I had a hard time finding documentation on this the first time I ran across it, though I'm sure someone will post a relevant link from BOL. What I did find was this helpful note about Sybase, and I guess not much has changed in this regard since the Sybase days:
"However, if you alter the structure of a view's underlying table by adding columns,
the new columns will not appear in a view that is defined with a select * clause unless the view is dropped and redefined.
This is because the asterisk in the original view definition considers only the original columns. "
http://manuals.sybase.com/onlinebooks/group-as/asg1250e/sqlug/@Generic__BookTextView/28420;pt=28336
Thanks for the question,
Rich