Venus, Our Solar System’s Version of “Hell”

Computer generated 3-dimensional perspective view of the "crater farm" on Venus (Magellan press release P-39146).

Computer generated 3-dimensional perspective view of the “crater farm” on Venus (Magellan press release P-39146).

Up until the 1960s, the planet Venus conjured up a very different image in people’s minds compared to today. The brightest object in the night sky after the moon, Venus has been known since ancient times as the morning or evening star. A glance through a telescope reveals a white globe covered in an impenetrable layer of clouds.

The Soviets were the first to launch a robotic space probe to Venus in 1961, the Venera 1. While the first mission failed, both the Soviet Union and the United States remained determined to find out what lay beneath the permanent and all-encompassing thick white cloud cover of the planet. Enthusiasts speculated that the planet, long described as Earth’s twin, would be a hot jungle world teaming with exotic life. Alas, in 1962, the readings from the U.S.-launched Mariner 2 space probe found something quite different. Subsequent missions also confirmed that Venus was, in fact, one of the most inhospitable places in the Solar System. The luxuriant jungle world hypothesis was utterly quashed – instead, Venus was revealed to be the veritable biblical hell.

Welcome to the Infernal World of Venus

Image Credit: NASA/Ricardo Nunes

Image Credit: NASA/Ricardo Nunes

Venus has an average surface temperature of 460°C, hotter than the surface of Mercury in spite of being considerably further away than the sun. This enormous temperature, hot enough to melt lead, is believed to be caused by a runaway greenhouse effect (though opinions vary on this point, and rightly so). Many scientists believe that Venus absorbs (or reflects…depending on whom you ask) much of the sun’s heat and it gets trapped beneath the permanent wall of cloud. The leading theory currently is that the clouds are so thick, that they reflect 90% of the sunlight that hits the planet. This makes Venus a fairly dark and gloomy world despite that fact that it is actually closer to the Sun than Earth.

This burning dark world may already sound inhospitable enough, but that is nowhere near where it ends. Venus also has a crushing atmosphere with air pressures 92 times higher than those experienced on Earth at sea level. This is roughly equivalent to the pressure experiences over 1/2 mile beneath the surface of the ocean. All of the landing modules sent to Venus were ultimately crushed under this immense pressure. And still, it gets worse.

The Venusian weather is truly horrendous. The clouds that completely cover the surface spin more than twice faster than the strongest hurricanes on Earth. Above a dense carbon dioxide layer of the atmosphere are clouds filled with sulphuric acid. In the upper atmosphere, sulphuric acid rains from the skies, although this evaporates long before it meets the surface. Thunderstorms are constant and far more formidable than those experienced on Earth. Bolts of lightning rip through the skies adding to the nightmare.

To add to the hellish climate and atmosphere, Venus is also dominated by volcanoes. Much of the surface is covered by a smooth layer of volcanic basalt and planes of lava. Although there are at least 1600 large volcanoes on the planet, most of them are believed to be extinct. Nonetheless, the amount of sulphur constantly hurled into the atmosphere suggests that eruptions continue to occur in some areas.

Venus also has other properties making it distinctly different from Earth. The most notable is that the length of the Venusian day is 243 Earth days, making the day even longer than the year which is 224.65 Earth days. Even more bizarrely, Venus rotates in retrograde (backwards) motion. Venus has a negligible axial tilt whereas Earth has a tilt of 23°. This means that the planet has no seasons.

Venus almost completely lacks a magnetic field, something that is critical to life on Earth. The magnetosphere on Earth provides protection against cosmic radiation and without it, life on Earth would completely cease to exist. Venus also has no natural satellite (moon), so there are no tidal forces on the planet (except for those from the sun).

Venus was originally thought to be Earth’s sister planet until the true nature of its surface came to light. Nonetheless, Earth and Venus do share a few things in common. Venus has a very similar size and density to Earth. This means that the gravity is very similar. The planet’s composition is also quite similar.

