Space Dust: Interesting Facts

      Yanna Borbon Cueto 

      A couple of days ago I was watching a fiction movie called Stardust. The movie is about a young man who promises his girlfriend that he will venture into a magical world to retrieve a fallen star for her. Lovely story! But what really caught my attention about the movie was the fallen star; I know that probably is impossible for a star to fall on Earth but how about stardust or space dust? What is space dust? Is it possible that space dust falls on Earth even though is travelling or moving in space? How does space dust affect Earth? Does space dust settle on space shuttles? There were many things I didn’t understand so I decided to do a little research on the topic.

      Space dust or cosmic dust is a type of dust in space that is composed by small particles from asteroids or comets. It is just a few molecules to 0.1mm in size and covers the solar system in a thin cloud. Apparently, this dust bothered the astronomers just as dust bothers us here on Earth since it obscured the objects they wanted to observe. When infrared astronomy was developed the astronomers realized that the dust particles that used to bother them were “vital components of astrophysical processes”. For example, cosmic dust plays an important role on star formation; stars are made (“born”) on giant clouds of dust and gas. Infrared light can penetrate the cosmic dust clouds which allow astronomers to see into regions of star formation and the centers of galaxies. In our solar system this dust also plays an important role in zodiacal light, which is produced by the sunlight reflecting off dust particles. Even though cosmic dust is travelling in space, it falls settling through the atmosphere and onto the Earth’s surface. An average of 40 tons per day falls on Earth. These particles are collected in the Earth’s atmosphere using plate collectors that are placed under the wings of stratospheric-flying NASA airplanes and are collected from surface deposits in Antarctica and Greenland. Scientists found that collecting and studying cosmic dust is important in order to understand the origins of the solar system, also their mineral content records the conditions under which comet, planets and asteroids were formed. According to Dr Mathew Genge, from Imperial College London's Department of Earth Science and Engineering, “There are hundreds of billions of extraterrestrial dust particles falling though our skies. This abundant resource is important since these tiny pieces of rock allow us to study distant objects in our solar system without the multi-billion dollar price tag of expensive missions."

      Going back to one of my first questions, does space dust affect Earth in any way? According to Donald Brownlee astronomer at the University of Washington in Seattle, “the dust grains pose no serious threat to the planets. But they could chip away at the solar panels on spacecraft, causing a gradual loss of power, and knock particles off asteroids, filling the solar system with even more dust”. How can tiny particles chip away at the solar panels on spacecrafts? I’ll answer this question by answering one of my first questions: Does space dust settle on a space shuttle that is orbiting the Earth just like dust settles on a table or a moving car? The answer is no. Even though a shuttle orbiting the Earth is in free fall it never reaches the Earth because is moving sideways really fast. Well, because they are above the atmosphere where there is no air the dust particles also fall freely, these particles have great horizontal speeds and orbit the Earth just like small space shuttles.  According to Louis A. Bloomfield author of “How Everything Woks: The Physics of Everyday Life” “The relative speed between a dust particle and the shuttle can easily exceed 10,000 mph” when this little particle hits the space shuttle it collides with the shuttle’s surface instead of settling, so these violent collisions are what cheap away at the solar panels. 

      Unlike the dust we find in a tabletop or in our night stand, cosmic dust is very important. As I mentioned before, this dust particles are “vital components of astrophysical processes”. According to Dr Mathew Genge “The answer to so many important questions, such as why we are here and are we alone in the universe, may well lie inside a cosmic dust particle. Since they are everywhere, even inside our homes, we don't necessarily have to blast off the Earth to find those answers. Perhaps they are already next to you, right here and right now." 

      References:

http://www.scienceray.com/Astronomy/Space-Dust.281487

http://www.astrobio.net/news/index.php?name=News&file=article&sid=2864&theme=Printer

http://www.howeverythingworks.org/HTW4eBI.html

http://news.nationalgeographic.com/news/2003/08/0827_030827_spacedust.html