A Surprising Planetary Feature Has Been Discovered on Venus
Venus may be a deadly hell-planet, but fresh research indicates that it may share more similarities with Earth than previously thought.
Scientists have recently discovered evidence that Venus’ crust may include tectonic chunks that scrape against one another, much like fractured blocks of pack ice. While this is not identical to Earth’s plate tectonics, it does indicate that the planet’s crust is not a single globally continuous lithosphere and that convective motion swirls beneath.
This not only sheds light on Venus; it may also aid in our understanding of the evolution and dynamics of tectonics on early Earth.
“We’ve identified a previously unrecognized pattern of tectonic deformation on Venus, one that is driven by interior motion just like on Earth,” stated North Carolina State University planetary scientist Paul Byrne.
“Although different from the tectonics we currently see on Earth, it is still evidence of interior motion being expressed at the planet’s surface.”
Earth is indeed a one-of-a-kind tiny eccentric in the Solar System, in a variety of ways. One of those ways is through its system of plate tectonics, which involves shifting crustal scales grinding against one another and overlapping (subducting) as they move through a hot, molten interior planetary layer.
Mercury, Mars, and the Moon do not exhibit this type of behavior. And we do not detect it on Venus either, which is remarkable given the planets’ similar sizes and geological compositions.
Despite their similarities, the two planets evolved in radically different ways, and the reasons for this are not fully understood. If we can figure out how and why Earth and Venus became a lush, thriving ocean world and a scorching wasteland, respectively, we will have a better hold on similar exoplanets further out in the galaxy.
Byrne and his colleagues were studying the surface of Venus in the 1990s using radar photos captured by NASA’s Magellan mission. They discovered that certain patterns in the lowlands appear to indicate large-scale movement – shear stresses and deformations caused by the motions and interactions of huge crustal blocks.
The team used modeling to determine whether what they were seeing was indeed what they thought they were seeing. They discovered that if the crust of Venus were broken up into huge chunks rather than plates, convective movement beneath the crust might produce the observed characteristics.
“On Earth, plate tectonics is governed by mantle convection. The mantle is hot or cold in various locations, it moves, and some of that movement is transferred to the Earth’s surface via plate movement “Byrne elaborated.
“Venus appears to be experiencing a version on that topic as well. There is not plate tectonics on Earth’s scale – there are no massive mountain ranges or massive subduction systems here – but it is evidence of deformation caused by internal mantle movement, which has never been proved on a global scale previously.”
Venus may potentially still be volcanically active, according to recent data. According to a research published last year, the volcanic features on the planet’s surface are quite recent. Additionally, we know that the majority of the globe has been resurfaced by volcanic activity in the previous billion years or so.
To form the features discovered by Byrne’s research, the tectonic shenanigans must have occurred following the resurfacing. This indicates that not only is this action recent, but it may also be continuous.
This represents a transitional stage of tectonic activity between the permanent global shells of Mercury, Mars, and the Moon and the more mobile tectonic plates on Earth. This could aid in our understanding of exoplanets in the ‘Venus zone’ of their host stars’ orbits, as well as the interiors of rocky planets.
Additionally, it may shed light on the tectonic processes that occurred on early Earth.
“The thickness of a planet’s lithosphere depends mainly upon how hot it is, both in the interior and on the surface,” Byrne explained.
“Heat flow from the young Earth’s interior was up to three times greater than it is now, so its lithosphere may have been similar to what we see on Venus today: not thick enough to form plates that subduct, but thick enough to have fragmented into blocks that pushed, pulled, and jostled.”
Future investigations of Venus by NASA and the European Space Agency’s future Venus missions will provide additional information about this exciting discovery.
The study was reported in PNAS.