cloud around
the magnet. This cloud would surround the magnet,
but would leave a very deep depression at each of
the poles as the magnetic lines of force swept downward
carrying filings toward each of the poles (see
picture at the left).
Earth acts as if it had a large bar magnet going
through its center surfacing at the magnetic poles.
The north and south magnetic poles are near the north
and south celestial poles, which are sometimes referred
to as the rotational axis. If the magnetic field
could be seen and if it were not for the effects of
many other forces, Earth’s magnetosphere would
look something like the diagram to the right. How-
Earth’s magnetic lines of force without outside forces
acting upon them.
see Earth’s total magnetosphere,
it would probably look like a
comet with an extended tail that
always points away from the
Sun. This pointing away from the
Sun, of course, is caused by the
pressure of solar radiation pushing
outward from the solar
sphere.
Solar Wind. The normal solar
wind, or solar plasma, strikes
the Earth’s magnetosphere with
considerable collective force.
This force is such that it forms a
bow shock wave where the magnetic
lines of force of the magnetic
field are struck by the solar
plasma. The resulting bow shock
wave distorts Earth’s magneto-
ever, forces such as the solar wind alter the patterns
of the magnetic lines.
If a way could be found for space travelers to
508
Magnetosphere
sphere. The extent of the distortion of the magnetosphere by the solar wind is not precisely known, but
it is known that it sweeps the magnetosphere beyond the orbit of the Moon.