The English name for this planet is Venus, also named after the ancient Roman goddess of love and beauty. But if you observe and study this planet, you’ll find that it’s not as beautiful and romantic as its namesake. In fact, it’s an extreme planet with a climate that can be compared to a furnace. Therefore, if you’re looking for a “hellish” planet within the Solar System, Venus certainly fits the bill.
Landing on Venus is not an easy task.
Since the 1960s, humans have launched over 40 spacecraft to study Venus. Among them, 11 missions were unsuccessful, 7 space probes failed to approach, and only 9 were able to get close to the planet. This is also why we know very little about the surface of Venus.
The atmosphere of Venus
Observing Venus through astronomical telescopes, you won’t see the reddish-yellow hue as depicted in images. The actual color is a guess made by astronomers, as nobody knows the true color of the planet’s surface.
Typically, we see Venus with a dense atmospheric layer like the image below, captured by NASA’s MESSENGER mission. Venus appears to be shrouded in clouds with no visible gaps.
However, using an infrared camera to capture images of Venus from up close, you’ll get a different perspective of the planet.
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This implies that the atmosphere of Venus is in rapid motion. In reality, it has winds reaching speeds of up to 300 km/h.
The atmospheric mass of Venus is 93 times that of Earth. With a size nearly comparable to Earth, the atmospheric pressure on the surface of this planet is over 90 times that of Earth, equivalent to the pressure 1 km below sea level on our planet.
Within the dense atmosphere of Venus, carbon dioxide makes up 96.5%, with the remaining 3.5% being nitrogen and trace amounts of other gases, likely including sulfur dioxide, water vapor, and droplets of sulfuric acid.
Because carbon dioxide is a greenhouse gas, such a dense atmosphere results in extremely high temperatures on the surface of Venus. The average surface temperature of this planet reaches 462°C, enough to melt lead, much hotter than our conventional furnaces. Even at its polar regions, the temperature remains above 450°C day and night. This is due to the strong convection of Venus’ atmosphere and the high thermal inertia of its dense carbon dioxide.
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Venus is so hot that any spacesuit or landing craft made by humans so far would melt upon landing on its surface. Therefore, up to the present time, Venus remains the most enigmatic “neighbor” of ours.
Why is Venus so hot?
In fact, billions of years ago, Venus was not like it is today. It once had extensive oceans, even an environment more suitable for life than Earth at that time.
When the Solar System was forming, there were a large number of fragments, asteroids, and planetesimals wandering around. However, due to the gravitational effect of the Sun, they bombarded planets in the closest orbits for millions of years.
As a result, Venus was constantly bombarded, preventing it from having the same rotation as other planets. Instead, it rotates in the opposite direction at a very slow pace. On Venus, the Sun rises from the west and sets in the east, and a day on Venus lasts 243 Earth days, while it takes Venus only 224.7 Earth days to complete an orbit around the Sun. This means a day on Venus is even longer than a year on this planet. This also means that Venus barely rotates on its axis, its core has stopped moving, and it has gradually lost its magnetic field.
Worse still, the strong impacts of celestial bodies shattered Venus’ outermost shell. Continuous volcanic eruptions carried carbon dioxide and sulfur dioxide from the ground into the atmosphere, resulting in the greenhouse effect causing all the water to evaporate. As a result, the greenhouse effect spiraled out of control, causing the planet to become hotter and hotter.
The evaporated water in the atmosphere cannot be retained for long, and Venus lost the protection of its magnetic field. It cannot withstand the intrusion of solar radiation. Solar winds and ultraviolet rays will dissociate water molecules in the atmosphere, breaking them down into hydrogen and oxygen, then blowing them into space. A small amount of water molecules remaining in the atmosphere will combine with sulfur dioxide to form sulfuric acid hydrates, creating sulfuric acid clouds in Venus’ atmosphere.
Venus’s magnetic field
Astronomers have two different viewpoints about Venus’s magnetic field. One viewpoint suggests that Venus’s core has completely solidified, condensed with a covering layer, and the temperature of this covering layer has increased, reducing the core’s heat flow and preventing the formation of a “dynamo effect.” Therefore, Venus lacks a magnetic field.
Another viewpoint suggests that Venus’s core is still a completely liquid “ocean” of iron, and the entire inner part of the core has nearly the same temperature, lacking a temperature difference that would cause convection and generate a magnetic field.
Although both viewpoints are speculative, their conclusions are the same: Venus lacks a magnetic field like Earth.
In reality, there is a faint magnetosphere around Venus. However, this magnetosphere is not generated by Venus’s own magnetic field. Instead, it is created through interactions between the ionosphere layers of Venus’s atmosphere and solar wind. This magnetosphere offers minimal radiation protection to Venus’s atmosphere, allowing water to continue to be decomposed and blown into space. Consequently, this planet is also becoming less suitable for life.
Why is Venus’s atmosphere still preserved?
Solar radiation can split water, but it doesn’t have enough energy to decompose carbon dioxide, sulfur dioxide, and sulfuric acid. Additionally, volcanic activity on the planet’s surface has continuously pumped carbon dioxide and sulfur-containing gases into the atmosphere for billions of years. This has allowed these gases to accumulate.