The Rocky Planet Venus
To continue my planet series, this guide is on Venus, the Rocky Planet!
The Rocky Planet Venus
Venus is a geologically active planet and quite interesting. It is interesting because it is one of the closer planets to us on Earth and fairly easy to study. It is a pretty bright planet in our night sky. One of the reasons it is so bright is that it is relatively close to us. So, it shows up nicely! You can check it out either in the early morning or the late evening.
We have already said that Venus is pretty bright and therefore, easy to see. In fact, early astronomers noticed it has phases like our Moon. Unfortunately, Venus has a very thick cloud cover. This prevents the surface from being seen.
Since we cannot see the surface of Venus, it is harder to calculate rotation. We have to use radar signals. Astronomers bounce these radar signals off Venus and the time until arrival lets us calculate rotation. The rotation period is around 243 days, so quite long. The other interesting fact about Venus is that it rotates backward.
The surface of Venus is very similar to Earth. There are large flat areas and mountainous areas too. There is no water or ice on Venus and wind speeds are low. It is very volcanic in nature. It appears there are no plate tectonics, which is another interesting feature. This is interesting because there is convection and great pressure below the surface. This usually causes or indicates tectonics.
There are many impact craters. Most craters are 10 km in diameter or more. Most objects smaller than that burned up in the atmosphere. So, this gives an indication of a planet’s age. The most impact craters are, the older a planet is. This is still a rough way to estimate age but it is still useful.
The average surface age is between 300 and 600 million years old. This indicates there is constant volcanic activity and it is very widespread.
There is continual volcanism on Venus and it has been going on for a very long time. This renews the surface on a regular basis. Volcanoes are an outlet of the mantles' convection and there are thousands of them. When these volcanoes pop, lava goes everywhere. Most of the surface is covered by this lava.
The atmosphere of Venus is very thick. It makes everything look red. This is because the atmosphere blocks visible blue light particles. It is mostly hot and dry with a small wind. It is about the same across the whole planet. Carbon dioxide accounts for 96% of the atmosphere. Talk about greenhouse gas buildup.
Venus is hot, very hot. It is around 700 K. That is extreme heat and is caused by the buildup of greenhouse gasses. This is why we need to get Earth’s environment under control, or this will happen to us and all life will be extinguished. Carbon dioxide cannot escape the planet because of the thick atmosphere. So, it just sits there and contributes further to the heat problem.