Måned: april 2014

On 19th April a dashcam recording of a large fireball in the Murmansk region video made international headlines. While an infrasound analysis gives a good estimate of the area where the fireball fell, photographic evidence has the potential of providing better accuracy. There also exists another dashcam video of this fireball, but it’s recorded from a countryside road with no usable landmarks or references. Further away in Finland there is direct photographic evidence from Kuusamo and Mikkeli. The Kuusamo image is promising, but it still requires some careful analysis. Finnish fireball watchers are on the case.

Meanwhile, let’s find out what the dashcam video can tell us. This task is actually quite fun. It’s amazing how efficiently it can be done with the help of Internet. There is no need to book a flight to Murmansk and bring a theodolite.

The video was widely reported in international news as recorded in Murmansk, but skimming through Russian commentary quickly revealed that it was in fact recorded in Snezhnogorsk, an hour’s drive north of Murmansk. Which is good news, since finding the correct street in a large city like Murmansk in a country where all apartment blocks look pretty much the same is no easy task even with useful tools like Google Earth. Snezhnogorsk is a small place with only a few streets, and we already know the general direction that the driver had to be going.

(Video: Alexandr Nesterov)
Fortsett å lese «The Kola fireball: A dashcam analysis»

Ildkula som gikk over Kolahalvøya nær finsk og norsk grense natt til påskeaften er fotografert fra finsk og russisk side, registrert av norske, svenske og finske infralydstasjoner, og det fins mange vitneobservasjoner fra Norge, Finland og Russland. Foreløpige analyser tyder på at ildkula har gått noe øst for grensa mellom Finland og Russland i en nordlig retning, kanskje så langt som området øst for den norsk-russiske grensa.

Finnenes foreløpige analyse plasserer fallstedet litt øst for den norsk-russiske grensa, mens en analyse av NORSAR plasserer området et stykke øst-sørøst for treriksrøysa.

Antakelig vil en grundig analyse av bildene/videoene som viser hendelsen kunne gi et mer presist svar på hvor ildkula har gått, men det krever innhenting av mer informasjon om hvordan bildene/videoene er tatt. Et fint bilde, dessverre med dogg i linsa som visker ut mulige stjernereferanser, tatt av Asko Aikkila i Kuusamo, kan ses her.

Infralyden er en sterk indikator på at det har falt ned meteoritter. Eksakt sted er altså ennå noe uklart, men det virker sannsynlig at det er på russisk side av grensene.

(Kart: Steve Gibbons / NORSAR)

On 17th June 2012 Anders Helstrup was skydiving using his wingsuit. In one of the jumps something very unexpected happened, and his two helmet mounted camera confirmed it: A rock fell from the sky, just past Anders towards the ground. There was no one or nothing above him that could have dropped it. He contacted some geologists and meteorite experts, and an investigation was under way. The videos were analysed and the area was searched, but the only conclusive proof for a meteorite, the meteorite itself, was not found. We know that a few meteorites fall over populated areas on Earth every day, often unnoticed. Relatively slow fireballs may be fainter than the full moon and still drop meteorites, and they may be very hard to see in the glare of the sun or behind clouds. A sonic boom could be mistaken for thunder or human activity. Considered the many million cameras now in use worldwide, one is occasionally bound to capture something extremely unlikely. So however unlikely a near hit of a meteorite is, it is certainly a possibility. Due to its extreme low probability, it’s naturally the last pick of all the thinkable actual possibilities. A number of scenarios were considered, but all apparently failed to explain what is seen in the video. We were left with scenarios that we were unable to find possible solutions for against something that fits but is extremely improbable, though possible. We seemed to get no further, and we decided to go public with what we had and at the same time invite anyone to have a go at the puzzle. The story was announced here on the web pages of the Norwegian Meteor Network, where we expressed our hope that it would go viral and scrutinised for something that we might have missed, and the result was beyond our expectations.

Fortsett å lese «Fireballs vs. eyeballs»

NRK’s populærvitenskaplige program Schrödingers katt forteller i dag fallskjermhopperen Anders Helstrups fantastiske historie. Under et hopp over Østre Æra flyplass ved Rena den 17. juni 2012 skjer det noe helt usannsynlig: Like etter at han løser ut skjermen 1000 meter over bakken, suser en mørk stein i stor fart rett forbi. To hjelmkameraer dokumenterer det hele. Hvordan kan en stein komme til syne rett over Anders 1000 meter over bakken? Det er ingen over han, verken fly eller andre hoppere. Det er vanskelig å finne andre forklaringer enn den usannsynlige: en meteoritt har falt rett forbi.

(Foto: Anders Helstrup / Dark Flight, montasje: Hans Erik Foss Amundsen)
Fortsett å lese «Fallskjermhopper filmer fallende meteoritt»

Today the Norwegian broadcasting corporation NRK will air the popular science programme Schrödingers katt which features the incredible story of the skydiver Anders Helstrup. In a jump above Østre Æra 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.

(Photo: Anders Helstrup / Dark Flight, photomontage: Hans Erik Foss Amundsen)
Fortsett å lese «Skydiver films falling meteorite»