What would the universe look like if you were a billion times smaller or a billion times bigger?

In this mind-bending 2x60’ series for BBC Four and iPlayer, Secrets of Size: Atoms To Supergalaxies, Professor Jim Al-Khalili will see the universe at different scales, from the tiniest objects just a few atoms in size, to vast structures consisting of hundreds of thousands of interconnected galaxies.

Investigating these astonishing objects will reveal fundamental truths about our universe. At the end of each film, the audience will see the largest structure ever discovered by scientists in the universe, and the smallest thing in existence which science has managed to photograph.

Jim starts off by “Going Small”. In this episode, he will enter the Alice in Wonderland world of objects that are too tiny to glimpse with the naked eye. Starting with the smallest insects, he moves on to encounter living cells with amazing super-powers and confronts some of humanities deadliest enemies in the form of viruses.

Going smaller still, he encounters wondrous new nanomaterials such as graphene and its discoverer Andre Geim—these are revolutionising engineering, medicine, computing, electronics and environmental science. Ultimately, Jim comes face to face with the fundamental building blocks of the world around us—atoms. Understanding the science of the “small” is crucial to the future of humanity.

In the “Going Big” episode, Jim encounters ever larger cosmic structures to reveal the latest breakthroughs in our understanding of the universe. For example, there’s the heliosphere, a vast cloud of solar plasma which surrounds and protects the solar system. Its unique physics will help us understand how life is possible.

Larger still, Jim comes face to face with our galactic home, the Milky Way, a monstrous structure sculpted by the gravitational forces of dark matter. From pioneering researcher, Andrew Fabian, Jim finds out about the black hole at its centre whose strange behaviour includes emitting the lowest note ever heard in the cosmos. A

t an even greater scale, Jim will encounter huge structures such as the Laniakea galactic super-cluster of which the Milky Way is a tiny part. Then there’s “the giant arc”, a collection of galaxies which spans more than three per cent of the observable universe.

From its discoverer, British PhD student Alexia Lopez, Jim finds out this gargantuan structure is forcing scientists to reassess their theory of how the universe evolves and may overturn some of the most fundamental principles in physics.

Secrets of Size: Atoms to Supergalaxies, a 2x60’ for BBC Four and iPlayer, is made by Furnace TV, co-produced by The Kavli Prize.