home *** CD-ROM | disk | FTP | other *** search
- Study of available geological evidence indicates that it is
- more common for our planet to be in an ice age than it is to
- be in it's present state. The duration of a common ice age
- is approximately one hundred thousand years, while
- intermittent periods, such as that of our own time, tend to
- last about fifteen thousand years. What causes an ice age?
- During cool summers in the northern hemisphere, snow at high
- altitudes fails to melt. This build up forms thick layers of
- ice. Because these layers of ice reflect the suns rays,
- subsequent summers will be colder as the ice build continues.
-