Earth is the only home we've ever known, and it's treated us well so far. But whether it’s climate change, an apocalyptic asteroid, or some horrifying disaster we don’t even know about yet, the Earth won't live forever.
Now that we’re done with the planets, asteroid belt, and comets, we’re heading to the outskirts of the solar system. Out past Neptune are vast reservoirs of icy bodies that can become comets if they get poked into the inner solar system. The Kuiper Belt is a donut shape aligned with the plane of the solar system; the scattered disk is more eccentric and is the source of short period comets; and the Oort Cloud which surrounds the solar system out to great distances is the source of long-period comets. These bodies all probably formed closer into the Sun, and got flung out to the solar system’s suburbs by gravitational interactions with the outer planets.
Untangling Alzheimer's is a dramatic and inspiring medical investigation driven by David Suzuki's journey to understand the science of Alzheimer's and the surprising new insights into its cause. David has a very personal interest in the disease because his mother, aunt and two uncles died of it. We join David on an intimate journey as he explores the newest breakthroughs in this devastating disease as well as his own chances of contracting the cruel condition. Alzheimer's today is the only leading cause of death that cannot be cured, prevented or even slowed. Worse, it's the only leading cause of death that is on the rise – and not simply because baby-boomers are getting older. Studies show that the increase is absolute across all age groups, and death rates continue to climb. With a new case developing every 69 seconds, scientists now speak of the Alzheimer's epidemic.