Searching for Home Elsewhere Series: Can humans survive on Venus?

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Venus

We are right now thousands of years away from a mass extinction event. However, the current pandemic has shaken the world as we know it. I am sure we will survive the coronavirus crisis and prevail, but what if we have to search for life elsewhere due to a future disaster?

This is Part-1 of the series, ‘searching for home elsewhere.’ Let’s look at the unfriendly candidate today.

Venus

Venus is the second planet from the Sun. It is named after the Roman goddess of love and beauty. As the second-brightest natural object in the night sky after the Moon, Venus can cast shadows and, rarely, is visible to the naked eye in broad daylight. Venus lies within Earth’s orbit, and so never appears to venture far from the Sun, either setting in the west just after dusk or rising in the east a bit before dawn. Venus orbits the Sun every 224.7 Earth days. With a rotation period of 243 Earth days, it takes longer to rotate about its axis than any planet in the Solar System and does so in the opposite direction to all but Uranus (meaning the Sun rises in the west and sets in the east). Venus does not have any moons, a distinction it shares only with Mercury among planets in the Solar System.

Life on Venus

The speculation of life currently existing on Venus decreased significantly since the early 1960s, when spacecraft began studying the planet and it became clear that its environment is extreme compared to Earth’s.

Venus’s location closer to the Sun than Earth and the extreme greenhouse effect raising temperatures on the surface to nearly 735 K (462 °C; 863 °F), and the atmospheric pressure 90 times that of Earth, make water-based life as we know it unlikely on the surface of the planet.

Between its romantic, red-orange display and ground temperatures hot enough to melt iron, Venus is our solar system’s long preserved hell. Setting up a livable base on the planet is a feat far beyond our technological capabilities right now, but here’s what life would be like if we could actually live on Venus.

Although there is little possibility of existing life near the surface of Venus, the altitudes about 50 km (31 mi) above the surface have a mild temperature, and hence there are still some opinions in favor of such a possibility in the atmosphere of Venus.

In the analysis of mission data from the Venera, Pioneer Venus and Magellan missions, it was discovered that carbonyl sulfide, hydrogen sulfide and sulfur dioxide were present together in the upper atmosphere. Venera also detected large amounts of toxic chlorine just below the Venusian cloud cover. Carbonyl sulfide is difficult to produce inorganically, but it can be produced by volcanism. Sulfuric acid is produced in the upper atmosphere by the Sun’s photochemical action on carbon dioxide, sulfur dioxide, and water vapour.

Solar radiation constrains the atmospheric habitable zone to between 51 km (65 °C) and 62 km (−20 °C) altitude, within the acidic clouds. It has been speculated that clouds in the atmosphere of Venus could contain chemicals that can initiate forms of biological activity. It has been speculated that any hypothetical microorganisms inhabiting the atmosphere, if present, could employ ultraviolet light (UV) emitted by the Sun as an energy source, which could be an explanation for the dark lines (called “unknown UV absorber”) observed in the UV photographs of Venus. The existence of this “unknown UV absorber” prompted Carl Sagan to publish an article in 1963 proposing the hypothesis of microorganisms in the upper atmosphere as the agent absorbing the UV light.

In August 2019, astronomers reported a newly discovered long-term pattern of UV light absorbance and albedo changes in the atmosphere of Venus and its weather, that is caused by “unknown absorbers” that may include unknown chemicals or even large colonies of microorganisms high up in the atmosphere.

In January 2020, astronomers reported evidence that suggests Venus is currently volcanically active, and the residue from such activity may be a potential source of nutrients for possible microorganisms in the Venusian atmosphere, according to researchers.

So what’s the conclusion?

The sky that we see on earth is mostly blue. The sky on Venus, however, will be a dusky orange. You should get use to that visual. You wouldn’t see the sun as orange giant in the sky every afternoon, but rather a hazy, yellowish tint behind the dense clouds.

High in Venus’s altitude, winds speed up to 400 km/h — faster than all the tornado and hurricane winds on Earth. But on the planet’s surface, the wind only travels at about 3 km/h. And though the planet does have lightning, the blinding flashes thankfully never reach the surface. Plus, no rainstorms.

The active volcanoes on Venus, as mentioned above in life on Venus section, may be dangerous

Rejoice, Venus likely doesn’t have earthquakes because it lacks tectonic plate activity that releases heat from its interior. Instead, what may happen is that the heat builds to a critical point over millions of years, and then suddenly gets released from some kind of mechanism, such as large-scale volcanic activity that remolds the surface of the planet. Ouch!

So, future humans may survive on Venus but right now, the chances are close to none.

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