[Top View] — The current night sky is dominated by the white glow of myriad middle-aged stars along the lane of the Milky Way. Interstellar "pollution" from thick dust lanes can be seen threading through the long band of stars. They are interspersed with a few pinkish emission nebulae from ongoing star formation. Thousands of stars appear as pinpoints of light throughout the sky.

[Bottom View] — This is an imaginary view of our young Milky Way as it may have appeared 11 billion years ago, as seen from the surface of a hypothetical planet. The night sky looks markedly different than the view today. The Milky Way's disk and central bulge of stars are smaller and dimmer because the galaxy is in an early phase of construction. The heavens are ablaze with a firestorm of new star formation, seen in the pinkish nebulae glowing from stars still wrapped inside their natal cocoons. The handful of stars visible in the night sky are blue and bright because they are young.

The graphic of today's Milky Way was based on an all-sky image from Axel Mellinger and the Finkbeiner all-sky H-alpha survey. The illustration of the early Milky Way was constructed from the all-sky image from Axel Mellinger and Robert Gendler's image of the M33 galaxy

source: http://hubblesite.org/newscenter/archive/releases/2013/45/image/b/