Catch up TV
2018: 5. Jupiter Revealed
'To send a spacecraft there is a little bit insane,' says Scott Bolton when talking about Jupiter, the largest planet in the solar system. But that is exactly what he has done, because Scott is head of Juno, the Nasa mission designed to peer through Jupiter's swirling clouds and reveal the wonders within. But this is no ordinary world. This documentary, narrated by Toby Jones, journeys with the scientists into the heart of a giant.\n\nProfessor Kaitlin Kratter shows us how extreme Jupiter is. She has come to a quarry to measure out each planet's mass with rocks, starting with the smallest. Mercury is a single kilogram, and the Earth is 17. But Jupiter is on another scale entirely. It is seven tonnes - that is two and a half times the mass of all the other planets combined. On Kaitlin's scale it is not a pile of rocks, it is the truck delivering them. With extreme size comes extreme radiation. Juno is in the most extreme environment Nasa has visited. By projecting a 70-foot-wide, life-size Juno on a Houston rooftop, Scott shows us how its fragile electronics are encased in 200kg of titanium. As Scott puts it, 'we had to build an armoured tank to go there.'\n\nThe team's efforts have been worthwhile. Professor Andrew Ingersoll, Juno's space weatherman, reveals they have seen lightning inside Jupiter, perhaps a thousand times more powerful than Earth's lightning. This might be evidence for huge quantities of water inside Jupiter. Prof Ingersoll also tells us that the Great Red Spot, a vast hurricane-like storm that could swallow the Earth whole, goes down as far as they can see - 'it could go down 1,000s of kilometres'.\n\nDeeper into the planet and things get stranger still. At the National Ignition facility in northern California, Dr Marius Millot is using powerful lasers normally used for nuclear fusion for an astonishing experiment. He uses '500 times the power that is used for the entire United States at a given moment' to crush hydrogen to the pressures inside Jupiter. Under these extreme conditions, hydrogen becomes a liquid metal. Juno is finding out how much liquid metallic hydrogen is inside Jupiter, and scientists hope to better understand how this flowing metal produces the most powerful aurora in the Solar System.\n\nBut what is at Jupiter's heart? In Nice, Prof Tristan Guillot explains how Juno uses gravity to map the planet's centre. This can take scientists back to the earliest days of the solar system, because Jupiter is the oldest planet and it should contain clues to its own creation. By chalking out an outline of the Jupiter, Tristan reveals there is a huge rocky core - perhaps ten times the mass of Earth. It is now thought Jupiter started as a small rocky world. But there is a surprise, because Juno's findings suggest this core might be 'fuzzy'. Tristan thinks the planet was bombarded with something akin to shooting stars. As he puts it, 'Jupiter is quite unlike we thought'.
Source: BBC 2
Most recent episodes of Horizon
Horizon
The Great British Drought
Documentary from 1976 that explores the drought crisis of that year, going behind the scenes to discover its impact on farming, the landscape and industrial and domestic consumers.
13-06-2026
BBC 2
Horizon
2020: Pluto: Back From The Dead
The incredible story of how Pluto has been propelled from an unremarkable ball of ice on the edge of the solar system to a world of unimaginable complexity - where some form of ...
13-04-2026
BBC 2
Horizon
1997-1998: Mir Mortals
First transmitted in 1998, this is the story of four men who orbited Earth on board the ill-fated Mir space station, which NASA declared unsafe in 1991. Although Mir had been li ...
10-02-2026
BBC 2
Horizon
2022: How To Sleep Well With Michael Mosley
A third of the population regularly struggle with our sleep, which rose to one in two during the pandemic - the highest it’s ever been. However, as more and more people se ...
07-01-2026
BBC 2
Horizon
2020: Hubble: The Wonders Of Space Revealed
To celebrate the 30th anniversary of its launch, this film tells the remarkable story of how Hubble revealed the awe and wonder of our universe and how a team of daring astronau ...
24-04-2025
BBC 2
Most popular episodes of Horizon
Horizon
The Great British Drought
Documentary from 1976 that explores the drought crisis of that year, going behind the scenes to discover its impact on farming, the landscape and industrial and domestic consumers.
13-06-2026
BBC 2
Horizon
2012-2013 - Swallowed By A Black Hole
As a gas cloud strayed within the gravitational reach of a black hole at the centre of the Milky Way, it was hoped we would observe a feeding supermassive black hole in action.
18-09-2014
BBC 2
Horizon
2018: 12. Diagnosis On Demand? The Computer Will See You Now
Could a machine replace your doctor? Dr Hannah Fry explores the incredible ways AI is revolutionising healthcare - and what this means for all of us. This film chronicles the in ...
29-11-2018
BBC 2
Horizon
2018: 1. My Amazing Brain: Richard's War
Horizon follows the story of Richard Gray and his remarkable recovery from a life-changing catastrophic stroke. The film shows the rarely seen journey back to recovery. Recorded ...
08-04-2019
BBC 2
Horizon
The U00a310 Million Challenge
Series exploring topical scientific issues. To celebrate its 50th birthday, Horizon invites the public to play a role in tackling the greatest challenges facing science today.
11-06-2014
BBC 2
Horizon
2018: 7. A Week Without Lying - The Honesty Experiment
Deception is an integral part of human nature and it is estimated we all lie up to nine times a day. But what if we created a world in which we couldn't lie? In a radical experi ...
03-02-2022
BBC 2
Horizon
2013-2014 - What's Wrong With Our Weather?
Physicist Dr Helen Czerski and meteorologist John Hammond make sense of Britain's extreme weather and discover that recent extreme winters are connected by the jet stream.
11-02-2024
BBC 2