No ground to stand on

About this video

Beyond Mars are the four giant planets: Jupiter, Saturn, Uranus and Neptune. Put the four rocky planets side by side and Jupiter is still almost four times as wide. At their true sizes, Jupiter is about 11 times as wide as the Earth, Saturn about 9 times, and Uranus and Neptune about 4 times.

The giants are mostly gas, with no ground. You could never land on one: a spacecraft falling in would sink deeper and deeper, into thicker and hotter gas, until the weight of the gas above crushed it.

Jupiter, the biggest, has a storm called the Great Red Spot that is wider than the whole Earth and has been blowing for more than 150 years. More than 1,000 Earths would fit inside Jupiter.

Saturn's rings are not solid. They are countless pieces of ice and rock, from specks of dust to pieces the size of a house, each going around Saturn on its own. Saturn is so light for its size that it would float in water, if there were a bath big enough.

Uranus and Neptune are freezing blue worlds of gas and slushy ice. Uranus goes around the Sun lying on its side, so each of its poles gets about 42 years of sunlight and then about 42 years of dark. Neptune has winds of about 2,000 km/h, and since it was found in 1846 it has gone around the Sun only once.

The giants also have many moons: Jupiter nearly 100 and Saturn more than 250. Jupiter's moon Ganymede is bigger than the planet Mercury.

Transcript

1. 0:00Put the four rocky planets side by side, and Jupiter is still almost four times as wide.
2. 0:11It is the biggest of the four giant planets, far out beyond Mars.
3. 0:22Here are the giants at their true sizes, next to the Earth. Jupiter is about eleven Earths wide, Saturn about nine, Uranus and Neptune about four.
4. 0:36Beside them, the rocky planets look like crumbs.
5. 0:48But you could never land on one. The giants are mostly gas, with no ground.
6. 0:58A ship falling in would just sink deeper and deeper, until the weight of the gas above crushed it.
7. 1:12Jupiter has a storm called the Great Red Spot. It is wider than the whole Earth, and it has been blowing for more than a hundred and fifty years.
8. 1:26More than a thousand Earths would fit inside Jupiter.
9. 1:36Saturn's rings are not solid. They are countless pieces of ice and rock, from specks of dust to the size of a house.
10. 1:48And Saturn is so light for its size that it would float, if you could find a bath big enough.
11. 2:00Uranus and Neptune are freezing blue worlds of gas and slushy ice.
12. 2:08Uranus lies on its side. So each pole gets about forty-two years of sunlight, then forty-two years of dark.
13. 2:20Neptune's winds blow at about two thousand kilometres an hour. Since it was found in 1846, it has gone around the Sun only once.
14. 2:32The giants have many moons. Jupiter has nearly a hundred, Saturn more than two hundred and fifty. Jupiter's moon Ganymede is bigger than the planet Mercury.
15. 2:46Four giant worlds of gas and ice, with no ground to stand on.