# If the anomaly is real new physics, what kind? · Earth flyby anomaly > Four answers have been proposed. None is ahead on the evidence yet. Four are still possible. Source: https://mysteriesdept.com/mysteries/flyby-anomaly/questions/QST0CWYE9R02K3H/if-the-anomaly-is-real-new-physics-what-kind Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-26T11:57:26+00:00 --- **0** # If the anomaly is real new physics, what kind? Asked 26 Oct 2026 by [**apollo** ](https://mysteriesdept.com/u/apollo)·Part of [What produces the velocity changes seen in some Earth flybys?](https://mysteriesdept.com/mysteries/flyby-anomaly/questions/QST0CWYE98C43P6/what-produces-the-velocity-changes-seen-in-some-earth-flybys)·4 answers·0·0 following **Four answers, none ahead** None is ahead yet. See what would settle it. ## Where it stands Four answers have been proposed. None is ahead on the evidence yet. Four are still possible. ## Why it matters Several theories have been fitted to the flyby values⁠[[1]](https://mysteriesdept.com/sources/SRC0CWYE2NE1TYK/modelling-the-flyby-anomalies-using-a-modification-of)⁠[[2]](https://mysteriesdept.com/sources/SRC0CWYE2X841RN/can-the-flyby-anomaly-be-attributed-to-earth-bound-dark)⁠[[3]](https://mysteriesdept.com/sources/SRC0CWYE3MP62XM/flyby-anomaly-in-the-variational-principle-of-general); each must also survive the null flybys and other precision tests near Earth. ## Answers 4 [**A modification of inertia depending on acceleration relative to the rotating Earth.** ](https://mysteriesdept.com/mysteries/flyby-anomaly/answers/ANS0CWYEFVA5SZ8/a-modification-of-inertia-depending-on-acceleration-relative) Not tested enough to call either way Evidence: 1 for Still possible [**An effect within a reformulation of general relativity.** ](https://mysteriesdept.com/mysteries/flyby-anomaly/answers/ANS0CWYEGTJ3KQ7/an-effect-within-a-reformulation-of-general-relativity) Not tested enough to call either way Evidence: none yet Still possible [**None of these.** ](https://mysteriesdept.com/mysteries/flyby-anomaly/answers/ANS0CWYEH2C4M7F/none-of-these) Not tested enough to call either way Evidence: none yet Still possible [**Scattering off dark matter bound to Earth.** ](https://mysteriesdept.com/mysteries/flyby-anomaly/answers/ANS0CWYEGAY08DT/scattering-off-dark-matter-bound-to-earth) Failed a test; not refuted outright Evidence: 1 against Disputed ## History 1. 2008[McCulloch puts forward: a modification of inertia depending on acceleration relative to the rotating Earth.](https://mysteriesdept.com/sources/SRC0CWYE2NE1TYK/modelling-the-flyby-anomalies-using-a-modification-of) 1. 2008[McCulloch: three of six early flybys reproduced within error; the others off by 1 to 3 mm/s.](https://mysteriesdept.com/sources/SRC0CWYE2NE1TYK/modelling-the-flyby-anomalies-using-a-modification-of)For: A modification of inertia depending on acceleration relative to the rotating Earth. 1. 2009[Adler puts forward: scattering off dark matter bound to Earth.](https://mysteriesdept.com/sources/SRC0CWYE2X841RN/can-the-flyby-anomaly-be-attributed-to-earth-bound-dark) 1. 2009[Adler: requires densities many orders above the halo and unusual dark matter properties.](https://mysteriesdept.com/sources/SRC0CWYE2X841RN/can-the-flyby-anomaly-be-attributed-to-earth-bound-dark)Against: Scattering off dark matter bound to Earth. 1. 2026[Biswas puts forward: an effect within a reformulation of general relativity.](https://mysteriesdept.com/sources/SRC0CWYE3MP62XM/flyby-anomaly-in-the-variational-principle-of-general) 1. 26 Oct 2026Asked on this site ## Discussion 0 [Add to the discussion](https://mysteriesdept.com/signin?next=/mysteries/flyby-anomaly/questions/QST0CWYE9R02K3H/if-the-anomaly-is-real-new-physics-what-kind%23discussion) Help with this question [ **Propose an answer** Something the evidence could support or rule out ] [ **Propose an answer** Something the evidence could support or rule out ](https://mysteriesdept.com/signin?next=/mysteries/flyby-anomaly/questions/QST0CWYE9R02K3H/if-the-anomaly-is-real-new-physics-what-kind%23add-answer) [ **Add evidence** A result for or against an answer ] [ **Add evidence** A result for or against an answer ](https://mysteriesdept.com/signin?next=/mysteries/flyby-anomaly/questions/QST0CWYE9R02K3H/if-the-anomaly-is-real-new-physics-what-kind%23add-evidence) [ **Ask a sub-question** A smaller question that would help settle this one ] [ **Ask a sub-question** A smaller question that would help settle this one ](https://mysteriesdept.com/signin?next=/mysteries/flyby-anomaly/questions/QST0CWYE9R02K3H/if-the-anomaly-is-real-new-physics-what-kind%23add-question) [ **Add a source** A paper, archive record or image ] [ **Add a source** A paper, archive record or image ](https://mysteriesdept.com/signin?next=/mysteries/flyby-anomaly/questions/QST0CWYE9R02K3H/if-the-anomaly-is-real-new-physics-what-kind%23add-source) Where it fits Earth flyby anomaly [**What produces the velocity changes seen in some Earth flybys?** ](https://mysteriesdept.com/mysteries/flyby-anomaly/questions/QST0CWYE98C43P6/what-produces-the-velocity-changes-seen-in-some-earth-flybys)Key question · most likely an error or inconsistency in trajectory modelling and navigation software (reference frames, spheres of… [Does the anomaly occur at other planets?](https://mysteriesdept.com/mysteries/flyby-anomaly/questions/QST0CWYE9ZT1W27/does-the-anomaly-occur-at-other-planets)Open · 3 answers, inconclusive **If the anomaly is real new physics, what kind?** You're here · 4 answers, inconclusive [What decides which flybys show an anomaly?](https://mysteriesdept.com/mysteries/flyby-anomaly/questions/QST0CWYE9G65APR/what-decides-which-flybys-show-an-anomaly)Open · 5 answers, inconclusive [ Ask a question under this one ]