Sky Dust

The sky is full of invisible dust that can help scientists study weather patterns, pollution, and the history of the solar system. But this dust isn’t just for scientists — kids are collecting and studying it, too.

Tons of tiny dust particles fall onto our planet every day — pollen, insect parts, soot — and even tiny bits of comets and asteroids raining down on us at all times.

This invisible sky dust can help scientists study weather, pollution, insect invasions, climate change, the spread of disease and even the history of our solar system. Geologist Dan Murray, of the University of Rhode Island, says students can help collect and study sky dust. All they need is a sheet of a special nonstick material — a filter — a microscope — a special kind of tape used at crime scenes — and a few household items.

Dan Murray: It’s a sort of low-tech kind of collecting thing, but the nice thing about it is that you can have lots of collection sites as opposed to a hi-tech thing which would be a very expensive jet plane flying in the upper atmosphere collecting samples, and that’s hundreds of thousands of dollars per shot.

This past school year, students in a Rhode Island high school collected dust containing particles of soot and searched for the fires that produced them. Meanwhile, Dan Murray has applied for a grant to supply dust collection materials to teachers and to build a web site so that participants can share their data. He’d like to see tens or even hundreds of student sky dust collection sites around the world.

The dust collection program was started about six years ago by Jim Sammons, a science teacher and research biologist in Rhode Island.

The study of sky dust might someday help predict bad bug seasons, pick up subtle effects of climate change, or reveal basic information about the formation of the solar system.

Collecting sky dust is easy, says University of Rhode Island geologist, Dan Murray. His favorite method involves lining an inflatable kid’s swimming pool with a special kind of Gore-Tex-like fabric, which is slick, tightly woven, and static resistant. You leave the pool out in the open and away from trees for about 48 hours. Then, with the kind of tape that investigators use to collect evidence from crime scenes, you pick up whatever has settled. Next, the tape goes into a beaker of water to dissolve. Finally, you put water samples under a microscope, and figure out what you’ve got.

With just a basic high school microscope and an identification key, it’s not hard to tell the difference between Mongolian dust and Saharan sand, Murray says. Micrometeorites are perfectly round, magnetic balls that measure less than 100 microns across, about the width of a human hair. An electron scanning microscope reveals even more details.

Of all the kinds of particles that make up sky dust, the most exotic comes from outer space. Scientists are especially interested in micrometeorites and other types of cosmic dust, because much of it comes from comets, asteroids, and loose debris that formed when the Universe was born. Life on Earth wouldn’t be possible without nutrients and water that most likely came originally from comet dust. In that sense, studying micrometeorites is a way of studying ourselves.

Most studies of cosmic dust involve fancy, expensive equipment. Dan Brownlee at the University of Washington in Seattle works with a team that sends U-2 airplanes to altitudes above 65,000 feet. The aircraft fly at 3/4 the speed of sound for 50 hours or so, traveling the equivalent of several trips around the world, to collect cosmic dust on a sterile filter about the size of a deck of cards. Brownlee’s team has also sent a spacecraft called Stardust to collect samples from a comet for the first time. If everything goes as planned, Stardust will fly past Comet P/Wild-2 next January and bring samples back in 2006. It will be the first mission to collect material from space since astronauts brought moon rocks back in 1972. “The Earth is actually made from these things,” Brownlee says. “That’s the exciting thing.”

Murray and colleague Jim Sammons hope the Skydust project will bring that kind of scientific excitement down to earth for kids and adults alike. Getting lots of ordinary people to participate might also eventually help the planet, if data turns up pollution, pollen, or other debris in unexpected places. “Having lots of sites sampled in a fairly simple way could be sort of an early warning system,” Murray says, “like having a lot of canaries in the mine.”

Jim Sammons was a science teacher for thirty years and is now retired. He was also a research biologist. Now he develops science education materials for students in middle school through high school. He also does basic science research. In an email dated 13 May, 2003, he said, “I began testing the protocols for dust collection about six years ago, but it wasn’t until Dan provided his support three years ago that the project gathered headway.”

Dan Murray described Jim’s work this way, “Jim Sammons taught ninth grade science for nearly thirty years, before retiring two years ago. During that time he received a variety of awards, including the National Association of Geology Teachers award, for the best teacher in New England. Currently, he is involved in a number of projects, including: 1) writing science education texts for WGBH, to accompany NOVA programs; 2) as a co-PI or Senior Personnel on several projects with me and others, that are funded by FIPSE, NASA RI SPACE, GRANT, and NSF; and 3) authoring science education, lab oriented, science materials for K-12 (I don’t know the name of the publisher). He also has worked with me on my own research on granites in Yosemite, neotectonics in eastern California, and Appalachian tectonics in southeastern New England.”

The researchers have a collection site set up in Palo Alto, California near Stanford and another in Rhode Island. They’re planning to set up one in Argentina. Eventually, they would like to have hundreds of such sites around the world.

In the Fall of 2001, Murray and his colleagues in Rhode Island collected dust from Mongolia that drifted with the wind across North America.

