The Possibility Of A Giant Impact On Venus

Giant impacts were common in the early evolution of the Solar System, and it is possible that Venus also experienced an impact. A giant impact on Venus could have affected its rotation rate and possibly its thermal evolution.

In this work, we explore a range of possible impacts using smoothed particle hydrodynamics (SPH). We consider the final major collision, assuming that differentiation already occurred and that Venus consists of an iron core (30% of Venus’ mass) and a forsterite mantle (70% of Venus’ mass). We use differentiated impactors with masses ranging from 0.01 to 0.1 Earth masses, impact velocities between 10 and 15 km/s, various impact geometries (head-on and oblique), different primordial thermal profiles, and a range of pre-impact rotation rates of Venus.

We analyse the post-impact rotation periods and debris disc masses to identify scenarios that can reproduce Venus’ present-day characteristics. Our findings show that a wide range of impact scenarios are consistent with Venus’ current rotation. These include head-on collisions on a non-rotating Venus and oblique, hit-and-run impacts by Mars-sized bodies on a rotating Venus.

Importantly, collisions that match Venus’ present-day rotation rate typically produce minimal debris discs residing within Venus’ synchronous orbit. This suggests that the material would likely reaccrete onto the planet, preventing the formation of long-lasting satellites – consistent with Venus’ lack of a moon.

We conclude that a giant impact can be consistent with both Venus’ unusual rotation and lack of a moon, potentially setting the stage for its subsequent thermal evolution.

Mirco Bussmann, Christian Reinhardt, Cedric Gillmann, Thomas Meier, Joachim Stadel, Paul Tackley, Ravit Helled

Comments: Accepted for publication in A&A, 12 pages, 9 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2508.03239 [astro-ph.EP] (or arXiv:2508.03239v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2508.03239
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Submission history
From: Mirco Bussmann
[v1] Tue, 5 Aug 2025 09:12:48 UTC (5,186 KB)
https://arxiv.org/abs/2508.03239
Astrobiology,