Venus is a planet that is often called the sister planet of Earth. It resembles Earth in many ways, but it also has huge differences. Venus is an interesting target for colonization because it is located very close, but it also poses huge challenges.
Venus has a mass and diameter quite similar to the Earth. The radius of Venus is about 6 050 kilometres, which is about 95 percent of the radius of the Earth. Venus is slightly lighter than Earth, as its mass is about 82 percent of the mass of the Earth. The gravity on Venus is about 90 percent of the gravity on Earth, which is very comfortable for colonizers.
It has been suggested, that the internal structure of Venus is very similar to the structure of the Earth. Most likely Venus has a dense core, that is partially molten. In addition, Venus has a mantle like the Earth does, and a crust on top of the mantle. Venus does not have a magnetic field that would stem of its core. Instead, is has a weak magnetic field, which is created when the strong atmosphere and solar winds interact with each other.
Orbit and rotation
Venus is the second planet from the Sun, orbiting it nearer than the Earth does. Venus orbits the Sun in around 225 days, so the year is slightly shorter than the Earth year. When compared to other planets, Venus rotates on the opposite direction. Venus rotates very slowly, once in every 243 days. Therefore, the year on Venus is shorter than the day on Venus.
The surface of Venus is mostly lava, caused by active volcanoes. There are mountains, valleys and large open areas. The amount of craters is relatively low, because a couple of hundred million years ago the whole crust was renewed by massive volcanoes.
Venus has a very thick atmosphere, which is problematic for humans. The atmosphere consists mostly of carbon dioxide, with few percent of nitrogen and trace amount of other substances. On top of the carbon dioxide layer, the atmosphere has a layer of sulfur dioxide and sulfuric acid, that causes acid rains on the planet. The atmosphere is in a constant storm, with wind speeds up to hundreds of kilometres per hour. The wind speeds near the surface are usually lower.
The pressure on height of 50 kilometres is about the same as the pressure on sea level on Earth. On the surface, the pressure is 93 times higher than on Earth. Because of the high pressure, staying on the surface level is hard for humans. Therefore, the best option for habitats is in the areas, where the pressure is suitable.
Because of the thick atmosphere, which also has a lot of carbon dioxide, Venus is a very hot planet. The temperatures on the surface are about 460 °C on average, which is unbearable for humans. Because the thick atmosphere evens out the temperatures, there are no significant temperatures differences on different areas.
Venus is located quite close to Earth, so traveling there is quite fast. Depending on available launch windows, traveling to Venus takes from three to five months. With advance in technology, travel can be probably done even faster.
Because the temperatures and the pressure on the surface are too high for current technology, the habitats should be floating bases. The bases could be filled with air, so people could float normally. Because of the high pressure, the bases would float in the height of about 50 kilometres without consuming energy at all to float.
People could move outside the bases normally, provided with oxygen masks and protection from acid rains. The pressure on height of 50 kilometres would be equal to sea level pressure on Earth, and temperatures at that height range from 0 to 30 °C. The winds, however, might be quite strong, which makes staying outside dangerous.
Venus has considerable amounts of carbon dioxide, that plants could use for photosynthesis. Photosynthesis would create breathable oxygen, so the base could be quite independent. The problem is, however, that Venus has only trace amounts of hydrogen, and therefore, only trace amounts of water. The trace amounts of hydrogen could be collected from the atmosphere, and water could be recycled carefully.
If floating bases were built, these could be powered by solar energy. Because the bases would be above the thickest part of the atmosphere, solar light would come through. There would be a lot of geothermal energy on the surface, but using it might be too challenging.
Even though Venus is located relatively close, the signal delay is still noticeable. When planets are close to each other, messages will be delivered in under three minutes. When they are far, the messages will be delivered in under 15 minutes. There may be communication cut-offs when Venus and Earth are on the opposite sides of the Sun.
Because the geology of Venus is not very well known, we do not know enough about the available resources. It is very likely, that there will be a lot of metals available. However, if we don’t terraform the planet, mining these resources is almost impossible.
Venus is one of the most intriguing planets for terraforming. Even though Venus is really hot and suffers from runaway greenhouse effect, by changing the climate it could become suitable for humans. This process, however, would require a few big changes to the planet.
The two main goals, lowering the temperatures and removing the high pressure atmosphere, are closely related. Probably the easiest method would be to make most of the carbon dioxide solid. We could bring large amounts of hydrogen to the planet, which would, by chemical reaction with carbon dioxide, transform into graphite and water. After this, the atmosphere of the planet would consist mostly of nitrogen, and the temperatures would be suitable for humans.
There are other suggestions on how to remove the thick atmosphere. One suggestion is to use bacteria, that would eat the carbon dioxide. It has been also suggested that the planet could be shaded with solar shades, and some suggest that the carbon dioxide could be transformed into carbonates. Some have even suggested, that the excess carbon dioxide could be moved to space. However, none of these solutions address the problem of missing hydrogen.
One problem of Venus is its low rotation speed. It rotates around its axle once in every 243 days. Because the planet moves around the Sun at the same time, this effectively makes one day last for 117 days. Long nights and days would be challenging for plants and humans, though artificial lights help to mitigate this problem. However, during the days temperatures could be very hot, and very cold during the nights.
There have been some suggestions on how to increase the rotation speed, but with current technology its practically impossible. Adding rotation speeds would require incredible amounts of energy, if it isn’t done with colliding Venus with another object. The problem of long days could be circumvented with a system of solar shades and mirrors, which would allow artificial day-night cycle.
Terraforming and removal of strong atmosphere would also remove the magnetic field that protects the surface from space radiation. Therefore, colonizers should protect themselves from the radiation, or we should create another way to shield the planet. Also, the volcanic activity of Venus might pose additional problems.
Venus is an interesting target for colonization. Even though we’re probably unable to create surface habitats, floating bases could offer humans a place to live. Venus is relatively near, so traveling there is fast and the communication delays aren’t massive.
The largest problem of Venus is its carbon dioxide atmosphere and the lack of hydrogen. Without hydrogen and water survival of humans, animals and plants is impossible. There are trace amounts of hydrogen in the atmosphere, that could be collected, or large amounts of hydrogen could be brought from elsewhere. Sparse hydrogen should be recycled efficiently.
Terraforming is one of the most interesting candidates for terraforming. If we were able to bring Venus large amounts of hydrogen, the planet could be very Earth-like. With current technology this isn’t possible, but if transporting hydrogen would become feasible, Venus might well become the first terraformed planet.