They were the talk of the amateur space community—yellow balls (above) that kept bubbling up when citizen scientists eyed the skies for the Milky Way Project. And so researchers investigated the stellar mystery.
The suspects in the case revealed a new way of detecting the formation of massive stars.
Not actually yellow, but assigned that color in infrared images, the balls turned out to be hidden links between nascent stars, still hidden in the dark, and more mature ones in a later stage of star formation characterized by green gas bubbles. (See "Glowing, Green Space Blob Forming New Stars, Hubble Shows.")
—By Jane J. Lee, photo gallery by Nicole Werbeck
Week's Best Space Pictures: Mars Blasts Puff, Bubble Blows Rough, and Rockets Sound Off
Northern lights gleam, stellar debris blows into a bubble, and gassy explosions leave behind pits in this week's best space pictures.