Witnesses across much of Western Europe have reported observing a
bright fireball at about 2.30 am local time on slightly after 5.40 pm GMT on Saturday 28 November 2020. The fireball is described as
having moved from east to west, and as having been brighter than the
Full Moon, as well as having made an audible boom which caused windows
to rattle. A fireball is defined
as a meteor
(shooting star) brighter than the
planet Venus. These are typically caused by pieces of rock burning up in
the atmosphere, but can be the result of man-made space-junk burning up
on re-entry.
The fireball was seen from France, Belgium, Luxembourg, The Netherlands, England, Denmark, Germany, and Switzerland, and has been calculated to move from west to east over central Germany, dissapearing to the northeast of the town of Harzgerode in Saxony-Anhalt. The fireball has been described as being greenish in colour, which tends to be indicative of a body with a high magnesium content.
Heat map of Western Europe
showing areas where sightings of the meteor were reported (warmer colours indicate more sightings), and the
apparent path of the object (blue arrow). American Meteor Society.
Objects
of this size probably enter the Earth's atmosphere several times a
year, though unless they do so over populated areas they are unlikely to
be noticed. They are officially described as fireballs if they produce a
light brighter than the planet Venus. The brightness of a meteor is caused by friction with
the Earth's atmosphere, which is typically far greater than that caused
by simple falling, due to the initial trajectory of the object. Such
objects typically eventually explode in an airburst called by the
friction, causing them to vanish as an luminous object. However this is
not the end of the story as such explosions result in the production of a
number of smaller objects, which fall to the ground under the influence
of gravity (which does not cause the luminescence associated with
friction-induced heating).
These 'dark objects' do not continue along the path
of the original bolide, but neither do they fall directly to the ground,
but rather follow a course determined by the atmospheric currents
(winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark
objects derived from meteors using data from weather monitoring services.
See also...
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