We have all come in contact with dust one way or another, either in buildings (domestic or house dust) or outside, on roads, in mines, or just in the general atmosphere (atmospheric dust). But there is plenty of dust in outer space as well, usually known as cosmic dust. In fact, it has been suggested that we humans are made of “stardust,” or “star stuff,” that is, the material world that we know and experience every day, and even our own bodies, are ultimately the products of dust from space.
Cosmic dust is also of different kinds; most importantly, distinctions can be made based on where the dust is found, so there is intergalactic dust, interstellar dust, interplanetary dust, and circumplanetary dust. Cosmic dust is a very important part of outer space and its astrophysical characteristics and processes, although this was not always realized by astronomers. For a long time, earlier astronomy focused on certain cosmic objects–stars, planets, moons, etc.–and astronomical observations of these objects with early modern equipment were often impeded by cosmic dust. But with the advent of infrared astronomy, people in the field realized that cosmic dust plays a large role in shaping the processes of our universe. For instance, while people’s conceptions of our solar system usually include the Sun, Moon, the planets and their satellites, as if there was nothing but vacuum in between, there are interplanetary dust clouds between the planets, which, when illuminated by the sun, can give rise to the phenomenon known as zodiacal light.
The study of cosmic dust and its effects on our universe may not be as relevant to many people as, for instance, knowledge of domestic and atmospheric dust, which affects our everyday lives more visibly. But cosmic dust also plays a very important role in the formation and the operation of our cosmos, and its study may provide us with valid insights that can have consequences in future space exploration and our understanding of the world around us.