3-19-01   ch.16 review 3

       A molecular clouds are cool, denes interstellar clouds in which the 
low temperatures allow hydrogen atoms to pair up into hydrogens molecules 
(H2).
       As a piece of a molecular cloud starts to collapse, gravitational 
constriction increases, which increases the cloud's density.  Thermal energy 
becomes trapped increasing temperature and pressure.  The rising temperatures 
fight back against the crush of gravity.  the dense cloud fragment becomes a 
protostar.
       Angular momentum ensures that the fragment spins faster, flattens to 
form the protostellar disk as it shrinks.

i came to class but left at 7:25.  i am interested to hear if i missed 
anything.  are we still having the exam next week and if so what chapters? 
6,7,8, and 16?   let me know.  thank you, Leanne Erickson