How come the crescent Moon doesn’t look like this? For one reason, because your eyes can’t simultaneously discern bright and dark regions like this. Called earthshine or the da Vinci […]

How did a star create the Helix nebula? The shapes of planetary nebula like the Helix are important because they likely hold clues to how stars like the Sun end […]

From July of 1997, a ramp from the Pathfinder lander, the Sojourner robot rover, airbags, a couch, Barnacle Bill and Yogi Rock appear together in this 3D stereo view of […]

The arms of a grand design spiral galaxy 60,000 light-years across are unwound in this digital transformation of the magnificent 2005 Hubble Space Telescope portrait of M51. In fact, M51 […]

Shrouded in a thick atmosphere, Saturn’s largest moon Titan really is hard to see. Small particles suspended in the upper atmosphere cause an almost impenetrable haze, strongly scattering light at […]

Does the Sun change as it rotates? Yes, and the changes can vary from subtle to dramatic. In the featured time-lapse sequences, our Sun — as imaged by NASA’s Solar […]

Do other stars have planets like our Sun? Previous evidence shows that they do, coming mostly from slight shifts in the star’s light created by the orbiting planets. Recently, however, […]

Why would meteor trails appear curved? The arcing effect arises only because the image artificially compresses (nearly) the whole sky into a rectangle. The meteors are from the Perseid Meteor […]

In the center of this serene stellar swirl is likely a harrowing black-hole beast. The surrounding swirl sweeps around billions of stars which are highlighted by the brightest and bluest. […]

Does the Moon ever block out Mars? Yes, the Moon occasionally moves in front of all of the Solar System’s planets. Just this past Sunday, as visible from some locations […]