Cosmic Radiation

On Wednesday, September 24, 2003, at 11:13 AM, Lucio de Souza Coelho

> The point that TangoMan is explaining is that the play of Earth's bulk
> in
> radiation shielding is negligible, because this bulk is enveloped by a
> spherical atmospheric shield that already blocks virtually all
> radiation
> coming from every direction before they ever hit Earth's bulk.
>

Are you sure this is true? I don't think so. Why do you think the
atmosphere blocks essentially all incoming radiation?

The dinosaurs were destroyed by an asteroid because they weren't
space-faring. It's almost as if Gaia then thought "Well, dinosaurs
worked pretty well, but space-faring is necessary. Maybe I'll should
try mammals this time." Humanity is now developing systems to detect
and deflect asteroids, and could build orbital space colonies to spread
beyond Earth to insure life would survive a planetary catastrophe.

Al Globus
CSC at NASA Ames Research Center
http://www.nas.nasa.gov/~globus/home.html

Views expressed in this email are only my opinions and are not the
position of any organization I'm familiar with.