A milestone in physics: In 2015, scientists proved the existence of gravitational waves. These waves travel billions of light-years through space, eventually reaching Earth and bringing us insights that were previously unattainable.
Astronomers are laying the groundwork to locate a new planet for the human race to inhabit, and the more alien worlds they discover and encounter, the more they unmask the mysterious and truly destructive nature of the cosmos.
Life once existed on Mars, but a series of devastating mass extinctions have made present-day life nearly impossible. The latest science shows how Martian life keeps bouncing back as it transforms from a watery world like Earth into a desert planet.
Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners, but instead exist in smaller groups and larger clusters. Our Milky Way is part of the Local Group, and will one day collide with the Andromeda galaxy. Clusters of galaxies also clump together to form superclusters, the largest structures in the Universe. In total, there are hundreds of billions of galaxies in the Universe.
Almost everything we know today about the beautiful giant ringed planet comes from Cassini, the NASA mission that launched in 1997 and arrived at Saturn in 2004. Since then, the space probe has been beaming home miraculous images and scientific data, revealing countless wonders about the planet, its rings and 62 moons - including some that could harbor life. As the mission approaches its final days in 2017, it attempts one last set of daring maneuvers - diving between the innermost ring and the top of Saturn's atmosphere. Aiming to skim less than 2000 miles above the cloud tops, no spacecraft has ever gone so close to Saturn, and hopes are high for incredible observations that could solve major mysteries about the planet's core. But such a daring maneuver comes with many risks and is no slam dunk. In fact, slamming into rocks in the rings is a real possibility. Join NASA engineers for the tense and triumphant moments as they find out if their bold re-programming has worked, and discover the wonders that Cassini has revealed over the years.