Humans have long gazed up at the night sky, wondering whether other lifeforms and intelligences could be thriving on worlds far beyond our own.

Answering that question seemed fated to remain pure speculation. But over the last few decades, ultra-sensitive telescopes and dogged detective work have transformed alien planet-hunting from science fiction into hard fact. Gone are the days of speculation; the hunt for extraterrestrials has become a matter of serious scientific inquiry.

As the hunt for alien worlds began, 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. Our latest survey of the galaxy estimates that there are billions of rocky planets 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.

With over 2,800 exoplanets confirmed by Kepler and discoveries still rolling in, Brian lays out his own answer to the age-old question with thrilling new science: are we alone?

Professor Brian Cox continues his epic exploration of the cosmos by looking at the faint band of light that sweeps across the night sky – our own galaxy, the Milky Way. The Sun is just one of almost 400 billion stars that form this vast, majestic disk of light, our own home in the universe. We’ve longed to understand our galaxy’s secrets since the time of the ancient Greeks, yet it’s only very recently, thanks to a cutting-edge space telescope, that we’re finally able to reveal the Milky Way’s dramatic history and predict its cataclysmic future.

One mission more than any other has deepened our understanding of the galaxy, the European Space Agency’s Gaia Space Telescope. It painstakingly measures the true position of over a billion stars, producing the most accurate map of our galaxy ever created. But more than mapping stars, Gaia also measures their movement, allowing us to track their positions back through time – to rewind the history of the Milky Way. It has created a new kind of science: galactic archaeology.

Our galaxy started to form shortly after the Big Bang around 13.6 billion years ago. It started out a fraction of the size it is today, and Gaia has revealed how it grew over the eons. Beautifully rendered VFX based on the very latest Gaia data has uncovered the remarkable story of our galaxy’s evolution. As our young galaxy encountered rival galaxies, it experienced a series of violent growth spurts and intense periods of cataclysmic change while battling to survive.

Over billions of years, our Milky Way cannibalised neighbouring galaxies, adding countless new stars and triggering great epochs of creation. Brian reveals we may even owe our own existence to one of these galactic collisions. Each time our galaxy feeds, a new era of star formation begins, fuelled by incoming torrents of fresh gas and energy. The latest evidence suggests that our own star was possibly born in one such event.

We may be small compared to the universe, but we are the consequence of grand events, and there is another collision to come. Another, larger galaxy is coming our way. Andromeda is heading straight for us at a quarter of a million miles per hour. The Milky Way’s long-term fate is in the balance.

Professor Brian Cox continues his epic exploration of the universe with a journey into darkness. The centre of our galaxy is home to an invisible monster of unimaginable power – a supermassive black hole named Sagittarius A*. Weighing four million times the mass of the Sun, it’s an object with such an immense gravitational field that nothing can escape – not even light.

For decades, black holes existed purely in the minds of theoretical physicists – the idea was so absurd, scientists thought they couldn’t possibly exist in nature. But recent astronomical breakthroughs have confirmed not only that black holes like Sagittarius A* exist, but that these bizarre invisible objects may be the ultimate galactic protagonists.

Stunning CGI takes us back to witness the fiery origins of our galaxy’s black hole 13.6 billion years ago, when the early universe was home to colossal blue stars hundreds of times more massive than our sun. These stars lived fast and died young, and when they ran out of fuel, they collapsed under their own enormous mass, crushing down into an object so small and so dense it punched a hole in the fabric of the universe. That is how our galaxy’s black hole was born.

The story of Sagittarius A* is a tale of both destruction and creation. Over billions of years, it feasted on nearby gas and stars, and through cataclysmic mergers with other black holes it sent ripples through the fabric of the universe. But Brian reveals that we have recently come to understand how our black hole is also an agent of creation. A breakthrough discovery by Nasa’s Fermi gamma-ray telescope has shown that our black hole once had the power to sculpt the entire galaxy, creating vast bubbles of gas above and below our galaxy that persist to this day. We may even have Sagittarius A* to thank for our own existence.

In a mind-bending conclusion, Brian reveals how our modern understanding of black holes is challenging our concepts of reality to the breaking point. He takes us on a trip inside Sagittarius A*, where we discover that the interior of a black hole is not a tomb but a gateway to the end of the universe. And weirder still, in trying to understand the fate of objects that fall into Sagittarius A*, scientists have come to a stunning conclusion: space and time, concepts so foundational to how we experience the world around us, are not as fundamental as we once thought.

Professor Brian Cox asks the ultimate question: how did the universe come to be? It is daunting in its scale. We live on one planet of eight that orbit just one of the 400 billion stars in our galaxy, which in turn is one of trillions in the universe. Yet it is amongst those galaxies that we have been able to unravel the story of the universe’s creation. Thanks to a series of discoveries, our most powerful space missions have unravelled 13.8 billion years of cosmic evolution and revealed the story of our universe from its birth all the way to the arrival of our nascent civilisation.

Our guide on this odyssey back to the dawn of time is light. Telescopes are time machines – by looking out into the distant universe, they open a window to the past. One telescope more than any other has helped us journey through the history of the universe: NASA’s Hubble Space Telescope. Over the course of three decades, Hubble has shown us cosmic evolution in action – including stars and planets being born and galaxies colliding. Remarkably, Hubble has even found one of the first galaxies ever to exist in the universe, which was born some 13.4 billion years ago. It’s a discovery that hints at the beginnings of our own Milky Way. Vivid CGI brings this ancient galaxy to life, allowing us to witness for ourselves the first dawn. It was the beginning of a relationship between stars and planets that would, on a faraway world, lead to the origin of life – and ultimately to us.

Hubble’s incredible discoveries have allowed scientists to piece together much of our cosmic story, but it cannot take us back to the most important moment in history: the Big Bang. For decades, the moment the universe began was the subject of pure speculation, but by combining astronomy and cosmology, scientists have finally found a way to put their theories to the test and study the momentous events that took place during the Big Bang. They can do this because the European Space Agency’s Planck space telescope has seen the afterglow of the Big Bang itself – something we call the cosmic microwave background. The unparalleled detail Planck gave us has helped confirm something remarkable: the Big Bang may not be the beginning. There was a time before the dawn – a place beyond anything we can comprehend. Brian transports us back to the fraction of a second before the Big Bang, when the seeds of our universe were planted.

The story of our universe’s origin is an improbable odyssey, one that helps us understand how we came to be here, contemplating this vast cosmic drama.