In the authors' simulations, the starting mass of each embryo determines how big the Moon-forming impactor is and how fast Mars grows.

The paper

The paper's details are OpenAlex's; the citation count is OpenAlex's, 18 Oct 2026. The line on the paper is machine-written, as noted under Why it matters.

Why it matters

Written by Claude (claude-sonnet-5-5) on 18 Oct 2026 from the paper's abstract (as arXiv publishes it) and its OpenAlex record. Machine-written context to help a reader: it is not evidence, it moves no number, and it may be wrong. The quoted sentence is the claim; where it stands is computed from the record. If it misreads the paper, tell the stewards.

The story so far

1. 1

   What the authors did

   The authors ran a large number of N-body simulations (computer models of many bodies pulling on each other) of the giant impact phase. They varied the embryo-to-planetesimal mass ratio and the mass of individual embryos, then compared outcomes with the real planets.

   Machine-written from the paper's abstract, as noted under Why it matters.

2. 2

   What they found

   • The total mass ratio of embryos to planetesimals controls the timing and violence of the last giant (Moon-forming) impact.
   • Matching the planets' orbits and geochemical constraints suggests the disc had most of its mass in Mars-sized embryos and only a small fraction in planetesimals.
   • The authors infer the Moon-forming event occurred roughly 60 to 130 million years after the first solids formed, most likely caused by an object of about Mars's mass.

   Machine-written from the paper's abstract, as noted under Why it matters.

3. 3

   What has been checked on Ecdysis

   Exuvia registered the claim on 18 October 2026, with a test written from the paper. No check has been filed yet.

What would check it

How far it has been checked

1. 1
   The object itself, checked againverification · not yet

   Not yet: re-run the paper's analysis on its own data, where the authors have published it.

2. 2
   New instances of the constructionreproduction · not yet

   Not yet: the same construction run afresh.

3. 3
   The designrobustness tests and arguments · not yet

   Nothing yet: change the method or the data and see whether it holds (a robustness test), or argue that the method does not test what the claim says.

How sure is the record?

Share this finding

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Click a post's text to select all of it. Both posts give the claim's standing on the record, and the longer one says what the checks show and what they do not; the wording changes when the record does. The longer post quotes the paper first, then gives the machine-written headline, marked as such; edit it as you like. To cite the claim, see Cite this claim.

What would prove it wrong

Refuted if independent N‑body simulations that vary only the initial embryo mass produce lunar impactors of similar sizes and/or Mars growth rates regardless of that mass, indicating no causal link.

The test as Exuvia registered it on 18 Oct 2026, written from the paper's words.

The wider literature

Other claims from the same paper

• uncheckedIn the authors' simulations, the ratio of total embryo mass to total planetesimal mass sets when the last giant, Moon-forming impact happens and how violent it is.“The total mass ratio of embryos to planetesimals controls the timing of the last giant (Moon forming) impact and its violence.”
• uncheckedSimulations matched to the real terrestrial planets suggest the early disc held most of its mass in Mars-sized embryos, with few planetesimals.“After comparing our simulated outcomes with the actual orbits of the terrestrial planets (angular momentum deficit, mass concentration) and taking into account independent geochemical constraints on…”

Headlines are machine-written from the paper's abstract, or from the quote and the paper's title where no abstract is open; each claim's own words are quoted beneath its headline.