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Sunday, 10 March 2019

Fireball over the United Arab Emirates.

The International Astronomy Centre in Abu Dhabi has reported a fireball meteor over the United Arab Emirates on Tuesday 5 March 2019. The object is estimated to have entered the atmosphere at a speed of 67 000 km per hour at about 7.40 pm local time (about 3.40 pm GMT) over the Al Quo'a and Umm Al Zamul area in the south of the country, and to have exploded in an airburst about 35 km above the Razeen area in the north, suggesting an object about 6 m in diameter. 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.

Image of a fireball meteor captured by one of the network of skywatching cameras operated by the International Astronomy Centre in Abu Dhabi in collaboration with NASA. International Astronomy Centre.

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. This object appeared to move southeast to northwest, and was observed by two of the network of sixteen skywatching cameras operated by the International Astronomy Centre in Abu Dhabi in collaboration with NASA.

Map showing the apparent direction of the 5 March 2019 United Arab Emirates based upon observations by the network of skywatching cameras operated by the International Astronomy Centre in Abu Dhabi in collaboration with NASA. International Astronomy Centre/Google Earth.

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. On this occasion there thought to be a strong likelihood that fragments of meteorite will have fallen to Earth in the region to the south of Al Wathba.
 
See also...

https://sciencythoughts.blogspot.com/2019/03/looking-for-source-of-heavy-nitrogen-in.htmlhttps://sciencythoughts.blogspot.com/2019/02/fireball-meteor-over-colorado.html
https://sciencythoughts.blogspot.com/2019/02/meteorites-fall-on-cuban-town-after.htmlhttps://sciencythoughts.blogspot.com/2019/01/bright-fireball-meteor-off-east-coast.html
http://sciencythoughts.blogspot.com/2019/01/fireball-meteor-over-bay-of-plenty-new.htmlhttps://sciencythoughts.blogspot.com/2019/01/the-quadrantid-meteor-shower.html
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