Ådalen / Revelsta / Altuna / Fjärdhundra (prov.) iron meteorite of 7 November 2020 (21:27:04 UT) bolide found near Revelsta, Altuna, Fjärdhundra, Enköping Municipality, Uppsala County, Sweden
Last update: 4 February 2022
The regmaglypted ‘Ådalen’ (prov.) iron meteorite with its velvety fusion crust. Photo: Andreas Forsberg and Anders Zetterqvist
On 23 February it was announced that on 5 December 2020 a 13.8-kilogram iron meteorite (30 centimeters long) was found by Andreas Forsberg, geologists from Stockholm, about 70 meters away from the location of the rock mark and the damaged roots in the ground, which were discovered by geologist Anders Zetterqvist on 16 November. The meteorite is reported to have bounced against a boulder and then a flat rock outcrop on the ground, before it became embedded into the soil surrounded by roots and moss, 75 ± 1 metres away from the boulder in a south-southwestern direction (azimuth 200°). Forsberg says he saw something ‘glowing’ well embedded and sticking up from the mossy ground, which attracted his attention. Immediately after the find he didn’t dig it out but covered it with moss, went back to his car and called Zetterqvist who convinced him to dig out ‘the find of his lifetime’ immediately. The mass was larger than expected. The meteorite shows signs (a large crack and impact marks) of its collision with the big boulder. It is considered to be the ‘main mass’ of the fall, but other masses (with an approximate total weight equal to that of the found specimen) might be found in the area. The meteorite has been handed over to the Swedish Museum of Natural History, on loan for a year. Forsberg apparently would like it to be exhibited there and hopes to get a reasonable compensation. The Swedish Museum of Natural History equally hopes to acquire the meteorite for its collection.
Before, on 26 January, the Uppsala University and the Swedish Royal Museum of Natural History reported that ‘following tips of meteorite collectors’ on 17 November the mineralogist Jörgen Langhof, Curator of minerals at the Swedish Royal Museum of Natural History, found ~20 small nickel-containing fragments (1-6 mm) of a meteorite which were thought to have fallen at ~21:27:04 UT on 7 November 2020. The fragments were reportedly found with a magnet on the mossy ground near the village Ådalen, north of Fjärdhundra, Sweden, about 2.8 kilometers (on the ground) northeast of the calculated end of the bolide’s luminous trail. The fragments were reportedly found within a radius of 10 meters around a boulder which was thought to have been hit by a hard object and a metre long pit with damaged tree roots which was supposed to have been caused by the impact of a ‘fist-sized object’. The place with the roots and the rock had reportedly been found on 16 November by one of the ‘hobby meteorite hunters’, Anders Zetterqvist, who then told Langhof about it. According to Langhof, after his arrival at the site he searched the area around the pit for merely five minutes while using a neodymium magnet before he found the fragments.
If a very short terrestrial age of the meteorite (which, we believe, must be determined by properly measuring short-lived isotopes of this specimen very soon) confirms its connection to the bolide of 7 September 2020, it will be the first known meteorite fall in Sweden since 1954.
In April 2021 it was reported that a conflict concerning the ownership of the meteorite had emerged. The owner of the 1000-hectare Refvelsta estate on which the meteorite was found, the 44-year old Count Johan Benzelstierna von Engeström, claims ownership of the meteorite, which he calls ‘Refvelstameteoriten’, and has taken legal action. He claims the ‘Allemansrätten’, the Swedish ‘Right of public access’, does not apply in the case of a meteorite find, because according to him the removal of objects of economic value from someone’s property is not covered by this law. Benzelstierna von Engeström claims he does not want to sell the meteorite but instead wants to see it on exhibition in a Swedish museum. He claims he does not want to give up ownership of the meteorite. By 24 October 2021 the dispute could not be settled and will have to be decided in court. The main hearing in court is planned for April 2022. There is no explicit Swedish law concerning meteorite finds in Sweden. As confirmed by the Swedish Environmental Protection Agency it is however apparently forbidden by the Criminal Code to remove terrestrial stones, gravel or peat from someone’s property without permission.
The finders, Anders Zetterqvist und Andreas Forsberg, who refer to the ‘Allemansrätten’ claim that found meteorites as ‘non-terrestrial objects’ have traditionally belonged to the finders. The Swedish Museum of Natural History, where the meteorite is currently curated has commissioned a law firm to conduct a legal investigation on the matter.
On 23 February 2021 it was reported that Johan Benzelstierna von Engeström has planned to erect a meteorite memorial on his property.
Moilanen J. Gritsevich M.
LPSC 2022 abstract [#2933]
“We study is it possible that a 14 kg iron meteorite can jump 75 meters after hitting on a granite boulder.”
Kyrylenko I. Golubov O. Slyusarev I. Visuri J. Gritsevich M. et al.
LPSC 2022 abstract [#2655]
“We determine the orbit of the first iron meteoroid with instrumentally recorded fall, simulate its past orbital evolution and origin in the main asteroid belt.”
Moilanen J., Gritsevich M.
84th Annual Meeting of The Meteoritical Society 2021 (abstract # 6252)
“On the difference between density and mass distribution per surface area heat maps made from dark flight Monte Carlo (DFMC) simulations. Using simulations for a recent, but still unclassified, iron meteorite fall in Sweden as an example.”
The meteorite ‘in situ’ on 5 December 2020. Photo: Andreas Forsberg
Johan Benzelstierna von Engeström pointing at the exact find location of the meteorite next to a tree. Image: SVT
Andreas Forsberg and Anders Zetterqvist presenting the meteorite. Photo: Andreas Forsberg and Anders Zetterqvist
The probable path of the bouncing meteorite mass. Photo: Anders Zetterqvist
The impact site on the granite boulder. The impact mark on the southwestern slope (45 – 50° from the vertical) of the boulder is 22 cm long and 9 cm wide. Image: SVT
The probable impact mark of the bouncing meteorite mass, apparently photographed before it has been rummaged. Photo: Anders Zetterqvist
The probable impact mark of the bouncing meteorite mass, apparently photographed after it has been rummaged for a meteorite. Photo: Anders Zetterqvist
Three fragments. Photo: Naturhistoriska riksmuseet
Photo: Naturhistoriska riksmuseet
LINK Naturhistoriska riksmuseet – Press release (23 February 2021)
LINK Naturhistoriska riksmuseet (23 February 2021)
LINK (23 February 2021)
LINK (Uppsala universitet, 26 January 2021)
LINK (Naturhistoriska riksmuseet, 26 January 2021)
Lantbrukets Affärstidning (23 April 2021)
SVT (24 October 2021)
The preatmospheric orbit
Trajectory calculations (Norsk meteornettverk)
The preatmospheric orbit (orbit elements: perihelion distance: 0.898 AU, eccentricity: 0.546, inclination: 15.0°, knot length: 225.6°, perihelion argument: 222.7°, mean anomaly: 348.8°
Video recordings of the bolide
Video from Larvik, Norway. Video: Norsk meteornettverk
Bolide (00:03-) and detonation booms (00:33-). Video: biancoczt1 (16 November 2020)
Bolide (00:03-) and detonation booms (00:35-). Video: biancoczt1 (16 November 2020)
Video from Tampere, Finland. Video: kakuure
Video from Merikarvia, Finland
Video from Västerås, Schweden. Video: Cadde News
NORSAR’s infrasound station in Løten registered clear signales in an easterly direction (azimuth 111) 22:48 (21:48 GMT) 2020