New experiments, carried by the EU scientists, managed to estimate how much cosmic dust enters Earth's atmosphere for the first time. The dust particles impact our atmosphere causing a wide range of phenomena, and further research hopes to address them.
Dust particles, originating from comet's orbiting the Sun, frequently enter Earth's atmosphere where they collide with air molecules at speeds between 40 000 and 260 000 km/h (24 854.8 and 161 556.5 mph) and generate flash heating followed by melting and evaporation of the particles.
"Sometimes this dust is visible as meteors, which is the case of dust particles greater than 2 mm. But most of the dust mass entering the atmosphere is so small that it can only be observed using specialized meteor radars," explained John Plane, the CODITA Project Lead.
However, so far, very little has been known about exactly how much dust enters the atmosphere and what impact it has. It has been estimated that between 3 and 300 tons of particles enters our planet's atmosphere on a daily basis.
The CODITA project is focused on discovering the exact amount and impact the dust particles have on Earth's atmosphere. In order to investigate this, two experiments have been set up with a goal to research the chemistry of the metallic molecules and ions produced in the evaporation process.
The first experiment utilizes a flow tube reactor coupled to a time-of-flight mass spectrometer to detect the metallic molecules by means of pulsed laser radiation which ionizes the molecules. The experiment was successful in investigating the molecules' reactions for the first time.
In the second experiment, a flow tube was used in combination with a plasma source and coupled to a quadrupole mass spectrometer, enabling the experts to study the dissociative recombination of metal-containing ions with electrons, a key process in neutralizing the ions of the upper atmosphere.
Conducted experiments, in combination with an astronomical model of dust evolution and high-performance radar measurements, suggest about 40 tons of tons enters our planet's atmosphere every day. According to the scientists, the metals entering our atmosphere are causing a series of phenomena, such as noctilucent clouds.
The noctilucent clouds are formed as the metallic molecules condense into extremely fine dust, named meteoric smoke. The are known to occur at heights of about 82 km (50.9 miles) during the summer season, in the polar regions.
"The clouds first appeared in 1886, and their increasing occurrence appears to be signal of climate change in the middle atmosphere, where water vapor is increasing and temperatures are falling because of increased levels of greenhouse gas – the reverse of the lower atmosphere. Meteoric smoke also affects polar stratospheric clouds that cause depletion of the ozone layer, and the deposition of cosmic iron in the Southern Ocean provides a critical nutrient for plankton, which draw down carbon dioxide from the atmosphere," said Plane.
The CODITA project enabled the modeling of cosmic dust effects from the outer solar system to our planet's surface. The goal of the project is also to investigate the effect the meteoric smoke produced in other solar systems bodies, for example, high-temperature chemistry on Venus or the formation of noctilucent clouds on Mars.
Featured image: Noctilucent clouds, June 20, 2014. Image credit: Pawel Maryanov (Flickr-CC)
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