Astronomy in the Rain: How to Find Meteorites

When your stargazing plan gets washed out, go on a quest for micrometeorites!


Well, the weather forecast for Tuesday, June 5, currently looks grim for the here in Connecticut — rain starts Monday and the first clear day may be Friday. In the event of sudden change in weather patterns, recall that the transit starts at about 6:05 p.m. and will continue past sunset on Tuesday.

So what can an eager amateur astronomer do in the rain? How about going on a meteorite hunt in your backyard?

When the solar system formed, starting some 5 billion years ago, it started from a vast cloud of gas (mostly hydrogen and helium), ice (frozen gas and water) and dust (silicon, iron, nickel, as well as all of the other solid materials we have here on Earth). As this cloud shrank under its own gravity, the majority of the gas formed the Sun, and the ice and dust formed planets, moons, asteroids, and comets. 

Comets are made of frozen gas, water ice, and dust. Periodically they visit the inner solar system, heating up the dust-laden ice, and creating enormous tails behind them of gas and dust which reflect sunlight and can be seen from Earth as some of the most majestic and awe-inspiring objects in the sky. When the comet has passed through the inner solar system several times, its orbit gradually fills with a trail of dust that continues to orbit the Sun long after the comet vanishes from sight.

Many of these dusty comet orbits cross Earth’s orbit. When the Earth passes through a comet’s orbit, we experience a “meteor shower” as the comet’s trail of dust is pulled down through the atmosphere by Earth’s gravity. The individual grains of material — mostly the size of a pea or smaller — traveling at speeds from 25,000 to over 150,000 miles per hour, are heated by friction with the atmosphere to temperatures approaching 10,000 degrees. The meteors mostly vaporize at these temperatures, and it is the bright plasma from this vaporization that we see as a “shooting star."

However, all but the smallest of meteors will burst into very fine dust high up in the atmosphere. This meteoric dust will persist in the upper atmosphere until it is brought down to the ground in a rain storm. And this is where our rainy day adventure begins!

The most unusual piece of equipment you will need in your quest is a microscope, though you may have some success with a powerful magnifier. You will also need a magnet, some string, and either a non-magnetic pair of tweezers, or a toothpick.

Most meteors are made of silicate rock — not appreciably different from the rocks you’ll find in your backyard, and therefore we won’t be looking for these. About 5 percent of meteors are made of nickel-iron alloys. These meteorites will be attracted to a magnet, and that is the key to our success!

During or after a heavy rain, go outside and look for puddles of water, preferably away from areas where cars or other metal objects may have been placed (we want to avoid finding too much rust). If you are planning ahead, you can improve your chances of not getting frustrated later in the quest by placing a clean plastic or glass container outside to collect rain water. If you’re in a hurry, you can place such a container at the outlet of your gutter downspout (assuming your gutters are not made of rusting metal), and collect a good sample in a matter of minutes.

Once you’ve got your container of rain water — either in a puddle or in a container you’ve commandeered for science — tie your magnet onto some string, and dip it into the water. Swish it around for a bit and pull it out. If this is a mud puddle you’re working with, take the magnet to a faucet and gently rinse off any loose dirt.  Examine your magnet carefully — if you have little pieces of what look like sand stuck to it, you’re in business.

Next comes the tricky part. You’ve collected some iron or nickel, but are these bits of stuff meteorites, or just parts of your muffler? Set up your microscope, and pull out a clean microscope slide. Using your non-magnetic tweezers or toothpick, pluck off some of the sand that is stuck on the magnet, and place it on the slide. 

If there is a lot of material, or it is clumped together, do your best to separate it into its parts.  Avoid anything that looks yellow or reddish — that would be rust, not meteorites.

Now, look at what you have on your slide in the microscope. The difference between meteorite material and just plain rocks that have been in your yard for millennia is that the meteorite has seen extremely high temperatures, and has been recently melted. The edges of the meteorite particles will be smoothly rounded, and may show smooth pits.

If you find such things, congratulations! You have in your possession a sample of a comet! 

I have done this activity on a few occasions. The toughest part — for me — has been trying to record my results photographically. In the images accompanying this article, you will find the only reasonable photo I’ve made of a micrometeorite. To see some incredible results, and much better photos (and some proof that I’m not all wet), look at http://micrometeorites.weebly.com/miscellaneous-photos.html.

Have children between 8-18 years old who have an interest in astronomy?  My next astronomy classes start in mid-August, and I have a couple spots left to fill.  Please visit the course site at www.turnerclasses.com for more information.

This post is contributed by a community member. The views expressed in this blog are those of the author and do not necessarily reflect those of Patch Media Corporation. Everyone is welcome to submit a post to Patch. If you'd like to post a blog, go here to get started.

Aaron Turner June 11, 2012 at 01:43 AM
There are very few truly dark sites left on the East Coast, and mostly in very difficult areas to reach. That being said, in Connecticut your best bets are the Northwestern Hills (Kent Falls comes to mind), or in the eastern areas of the state, but not too close to Rhode Island. Despite appearances, I am not a "have scope will travel" type of guy. A telescope has been in my car only four times in the last five years, and only once for an actual night time observing session. I observe from my front yard in Southbury (Kettletown Park area) and I find there is an awful lot of excellent objects to observe that can be seen in our not-so-dark skies. Galaxies are very tough, but patience and "learning to see" are essential to appreciate what can be seen.
Jaimie Cura June 11, 2012 at 04:46 AM
Aaron, have you had any experience with Silver Sands? They sometimes do Astronomy Nights there.
Aaron Turner June 12, 2012 at 12:15 AM
There are a variety of places and groups that do periodic observing. I haven't been to these, including Silver Sands, but there is also the McCarthy observatory at New Milford High School, a New Haven group has an observatory in Beacon Hill, and there used to be a group centered at Naugatuck Community College that had an observatory there and in White Memorial up in Litchfield. That group might be defunct. WestConn also has an observatory that is occasionally open to the public. One problem with the larger observatories is that they are in populated areas with lots of surrounding light, so little can actually be seen.
Jaimie Cura June 12, 2012 at 12:47 AM
Thanks for the info, Aaron - much appreciation!
citizen June 12, 2012 at 01:11 PM
Yes, thanks for the great interesting articles, as always.


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