Blue Magic Wand Kaleidoscope
An incandescent light bulb contains a thin wire filament (usually tungsten) that glows hot
when an electric current is run through it. In the presence of oxygen, the filament would
burn up as a result of the high temperature. A glass bulb, then, is used to keep oxygen
away from the filament.
While a vacuum will work, any inert gas that inhibits combustion will also work. Since the vacuum of space would have no oxygen, a bare filament WOULD work as a light bulb without the glass globe.
By the way, even without oxygen present a filament eventually deteriorates as its atoms dissipate. The presence of a halogen gas actually inhibits this deterioration, allowing higher filament temperatures and brighter light bulbs. So the glass globe can also help enhance a bulb's capability.
More info on light bulbs:
Tungsten filament close-up image by Dr. Howell at PSU, Material Science Dept.
Answered by: Paul Walorski, B.A., Part-time Physics Instructor
'In a way science is a key to the gates of heaven, and the same key opens the gates of hell, and we do not have any instructions as to which is which gate. Shall we throw away the key and never have a way to enter the gates of heaven? Or shall we struggle with the problem of which is the best way to use the key?'
Richard Phillips Feynman