Humans have long gazed up at the night sky, wondering whether other lifeforms and intelligences could be thriving on worlds far beyond our own. But over the last few decades, ultra-sensitive telescopes and dogged detective work have transformed alien planet-hunting from science fiction into hard fact. We expected to find worlds similar to the planets in our own solar system, but we instead discovered a riot of exotic worlds. Vivid animation based on data from the most successful planet hunter of them all, the Kepler space telescope, brings these worlds into view: puffy planets with the density of polystyrene, unstable worlds orbiting two suns and 1,000-degree, broiling gas giants with skies whipped into titanic winds.
But perhaps the most startling discovery was the number of worlds that may be contenders for a second Earth, at the right distance from their sun to have that ingredient so crucial for life as we know it, liquid water. Amongst them, we witness the most tantalizing discovery of all: a so-called ‘super-Earth’, situated in the Goldilocks zone - the area just the right distance from a sun to potentially support life - and with the faint signal of water in its atmosphere.

In just one generation, our ability to search for planets beyond our solar system has transformed. With modern techniques and telescopes, planetary scientists have found thousands of exoplanets in our universe, and many of them have the perfect conditions for life. Are we about to find Earth’s twin?

The meteoric rise of renewable energy has consequences for our electricity supply. While coal and gas fired power stations can generate electricity whenever you need it, renewables are intermittent by nature. So we need a backup plan for when the wind stops or the sun goes down.
All over the world, engineers and scientists are racing to solve one key problem; how to safely and efficiently store electricity at a huge scale but at a low cost. The quest is producing some truly remarkable ideas and this episode details three of them.

Voyager, the most ambitious space mission in history. They're the first probes to truly explore half the planets in our solar system: Jupiter, Saturn, Uranus and Neptune. These went from dots of light in the sky, to real worlds. The Voyager missions have ventured far beyond where other probes have explored. They're the first spacecraft to taste interstellar space, exploring further than any human made spacecraft has gone before. They are the greatest space mission ever. The legacy of Voyager is our remnant, it is our memory. It is a sampling of humanity that is out there now among the stars. And if they last until the death of the Universe, as the final stars fade, and everything goes dark, they will be humanity's final statement: ‘We were here.’
In the last episode of the season 10, experts explore the ultimate, ongoing mission of the Voyager spacecrafts.

New discoveries have rewritten the history of our solar system, revealing a complex and violent story that begins with the birth of our Sun from the debris of a massive galactic collision, to its eventual fate as a lone zombie star.
It is a dramatic history of elegant beauty and extreme violence. The inner solar system was like a congested highway. Planets crossing lanes, frequent collisions. There were a lot of planets that could have made it but didn't, and we just happen to be one of the lucky ones that did. The players in our solar system's story are more tangled up than we ever imagined. Without all of these things interplaying, the Earth wouldn't have the stable environment that we have today, and life wouldn't be able to exist.

As summer spreads across our planet, honey bees toil, snow geese breed, tadpoles awaken and lions stalk wildebeest in search of lush grass.
Our planet is solar-powered. But due to the Earth's tilt, it doesn't strike its surface evenly. This solar energy arrives in varying amounts at different times of the year. The huge increase that comes with summer also triggers countless migrations.