Venus, the second planet from the Sun, has a thick, opaque atmosphere, preventing optical-based telescopes and orbiting space probes from observing its surface. This didn’t prevent Earth’s scientists from mapping the planet’s surface; they used radar to unveil what’s below Venus’s clouds.
1
Venus is a Victim of a Rampant Greenhouse Effect
Venus’s atmosphere is made mostly of carbon dioxide, one of the greenhouse gasses that traps heat and causes the greenhouse effect. Carbon dioxide makes up about 96% of the atmosphere, with the remaining 4% being nitrogen.
Since there’s so much of the gas in the planet’s atmosphere, the greenhouse effect on Venus went rampant a long time ago, driving the surface temperature to scorching hot levels.
The cause of this much carbon dioxide and nitrogen in the atmosphere was intense volcanic activity in the planet’s early days combined with resurfacing events triggered by the movement of plate tectonics, both of which released immense amounts of carbon dioxide. Nowadays, the surface is immobile, and the planet is not as volcanically active as in its distant past, with only a couple dozen volcanoes showing signs of activity.
The planet’s atmosphere is also extremely dense and thick, about 90 times more dense than ours, with clouds made of sulphuric acid. All this weight is pressing down on the planet, increasing the surface pressure to amounts equivalent to about 2953 feet (900 meters) under the surface of Earth’s bodies of water, which is about 1350 pounds per square inch (PSI).
The pressure was high enough to crush multiple probes that entered the planet’s atmosphere, and subsequent lander missions had to be specially engineered to survive the intense pressure on the surface.
2
Venus is the Hottest Planet In Our Solar System
The rampant greenhouse effect, most likely triggered in the planet’s distant past, has caused the surface temperature to reach 870 degrees Fahrenheit (~466 degrees Celsius), making the surface of Venus the hottest place in our solar system, excluding the sun. Even Mercury, the planet closest to our Sun, isn’t as hot, with surface temperatures reaching about 800 degrees Fahrenheit (427 degrees Celsius) during daytime.
3
Venus Has The Most Volcanoes in the Solar System
The Magellan mission, which mapped almost the entire surface of Venus with radar, initially discovered around 1,660 volcanoes on the surface of Venus. That’s more than what we’ve got here on Earth, with numbers ranging from 1,350 to about 1,500 volcanic landforms.
However, once scientists had sat down and further analyzed data collected by the Magellan mission, the final tally rose to more than 85,000 volcanoes! Virtually every single one of them is inactive, with fewer than 40 showing signs of activity, according to a recent study published in Nature.
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The Longest a Spacecraft Has Survived On Venus is Just Over Two Hours
All that pressure, temperatures high enough to melt certain metals, and the corrosive effect of carbon dioxide equals an extremely inhospitable environment for landers. The longest a spacecraft has survived on the surface of Venus is just over two hours!
The lander in question was Venera 13, made by the Soviet Union. It landed on Venus’ surface on March 1, 1982, and survived for 127 minutes. While it didn’t last long, Venera 13 managed to send sounds of the wind blowing across the planet’s surface, the first time a spacecraft transmitted sounds from another planet.
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5
Venus and Earth Are Twins With Regard to Size and Structure
Venus and Earth are very similar in size. While Venus has a diameter of 7,521 miles (12,104km), our planet is just a tad larger, sporting a diameter of 7,926 miles (12,756 kilometers).
The two planets also share internal composition, and Venus is only about 2% less dense than Earth. Being a tad smaller and denser means that the surface gravity on Venus (8.87 m/s²) is slightly lower than on Earth (9.807 m/s²).
6
Venus Has No Moons Nor An Internal Magnetic Field
Venus and Mercury are the only planets in our solar system that don’t have moons. And despite its similarity to Earth in size and structure and its partially molten metallic core, the planet doesn’t have an internal magnetic field.
The reason for this is, according to a 2002 study, that for the last 500 million years, Venus has been lacking plate tectonics, which prevents core convection. Core convection is the main driver behind the dynamo effect that converts the kinetic energy of convection into magnetic energy and creates Earth’s internal magnetic field.
Venus does have a weak magnetic field caused by the interaction between our Sun’s magnetic field and the planet’s atmosphere, creating a type of magnetic field called induced magnetic field.
