Venus: Earth's evil twin

When we think of Venus, we immediately associate it with the goddess of love, fertility and beauty in Roman mythology, and we wonder: what is so special about the second planet in the solar system that it was named after their best goddess? In reality, the Romans did not know much about this planet, they only named it that way for being beautiful, and for standing out to the naked eye on our clear nights. But, there is so much about Venus that if the Romans had known, I highly doubt they would have named it after their best goddess.

For a long time it was believed that Venus was a planet with the potential to host life, as it has structural characteristics very similar to those that make up Earth, which is why they are said to be related. Well, they are very similar in size, Venus is about 95% the size of Earth; and both are rocky planets with a metallic core, mantle, and crust of almost the same proportions. The resemblance is undeniable, but once more details about Venus became known, the perspective on this planet changed from a possible new home to a total catastrophe.

Venus is known to be the hottest planet in the solar system, but why? Isn't Mercury the one closest to the Sun? Well, Venus earns this recognition thanks to the composition of its atmosphere, which is very dense due to being 96.5% carbon dioxide (CO2), and this causes nothing more and nothing less than the greenhouse effect and acid rain; and you may ask yourself, what is so special about that if it also happens on Earth? Well, it is because if we compare what happens on Venus with what happens on Earth, it would be like comparing the entire territory of Mexico with the area of a small town: it is the same phenomenon, but Venus's atmosphere holds hundreds of thousands of times more CO2 than Earth's.

Now you can get an idea of the scenario that exists on Venus: temperatures of about 467 °C that would roast you in less than a second, acid rain, a thick environment that causes an atmospheric pressure 92 times greater than that of Earth and an atmosphere that hardly allows the release of heat emitted by the sun. Add to that the lightning, a constant storm between the thick clouds, because the environment is so dense that the lightning cannot even cross it to reach the ground so they stay from cloud to cloud. Being an incessant storm, the sky is never clear, and it is thanks to its clouds that the planet is so bright, as they are excellent reflectors of sunlight.

And as if all of that was not enough, Venus is the planet with the most volcanoes in the solar system: it has about 1600 large ones, of which a study published in July 2020, with a University of Maryland coauthor, concluded that at least 37 large volcanic structures called coronae appear to be active. And it is not only the quantity that is frightening, but also the size: the best known of them, Maat Mons, stands 8 km above the mean radius of Venus. To give us an idea, it would be like stacking roughly 333 pyramids the size of Chichén Itzá's. And that giant was not asleep: in 2023, Robert Herrick and Scott Hensley compared Magellan radar images taken eight months apart and found that one of its vents had changed shape in that time, which they interpret as evidence that Venus is still volcanically active (Herrick and Hensley, Science, 2023).

Venus may seem very malicious compared to Earth, but we owe thanks to this planet and to all the information we have about it, because it is from this information that we have been able to understand in more detail the greenhouse effect that affects us here on Earth. One thing that is clear is that we do not need to reach conditions like those on Venus for large CO2 emissions to be a problem worth worrying about and acting on.