Dust, Dust, Anybody? No? Dust.
When you think of Earth what is the first thing that comes to mind? Do you think of the ocean? Do you think of Trees and grass? Do you think of mammals, fish, or birds? How many of you think of dust? Well, that is what we are all made of; dust.
Most physicists believe that our universe as we know it originated with the big bang some 14 billion years ago (Lehners and Stelle, 2019), and it is generally agreed that the vast majority of elements are forged in the hearts of stars. The nuclear reactions bubbling away in the centre of our universes earliest stars are thought to have produced the atoms that form the universe we are now exploring. How wonderful to know we are all stars, well star dust, but it’s still good enough for me!
But why am I so interested in dust? Well to answer that I would have to give you a little insight into my daily life. I am currently trying to write up my PhD thesis. And if you don’t know, most of a PhD involves reading, and most of procrastinating doing your own PhD involves falling down a reading rabbit hole. This week my rabbit hole took me to the enlightenment that the Antarctic research centre collects samples of snow and have found a plethora of extra-terrestrial particles; dust for lack of a better word, and to keep a theme going! (Rojas et.al., 2021 if you’re interested – just don’t ask me how I got there because I really don’t know!).
Extra-terrestrial objects are those not originating from terra, Latin for earth. The most commonly recognised of these is probably a meteorite. These have always been a spectacle of human interest. We as a species are enamoured with the unknown. More so than that, however, over the bulk of our planets surface, even the meteorites that can survive the journey through our atmosphere (a feat in itself) are unlikely to last long once the make impact. Earth’s propensity for waterborne or wind erosive habitats makes for the accelerated breakdown of any mineral matter.
The Antarctic has a much less erosive environment and therefore we are more likely to find intact and testable meteorites in this environment. From their collections and extrapolations, they have deduced that our Earth collects more than 4,700 tonnes of extra-terrestrial dust every year. They accomplished these calculations with the knowledge that meteorites are more likely to fall at the equator, and by how these meteorites they found through several years of snowfall would have been preserved.
I don’t know how everyone else feels about this, but this excites both the scientist in me and my self-conscious side. If the earth can put on 4,700 tonnes a year, then my few kilos over lockdown is negligible. Not only that but I am a star and so are you, because the atoms that make us up were forged in the heart of a star and became us through star dust.
Sources
Lehners, J.L. and Stelle, K.S., 2019. Safe beginning for the Universe?. Physical Review D, 100(8), p.083540.
Rojas, J., Duprat, J., Engrand, C., Dartois, E., Delauche, L., Godard, M., Gounelle, M., Carrillo-Sánchez, J.D., Pokorný, P. and Plane, J.M.C., 2021. The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth. Earth and Planetary Science Letters, 560, p.116794.
Written by Libby Bowles
I’m a PhD Researcher at Prifysgol Aberystwyth, studying the perenniality syndrome in Grasses. I’m passionate about public engagement in science and the sharing of knowledge regarding the world we live in, especially the weird and wonderful.
