Chris Lintott and Maggie Aderin-Pocock report on the reaction to the dramatic announcement of the discovery of phosphine gas in the clouds of Venus, a gas that could be a sign of life. Venus remains an inhospitable and unlikely host. But if not Venus, where in the solar system is the best place to look for alien life? Chris and Maggie investigate the latest missions to Mars and the icy moons of Jupiter and Saturn. Away from the search for life, Pete Lawrencepreviews the best meteor showers of the year.

In these extraordinary times, there is one thing that can offer solace to everyone – the wonder of the natural world. In the most extreme of environments, from the hottest deserts to the freezing poles, from the highest mountains to underwater kingdoms, animals overcome adversity to survive and thrive, offering a message of hope to humanity.
To raise our spirits, David Attenborough, Hans Zimmer and Dave unite for a special Natural History event – Planet Earth: A Celebration. The special one-hour programme brings together eight of the most extraordinary sequences from Planet Earth II and Blue Planet II including racer snakes vs iguana, surfing bottlenose dolphins and rare footage of the Himalayan snow leopard.

In the fifth episode Neil deGrasse Tyson explores questions that have baffled scientists for centuries. Can we know the universe? Are our brains capable of comprehending the cosmos in all of its complexity and splendor?. We don't yet know the answers because our brain remains almost as much of a mystery to that questions as the universe itself. An abandoned orphan's dream opened the way to understanding the architecture of thought.

Why do we sleep? And what does sleep have to do with memory, trauma, and our emotions? From fruit flies to whales, virtually every animal sleeps. But why? Why do we need to spend nearly a third of our lives in such a defenseless state? Scientists are peering more deeply into the sleeping brain than ever before, discovering just how powerful sleep can be, playing a role in everything from memory retention and emotional regulation to removing waste from our brains. So why are we getting so little of it?

To celebrate the 30th anniversary of its launch, this film tells the remarkable story of how the Hubble Space Telescope revealed the awe and wonder of our universe and how a team of daring astronauts risked their lives to keep it working.
Additionally, a team led by Greg Bacon and Dr Frank Summers has transformed many of Hubble's most awe-inspiring images into visualisations - from the spectacular Orion Nebula to the fabulous Whirlpool Galaxy and ethereal Horsehead Nebula. One of the most mind-blowing of the visualizations takes the viewer on a remarkable journey, flying across the Universe to witness almost 13 billion years of cosmic evolution. It's called the 'Hubble Ultra Deep Field' and was created when Hubble stared at a small patch of sky for the equivalent of more than 11 days to see some of the most distant galaxies ever observed.

Hours before Mehmed II launches his final assault, an ominous sight shakes both sides. Rumors of a 40-ship fleet's imminent arrival have swirled for weeks, but it's exact whereabouts remained unknown. Ottoman cannons reduced the city walls to rubble, and Venetian reinforcements arrived too late. The conquest of Constantinople ushers in a new era for the Ottoman Empire, being a dominant force in world politics for 300 years. Mehmed II, in many senses, changed the nature of world history.