During the 2002-2003 school year, a 9th grade teacher at South Kingston High School in Rhode Island, Kristin Klenk, set up a collection site with her students. The students collected dust and analyzed it with microscopes in their school. The teacher also visited a lab with an electron microscope to see if some of the particles were micrometeorites. They turned out to be particles of soot. Now, she and her students are trying to find out what kinds of fires were going on at the time that could supply the soot. As an example, there were some large burns going on in Canada that colored the Rhode Island sunsets. So she’s looking at fires far afield.

Currently, this sky dust project is sponsored by Rhode Island Space Grant — a NASA outreach program. Dan Murray has applied for a National Science Foundation grant to expand the sky dust program. He expects to hear the results in August, 2003. The grant would supply the special material, forensic tape and identification materials to teachers to set up their own collection sites with students. It would pay for conferences to share information. It would also pay for the development of a Web site that students can use to share information. The plan also includes setting up a site in Argentina. The grant would allow some of the student samples to be sent to labs for analysis.

Excerpts from an interview with Dan Murray:

– “What we developed was this procedure which involved taking a piece of material which is like Gortex, it’s slick, it’s non-electrostatic, it’s tightly woven, so we can stretch it out on the ground, or actually what I use is a cheap kids swimming pool and I have bits of velcro so I can just put it on top of the pool and move it out so it isn’t under a tree or something. And let it sit there for 48 hours.”

– “And then what we do is we get tape, forensic tape, which is the kind of tape that’s used at crime scenes to pat down scenes to get the dust and hairs and all that stuff. We’d use that tape to pat down the material, and now we have all the dust or anything that settled on the tape. You can dissolve the material off the tape — the tape is designed for that — so now you have in a beaker all the stuff that settled in a 48 hour period over a square meter of cloth. And you can look for all sorts of things … ”

– “We picked up Mongolian dust that apparently drifted across North America. We’ve gotten a couple micrometeorites. You get a lot of neat little bits of pollen and insect parts, maybe exotic ones that are coming across the Atlantic or something. Saharan sand. So you’re sort of getting an inventory of all the stuff that’s settling on the Earth including the micrometeorites.”

– “Eventually we’d like to have a bunch of these sites, maybe 10 or maybe 100 of them, and we have them linked by a website, so that people can go and see what people [in] other places have collected on the same date. And they can compare them to weather information that’s up on the site and so people can begin to talk about the planet’s health …”

– “It’s a sort of low-tech kind of collecting thing, but the nice thing about it is that you can have lots of collection sites as opposed to a hi-tech thing which would be a very expensive jet-plane flying in the upper atmosphere collecting samples, and that’s about hundreds of thousands of dollars per shot.”

– “That’s exciting to kids, I think. You know, I don’t have an answer. So what are you going to find on a given day? Let’s just hang something out and see what the cat drags in.”

– “I think that’s kind of important that kids realize that science is just asking an interesting question, and then you don’t necessarily know what the answer is. And then you can sort of think about what the next question should be or how you should collect some information to better understand what you observed …

– “They in essence could become the early warning system for looking for things that might not be good things that are happening to this or that part of the planet.”

– “They could be having lots of sites sampling in a fairly simple way. It could be sort of an early warning system, like having a lot of canaries in the mine.”

– “But one way to test it is to put a sheet of material out on the ground or on a frame such as a kiddie swimming pool, which you can push around with your foot and just see whatever settles on that over a fixed period of time, let’s say 24 hours and you do it once every 10 days. 10 percent of the time, you actually are sampling what’s landing in a particular place. Then that material, whatever that dust is or the pollen or micrometeorites, it’s on a kind of cloth that’s fairly expensive but it’s sort of like Goretex, it’s very slick. Material doesn’t get stuck into the weave of the cloth and also the cloth is not electrostatic, you know that really fine material like most will just hop around because electrostatic charges are built up on the surfaces, and that’s bad because all your dust would hop off like a bunch of fleas going for a dog. And so we played around with the material and things, so we have a material that whatever you get on it you can get it off the material and we have found that this forensic tape which looks like masking tape, but it has a special kind of glue on it so that when you pat down the cloth, and you have the dust on the tape, you can then put the tape into the beaker of water, the dust will dissolve entirely off the tape and then you just pull the tape off and shake it in the water, so now your dust is entirely in the water. That’s how they pat down crime scenes and get the dust off the tape. And so now you have a beaker with the material you’ve collected over 24 hours on this say square meter of cloth. And then what you can do, we pour it through a filter — a millipore filter, which has five micron holes, so anything that’s bigger than 5 microns, you now have it on the filter surface itself. The filter looks like a little wafer and what you can then do is look at it under a simple microscope and you can see the material.”

– “You don’t know what you’re going to find. Kids can own the data. It’s their project and they figured it out themselves. And the way we would encourage these kinds of scenarios to end is that then they would write up these results in a little paper which the class would submit to the website, and it would be distributed nationwide. And perhaps it would be of interest to other people.”

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