Stellar NurseryThis cluster of primary colors is the Trifid Nebula—nicknamed the "star factory"—which sits in the Sagittarius constellation. Submitted to National Geographic's My Shot photo community on August 1, the colorful composition is also one of National Geographic's favorite space pictures this week.Trifid actually comprises three kinds of nebulae—great clouds of interstellar gas and dust.The "reflection nebula" at left scatters blue light from nearby stars. To the right, infant stars jammed in the center of Trifid heat surrounding gas, whose high hydrogen content explains the reddish glow. Finally, the star factory is cross-crossed by slender, light-obscuring "dark nebulae."(See more nebula pictures.)—Kastalia Medrano

Image by Stephen Mounioloux, Your Shot