THE GODFATHER OF OUR SOLAR SYSTEM

Beyond the inner solar system, past the asteroid belt lies Jupiter. 780 million kilometers away from the sun. Jupiter is a world as strange as it is remote. Jupiter have had a profound effect on the life on Earth is as it is now. 

Earlier on its life, the young Jupiter went on a rampage. The giant planet embarked on a voyage of destruction across the solar system that transformed the destiny of planets and course of life on Earth. Jupiter is the godfather of the planets. Understand it, and you'll understand how the solar system came to be. 

Jupiter is a completely different class of planet to Earth. A gas giant. A swirling ball of hydrogen and helium so large that you could fit 1300 Earths inside. Jupiter has two and a half times the mass of all the other planets, moons and asteroids in the solar system combined and there it has a strong gravitational pull. And this means Jupiter exerts an influence across the entire solar system that's second only to the Sun. That influence can change the history of worlds. 

We see the power of Jupiter's gravitational force in its influence on the closest of Jupiter's moons, Io. Io is the most volcanic world in the solar system, its surface covered in hundreds of active volcanos and lakes of molten lava. The largest known as Loki Patera, is more than 200 kilometers in diameter. A million times in area than any lava lake on Earth. Io is a vision of hell created by the Moon's proximity to Jupiter. The volcanos on Io are powered by tidal heating. The energy that is released in those volcanos doesn't come from within the moon, it is generated by gravity because Io orbits just about 350,000 kilometers from the tops of Jupiter's clouds. Tidal heating causes the raise of temperature to more than a thousand degrees celsius, creating lava lakes and volcanic plumes that rise up to 300 kilometers from moon's surface and out into space. Io provides the solar system of the vivid reminder of the giant planet's power. 

4.5 billion years ago when Jupiter was marching inwards to the inner solar system, had Jupiter continued moving inwards, the planet we inhabit might not have formed at all. Just as it looked that Jupiter would sweep everything away, something stopped the giant planet in its tracks. Because in the shadows of the outer solar system another planet was forming. The solar system's second gas giant, Saturn. And its birth changed everything. 

When a planet forms in a disc of material around a star, as Jupiter did in our solar system, it tends to clear out a gap in the disc. Now, the material tends to fall inwards the star - it's called accretion - that drags the whole thing inwards, and that's what happened to Jupiter. But then a less massive planet, Saturn, formed further out. It cleared out its own disc and it too fell inwards towards the Sun, but more quickly than Jupiter. That meant that Saturn got into resonance with Jupiter. That has the effect of cleaning out the whole region between the two planets. And that has the effect, through a serious of complicated gravitational interactions, of slowing and stopping the infall and eventually causing the two planets to move back out again. And that is what happened to Jupiter and Saturn in our solar system. Saturn caused Jupiter to retreat, leaving behind just enough material from which the inner planets could form. Mercy, Venus, Mars and our home, The Earth. By preventing the formation of super-Earths, Jupiter allowed our planet to grow.