Australian scientists say they are "really baffled" by what they have found on a planet that NASA says was once very similar to Earth.
"This study challenges our understanding of how planets evolve," geoscientist Fabio Capitanio of Monash University in Australia told Live Science.
Ishtar Terra region of the planet closest to Earth, where scientists found something puzzling - Photo: NASA
Research results recently published by Dr. Capitanio and colleagues in the scientific journal Nature Geoscience show that the oldest rocks of Venus may have been formed through processes very similar to the process that created the first continents of Earth.
"We did not expect that Venus, with its scorching surface temperature of 460 °C and lack of plate tectonics, would possess such complex geological features," Dr. Capitanio continued.
Our Earth's crust is quite complex compared to other planets. It is not continuous but is divided into many pieces, called tectonic plates.
These pieces of crust lie loosely on the surface, can rub against each other, slide under each other, and carry the constantly shifting continental and oceanic plates above.
That is why continents and oceans throughout the history of the Earth have changed shape many times, forming supercontinents - superoceans and then disintegrating.
The oldest parts of the Earth's continental crust are regions called "cratons," which are areas of older, denser, harder rock in the tectonic plates that support the continents.
In total, about 35 cratons have been identified around the globe, and scientists believe they are the first formations of the continents, the molten interior of the early Earth pushed up during the Hadean eon billions of years ago.
These cratons then act as seeds for the continent. This deep material, when brought to the surface, hardens and helps other continental materials to attach to and gradually grow.
This time, Australian scientists used an interesting dataset from NASA's Magellan spacecraft, which used radar probes to create detailed maps of the planet's surface.
They focused on a region of tesserae called Ishtar Terra, the largest plateau on Venus. Tesserae means “mosaic” in Latin, referring to the unusually complex geological formations that seem to be embedded in the planet's otherwise monotonous crust.
The results show that Venus's tesserae formed in exactly the same way that Earth's cratons did.
A 3D rendering of Ishtar Terra - Photo: ESO
The discovery offers a fascinating new perspective on Venus and its potential links to early Earth, supporting the theory that the two planets formed as twins ready to host life, the authors say.
Indeed, along with Earth and Mars, Venus is also in the Solar System's Goldilocks habitable zone.
New evidence suggests it may have started life as a perfectly Earth-like planet, ready to have continents and possibly complex plate tectonics.
Many previous studies have also shown that the harsh greenhouse effect and extremely slow rotation that make the environment difficult to live in only occur when Venus is at a certain age.
The reason why it turned into Earth's "evil" twin remains a mystery.