7
A Single Day on Venus Is Longer Than a Venusian Year
Venus rotates around its axis extremely slowly. In fact, the planet completes a full orbit around the Sun faster than it performs a full rotation on its axis. This means a Venusian year lasts about 224.7 Earth days, while a Venusian day lasts 243 Earth days!
8
Only the Moon Shines Brighter Than Venus in the Night Sky
Venus is the third-brightest natural object in the sky. During the day, the Sun reigns over the sky, but during the night, only our Moon is brighter than Venus.
9
Venus May Host Life, but Not on the Surface
Hellishly high surface temperatures combined with deep ocean-like pressure, and an oppressive environment on the surface means that Venus almost certainly doesn’t host life on its surface. High up in the clouds, however, life might’ve found a way to thrive.
Venus’ clouds made of sulfuric acid also contain water and nutrients that may support microbial life. Better yet, Venusian clouds, unlike its surface, bathe in sunlight.
While we’ve got microbes here on Earth that “breathe” sulfates, they still need water and food sources. Earth’s sulfate-reducing microorganisms feed on organic compounds and iron, so what would potential microbes on Venus feed on? According to Sanjay Limaye, a scientist working at the University of Wisconsin–Madison Space Science and Engineering Center, “Venus has a potential to harbor conditions for iron- and sulfur-centered metabolism.”
Limaye has authored multiple papers on Venus and has been researching the planet for decades. He believes that, up in the clouds, the environment might harbor enough nutrients, including water, to sustain microbial life. Since atmospheric pressures at altitudes of 30 to 43 miles are similar to Earth’s surface and the clouds provide some level of protection from ultraviolet radiation originating from the Sun, someday we might find definitive proof there’s life on Venus.
10
Venus Spins the Opposite Way to Other Planets
I’ve been saving the most bonkers fact about Venus for the end. Did you know that Venus is the only planet in our solar system that spins on its axis opposite to other planets? In other words, the planet spins clockwise, while most other planets in the solar system (Uranus is the exception) spin anti-clockwise. This backward spin is also called retrograde rotation. And we don’t really know why.
Several theories try to explain this peculiar phenomenon, and every single one is weird and exciting in its own way. An early hypothesis from the 1960s states that Venus was hit by a massive celestial object early in its life. The impact angle was just right to cause Venus to reverse its spin direction.
If you think that this sounds pretty far out there, you’d be right. While something similar happened to Earth in its early days, which most likely caused the formation of our Moon, when you add the numbers of the proposed Venus impact, the energy the impact would need to release to reverse the rotation of Venus would result in the complete destruction of the planet. In other words, while technically possible, this theory is most likely wrong.
The alternative version of this theory states that the object was as massive as early Venus itself. It struck Venus during its nascency, and, similar to what happened to Earth when the Moon was formed, the two objects merged and transformed into what is now Venus. But instead of creating a moon, the impact caused the reformed Venus to spin backward.
Another theory, dating from the 1970s, states that Venus didn’t switch its rotation but flipped its poles. In a nutshell, while Uranus is tilted on its side, Venus is flipped by 180 degrees, so its south pole was at one point its north pole, and vice versa. But how did this happen?
Venus’s atmosphere is so thick that it experiences tides caused by the Sun’s gravity and massive heat on the planet’s surface. Combine tidal “waves” in the atmosphere with the planet’s once-molten metallic core that spun against the planet’s mantle in the past, creating friction, and the resulting force may have put enough torque on the planet to make it spin on its head.
The data supports these claims, but only if the planet was already tilted at about 90 degrees when it formed. In other words, it is another bonkers theory that might be right but is likely wrong.
The third hypothesis claims that Venus sort of slowed down its rotation and then started rotating the other way around. The slowdown was caused by the interactions with the monstrous magnetic field of our star in combination with the aforementioned atmospheric tides. Once the planet stopped to a halt, its atmosphere started rotating retrograde, and the whole planet followed. Considering just how slow Venus is spinning on its axis, this theory sounds somewhat plausible.
Unfortunately, we’ll most likely never know what caused Venus to spin the opposite way to most other planets. For that, we’d need to travel billions of years back in time when Venus was still in its youth, because each of the theories needs a different set of starting conditions—such as the planet’s rotation speed, axial tilt, and size and mass at the moment of its formation—in order to work. What we do know is that whatever caused this anomaly most likely took place billions of years before our time.
Want to learn more about space? Check out these three mind-blowing space facts, find out which moons in our solar system are the largest, or find out why Pluto is no longer a planet.
