I want to design a plant-like organism that floats ~50km above the surface of Venus, where the conditions are somewhat Earth-like. I envision it to be a large photosynthesizing balloon on a very long tether to the planet surface, so that it has a method of obtaining nutrients: enter image description here Drawing not to scale

My primary concern is with the tether, because not only would this tether have to be very long and be able to transport nutrients to the balloon at the top, it would have to withstand temperatures of 880 degrees Fahrenheit as well as 190-mph winds.

Putting aside the question of how such an organism would not be roasted by the Sun because of Venus' slow day/night cycle, is this feasible? If so, what sort of material would it be constructed of, and what kind of biochemistry could it have? If not, how could I modify the design so that such a plant is possible?

  • $\begingroup$ Does it have to be tethered, or is it OK for it to be free-floating if it can obtain nutrients from the atmosphere? $\endgroup$ May 14, 2021 at 4:17
  • $\begingroup$ I would prefer tethered, so the wind doesn't blow it away. However, free-floating is okay if a tether is not possible. $\endgroup$
    – knosmos
    May 14, 2021 at 4:37
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    $\begingroup$ I doubt that a tether would work. Besides the obvious strength and temperature resistance problems, there's the weight issue. You'd need a very large balloon to support a tether, How would immature balloons grow their tethers? (Compare for instance kelp, which only grows in waters about 30 m deep, or less.) And how would the tether transport nutrients? It would presumably need a liquid, but is there anything that would remain liquid at both the surface and high atmosphere? $\endgroup$
    – jamesqf
    May 14, 2021 at 4:53
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    $\begingroup$ With u tags - nothing u can do, only handwavium with plausible shape and impossible substance. A thing to begin with, there is very little water on venus, and it is a problem because it means not enough hydrogen to make hydrocarbons. 20ppm of water is noticeable but it 1/20 of earth co2 concentration, and typical live as we now it needs more water 5-10x than it needs anything else. Artificial constructon of such design may work and be one of the ways, but live in the way we know it now - just no. Robotic plants yes, biological no. $\endgroup$
    – MolbOrg
    May 14, 2021 at 9:42
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    $\begingroup$ "it would have to withstand temperatures of 880 degrees Fahrenheit as well as 190-mph winds.".. Also the slight issue of Sulphuric acid clouds suspended in supercritical CO2 (the first is a very nasty acid, the second is an incredibly strong solvent) $\endgroup$
    – PcMan
    May 15, 2021 at 20:39

2 Answers 2


I may not be able to answer the biochemistry of this plant, but I came up with some of the basic answers:

How the OffSpring grow its tether?

Take the example of the banyan tree, It has aerial prop roots, that grow from top to bottom. Similarly for this plant, an offspring starts its journey as an epiphyte, i.e. a plant that grows on another plant, on the parent ballon in this case, and starts the growth of its tether, once the tether reaches the soil and establishes its roots, it gets detached. enter image description here

Tether Weight issues A single ballon may not be able to hold onto the heavy 50km tether, So to reduce the overall weight, the tether itself will have tiny balloons which will also help it to withstand the extreme temperatures.


The issues I have with the system are:

  • The length of the tether & getting any form of nutrients up and down such a long tether.
  • The atmospheric pressure of 92 bar, compared to 1 bar on Earth, plus 460 °C temperatures are extremely hostile to any forms of life and how does the plant not burn under such conditions?
  • I also question how would roots establish themselves it what is potentially active volcanic terrain.
  • I also question the nutrients that might be available and how any plant could exploit them.

It seems too implausible.


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