Hoba Meteorit
Hoba (also known as Hoba West) (pron. "HOE-bah") is a meteorite
that lies on the farm "Hoba West", not far from Grootfontein, in
the Otjozondjupa Region. It has been uncovered but, because of its
large mass, has never been moved from where it fell. The main mass
is estimated at over 60 tons, and it is the largest known meteorite
(as a single piece) and the most massive naturally-occurring piece
of iron known at the Earth's surface.
The Hoba meteorite is thought to have landed less than 80,000 years
ago. It is inferred that the Earth's atmosphere slowed the object
down to the point that it fell to the surface at terminal velocity,
thereby remaining intact and causing little excavation. The
meteorite is unusual in that it is flat on both major surfaces,
possibly causing it to have skipped across the top of the
atmosphere in the way a flat stone skips on water.
The Hoba meteorite left no preserved crater and its discovery was a
chance event. The owner of the land is said to have encountered the
object while ploughing one of his fields with an ox. During this
task, the farmer heard a loud metallic scratching sound, before his
plough came to a sudden stop. The meteorite was excavated soon
after and identified and described by scientist Jacobus Hermanus
Brits, whose report was published in 1920. This report can be
viewed at the Grootfontein Museum in Namibia.
Hoba is a tabloid body of metal, measuring 2.7 by 2.7 metres (8
feet 9 inches) by 0.9 meters (3 feet). In 1920 its mass
was estimated at 66 tons. Erosion, scientific sampling and
vandalism have reduced its bulk over the years. The remaining mass
is currently estimated at just over 60 tons. The meteorite is
composed of about 84% iron and 16% nickel, with traces of cobalt.
It is classified as an ataxite iron meteorite belonging to the
nickel-rich chemical class IVB. A crust of iron hydroxides is
locally present on the surface, owing to weathering.
In the attempt to control vandalism, the Government of Namibia
(then South West Africa), declared the Hoba meteorite to be a
National Monument on March 15, 1955 with permission of Mrs. O.
Scheel who was the owner of the farm at that time. In 1985, Rossing
Uranium Ltd. made resources and funds available to the Namibian
Government to provide additional protection against vandalism. In
1987 Mr. J. Engelbrecht, the owner of Hoba West farm, donated the
meteorite and the site where it lies to the State for "educational"
purposes. Later that year, the Government opened a tourist centre
at the site. As a result of these developments, vandalism of the
Hoba meteorite has ceased and it is now visited by thousands of
tourists every year.
(Wikipedia)
Hoba Meteorit
Der Hoba-Meteorit (engl. Hoba Meteorite; in der Fachliteratur
auch teilweise nur als Hoba bezeichnet) ist der bislang größte auf
der Erde gefundene Meteorit. Er befindet sich auf dem Gelände der
„Hoba“-Farm in den Otavibergen, etwa 20 km westlich von
Grootfontein. Die Angaben über das Gewicht schwanken zwischen 50
und 60 Tonnen. Seine ursprünglichen Abmessungen waren 2,70 m × 2.70
m × 0,90 m. Der Meteorit schlug vor zirka 80.000 Jahren auf der
Erde ein und liegt immer noch in der ursprünglichen Position. Sein
geschätztes Alter beträgt 190 bis 410 Millionen Jahre.
Der Meteorit besteht zu zirka 82 % aus Eisen, zu zirka
16 % aus Nickel und zu zirka 1 % aus Cobalt. Darüber
hinaus enthält er eine Reihe von Spurenelementen wie Chrom,
Gallium, Germanium, Iridium, Kohlenstoff, Kupfer, Schwefel und
Zink. Meteoriten mit Nickelgehalten von über 15 % werden als
Ataxite bezeichnet.
Am 15. März 1955 wurde er mit Genehmigung der damaligen
Farmbesitzerin Olga Scheel zum nationalen Denkmal erklärt. Der
Besitzer im Jahre 1987, J. Engelbrecht, hat dem Rat für Denkmäler
das Gebiet um den Meteoriten herum geschenkt. Daraufhin wurde das
Gelände um den Meteoriten herum vom Rat für Denkmäler
gestaltet.
Das Erdreich um den Meteoriten wurde ausgegraben und eine Art
Amphitheater angelegt. Ferner wurden Toiletten, ein ausgebauter
Pfad zum Meteoriten, ein kleines Kassenhaus mit einem Geschäft und
Grillplätze angelegt.
(Wikipedia)