Travel the universe with Dr. Ethan Siegel as he answers the biggest questions of all
Here’s how the closest place to “hell” in our Solar System might actually be home to life.
From afar, Venus seems like the most uninhabitable planet of all.
NASA’s Magellan mission conducted radar mapping of the entire surface of Venus, penetrating its cloud layer and enabling us to reconstruct the first 3D map of the Venusian surface. (NASA / JPL-CALTECH / MAGELLAN)
Beneath its carbon dioxide/nitrogen atmosphere, 90 times thicker than Earth’s, a hellscape of a surface awaits.
The surface of Venus, one of the Soviet Union’s old Venera landers: the only set of spacecraft to ever successfully land and transmit data from that world. The series of Venera landers survived for between 39 minutes to approximately 2 hours; no longer. (VENERA LANDERS / USSR)
Day or night, Venus’s surface is constantly 880 °F (470 °C): the hottest planet of all.
Venus’ surface, as seen by the Venera 14 lander. Humanity has not been back to the Venusian surface in any form in over 3 decades. (USSR / Venera 14)
Although we’ve successfully sent numerous landers, they’ve all failed after mere hours.
An infrared view of Venus’ night side, by the Akatsuki spacecraft. The features revealed here correspond to temperature variations across various layers and properties of the Venusian clouds. (ISAS, JAXA)
The reason? A layer of sulfuric acid clouds enshrouds Venus at high altitudes.
Multiple layers of clouds on Venus are responsible for different signatures in different wavelength bands, but all show a consistent picture of a “hothouse” planet dominated by a runaway greenhouse effect. (VENUS EXPRESS; PLANETARY SCIENCE GROUP AT HTTP://WWW.AJAX.EHU.ES/)
These radiation-reflecting clouds create a runaway greenhouse effect: responsible for Venus’s incredible temperatures.
Before we had explicit measurements of the temperature of Venus’s atmosphere at various altitudes and latitudes, we had some idea of the various cloud layers and what its temperature profile would generally look like, but a model such as this is no substitute for high-quality data. (ESA, SPICAV/SOIR TEAMS)
Above the cloud-tops, however, conditions become far more hospitable.
At 60 kilometers (36 miles) in altitude, temperatures and atmospheric pressures are similar to Earth’s.
Using data from the ESA’s Venus Express mission, both daytime and nighttime temperatures, as a function of planetary latitude, could be measured. Temperatures and temperature variations are quite Earth-like at altitudes approximately 60 km above the planetary surface. (ESA, VERA TEAM, (M. PÄTZOLD ET AL.))
The right ingredients for life, including carbon, oxygen, and nitrogen-rich molecules, are all abundant.
With a majority CO2 atmosphere alongside nitrogen gas, the presence of sulfur dioxide, water, and carbon monoxide provides an environment rich in the potential for organic molecules. (JUNKCHARTS / WIKIMEDIA COMMONS)
Ultraviolet image of Venus’ clouds as seen by the Pioneer Venus Orbiter. The dark regions are still not fully explained, and UV-absorbing microorganisms may yet play a role in Venus’s appearance. (NASA)
A zeppelin filled with breathable air would “float” at this altitude, making investigative missions feasible.
NASA’s hypothetical HAVOC mission, the High-Altitude Venus Operational Concept, would look for life in the cloudtops of our nearest planetary neighbor. At ~60 km in altitude, conditions may actually be quite comfortable for Earth-like organisms. (NASA LANGLEY RESEARCH CENTER)
This composite image of Venus’s night side (left, from Venus Express) and night side (right, from AKATSUKI) shows the “superrotation” of its atmosphere, which travels faster than the planet rotates. Superrotation is more uniform on the day side but becomes irregular and less predictable on the night side. (JAXA / ESA / J. PERALTA, JAXA / R. HUESO, UPV/EHU)
There is a detailed plan for the deployment and entry of a HAVOC airship destined for Venus, which could enable the first human crewed exploration of an inner planet in our Solar System. (ADVANCED CONCEPTS LAB AT NASA LANGLEY RESEARCH CENTER)
For life beyond Earth, the heavens of hell-planet Venus might, quite surprisingly, be “just right.”
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
Caption:“At this time in Mars’ history, we think CO2 is everywhere, in every nook and cranny, and water percolating through the rocks is full of CO2 too,” Joshua Murray says.
