Fireball Detection

On 9 December 1997, sensors aboard DOD satellites detected the impact of a meteoroid at 08:15:55 UTC roughly midway between Nuuk and Qaqortoq, Greenland. The object broke into at least 4 pieces. One piece detonated at an altitude of about 46 km at 62.9 degrees North Latitude, 50.9 degrees West Longitude.

The remaining 3 pieces detonated in close proximity to one another at altitudes between 28 km, at 62.9 degrees North Latitude, 50.1 degrees West Longitude and 25 km at 62.9 degrees North Latitude, 50.0 degrees West Longitude.

Fireball Detection

On 11 January 1998, sensors aboard DOD satellites detected the impact of a meteoroid at 07:11:13 UTC roughly midway between Denver and Grand Junction, Colorado. The object was detected at 39.4 degrees North Latitude, 106.4 degrees West Longitude.


Tycho Brahe Planetarium & Omnimax Theater
Copenhagen, Denmark

Danes Plan Meteorite Recovery Expedition to Greenland

The Tycho Brahe Planetarium & Omnimax Theater is now organizing a search for meteorites from the fall of December 9, 1997. Several institutions are involved in the preparing for an expedition that, considering the surface conditions, must take place in late July. Currently the area is covered by 2-3 meters (7-8 feet) of snow, which will normally melt in May and June. During this time the site will be a very dangerous area to visit. Floods and ice sumps cover the melting zone and there will be hidden ice canyons and holes in the surface, where the water suddenly disappears and falls hundreds of meters into deep tunnels. We have to wait until the surface dries out in late July.

Holger Pedersen and Torben Risbo (Niels Bohr Institute, Copenhagen) have put a lot of work into predicting possible locations of the strewn field, or dispersion ellipse, on the icecap. The suspected area is in the area of what we call the melting zone, about 10-15 km (8-10 miles) from the edge of the icecap on the southwest coast of Greenland.

The size of the original object was probably from meter-size to a small house. After the object had penetrated nearly 200 km (125 miles) of atmosphere it came to an explosive fragmentation at an altitude of 14 km (9 miles). Nearby eyewitnesses noticed that more than twenty larger fragments continued in the original direction, still moving fast enough to ionize the air around them, until they disappeared behind the local horizon (zenith distance 87=F8), equal to an altitude of 3.5 km (2.2 miles). The calculated fall area has an altitude of 1400-1500 meters (4200-4500 feet) and is located on the icecap.

The fact that the fragments continued to travel fast enough to cause ionization of the air around them tells us that they must be rather massive and of a size that should make it resonable to search for them, when icecap conditions permit.

We are now preparing a four man expedition. The logistics of such an expedition are difficult, but we are receiving great help from more experienced groups that have worked in similar regions.

We are convinced that this work is scientifically important, and it would be of a great help if anyone with satellite data (military or otherwise) that traced the visible or infrared signal from the meteor of December 9, 1997 (8.11 UT) over the southwestern coast of Greenland would contact us. We need this assistance to narrow our search area. We have two predicted areas, about 19 km (12 miles) apart. One is the direct result of geometric measurements from the eye-witness reports and the other is based on mathematical calculations of the track. The distance between the areas is not large, but considering the very difficult conditions we will be working under, concentrating the search in one 50-70 square kilometer (20-30 square mile) area rather than two will greatly aid our effort. We hope to solve this problem in one way or another before leaving for Greenland.

Involved in the search:

Tycho Brahe Planetarium web site (mostly Danish, but links in English).

Bjørn Franck Jørgensen

Press statement
Niels Bohr Institute, Geophysical Dept.

December 15, 1997 20.00 UT

A big meteor impact has probably occurred in Southern Greenland at 61 25N, 44 26W on Tuesday, December 9th app. 08.11UTC (05.11am local time). The position is on the ice cap app. 50 kilometers NE of Narsarsuaq Airport.

The position has been determined on the basis of observations made by a Danish and a Norwegian trawler near the east coast of Greenland, and a Danish trawler at a position in the bay off Julianehaab. Based on fairly accurate direction findings and the fact, that the trawlers were situated on both sides of Southern Greenland it can be determined, that the meteorite fell on land.

The relevant trawlers are:

Halten Trawl, Norwegian at 62 05N, 41 10W
Regina C, Danish at 60 55N, 51 35W
Timmarut, Danish at 60 13N, 46 43W

Observations of the satelite lighttrack from Nuuk indicates that the meteorite passed a bit south of Nuuk in southeasterly direction towards the mentioned impact site in Southern Greenland.

Seismic disturbances have been observed on Svalbard and Finmarka (Norway). These tremors are observed at 08.21UTC and 08.23UTC and are assumed to relate to the impact or the passage of the meteorite through the atmosphere. The signals did not allow a seismic localization of the event. The observations are made by NORSAR (Norwegian Seismic Array), Kjeller, Norway. Fainter signals were observed in Finland and Germany. The seismic stations in Greenland (Sonder Stromfjord and Danmarkshavn) has no observations. Further seismic data will be collected from Iceland and Canada in order to confirm the visual localization.

Observations from the satellites ERS1 and ERS2 are being planned. These satellites observe the surface of the Earth using radar.

The flashes observed in conjunction with the meteorite were so bright as to turn night into daylight at a distance of 100 kilometers and can be compared to the light af a nuclear explosion in the atmosphere. However, we stress that there is no reason to belive other than natural causes.

During the day, the position will be overflown by an ice reconnaissance plane, from the Ice Central in Narsarsuaq on its planned flight from Kap Farvel to Nuuk.

The event can in size probably be compared to the Kap York meteorite, that in prehistoric time fell in Melville Bay, Sassivik south of Thule. Findings from the meteorite consist of a number of iron meteorites totalling 50 tons. One of these ironfragments can be seen in Copenhagen outside the Geological Museum.

Collecting and studying material from this meteorite has great scientific value. It is fortunate that the meteorite fell on land, but a search on the ice cap is difficult and in winter impeded by bad weather and darkness. Since December 9th 30-100cm of snow has fallen in the area and before summer smaller fragments will be covered by 3 meters of snow. According to Danish law, findings of meteorite material must be turned over to the authorities, in this case they will be the property of the Greenland Home Rule.

These investigations are coordinated by Geophysical Dept. at the Niels Bohr Institute, University of Copenhagen in cooperation with:

Tycho Brahe Planetarium, Copenhagen.
Copenhagen Astronomical Society
National Survey and Cadastre, Denmark
NORSAR, Kjeller, Norway
Danish Center for Remote Sensing, Technical University of Denmark

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