Was Venus Once Like Earth?

Venus

Global radar view of the surface from Magellan radar imaging between 1990–1994

There is plenty of evidence to suggest that, billions of years ago, Venus was a more hospitable world than it is today. The Venus Express probe, launched in 2005, made some discoveries that support this evidence. Long ago, Venus’s atmosphere and surface contained hydrogen and oxygen – the two elements that make up water. As Venus lost its magnetosphere, any oceans would have evaporated over millions of years, being sucked out into space. When the planet was young, it could have experienced a brief habitable stage in which very basic forms of life may have formed. On the other hand, the entire surface may have also been extremely volcanically active and covered in molten lava flows rather like Earth in its earliest days before life came into being. However, even if life ever did exist on Venus, all traces of it are likely to have been long lost beneath a completely impenetrable surface of volcanic plains.

Future Human Exploration and Colonization of Venus

Since the discovery of the Venusian surface being so inhospitable, the world’s space agencies have turned their attention to the much more agreeable and promising conditions on Mars. It seems unlikely that any additional probes will be landed on Venus in the near future, although there has been a NASA proposal called the Venus In-Situ Explorer.

Colonization of Venus remains something belonging to the realms of science fiction but, it is not actually quite as outlandish as it may sound. In spite of the horrific surface conditions, Venus is also home to the most habitable place in the Solar System outside of Earth.

At an altitude of about 31 miles above the surface, the Venusian environment is by far the most similar to Earth in the Solar System. Air pressures here are about the same as they are on Earth at sea level and temperatures range from 0° to 50°C. This means that people would not even need to wear pressure suits in such an environment, although they would need to have air for breathing and some degree of protection from the sulphuric acid rain found in the upper atmosphere.

Colonizing this environment is almost certainly possible. Colonies would have to be located in aerostats floating about 50 kilometers above the surface (roughly 31 miles). These aerostats would not be tethered to the surface, but rather, would rotate at the same speed of the clouds, effectively making the Venusian day about four Earth days long. The aerostats would use a breathable mix of oxygen and nitrogen for lift, since these gasses provide far more lift than helium does on Earth thanks to Venus’s heavy, mostly carbon dioxide atmosphere.

Whether humanity will one day colonize Venus remains to be seen but, as our own world becomes progressively overcrowded and increasingly low on resources, such possibilities will eventually need to be taken seriously. I personally would rather take my chances with Mars or even the moon but I’m still a huge fan of Venus nonetheless.

Venus – Beautiful, Deadly, Strange or Fascinating?

Venus symbolizes femininity, beauty, and love. It is the twin planet to Earth, our world of vast green forests, deep blue seas, and majestic snow-capped mountains. Venus was formed at about the same time as Earth of the same type of material. It’s almost the same size as Earth and it is the planet closest to Earth. It is the second planet from the sun, the third brightest object in our sky after the Sun and the moon. Shining brightly near the horizon, it dazzles stargazers and inspires poets.

Close-up and personal, Venus must be heavenly – right? Not exactly. Hot and dry with an atmosphere that would choke an earthling to death – that’s Venus.  The atmosphere is made up of carbon dioxide, dioxide, nitrogen, water vapor, argon, carbon monoxide, neon, and sulfur dioxide. Carbon dioxide is the largest component of the atmosphere. Sulfuric acid is the largest component of the thick clouds that cover the planet so well that not even the largest earthbound telescope can gaze upon its surface. While keeping prying eyes out, the clouds keep the heat in. Temperatures reach 870 degrees Fahrenheit, which is enough to melt lead. Venus’ intolerable heat also discourages visitors by vaporizing them. Venera 13, a Russian Lander, holds the record as the surface visitor to last the longest. It operated for 127 minutes before being vaporized by the inhospitable planet.
Many other attempts have been made to investigate Venus in the form of unmanned spacecraft that journeyed to our sister planet. As mentioned, those that dared land on the planet met a quick demise. Venera 13 transmitted the first color pictures of the surface of Venus before it ceased functioning.  NASA’s Magellan Spacecraft orbited Venus from 1990 to 1994 using radar imaging to map 98% of its surface. The European Space Agency’s Venus Express arrived in orbit around the planet in 2006, and is currently studying its atmosphere and surface characteristics (this led to a recent discovery mentioned below).

