Kids, can you test for little bits of space in your own backyards? Every day, 500 tons of dust and rock from space collide with Earth. Much of this burns up in the atmosphere as ‘shooting stars’. However, particles smaller than a millimeter sometimes slip through the air without burning. These are micrometeorites. They can float through the sky as dust and fall to the ground in rain. With a powerful magnet and some luck you just might be able to find one of your own.
Please note: All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.
You’ll need a paper cup with two holes poked through the paper at the top near the lip of the cup, across from each other. Through these holes tie a loop of string about one foot long so that you have a basket. Into the cup place a very strong U-shaped or bar magnet. This is your micrometeorite collector. Bring it outside on a dry day and gently tap it over areas of ground that are dry (but that do get wet after rain) and not disturbed by people or vehicles. Good places to try might be near downspouts, areas of lawn not often used, or areas next to hiking trails.
When black specks become stuck to the bottom of the cup, take it inside and place the cup on clean white paper. Remove the magnet and tap the cup to shake off the specks. Use a magnifying glass and tweezers to pick out the roundest particles less than half a millimeter wide. These have the greatest chance of being micrometeorites made of iron or nickel, which are magnetic. Particles that aren’t round are flecks of iron from other sources.
If you have a microscope, put the best particles on a glass slide for examination. Micrometeorites often are smooth because the surface melts in the heat of entering the atmosphere.
What is a meteorite? These space rocks are fragments of broken asteroids. Meteorites made of iron are from the cores of asteroids.
Trivia: The dust on cars after a rain comes from high in the sky, too, and may contain desert sand and volcanic ash in addition to micrometeorites.
TIP: Don’t touch your dust with the magnet or it will stick and be very difficult to remove. This is why the paper cup shield is used.
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Kathleen Carrado Gregar, PhD, Argonne National Labs
[email protected]
June 2011
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References:
“Rock and Fossil Hunter”, a Smithsonian series book by Ben Morgan; DK Publishing, Inc. NY; 2005; page 36, “Rocks from space”.
