The Small Magellanic Cloud is a satellite galaxy of the Milky Way. It contains this group of baby stars that are still forming from collapsing gas clouds and have not yet ignited their hydrogen fuel.

This pinwheel-shaped spiral galaxy was home to a supernova whose light reached Earth in 2002. Scientists are using the supernova burst to measure the expansion rate of the universe.

The large Whirlpool Galaxy (left) is known for its sharply defined spiral arms. Their prominence could be the result of the Whirlpool's gravitational tug-of-war with its smaller companion galaxy (right).

This giant spiral disk of stars, dust and gas is 170,000 light-years across, almost twice the diameter of our Milky Way galaxy. M101 is estimated to contain at least one trillion stars.