The smallest planet, and the closest to the Sun. Fall onto ground that bakes by day and freezes by night, then down into a planet that is mostly metal.
For this trip you are indestructible. Nothing can hurt you. As you fall, we will tell you what a real body would be going through.
Scroll to fall
500 km above the ground
From here the Sun looks two to three times as wide as it does from Earth, and up to ten times as bright.
NASA's MESSENGER orbited Mercury for four years, then crashed into it in 2015 when its fuel ran out. A new mission, BepiColombo, is due to settle into orbit in November 2026.
A real body: There's no air at all, and nothing to shade you from that Sun.
0 km down
You land on grey, cratered rock, darkened in places by graphite.
By day the ground reaches 430 °C. At night, with no air to hold the heat, it plunges to −180 °C, the biggest swing of any planet.
Yet in deep craters near the poles that never see sunlight, MESSENGER found ice.
A real body: No air, and 430 °C in the sun: hot enough to melt lead. Step into shadow and it turns bitterly cold.
10 km down
As Mercury's insides cooled, the whole planet shrank: its radius is up to 7 km smaller than it once was.
Its crust wrinkled like the skin of a drying apple, leaving cliffs hundreds of kilometres long and up to 3 km high.
A real body: About 1,200 times Earth's air pressure and around 200 °C, in solid rock.
390 km down
Mercury's mantle is thin, only about 400 km, and at its bottom there may be something astonishing.
In 2024, scientists recreated the conditions down here in a lab. They found that carbon could have crystallised into a layer of diamond up to 18 km thick, wrapped around the core.
A real body: About 55,000 times Earth's air pressure and around 1,700 °C. If it's here, you're falling through solid diamond.
420 km down
Below the diamond is iron, and a lot of it. Mercury's core reaches 85% of the way to the surface: this planet is more metal than rock.
Its outer part is liquid and churns enough to make a weak magnetic field, about 1% as strong as Earth's.
A real body: About 60,000 times Earth's air pressure and around 1,800 °C, in a sea of molten iron.
2,440 km down
At the very middle, the iron turns solid.
In 2019, scientists measured how Mercury gently wobbles as it spins and worked out that it hides a solid inner core about 2,000 km across, nearly as wide as the planet Pluto.
A real body: Around 400,000 times Earth's air pressure and roughly 2,000 °C, in the iron heart of the smallest planet.
Through a wrinkled crust and a layer of diamond, to the iron heart of the smallest planet. You made it.
In sunlight you'd be standing on 430 °C rock with no air at all. Step into shadow and it drops towards −180 °C, the biggest swing of any planet.
Yet there is ice here, hidden in polar craters that never see the Sun.
Dig down and Mercury is mostly metal: its iron core reaches 85% of the way to the surface, perhaps wrapped in a layer of diamond up to 18 km thick.
Not without heavy protection. There's no air to breathe, the Sun is up to ten times brighter than on Earth, and the ground swings between 430 °C and −180 °C.
Yes. NASA's MESSENGER found water ice in deep craters near the poles, where the floors never see sunlight.
Iron, mostly. The core reaches 85% of the way to the surface. Its outer part is liquid and makes a weak magnetic field; the centre is solid iron about 2,000 km across.
No spacecraft has landed. MESSENGER crashed into it in 2015 when its fuel ran out, and BepiColombo is due to go into orbit in November 2026.
