'What is Venus hiding?: New research could shatter everything we know about planetary impacts
Produced by: Mohsin Shaikh
Venus Enigma
Venus has long baffled scientists. While its surface is peppered with impact craters, none are larger than 300 kilometers across. What secrets is this hellish planet hiding, and why do its impact scars look so different from those on other worlds?
Violent Beginnings
The early Solar System was a chaotic place. Rocks hurtled through space, colliding with young planets and leaving craters. Mercury, Mars, and the Moon wear these scars visibly. Even Earth bears traces of ancient impacts, though erosion has hidden much of the damage.
Hidden Impacts
New research suggests Venus has a colossal impact structure in disguise. The Haastte-Baad Tessera spans 1,500 kilometers and doesn’t resemble typical craters, hinting at a past collision that tore through the planet’s thin crust and into its molten interior.
Double Whammy
Scientists believe this structure formed from two consecutive impacts. The thin crust of early Venus couldn’t contain the violence, and magma surged to the surface, forming the unique tessera terrain.
Lessons from Callisto
A similar multi-ringed structure exists on Jupiter’s moon Callisto. The Valhalla crater stretches 3,800 kilometers and formed from an icy impact. Vicki Hansen of the Planetary Science Institute draws parallels between the two, helping us understand how impacts work on different planetary bodies.
Plateau Conundrum
One mystery remains: some tessera terrain sits atop plateaus, which doesn’t match typical impact models. Scientists wonder if other geological forces played a role or if the double impact scenario needs refining.
Rising Residuum
Hansen explains that molten mantle leaves behind solid, buoyant residuum. This material acts like an “air mattress” under Venus’s crust, lifting the tessera terrain and altering the landscape, a key clue in understanding Venus's past.
Lava’s Role
The fate of Venus’s landscape depends on lava. If it stays, the terrain remains raised; if it drains, the land sinks. This explains why Haastte-Baad appears sunken today, providing a glimpse into Venus’s ever-changing surface.
Earth’s Connections
Similar geological features exist on Earth, such as the dike swarm near Lake Victoria. Hansen’s work reveals that Venus’s thin lithosphere makes it distinct from Mars or the Moon, emphasizing how planetary history shapes impact outcomes. The findings are detailed in the Journal of Geophysical Research: Planets.