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A team of scientists from the UK has provided a new estimate of the amount of space rock that falls to Earth each year.
Exceeds 16,000 kg. This is for meteorite material above 50g mass.
It doesn’t take into account the dust that is continually settling on the planet, and of course only occasionally will we get hit by a real asteroid that will skew the numbers.
But the estimate is said to give a good idea of the overall amount of rock debris raining down from space.
“The vast majority of objects hitting Earth are really small,” explained Dr. Geoff Evatt.
“We are talking about objects for which, when they hit the ground, the fragments add up to more than 50g. So typically 50g-10kg total. Objects larger than this are very, very rare,” said the University of Manchester mathematician. he told BBC News.
University of Manchester / Katie Joy
Black on white: Manchester scientist Romain Tartèse sees a meteorite in Antarctica
One of the other results of the study, produced in collaboration with colleagues from the University of Cambridge, Imperial College London and the British Antarctic Survey, is that it allows for a risk assessment for the entire planet.
This reveals that the number of falls at the poles is approximately 60% of what one would expect at the equator.
Explain why you would absolutely want to put any long-term contingency facility at higher latitudes.
The Global Seed Vault, for example, whose goal is to retain copies of Earth’s plants in case of crisis, is located 78 degrees north in the Svalbard archipelago.
The new estimate,
published in Geology magazine
, emerged from the project to undertake the first UK dedicated meteorite hunt in Antarctica.
The Crop Trust
The contents of the global seed vault may be needed after a severe impact
The researchers involved in that effort wanted to make sure they would visit the most productive areas to conduct such a search.
The White Continent is the place on Earth where most of the meteorites have recovered, for good reason: the “black on white” contrast of space rocks dropped in snow and ice makes searching much easier. .
And hunters often go to places where the movement of the ice sheet concentrates the meteorological material, called stranding areas.
Dr. Evatt and his colleagues calculated how many objects should be in their chosen area, a place called the Outer Recovery Ice Fields, near the Shackleton Mountain Range in East Antarctica.
And they practically followed through on their expectations, finding nearly 120 meteorites in two systematic searches during 2019 and 2020.
But after having produced a reliable flow for the number of falls on the chosen terrain, the scientists realized that they could use this knowledge to anchor a global assessment.
This built-in orbital mechanics, how Earth’s gravity will attract nearby material, to determine how rates can vary by latitude. The model generates a grand total of approximately 17,000 falls per year.
And this can be proven by looking at the data from the fireball events. Orbiting satellites that track lightning in storms will also catch the searing trail of a space rock sinking into the atmosphere.
“The satellites monitor these explosions in the sky, calculating the energy of the events and also the longitude and latitude of the place where they occur. And from this you can see how they vary around the world with latitude, and very well the curve that you get these fireballs fit what we independently model using a purely applied mathematical approach, “said Dr. Evatt.
Professor Sara Russell leads the planetary materials group at the Natural History Museum, London. She was not involved in the research, but commented, “I think this is an amazing study, and this estimate seems to be in the right stage.”
“We believe that a total of approximately 40,000 tons (or 40,000,000 kg) of extraterrestrial material falls to Earth each year, but the vast majority of this is in the form of small grains of dust.
“This is a very difficult measurement to make accurately and you only see half a dozen meteorites fall each year, but of course almost all meteor falls are not observed because they fall into the sea, in unpopulated areas or just don’t “One is watching!” She told BBC News.
Fireballs reported by US government sensors. USA (April 1988 to March 2020)
A.B. Chamberlin (JPL-Caltech)
The total impact energy is indicated by the relative size of a circle and by a color. The redder the color, the greater the energy; the bluer the color, the lower the energy
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