Vast smooth plains cover about 65% of the surface. There are thousands of volcanoes ranging in all sizes from an extremely small half mile across to an extremely large 150 miles across. Of the six mountainous ranges, the highest range is Maxwell, which is seven miles high and 540 miles long. There are also circular structures called coronae or crowns that were formed when hot material from inside the planet bubbled up to the surface. The diameter of a crown varies from 95 to 365 miles.

And get this. According to a recent report in National Geographic, Venus is spinning even slower than astronomers originally thought, according to new data from a European space probe. In the early 1990s scientists with NASA’s Magellan mission calculated that a single rotation of Venus takes 243.015 Earth days, based on the speed of surface features passing beneath the orbiting spacecraft. If you’re paying attention and you do the math, you will see that a day on Venus is longer than a year on Venus! However, while Venus slowly spins, it manages to make a pretty quick trip around the Sun. Earth makes its yearly trip around the Sun in 365 days; Venus does it in only 224 earth days.

Anyhow, scientists now mapping Venus’s surface with the European Space Agency’s Venus Express orbiter were surprised to find the same features up to 12.4 miles (20 kilometers) from where they were expected to be, based on the previous measurements. According to the new data, Venus is rotating 6.5 minutes slower than it was 16 years ago, a result that’s been found to correlate with long-term radar observations taken from Earth.

Another point to think about. Venus may now resemble what Earth will become in millions of years time. When our Sun expands thereby heating the Earth, all of its surface water will be turned into a vapor thus trapping sunlight and heat in the atmosphere. The result will include suffocating conditions like those found on Venus today.

So now you’re probably saying to yourself, “Venus is strange.” And you would be right. It gets stranger. Venus is a contrary planet, no doubt about it. If you were to awaken on Venus in time to enjoy the sunrise over the barren lava plains to the east, you would be out of luck. However, if you were facing west, you would see the sun rise. Yes, that’s right. Old contrary Venus spins from west to east – the opposite direction of earth and the other planets in our solar system. This is called retrograde rotation.

You probably want to know why. Here are the four answers proffered by astronomers today. Take your pick:

A) Venus was hit by a very large object that changed the direction of its spin;

B) The Sun’s gravitational pull messed with the heavy clouds of Venus. Eventually, this caused the entire planet to flip over on its axis. Therefore, it is still spinning in the same direction as the other planets. It appears to be spinning in the opposite direction because it is upside down;

C) The Sun’s gravitational pull messed with the heavy clouds of Venus. However, it didn’t turn it upside down; it just reversed its spin;

D) Or my personal favorite – no one really knows!

Here again is the question posed by the title: Venus – beautiful, deadly, strange or fascinating? The answer: Absolutely!

Image Credit: European Space Agency.

Reference:

A. Moullet, E. Lellouch, R. Moreno, M. Gurwell, & H. Sagawa (2012). Wind mapping in Venus’ upper mesosphere with the IRAM-Plateau de Bure interferometer Astronomy & Astrophysics DOI: arXiv:1202.5279v1

Costantino Sigismondi (2012). Solar diameter with 2012 Venus transit Fourth French-Chinese meeting on Solar Physics Understanding Solar Activity: Advances and Challenges DOI: arXiv:1201.4011v1

Major, J. (2012, February 14). Venus Spinning Slower Than Thought-Scientists Stumped. National Geographic. Retrieved February 25, 2012, from http://news.nationalgeographic.com/news/2012/02/120214-venus-planets-slower-spin-esa-space-science/

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