In the 1950s and early '60s, a small band of high-altitude pioneers exposed themselves to the extreme forces of the space age long before NASA's acclaimed Mercury 7 would make headlines. Though largely forgotten today, balloonists were the first to venture into the frozen near-vacuum on the edge of our world, exploring the very limits of human physiology and human ingenuity in this lethal realm.
Asteroids have a bad reputation as deadly rocks from space. They wiped out the dinosaurs and will be back for us. But that's only half the story. Ancient asteroids built the Earth. And they may have brought life to its barren surface. Asteroids will shape our future as much as our past. They are the perfect location for deep space colonies and could be the stepping stones that eventually send humans out into the cosmos. From icy worlds with more fresh water than Earth to flying mountains of pure metal, a hundred miles wide, scientists are striving to unlock their secrets. Could these enigmatic space rocks hold the key to how life in the Universe arises and is extinguished?
NASA is on a mission to send humans to Mars within just 15 years, but to reach this next frontier of space exploration, experts must discover new technology and cutting-edge science that protects astronauts from the Red Planet's deadliest killers.
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.