This is the story of the most extraordinary journey in human exploration, the Voyager space mission. In 1977 two unmanned spacecraft were launched by NASA, heading for distant worlds. It would be the first time any man-made object would ever visit the farthest planets of the solar system - Jupiter, Saturn, Neptune and Uranus. On the way the Voyagers would be bombarded by space dust, fried by radiation and discover many of the remarkable wonders of the solar system. Now, at the end of 2012, 35 years and 11 billion miles later, they are leaving the area of the sun's influence. As they journey out into the galaxy beyond they carry a message from Earth, a golden record bolted to the side of each craft describing our civilisation in case of discovery by another. This is the definitive account of the most intrepid explorers in Earth's history.
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.
An exploration of the dramatic fate of our future descendants, the technology they'll need to survive the end of this world billions of years from now and our options for colonizing and starting again on a new planet somewhere far from Earth.
With repeated triumphs and new challenges comes increasing risk, until loss breaks the pattern. The white-knuckle suspense thriller of Apollo 13's famous near-disaster is only a triumphant prelude to darker moments ahead. The launch of the space shuttle program promises routine trips to Earth orbit for many new astronauts. But just when that promise seems fulfilled, routine shuttle launches begin to bore the public. NASA responds by training a school-teacher to fly, in order to teach children lessons from space. Christa McAuliffe's life is tragically cut short as she and the rest of the crew perish aboard the shuttle Challenger. All missions are halted. Eventually the shuttle returns to orbit, for fifteen years of successful missions until disaster strikes again with the shocking loss of Columbia. It would be the beginning of the end for the shuttle.
Over billions of years, planet Earth has become home to an amazing interdependent ecosystem, containing a dizzying variety of animals and plants. But how did life here begin? And does it exist anywhere outside of our solar system? We uncover the secrets of our world by tracking the evolution of the cosmos itself, from the Big Bang onwards. Follow scientists responsible for some of the major breakthroughs in understanding the origins of life and witness how their discoveries are fundamentally changing the way we perceive the universe.
2017 • Astronomy
Today we are talking about the life -- and death -- of stars. Low mass stars live a long time, fusing all their hydrogen into helium over a trillion years. More massive stars like the Sun live shorter lives. They fuse hydrogen into helium, and eventually helium into carbon (and also some oxygen and neon). When this happens they expand, get brighter, and cool off, becoming red giants. They lose most of their mass, exposing their cores, and then cool off over many billions of years.