Why is Venus weird? Because reasons.
How is weird? Let’s find out…
Venus is akin to Earth in many ways: it’s a terrestrial planet, similar to Earth in size, mass, proximity to the Sun, and overall composition.
But that’s where the similarities end.
Venus gravity: 8.87 m/s2, or 0.904 g.
Venus mass: 4.87 x 1024 kg.
Venus orbits the Sun every 224.7 Earth days. It rotates about its axis (sidereal) every 243 Earth days. A seen from ‘above’, Venus moves around the Sun clockwise, and rotates counter-clockwise. This rotation relative to the Sun (synodic) means a day on Venus – say sunrise to sunrise – is 117 Earth days.
Venus has no moons. Mercury is the only other planet in the Solar System to experience moon-less-ness.
And speaking of Mercury – the little planet is closer to the Sun than Venus, and we think of it as a pretty warm place, but Venus has the hottest surface of any planet in the Solar System, with temperatures averaging 737 K.
K is for kelvin, the base unit of temperature in the International System of Units. It gets its name from engineer / physicist William Thomson, 1st Baron Kelvin, and gives us an Absolute Zero of 0.
737 K a.k.a. 464 °C a.k.a. 867 °F.
Venus has the densest atmosphere of the four terrestrial planets. It’s more than 96% carbon dioxide. It’s thick and it’s heavy.
Atmospheric pressure on Earth at sea level is about 14.7 pounds per square inch.
How many ways can we measure it? Well, we’ve got our pascals, our millibars, and our millimeters of mercury –
101,325 Pa (1,013.25 hPa; 1,013.25 mbar), which is equivalent to 760 mm Hg, 29.9212 inches Hg, or 14.696 psi. Also known as 1 atm.
The atmospheric pressure on the surface of Venus is about 92 times that. That’s about 1,352 pounds per square inch. The sort of experience you could have on Earth if you ventured underwater about 900 meters.
Venus doesn’t have any water – we’re pretty sure – because it’s most certainly experiencing a runaway greenhouse effect.
A runaway greenhouse effect occurs when a planet’s atmosphere contains enough GHG to block thermal radiation from leaving the planet, thus preventing the planet from cooling and from having liquid water on its surface.
The primary greenhouse gases in Earth’s atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3).
The atmosphere of Venus is almost entirely carbon dioxide, but there’s a bit of nitrogen in there, too. And these exist as super-critical fluids.
Supercritical can be thought of as a ‘fourth state’, because it’s not solid, or liquid, or gas. It’s kind of like vapor, at high heat, under high pressure. Venus is kind of a pressure cooker of carbon dioxide.
And in the upper atmosphere, we’ve got sulfuric acid, which is very reflective – just another hindrance to ‘seeing’ Venus. But this upper atmosphere plays an interesting role.
Venus doesn’t really have a magnetic field, but its does have an induced magnetosphere.
When the Sun’s UV hits Venus day-side, it ionizes the planet’s upper atmosphere, forming a plasma a.k.a. ionosphere. The thermal pressure of this ionosphere pushes back against the magnetic pressure of the solar wind. This ‘pile up’ forms a magnetic barrier, which keeps the solar-wind plasma from penetrating deeper into the atmosphere.
Whereas Earth has its magnetic field to protect it from solar radiation, Venus has it’s crazy atmosphere.
It seems there’s been renewed interest in the oddities of Venus, recently by me, and then by NASA (though NASA has probably been thinking about it for a some time).
NASA has decided, after thirty years, to send two new missions to Venus (to launch somewhere around 2028-2030), to delve into its weirdness.
DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging)
This mission will be attempting to understand the atmosphere of Venus. There will be a descent sphere involved, which will dive in and measure the noble gases, and any other elements it might find.
This mission will also try to determining whether Venus ever had an ocean, if it has plate tectonics, and take some hi-res pics of the unique geology of Venus.
Goddard Space Flight is taking care of this one.
VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy)
This mission will map (in 3D) the surface of Venus, with the goal of understanding its history, looking for volcanism and plate tectonics.
This mission will also be looking for water vapor in the air (perhaps from volcanoes), and trying to determine what rock types make up the surface.
This is primarily a Jet Propulsion Laboratory mission, with some help from German Aerospace Center, Italian Space Agency, and Centre National d’Etudes Spatiales.
We won’t have the data from these missions for some years yet, but we think we know some things…
The surface of Venus appears to have been shaped by volcanic activity. Venus has many more volcanoes than does Earth. We’ve counted 167 volcanoes that are over 100 kilometers across. But the volcanoes of Venus aren’t really all that active.
Because of Earth’s tectonics, the surface is continually being recycled, but Venus doesn’t seem to do this.
But there’s obviously something going on, because we’ve seen the ebb and flow of the sulfur dioxide in the Venusian atmosphere – which suggests volcanic eruptions.
There’s also lightning on Venus, which could be from volcanic activity. Volcanic lightning is produced via colliding, fragmenting particles of volcanic ash, which create static electricity in the volcanic plume.
And we also have some evidence from Venus Express during its 2008-2009 endeavors. The first Venus exploration mission of the European Space Agency, Venus Express launched in, arriving at Venus in 2006.
Venus Express observed some ‘hot spots’ on the surface, though to be lava.
Part of the interest in collecting more data about Venus has to do with the fact that the little we do have suggests Venus might have been habitable in its past. And we’d like to know how it went from habitable to it’s current desiccated, pressure-cooker self.
Possibly because we’re a little bit afraid the same fate could befall Earth.
My own interest in Venus occurred recently as I was designing some NFTs. I’ve done quite a number of Mars-inspired works, and I wanted to try something new. ‘Venus,’ I thought. ‘Why are we neglecting Venus?’
And by ‘we’ I mean the various inhabitants of my psyche. (Psyche is also an M-Type Asteroid.)
And one of these inhabitants came up with some inhabitants of Venus. Venusians, if you will.
These NFTs are abstracted representations, originally more about shape and color than narrative, but as often happens with my inhabitants, the narrative started to form. The Venusians began to take on life.
You could say I discovered life on Venus.
And now their primordial forms can be found at OpenSea.
Maybe they’re why Venus is weird.