We are all seeing rather less of the Sun. Scientists looking at five decades of sunlight measurements have reached the disturbing conclusion that the amount of solar energy reaching the Earth's surface has been gradually falling. Paradoxically, the decline in sunlight may mean that global warming is a far greater threat to society than previously thought.
Between the blue sky above and the infinite blackness beyond lies a frontier that scientists have only just begun to investigate. In "At the Edge of Space," NOVA takes viewers on a spectacular exploration of the Earth-space boundary that's home to some of nature's most puzzling and alluring phenomena: the shimmering aurora, streaking meteors, and fleeting flashes that shoot upwards from thunderclouds, known as sprites.
As part of the connecting landmass between North and South America, Mexico has long been at the center of a tectonic tug of war spanning millennia. The result is two of the world's largest, most active volcanoes--the rumbling Popocatepetl and the menacing Volcano De Colima--whose vengeful displays of wrath are increasing in frequency. Could a cataclysmic eruption be just around the corner?
Ice may be nothing more than frozen water but, as Iain explains, it holds extraordinary power. Descending 150m down a frozen waterfall, he sees a glacier in action from below and discovers why the huge Jacobshaven glacier is retreating, he shows how it shaped our past and may now threaten our future.