# Could there be caves/underground tunnels in Venus?

If so, would they have the same pressure/temperature than of the surface of Venus? How could we "scan" the surface to gather that kind of information?

For reference, there are several images of lava tube "entrances" on the moon, (where they are much more visible due to almost no atmosphere) in the question Is there a map or list of all the lava tube skylights the LRO has detected on the Moon? as well as the answer there.

However, looking on Venus might be more of a challenge.

• A cave or tunnel with a connection to the surface would have the same pressure but the temperature would be between the minimum and maximum surface temperature. – Uwe Mar 22 '18 at 9:38
• A sealed tunnel with a lower pressure would have to be exceptionally strong to support itself against external pressure. Furthermore, at that temperature, many of the obvious building materials are inconveniently soft – Steve Linton Mar 22 '18 at 10:56

From what we know, Venus is still a geologically and volcanicly active planet. Because of this volcanic activity, Lava tubes may exist on the Venus.

A lava tube is a type of lava cave formed when a low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Tubes form in one of two ways: either by the crusting over of lava channels, or from pāhoehoe flows where the lava is moving under the surface.

There is evidence of lava tubes on the Moon and plenty of examples of lava tubes on Earth. The longest known lava tubes are in the Undara Volcanic National Park in Queensland Australia, where there are tubes up to 100 km in length.

Given the existence of lava tubes on Earth and the Moon and their volcanic histories it reasonable to assume such tubes could exist on Venus.

Edit:

Thanks to @uhoh, the question How livable would a lunar lava tube be? may be of interest.

• You might consider adding a link to the question How livable would a lunar lava tube be? as well. – uhoh Mar 22 '18 at 12:53
• Venus might be too hot for lava tubes to form and sustain. Stone on Earth may behave plastic over a very long time. But at much higher temperatures plastic behaviour might take less time. – Uwe Mar 22 '18 at 14:19
• @uhoh: Thank you for the suggestion. A link has been added. – Fred Mar 22 '18 at 17:37
• +1 again if I could. A further discussion of lava tubes on the Moon (as seen from MRO) as well as those of Undara on Earth can be found in the Earth Science SE question What conditions could produce 50 km long lava tubes? and its extensive answer. – uhoh Mar 22 '18 at 22:36