The sun gives us warmth and light. It is the fuel of life. Without the energy of the sun almost nothing grows, thrives or lives. But the sun was not put there for our benefit. It is not this big jolly ball of nice smiling down on us, wishing us all a good day. It is not our friend. The sun is a monster. A planet killer. And we don't see that side of the sun down here.
But eight astronauts, with over 1,000 days in space between them, can show us how being up there helped them understand the suns bright fury.

Widespread dietary changes are needed if we’re to combat the range of health problems associated with obesity and the environmental damage caused by industrial farming. Switching to a vegan diet is a potential solution, but selling the idea to the meat-eaters around the world is a tricky proposition.

At 11 o'clock on New Year's Eve of the Cosmic Calendar, Homo erectus stood up for the first time, freeing its hands and earning the species its name. They began to move around, to explore, daring to risk everything to get to unknown places. Our Neanderthal relatives lived much as we did and did many of the things we consider to be 'human.' More restless than their cousins the Neanderthals and Denisovans, our Homo sapiens ancestors crossed seas and unforgiving landscapes, changing the land, ocean and atmosphere, leading to mass extinction. The scientific community gave our age a new name, 'Anthropocene.'
Since the first civilizations we've wondered if there's something about human nature that contains the seeds of our destruction. Syukuro Manabe was born in rural Japan and took an intense interest in Earth's average global temperature. In the 1960's, he would assemble the evidence he needed to predict the increase of Earth's temperature due to greenhouse gases until it becomes an uninhabitable and toxic environment, leading to our extinction. 'This doesn't have to be,' says Neil deGrasse Tyson, 'it's not too late. There's another hallway, another future we can still have; we'll find a way.'

The search for climate change solutions requires passion, resources and a sense of urgency -- three qualities Bill Gates clearly possesses. Bill has founded a start-up called TerraPower. After extensive computer modelling, the idea showed promise. Its new reactor greatly reduced the chance of human error. Fuelled by depleted uranium, the travelling wave reactor functions like a slow-burning candle and requires refuelling only once every decade. Bill and his team believed they had finally developed the ideal energy source, a reactor that was clean, efficient, and most importantly, safe.

The polar regions of our planet may seem beyond the reach of most of us, but they are not beyond our influence. We, unintentionally, are changing these frozen worlds, and these changes will not just affect the poles but the whole planet. On the unforgiving frontier of climate change, polar bears, walruses, seals and penguins find their icy Edens in peril.

Everything that lives on land, animal or plant, depends on fresh water. Yet only part of it is within reach: Much of the planet's fresh water, is locked away, almost two-thirds of it lies frozen around the poles. Even away from the poles, much of the land's fresh water freezes each winter. The need for fresh water is as strong as ever. However, the supply is becoming increasingly unpredictable and uncertain for all manner of species. We are not alone in our need for water, but we have the ability to ensure the fresh waters of the world do flow, and we alone can determine how they are shared.