{"id":1399,"date":"2014-04-03T14:45:13","date_gmt":"2014-04-03T12:45:13","guid":{"rendered":"http:\/\/norskmeteornettverk.no\/wordpress\/?p=1399"},"modified":"2014-04-03T22:11:54","modified_gmt":"2014-04-03T20:11:54","slug":"skydiver-films-falling-meteorite","status":"publish","type":"post","link":"https:\/\/norskmeteornettverk.no\/wordpress\/?p=1399","title":{"rendered":"Skydiver films falling meteorite"},"content":{"rendered":"

Today the Norwegian broadcasting corporation NRK will air the popular science programme Schr\u00f6dingers katt<\/a> which features the incredible story of the skydiver Anders Helstrup. In a jump above \u00d8stre \u00c6ra airstrip near Rena in Norway on 17th June 2012 the totally improbable happens: Just after he deploys his parachute about 1000 metres above ground level a dark rock from above zips past him. His two action cameras document the incident. How can a rock suddenly appear this far above the ground? There is nobody above him, neither an airplane nor other jumpers. No other possible explanations seem to remain but the improbable: a meteorite just fell a few metres away.
\n\"Dark
\n(Photo: Anders Helstrup \/ Dark Flight, photomontage: Hans Erik Foss Amundsen)<\/small>
\n
\nMeteors enter Earth’s atmosphere at speeds ranging from 11 to 72 km\/s. The bigger ones will appear as fireballs in the sky. Most are completely vaporised, but some fragments sometimes reach the ground as meteorites. Most of the speed is maintained until an altitude of about 30 km, but from that point they rapidly decelerate and they completely fade about 20 km above ground. The speed has then been reduced to a few km per second, but the meteor will continue to decelerate until it reaches terminal velocity as if dropped from an aircraft. When the fireball is no longer emitting visible light, any surviving fragments will enter their dark flight<\/em> portion of their fall. These meteorites are usually small, a few kilograms or less, and will be moving at speeds around 300 km\/h (depending on shape and density) near the ground. They are for all practical purposes invisible and cannot be photographed. But Anders has videos telling us otherwise.<\/p>\n

Anders teamed up with a number of individuals including experts from the Geological museum of Oslo, the Norwegian Space Centre and the Norwegian Meteor Network, and a project to recover the meteorite was formed. The recovery of the meteorite would be the ultimate proof that the impossible really has been photographed. The videos have been carefully analysed in order to pinpoint the location of the skydiver at the time of the encounter. There have been many attempts to calculate the impact site, and hundreds of hours have been spent on the ground searching. It has been a really exciting project for those involved in the hunt. Yet, no meteorite has been found. The Norwegian broadcasting corporation NRK has documented parts of the hunt. Despite that the meteorite has not yet been found, Anders has now chosen to go public with his story and to publish the videos and analysis work done. This is, however, by no means the end of this story. We hope going public marks the beginning of a new chapter. Perhaps we missed important clues. And perhaps going public is the move required for the meteorite to be recovered. We sincerely hope that this story goes viral. All the material is copyrighted Anders Helstrup \/ Dark Flight<\/strong> and can not be used for commercial purposes without a written permit. Research institutes, schools and amateurs are welcome to use the material for free as long as the copyright holder is acknowledged. We hope that someone out there manages to crack the riddles and help us find the Dark Flight meteorite. Or prove that the rock is an illusion, a bowl of petunias falling from the sky, or something else. We guarantee that the videos are real and have not been manipulated.<\/p>\n

Anders has two cameras that recorded the event. Another skydiver films Anders at a distance, but too far away for the meteorite to be detected in that recording. The camera mounted on the front side of the helmet records in 1080p30 and captures the best details and the meteorite is visible in 7 frames. The recording shows that the meteorite is spinning very quickly, apparently at least 15 revolutions per second. The animation below shows drawings based on the video with the corresponding original image in the top left corner. The images have been resized corresponding to distance.
\n\"Meteorite\"
\n(Photo: Anders Helstrup \/ Dark Flight, animation\/drawing: Steinar Midtskogen)<\/small><\/p>\n

