The Planet Venus is the second planet from the sun and the hottest in our solar system. It’s a dry world whose water has all evaporated due to rampant climate change. Yet, you’d never suspect after seeing it in the sky. Venus appears as a bright, beautiful object which we can observe directly at sunrise. For this reason, it’s often called the Morning Star.
In Roman mythology, Venus was the goddess of love and beauty. The Romans might have given the planet this name because it shined so beautifully!
Venus is the second brightest object we can see at night (not including the ISS).
Yet, the Romans had no idea what Venus is really like when they named it. Until Russia sent spacecraft to the planet, no one did. That’s because it’s covered in extremely thick clouds. Venus’s atmosphere is actually 90x thicker than that of the Earth! So, for a long time, its features were a mystery to us.
Nowadays, having photographed the surface, we know that it’s anything but lovely.
Not So Beautiful After All
When people first sent spacecraft to Venus (in the 70’s), we found out that it’s really an awful place! For starters, it’s extremely hot – hotter even than Mercury, which is closer to the sun. This makes Venus a fiery wasteland. It’s totally covered in volcanic features, too. That’s because its heat keeps lava warm and liquidy so that it can flow great distances.
Surface flow lava oozes out of the nooks and crannies dried lava during an eruption from Kilauea volcano.
A Deformed Surface
Where there’s not just lava, Venus is marked by distorted landforms. We can find craggy landmasses called tessera throughout. They’re kind of like warped mountain ranges. Yet, they’re also the size of continents here on earth. This gives much of Venus a shifting, hilly topography. All of this planetary messiness has to do with Venus’s structure. Unlike Earth, Venus doesn’t seem to have a tectonic system. Yet, it did use to have extremely strong volcanism. For a long time, magma kept upwelling through its surface, bending the land out of shape. Scientists don’t know if this is still going on or if it has completely stopped. Regardless, it has already made Venus a frightening sight.
The atmosphere on Venus is even worse than its surface. It’s made up of a thick blanket of clouds. Clouds aren’t that bad, right? Wrong – these clouds are literally made out of acid and carbon dioxide! Their toxic mixture ensures that no life like that on Earth could survive on Venus.
Can you remember the thickest clouds you’ve ever seen? On Venus, it’s like that all time.
But, it wasn’t always like this. Astronomers, like Carl Sagan, believe that Venus was actually habitable a long time ago. And this kind of makes sense. The planet’s composition is similar to the earth’s, and it’s not that much closer to the sun. So, what makes it so inhospitable now?
Venus’s unbearable heat comes from a terrible cycle of climate change. Before it all began, the planet may have been quite like the Earth. The main difference was just that it was a little closer to the sun. But, as it turns out, that difference mattered A LOT.
This has to do with what’s called the greenhouse effect. Here’s how it works: When the sun’s heat reaches a planet, its atmosphere will trap some of it. Certain gases help to trap heat better than others. Carbon dioxide and water vapor are the best at doing so.
On Earth, the heating is regulated by other processes (glacial cooling, oceans absorbing heat, etc.). But, Venus’s slightly increased temperature upset this balance. Its warmer climate caused a lot of the water there to evaporate. Of course, this made even more water vapor, further heating the planet. And so, a vicious cycle of heating began.
Water boiling in a lake on earth. Fortunately, we’ve got a lot more in the oceans than in the air.
Eventually, all of the water on Venus evaporated. It became like a giant oven, trapping tons of heat and baking its own surface. The end result: Venus is now a terribly hot, inhospitable place.
Did You Know?
On Venus, the sun rises in the east and sets in the west. This is the opposite of how the sun appears to move from earth.