Our Most Fascinating Neighbor: Are We Looking at the Wrong Planet?

When the subject of the neighboring planet most likely to be colonized comes up, most believe the answer must be Mars.

But are we overlooking a better candidate?

What if we consider our other next door neighbor,Venus.

But to consider Venus, we first have to start by dispelling a few common misconceptions.

Venus is Too Hot, Too Windy, and has Too Much Pressure to Support Human Life

All true. The surface of Venus is hot--very hot! You might expect Mercury, which orbits close to our sun, would be the hottest planet in our solar system, but you'd be wrong. The atmosphere on Venus results in an average surface temperature of around 900 degrees Fahrenheit, where Mercury's average surface temperature is only (only?!?) 332 degrees Fahrenheit.

It's also true that the planet's cloudy, carbon dioxide-rich atmosphere gives it a surface pressure that's 90 times that of Earth's. Yes, 90 times. That's enough pressure to crush a submarine--just as the atmosphere has crushed every probe sent there, though a couple have managed to survive for a few hours. So Venus is unsurvivable for humans, even with very specialized suits. Combined with the hurricane wind speeds, it seems like an impossible spot to consider for a colony. Right?

Well, the key word in those facts is "surface." Maybe we've set our sites too low.

To make this lengthy explanation a whole lot faster, I'm going to plug in this 2015 video from PBS Space Time that answers many of the whys, wheres and hows of the colonization question.

Okay, but aside from (1) being closer to Earth, and (2) having near-Earth gravity, (3) more solar energy, (4) better radiation shielding and (5) survivable temperatures in its upper atmosphere, why else should we go there?

Venus Provides Unique Opportunities for Study

For one, Venus spins backwards, which is unique in our solar system. While Venus spins clockwise, all the other planets spin counter-clockwise. This means that the Sun rises in the west and sets in the east on Venus. It's called "retrograde" rotation, and it's another mystery about Venus that has yet to be adequately solved. Scientists are puzzled if the planet once spun in the "normal" way and the spin direction either changed due to some catastrophic event, or if the planet flipped 180 degrees on its axis at some point in its history. That should make for fascinating research. Venus' rotation is also by far the slowest in the solar system, which makes its rapid deceleration even more curious.

How slow is it? A day on Venus is more than the equivalent of 243 Earth-days! That also means a single day on Venus is actually longer than a Venusian year, which is roughly only 224 Earth-days in length. (Mercury also has long days, three days for every two Mercury-years. Imagine the crazy calendars you'd have on those two planets!) Some scientists speculate that the long days are caused by the planet being nearer to the sun, resulting in the sun's stronger pull on the planet's rotation.

Venus is also slowing down. Researchers discovered that Venus is rotating 6.5 minutes slower than it was just 16 years ago. In February 2012, the National Geographic reported that scientists with the European Space Agency who were mapping the planet's surface realized that the surface landmarks appeared to have "moved" up to 12.4 miles from where they were expected to be. This was a result of the slowing rotation. And 6.5 minutes slower is a dramatic decrease on a planetary level in just 16 short years! Now adjustments will need to be made for the calculations of future probe missions, or they will be landing in the wrong place.

Earth is also slowing down in rotation, but this is caused by the Moon's gravitational pull creating drag on the planet. Venus has no moon, so this isn't the explanation.

According to Venus Express project scientist Håkan Svedhem, "The origin of this could lay in the solar cycle or in long-term weather patterns that modify the atmospheric dynamics. But this puzzle is not yet solved."

So Venus does, indeed, provides a lot of research opportunities for science.

Could Venus Ever Have Harbored Life?

You wouldn't think so, but the answer is a definite maybe.

Turns out that billions of years ago, when Earth was going through it's frozen 'Snowball Earth" phase, Venus may have been warm and wet enough to allow favorable conditions for life to develop. At that time the Sun was 30% dimmer than it is today, and although Venus has no regular plate tectonics that help stabilize its atmosphere as Earth does, it did have intermittent tectonics that may have released the volume of gases needed to make the planet compatible with life.

In time, the Sun warmed and brightened, and large amounts of carbon dioxide build-up occurred in the atmosphere, triggering the greenhouse effect and evaporating the liquid water.

Astrobiologist David Grinspoon, a senior scientist at the Planetary Science Institute in Tucson, Arizona, believes Venus may, in fact, have been a habitable planet "for much of solar system history." There are even theories that we could actually find life that still exists today in the clouds of Venus.

This provides even more opportunities for study. Not only in searching for proof of the existence of extraterrestrial life, but also for studying the future of our planet, which in another billion years may be very much like Venus.

So maybe we should turn our focus a bit closer to home, and take a good, hard look at Venus as a potential colony site for our species. Our next home may be closer than we first thought.

Resources:
Scientific America: Why Venus Spins the Wrong Way
MNN: Scientists Baffled to Discover that Venus' Spin is Slowing Down
Cosmos: Venus May Have Hosted Life Researchers Say
Space: Was Venus Alive? 'The Signs are Probably There'
Space: Life on Venus: Why it's not an Absurd Thought

Have a great week!