In this Spitzer image, the two opposing bubbles are being formed in
opposite directions by the powerful outflows from massive groups of
forming stars. The baby stars can be seen as specks of yellow where the
two bubbles overlap.
When individual stars form from molecular clouds of gas and dust they
produce intense radiation and very strong particle winds. Both the
radiation and the stellar winds blow the dust outward from the star
creating a cavity or, bubble.
In the case of the Black Widow Nebula, astronomers suspect that a large
cloud of gas and dust condensed to create multiple clusters of massive
star formation. The combined winds from these groups of large stars
probably blew out bubbles into the direction of least resistance, forming
a double bubble.
The infrared image was captured by the Galactic Legacy Infrared Mid-Plane
Survey Extraordinaire (GLIMPSE) Legacy project. The Spitzer picture is a
four-channel false-color composite, showing emission from wavelengths of
3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0
microns (red).
