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.
2012 • Astronomy
Twelve billion miles away a tiny spaceship is leaving our solar system and entering the void of deep space. It is the first human-made object ever to do so. Slowly dying within its heart is a plutonium generator that will beat for perhaps another decade before the lights on Voyager finally go out. But this little craft will travel on for millions of years, carrying a Golden Record bearing recordings and images of life on Earth. The story of Voyager is an epic of human achievement, personal drama and almost miraculous success. Launched 16 days apart in 1977, the twin Voyager space probes have defied all the odds, survived countless near misses and almost 40 years later continue to beam revolutionary information across unimaginable distances. With less computing power than a modern hearing aid, they have unlocked the stunning secrets of our solar system. This film tells the story of these magnificent machines, the men and women who built them and the vision that propelled them farther than anyone could ever have hoped.
Thanks to the wonders of physics, astronomers can map a timeline of the universe’s history. Today, Phil’s going to give you an overview of those first few minutes (yes, MINUTES) of the universe’s life. It started with a Big Bang, when the Universe was incredibly dense and hot. It expanded and cooled, going through multiple stages where different kinds of matter could form. It underwent a phenomenally rapid expansion called inflation, which smoothed out much of the lumpiness in the matter. Normal matter formed atoms between 3 and 20 minutes after the bang, and the lumps left over from inflation formed the galaxies and larger structures we see today.
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.