Roy Uddin, a researcher at the University of California, Berkeley, and a co-author on the study. “So if you were to send these particles [through a detector] to see what happens, you’d expect them to bounce off the ground.”
A better measure, Uddin and his colleagues suggest, is to send them through the air rather than ground-based detectors. “Imagine that you’re walking down the street that has dust coming in every direction,” Uddin says. A dust-susceptible particle, called a nano- or nanosized particle, is created by any atom (or subatomic particle) that has a lower atomic number than its neighbor (or protons, for those of you not in the know [munch me]), and it’s generally the faster growing subatomic material and the bigger molecules that are responsible for the most collisions with each other.
As air-borne particles travel on their way from one part of the atmosphere to another, and as they bump into others (as in micro-meteorites), they absorb energy. The particles are then blown away by the wind, according to the results of Uddin’s study—a phenomenon known as atmospheric deposition. It turns out that these particles can travel at much greater distances than they do in the vacuum of space and that they interact with each other as they move.
The researchers show in an accompanying research paper that by exposing a ground-based detector to the particles of dust, they could accurately measure the energy they absorb so they could be used to calculate their orbital inclinations at the moment when they collide. Using a numerical model that describes dust as a single particle, with individual atoms suspended in a vacuum, the researchers constructed a model of the dust-sized particles. To calculate how often the particles would collide, they used the assumption that the particles fly through space at the speed of light, which is just 5.75 miles per second, equivalent to the speed of a particle traveling a thousand times the speed of light.
The model then showed that the particles in a dust particle will collide more frequently than when the particles would collide without the particles suspended within the vacuum, confirming that the particles exist as individual particles rather than as a mixture of different particle types, the authors note. This means that particles in dust are, in fact, free agents.
“What’s exciting is that at the particle scale, atoms and their interactions