Is there lightning on Venus?

Yes! Lightning has been detected inside Venus's acid clouds by several spacecraft, starting with the Soviet Venera missions in the 1970s. We're not totally sure how it forms in clouds without water, which is one reason scientists keep going back.

Venus's Atmosphere — Acid Clouds, Crushing Pressure and a Sky That Rains Acid

Venus's atmosphere is the polar opposite of nice. It's heavy enough to crush a car, made of poison gas, full of acid clouds, and home to wind speeds that would tear a hurricane to bits. It also has lightning, ferociously fast jet streams, and rain that never quite reaches the ground.

It is, in short, the wildest atmosphere of any rocky planet in our solar system. Let's go through what's actually up there.

What Venus's Atmosphere Is Made Of

Venus's air is roughly 96% carbon dioxide. The rest is mostly nitrogen, with a small amount of sulfur dioxide and tiny traces of other gases.

For comparison, Earth's air is 78% nitrogen, 21% oxygen, and only 0.04% carbon dioxide.

That tiny amount of CO₂ in Earth's air is enough to keep our planet pleasantly warm. Imagine what 96% does on Venus.

The carbon dioxide is what makes Venus the hottest planet in the solar system. CO₂ is brilliant at trapping heat, and Venus's atmosphere has so much of it that the planet's surface stays at 462 °C, day or night, for ever and ever. This is the runaway greenhouse effect, and you can read more about it in our Why Is Venus So Hot? The Greenhouse Effect Explained for Kids spoke.

Why Is the Air Pressure So Crushing?

Venus's atmosphere isn't just made of strange gases. There's also a lot of it.

The air at Venus's surface presses down with 92 times the force of Earth's air at sea level. That's roughly the same pressure you'd feel about 1 km underwater on Earth.

If you stood on Venus's surface, the air alone would crush you flat in less than a second. It's so dense that it doesn't really behave like a gas anymore. Down at the surface, Venus's air moves more like a slow, heavy liquid.

That's also why no spacecraft has ever survived for very long down there. Even the strongest robot landers get squished by the pressure within an hour or two. Venus's atmosphere is the toughest enemy any space mission has ever faced.

Sulfuric Acid Clouds

The clouds floating around Venus aren't fluffy water clouds like the ones you see drifting over your house. They're made of sulfuric acid.

Sulfuric acid is the same kind of acid that, on Earth, can dissolve metal if you give it long enough. It's the stuff inside car batteries. The whole planet of Venus is wrapped in a thick yellow-white layer of it, three layers deep, stretching from about 48 km to 70 km above the surface.

These clouds are part of what makes Venus look so creamy yellow when you see it from space. They reflect about 70% of the Sun's light straight back into space, which is why Venus is the brightest planet in our sky.

But while the clouds are pretty from far away, they're terrible up close. The acid drops would burn through any unprotected material almost instantly.

Acid Rain That Never Reaches the Ground

Here's where things get genuinely surreal.

Just like on Earth, Venus's clouds produce rain. Drops of liquid sulfuric acid form high up, gather size, and fall.

But the surface of Venus is so hot that as the acid drops fall, they boil back into gas before they can land. They evaporate halfway down through the sky.

This kind of rain that never lands is called virga, and it happens on Earth too in places like the desert, when the air below the cloud is too dry. But the Venus version is on a planet-wide scale, every day, made of acid. It's a strange thing to imagine: rain falling forever from clouds that never run out, and never actually reaching anywhere.

Wind Speeds That Beat Any Hurricane

Up at the top of Venus's clouds, the wind doesn't mess about.

Cloud-top winds blow at roughly 360 km/h (224 mph). That's faster than the strongest hurricane Earth has ever produced. (For reference, a Category 5 hurricane on Earth has winds of around 250 km/h.)

What's even weirder is that these winds blow so fast they actually overtake the planet itself. Venus spins very, very slowly — once every 243 Earth days — but the upper atmosphere makes a complete trip around the planet every 4 Earth days. So the air is moving roughly 60 times faster than the ground beneath it.

Scientists call this super-rotation. Nobody completely understands why it happens. The thick atmosphere seems to behave almost like a separate, fast-spinning planet of its own, riding on top of the slow-spinning solid Venus underneath. It's one of the biggest mysteries in planetary science.

Lightning on Venus

There's lightning in Venus's atmosphere too.

It was first detected by Soviet Venera probes in the 1970s and confirmed by NASA's Pioneer Venus and ESA's Venus Express missions. The lightning happens inside the sulfuric acid clouds, similar to thunderstorm lightning on Earth, but inside acid clouds instead of water clouds.

We don't know exactly what causes Venus lightning. On Earth, lightning forms when ice crystals and water drops crash into each other inside storm clouds, separating electric charges. Venus has no water and no ice, so something else must be going on. Future missions will help us figure it out.

Frequently Asked Questions

What is Venus's atmosphere made of?

About 96% carbon dioxide and 3.5% nitrogen, with small amounts of sulfur dioxide and other gases. The clouds are made of sulfuric acid.

Why is Venus's atmosphere so heavy?

Because Venus has so much carbon dioxide in it, and the planet's gravity holds it all in place. The air at the surface is 92 times heavier than Earth's, which feels roughly like being 1 km underwater.

Does it rain on Venus?

Yes, but it rains sulfuric acid, not water. And the rain never actually reaches the ground because the surface is so hot it boils the drops back into gas before they can land. This kind of rain is called virga.

Why is Venus so bright?

Because its thick clouds reflect about 70% of the Sun's light back into space. That makes Venus the third-brightest object in our sky, after only the Sun and the Moon.

How fast is the wind on Venus?

The cloud-top winds blow at about 360 km/h, faster than any hurricane on Earth. They're so fast they wrap right around Venus every 4 Earth days, which is much faster than the planet itself spins. Scientists call this super-rotation.