An asteroid nine times the size of a cruise ship is dropping by Earth on Friday, and it's not coming alone. Asteroid 1998 QE2 will be about 3.6 million miles from our planet at its closest approach. And its proximity has already given scientists a surprise: It has its own moon, measured at about 2,000 feet wide.
There was great fanfare when the Mars Science Laboratory launched in November 2011, and again when its precious cargo — NASA's Mars rover Curiosity — touched down on the red planet in August 2012.
The eight months in between had drama of their own. Curiosity was constantly bombarded with radiation as it traveled through space — high-energy protons thrown out by the sun, and galactic cosmic rays slicing through the solar system from distant supernovas.
The Ring Nebula, whose iconic shape and large size make it a favorite of amateur astronomers, can now be seen in new detail, after NASA's Hubble Space Telescope captured a sharp image of the nebula. Researchers say the new clarity reveals details that were previously unseen, and a structure that's more complex than scientists had believed.