It's in the dirt on the ground, the debris (碎片)on your roof, and the dust that tickles your nose --tiny pieces of "cosmic dust", everywhere. These microscopic particles from outer space are micrometeorites(微陨石)--mostly the debris from comets and asteroids(小行星) --and they have settled all over our planet.
Once the particles settle to the ground, they can be found anywhere; they could be sitting on your clothes right now. But despite their widespread presence, finding cosmic dust isn't easy. One place that the particles show up more easily is Antarctica. Around a decade ago, Mattew Genge at Imperial College London spent seven weeks searching for and collecting dust there.
The downside to collecting dust from Antarctica is the cost and complications of travelling there. That's why Penny Wozniakiewicz of the University of Kent in the UK has focused her research closer to home. The key is to collect materials from a fairly undisturbed spot. For instance, she samples on the rooftops of old cathedrals in the UK.
She focuses on these roofs because they are old and more untouched than modern buildings. What's more, historic buildings like cathedrals usually have well-kept records that indicate when maintenance and cleaning have been done. That makes it easier to determine how long cosmic dust has been collecting and gives researchers insight into what other particles might be present in the dust they collect. This allows them to more efficiently remove the Earth stuff, and focus on the space stuff.
Each year, approximately 100 billion particles of space dust land on Earth, carrying secrets from asteroids and offering glimpses into the formation of galaxies. These micrometeorites not only contain water but also organic molecules (分子);they potentially serve as the building blocks for life on Earth. Cosmic dust could, therefore, tell scientists about the intricate(错综复 杂的)relationship between these celestial bodies and Earth. It acts as a bridge, connecting us to the wider universe.