The video mounted on the back of the helmet records in 720p50 with a wider lens and no details of the meteorite are visible. The video does confirm that something fell at a great speed towards the ground, and it shows the position of the meteorite relative to the photographer and the ground, but since the photographer is also moving, it’s a non-trivial task to calculate the impact site. The video also makes it possible to estimate the albedo of the meteorite, approximately 0.12 which is pretty typical for meteorites. The picture below shows the path of the meteorite (marked with yellow dots) relative to the background.
\n\"Back
\n(Photo: Anders Helstrup \/ Dark Flight, photomontage: Steinar Midtskogen)<\/small><\/p>\n

The exact size of the meteorite is not known, but it appears to weigh several kilograms. We can assume that it’s falling at a speed greater than 220 km\/h, more likely around 280 km\/h. We also assume that Anders is falling vertically at a speed of at most 100 km\/h, and the relative speed is correspondingly lower. We then find that the meteorite measures at least 7\u00d79 cm weighing 900g (assuming a density of 3.2 g\/cm\u00b3) zipping past 2.5 metres away. More probably it’s measuring 12\u00d716 cm at 4.6 kg 4.6 metres away. The upper limit for the meteorite seems to be 18\u00d724 cm at 20 kg zipping past at a distance of 6.5 metres. This means that the meteorite appears to be roughly the same size as the Valle meteorite, the most recent meteorite discovery in Norway. If Anders had been struck by the meteorite, the outcome would likely be lethal, and the accident investigators would surely be puzzled!
\n\"Size\"
\n(Photo: Anders Helstrup \/ Dark Flight, figure: Hans Erik Foss Amundsen)<\/small><\/p>\n

Several independent approaches have been applied to pinpoint the exact location of the encounter. All of them point to a location almost directly above Kj\u00f8ls\u00e6tra, an old summer farm a bit south of the airstrip. But what if we made some mistakes? Perhaps we’ve done the most thorough search on the wrong side of Kj\u00f8ls\u00e6tra? We hope that others will study the videos with fresh eyes and come up with alternative solutions. The picture below shows the encounter as seen from the second jumper, Jon Vegar, and the figure shows what direction Anders must have been travelling in assuming that the meteorite falls dead vertically. Kj\u00f8lsetra is seen at the bottom of the picture.
\n\"Jon
\n(Photo: Jon Vegar Andersen \/ Dark Flight, photomontage: Hans Erik Foss Amundsen)<\/small><\/p>\n

The weather was fair with south-western winds around 5 m\/s. The approximate local time of the incident was 14:06. There is an uncertainty of a couple of minutes. The wind is confirmed by both weather models and cloud movement seen in the videos. We have examined camera recordings showing the sky over Oslo at the same time looking for signs of a fireball, but it was more cloudy in Oslo. We have no reports of a fireball from witnesses, but it could have been impossible to see because of the clouds or the glare from the sun. Even seismic data have been examined for hints of a fireball without luck. And any people who might have heard something might easily mistake a sound from a fireball for thunder or construction work. It is not uncommon that meteorites fall in populated areas without reports about anything unusual, the Oslo meteorite in 2012 being the most recent example.
\n\"Wind
\n(Wind profile: Norwegian Meteorological Institute)<\/small><\/p>\n

More information will shortly be published. All the videos have been posted on YouTube<\/a>, and a dedicated website<\/a> is in the making (not yet online at the time of writing) which will include videos and some information on the work that has been done so far.<\/p>\n

Anyone who finds a meteorite in Norway can claim ownership of it, and a 5 kg meteorite will fetch a handsome price on eBay. However, this meteorite will be worth a lot more if it is bundled with the film footage and the story, and perhaps wrapped in a piece of the parachute when offered for sale. So we hope that the lucky finder will join the project to get the maximum reward. The meteorite should be made available for research and for the public, and we aim to give the Norwegian National Meteorite Collection the first right of refusal to acquire a piece of the meteorite.<\/p>\n

Dark Flight project contacts:
\nAnders Helstrup, reisefotanders@gmail.com<\/a>
\nMorten Bilet, mbgeotop@gmail.com<\/a>
\nHans E.F. Amundsen, ha@epx.no<\/a>
\nSteinar Midtskogen, steinar@norskmeteornettverk.no<\/a><\/p>\n

NRK story:
\n