infrared image of the star formation region Messier 17. Three
infrared wavebands, from 1 to 2.2 microns, have been combined to
provide a visual representation of the region as if we had
infrared eyesight. The circles show the regions studied with the
UNSWIRF camera - the northern and south-western bars of the M17.
Original image provided by Michael Merrill from the US National
Optical Astronomy Observatories. molecules in space are
comprised of the simplest kind, the hydrogen molecule. It is
over 10,000 times more abundant than the next most common
molecule, carbon monoxide. It might therefore be thought that
the study of molecular clouds, the sites for star formation
within the Galaxy, would be dominated by various types of
measurement of molecular hydrogen line emission. However this is
not true. The lowest lying energy levels of the hydrogen
molecule are several hundred degrees above the ground state, and
therefore are not excited in the cold conditions which are
prevalent within molecular clouds. emit whe