A new image from NASA's Spitzer Space Telescope shows giant "bubbles" of dust and gas bursting with new star formation many light-years away.
The bubbles are about 10 to 30 light-years across, based on what astronomers know about them and other cosmic bubbles.
However, the space agency noted that figuring out the exact sizes of individual bubbles can be challenging, because their distance from Earth is hard to measure.
"Flows of particles emitted by the stars, called stellar winds, as well as the pressure of the light the stars produce, can push the surrounding material outward, sometimes creating a distinct perimeter," NASA said in a statement accompanying the image.
Spitzer sees infrared light, which isn't visible to the human eye. Many of these interstellar nebulas -- which are clouds of gas and dust in space -- are best observed in infrared light because infrared wavelengths can pass through intervening layers of dust in the Milky Way galaxy.
Visible light, however, can be blocked more by dust, according to NASA.
The Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington.