This article is part of a mini-series about the planets in our Solar-System. Check back soon for more!
With a constant furnace on the surface of the planet, Venus is the most inhospitable planet in the inner solar system. You may land on Mars and you may visit Mercury's surface if you're careful about your landing spot, but you'll definetely not be able to visit Venus's surface without some Star Trek tech on your hands. It's Earth gone wrong.
1. How do we know about it ?
Because the planet is the brightest star on the night sky, it's not hard to figure out how the ancient astronomers discovered it. As with Mercury, they thought that there were two planets: "The Morning Star" and "The Sunset Star", and it was the babylonians who figured out that it was really just one body, around 1581 BC. Later observations revealed that it was a planet closer to the Sun and the Earth was, and that's about it. No major discoveries regarding the planet were made until the 20th century technology came into play.
The first UV observations from the ground were carried out in 1920 and it revealed that Venus had a very thick atmosphere, with clouds covering the entire planet. In the 1950s we learned that the planet's rotation was retrogade.
Now, up until this point in history, everyone thought that Venus was harboring life. All the clues were there right ? About the same on size and gravity, and it wasn't that much closer to the sun. So if all that's different from the Earth is its closer location to the Sun, than it must be a planet covered by tropical jungles. And since we don't have any signals of alien life from there, not even radio or something similar, life on the planet is somewhat primitive, compared to what's here. They were in for a shock. In 1961, the Russians shot the first probe towards Venus, but they lost the connection with the probe 7 days into the mission. The americans weren't that much more successful; their probe blew up on the launch pad one year later and it wasn't until their second probe that they successfuly achieved their first interplanetary mission. But, instead of Miami, they found the downtown crematory: 425 degrees Celsius was the first temperature reading from the orbit.
Diameter: 12,100 km
Mean temperature on surface: 460 °C
Medium distance from the Sun: 108,208,930 km
Atmosphere composition: Carbon dioxide (95%), nitrogen, sulfuric acid
1 Venusian Day : 243 Earth days
Rotation around the Sun: 225 Earth days
The surface of Venus is relatively new. The whole crust is between 300-600 million years old. That means that something did happen to this planeet. We know it had water in the past because hydrogen and oxygen are escaping the atmosphere separated. That means that something violent occured eithr 300-600 million years ago, or it happened a very long time ago and it turned into a cycle. With no water, there are no plate tectonics, so the only way for the planet to cool off its mantle is to have massive process of resurfacing every 500 million to 1 billion years.
One fact we know for sure is that scientists found out that Earth and Venus WERE exchanging matter through asteroids, so presumably one can safely assume that life on Earth could have originated on Venus or vice-versa. We know it had water so life developing there is a certainty, what we don't know is where did life start first in our Solar System !
3. It's lovely this time of the year ! Want to go sightseeing ?
Sorry, all we got is a temperature of 460 °C and a pressure comparable to what you might find 1 kilometer beneath the ocean on Earth. That means you can't go to the surface with today's technology. We can deal with the pressure by using huge suits designed for high-pressure environments, but they can bearly move in the water by using propelers. That would not be an option on the surface of Venus. But, if the pressure doesn't get to you, the temperature will. We have nothing against that level of heat for a longer period of time in order to protect the human body from high temperatures.
As for the sightseeing, all we have is about 1000 craters in pristine condition because of the relatively new surface and sulfuric acid rains.
The biggest pressure cooker in our Solar System still has some more secrets to reveal and maybe we'll find some solutions to get to the surface, at least be able to stay there for a little while. The fact is, Venus is Earth's evil twin. We can't really figure out what happened, but there might be a couple of explanations: either some civilization formed up, like us, started some car industry, started using a lot of oil (who knows maybe they had more and it was really cheap) and the result is self-explanatory (with 96% CO2 you can't go wrong) or maybe it had a moon and it crashed into the planet, evaporating all the oceans, resurfacing the planet, liberating all the CO2 stored in rocks and organic matter and we end up there again. The fact is, it's one of the most interesting planets in the Solar System and it may be the origin of life on Earth.
Article about Mercury can be found here. Thank You