Over 2 decades of Chandra X-ray Observatory views of the Crab Nebula and Cassiopeia A have been time-lapsed. The Chandra team explains here. Credit: NASA/CXC/A. Hobart Top 30 Greatest Teen Movie ...

From the mysterious 'Pillars of Creation' to the iconic Horsehead nebula, check out these 7 breathtaking images of Nebulae ...