Fireball from September 21, 2012

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The bolide of September 21, 2012 was an unexpected, spectacular celestial event that frightened and fascinated numerous people in Central and Northern Europe in the late evening hours. It is still unclear whether it might not have been a matter of burning up space debris. In addition, a link to a similar phenomenon in North America was investigated a few hours later, which was suspected to have been the same object.

Observations

At around 11:34 p.m. (all data CEST ), numerous eyewitnesses and stationary cameras in the southern parts of Finland registered a ball of fire moving rapidly in a westerly direction. According to the Finnish mathematician Esko Lyytinen, she moved at an initial height of around 80 kilometers. It was sighted between Helsinki in the south, Oulu in the north, Turku in the west and Kerimäki in the east.

The bolide later appeared in the night sky over northern Germany and was seen in Bremen , Osnabrück and Lingen (Ems) , for example . It presented itself with a yellow-greenish glow with a long white-orange tail. It can be assumed that it passed the coastline at about the level of the Elbe estuary and moved further north-west across the North Sea . After corresponding observations were also reported from the Netherlands - for example from Almelo , Rhenen and Uden - the fireball subsequently crossed northern England , the Isle of Man and around 11:55 p.m. Ireland , where by far the most sightings took place. At this point, however, the object had already broken into numerous fragments, which initially flew together and then moved further and further apart. The bolide could be seen everywhere in the British Isles , its visibility extended to the Shetlands .

Depending on the location, the duration of the bolide's visibility varied considerably. Tim O'Brian of the Jodrell Bank Radio Observatory estimated it to be about 40 seconds.

Origin, whereabouts and context

"I have never seen anything like it before in my life."

- David Moore, Chairman of Astronomy Ireland

Particularly in the United Kingdom and Ireland, where the event resulted in countless calls from concerned citizens to authorities and emergency services and received wide media coverage, several experts spoke up within a few hours with their hypotheses regarding the origin of the object.

The astronomer and presenter of BBC Two telecast Stargazing Live , Mark Thompson , for example, expressed, it would most probably space junk - about a crashing old artificial satellite - traded. As an argument he cited, among other things, the coloration, which is not characteristic of a meteor or meteoroids , which otherwise usually have a whitish trail. The same opinion was shared by Tim O'Brian, who told the BBC that the fireball was traveling at a speed of about 18,000 kilometers per hour. In his opinion, their relatively long visibility indicates that space debris is burning up. David Moore, chairman of the popular astronomy club Astronomy Ireland, agreed with O'Brian that he too noted that the phenomenon had been too slow for ordinary atmospheric decline. But he also pointed out that it was pulled in the wrong direction in order to maintain the space junk hypothesis. However, this is only true if it was not one of the rare satellites in retrograde orbits .

Esko Lyytinen is certain that the fragments of the bolide would not have penetrated the atmosphere to a possible impact on the surface of the earth, at least over Europe, but would rather have moved further west. He believes it is possible that a ball of fire that appeared 155 minutes later over the United States and Canada was one and the same object. Accordingly, the bolide entered the atmosphere over Europe at a relatively slow 13 km / s - which is only slightly more than the escape speed . The braking and glowing through the friction of the atmosphere reduced the speed to 9.2 km / s; Lyytinen calculated that the object reached an altitude of 53 kilometers at its closest point to the earth. The low speed in combination with the entrance angle led to a curvature of the trajectory due to the earth's gravity . This enabled an extraordinarily long passage through the atmosphere. According to Lyytinen, the bolide left the atmosphere west of Ireland, but remained in an earth orbit. It may then have completed a complete orbit around the world before re-entry via North America . There, the majority of sightings were concentrated in New England and the Canadian province of Québec , but reports also came from Florida and the west coast . This hypothesis is supported by the aerospace engineer and meteor expert Robert Matson , who also calculated independently of the Finn that the bolide would regain altitude at the end of the orbit that can be observed in Europe. On October 7 of the same year, Matson announced that it had been agreed that there was no connection between the two celestial events.

Individual evidence

  1. ↑ a b c Esko Lyytinen: "Breaking News - Finland Bolide Fireball Meteor 21SEP2012" , on September 23, 2012 on lunarmeteoritehunters.blogspot.de . Retrieved October 1, 2012
  2. ↑ a b c Genevieve Carbery: "Fireball may have been space junk" , on September 23, 2012 on irishtimes.com ( The Irish Times ). Retrieved October 1, 2012
  3. ↑ "Meteor Blazes Across Ireland and UK" ( Memento of the original from September 27, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , on September 22, 2012 on astronomy.ie (Astronomy Ireland). Retrieved October 1, 2012  @1@ 2Template: Webachiv / IABot / astronomy.ie
  4. ↑ "Fireball in sky above Sheffield believed to be 'space junk'" , on September 25, 2012 on thestar.co.uk ( [[The Star (Sheffield) |]] ). Retrieved October 1, 2012
  5. ↑ "Breaking News - NE US / Canada Bright Meteor 21SEP2012" , on September 22, 2012 on lunarmeteoritehunters.blogspot.de . Retrieved October 1, 2012
  6. ↑ Mikko Suominen, Marko Pekkola: "Breaking News - UK Earth-hugging Asteroid Circled the Earth and Hit Again" , on September 28, 2012 on lunarmeteoritehunters.blogspot.de . Retrieved October 1, 2012

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