# Was the iodine-131 in Australian sheep thyroids fallout from the event? · 1979 Vela incident > Three answers have been proposed. The iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over… leads, with evidence… Source: https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WYF84TRD/was-the-iodine-131-in-australian-sheep-thyroids-fallout-from Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-26T11:59:03+00:00 --- **0** # Was the iodine-131 in Australian sheep thyroids fallout from the event? Asked 26 Oct 2026 by [**apollo** ](https://mysteriesdept.com/u/apollo)·Part of [Was the signal of 22 September 1979 a nuclear explosion?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WXZM2TV0/was-the-signal-of-22-september-1979-a-nuclear-explosion)·3 answers·0·0 following **Most likely: the iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over…** Ahead on the evidence, not yet confirmed. It needs two reviews to be accepted. ## Where it stands Three answers have been proposed. The iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over… leads, with evidence 2 for, 1 against: partly supported by its tests. Two are still possible. ## Why it matters Iodine-131 has a half-life of eight days, so its presence in October 1979 requires a recent fission source; it is the only radionuclide evidence claimed⁠[[1]](https://mysteriesdept.com/sources/SRC0CW4WMYJ4E2N/the-22-september-1979-vela-incident-radionuclide-and). ## Answers 3 [**The iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over…** ](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X5A032M1/the-iodine-131-came-from-a-test-near-the-prince-edward) Partly supported by its tests Evidence: 2 for, 1 against Most likely [**None of these.** ](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X70P5C1K/none-of-these) Not tested enough to call either way Evidence: none yet Still possible [**The readings were background, contamination or measurement error.** ](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X69827MZ/the-readings-were-background-contamination-or-measurement) Tested, but the results don't decide it Evidence: 2 for Disputed ## History 1. 2018[De Geer & Wright puts forward: the iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over…](https://mysteriesdept.com/sources/SRC0CW4WMYJ4E2N/the-22-september-1979-vela-incident-radionuclide-and) 1. 2018[De Geer & Wright puts forward: the readings were background, contamination or measurement error.](https://mysteriesdept.com/sources/SRC0CW4WMYJ4E2N/the-22-september-1979-vela-incident-radionuclide-and) 1. 2018[De Geer & Wright: air-sampling networks in Australia and New Zealand detected nothing.](https://mysteriesdept.com/sources/SRC0CW4WMYJ4E2N/the-22-september-1979-vela-incident-radionuclide-and)Against: The iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over… 1. 2018[De Geer & Wright: one sample slaughtered 22 October gave about 1.9 ± 0.6 pCi/g corrected to slaughter; three spectra show…](https://mysteriesdept.com/sources/SRC0CW4WMYJ4E2N/the-22-september-1979-vela-incident-radionuclide-and)For: The iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over… 1. 2018[De Geer & Wright: vanMiddlesworth's first reading in November 1979 found no abnormal radioactivity.](https://mysteriesdept.com/sources/SRC0CW4WMYJ4E2N/the-22-september-1979-vela-incident-radionuclide-and)For: The readings were background, contamination or measurement error. 1. 26 Oct 2026Asked on this site ## Discussion 0 [Add to the discussion](https://mysteriesdept.com/signin?next=/mysteries/vela-incident/questions/QST0CW4WYF84TRD/was-the-iodine-131-in-australian-sheep-thyroids-fallout-from%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/vela-incident/questions/QST0CW4WYF84TRD/was-the-iodine-131-in-australian-sheep-thyroids-fallout-from%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/vela-incident/questions/QST0CW4WYF84TRD/was-the-iodine-131-in-australian-sheep-thyroids-fallout-from%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/vela-incident/questions/QST0CW4WYF84TRD/was-the-iodine-131-in-australian-sheep-thyroids-fallout-from%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/vela-incident/questions/QST0CW4WYF84TRD/was-the-iodine-131-in-australian-sheep-thyroids-fallout-from%23add-source) Where it fits 1979 Vela incident [**Was the signal of 22 September 1979 a nuclear explosion?** ](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WXZM2TV0/was-the-signal-of-22-september-1979-a-nuclear-explosion)Key question · most likely a low-yield atmospheric nuclear test of a few kilotons, near the ocean surface [Did the hydroacoustic signal come from the same event as the flash?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WY7E4HGQ/did-the-hydroacoustic-signal-come-from-the-same-event-as-the)Most likely · the Ascension and Argentia signals came from an explosion near the Prince Edward Islands at the flash time **Was the iodine-131 in Australian sheep thyroids fallout from the event?** You're here · the iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over… [ Ask a question under this one ]