STEM Nibbles
September 11, 2021

A Day on Venus: What Is It Really Like on Earth’s ‘Twin’ Planet?

Venus is named after the Roman goddess of love and beauty. If you’re a sky-gazer, you might know this planet Venus as the brilliant, steady “star” that appears in the evening or morning. Its bright appearance in the Venus night sky earned it the names “Evening Star” and “Morning Star.”

In many ways, Venus is Earth’s twin. The two planets share a similar size, mass, and composition, with a comparable crust, mantle, and core. This striking resemblance is why the Earth vs Venus comparison is so fascinating.

But don’t be fooled by its shiny facade or “twin” status. The similarities end there. Venus is a hellish world with extreme temperatures and conditions that are the complete opposite of life-sustaining Earth.

Why is it so harsh? And was it always this way? Stick around as we explore the answers.

Landing on the Venus Surface

Let’s imagine we rent a spaceship for a trip to Venus. After a journey of several months, you might be eager to step out and explore. But before you do, here are a few Venus planet facts to keep in mind about the hostile environment awaiting you.

The surface temperature on Venus averages a staggering 462°C (864°F). For comparison, the highest temperature ever recorded on Earth was 56.7°C (134°F). An electric grill is set to around 135°C (275°F), and a home oven bakes a cake at 180°C (350°F). In short, the Venus ground is hot enough to melt lead.

If you could survive the heat, the landscape of Venus would be a dim, crushing, and bleak place. The surface is covered in volcanic rock, vast plains, and countless craters. Towering shield volcanoes, like the massive Maat Mons which rises 8km (5 miles) high, dominate the terrain.

And what color is Venus? From space, its thick clouds make it appear a placid, yellowish-white. But on the surface, the rocks themselves are a dark, basaltic grey. The thick, carbon-dioxide atmosphere would filter the sunlight, casting the entire landscape in a gloomy, orange-red glow.

The atmospheric pressure on Venus is over 90 times that of Earth’s—equivalent to being nearly a kilometer (over half a mile) deep in the ocean. The weather is just as extreme, with winds whipping around the planet at hurricane speeds and clouds that rain down corrosive sulfuric acid instead of water.

As you’ve probably gathered, a trip to the Venus surface is not a pleasant vacation.

Inside the Thick, Toxic Atmosphere of Venus

(Depiction of Venus’s atmosphere, Source: Astronomy.com)

So, what went wrong with the Venus atmosphere?

Like Earth, Venus has an atmosphere. However, it’s composed almost entirely of carbon dioxide, a potent greenhouse gas. This has triggered a runaway greenhouse effect, trapping heat and making Venus the hottest planet in our Solar System—even hotter than Mercury, which is closer to the Sun.

But scientists speculate Venus wasn’t always this way. Billions of years ago, it may have been a habitable world with temperatures just a few degrees cooler than Earth’s and shallow oceans of liquid water. So what transformed it into the inferno it is today? The exact cause remains a topic of intense scientific study.

Could There Be Life on Venus?

Based on the surface conditions, the prospect of life on Venus seems impossible. However, some scientists haven’t given up hope.

Roughly 50 km (30 miles) up in the atmosphere, the temperature and pressure are surprisingly similar to Earth’s. Could microbial life exist, floating in the clouds? This theory gained attention when researchers detected traces of phosphine gas—a potential sign of biological activity. While this finding is now heavily debated, with some suggesting the signal came from volcanoes or was a misreading, it keeps the tantalizing question of life on Venus open for future missions to explore.

Earth vs. Venus: A Cautionary Tale

Venus serves as a terrifying example of a planet’s climate gone wrong. If scientific models suggesting Venus once had Earth-like conditions are correct, it’s a stark reminder of how fragile a planetary environment can be.

As we face our own climate challenges with rising greenhouse gases, the story of Venus is more relevant than ever. The bone-melting heat and devastating acid rain of our twin planet offer a glimpse into a worst-case scenario, urging us to be more conscious of our own planet’s well-being.

Returning to Earth (After a Very, Very Long Day)

Alright, our imaginary tour is over! It’s clear Venus isn’t a place you’d want to stay for long.

But here’s a final twist: a single day on Venus (one full rotation) lasts for 243 Earth days. That’s longer than a Venusian year, which is only 225 Earth days! So, if you landed for just “one day,” you’d be stuck there longer than it takes the planet to orbit the sun. Time to head home!

References