Meteorites are Discovered Using Common Sense

The Fab Four Methods

Meteorites come to light in one of several ways. For simplicity, we’ve grouped their discovery in five categories. The first 4 are known methods, the fifth, is pure luck.

• Chicken Little: Wait for the sky to fall
• Niningeresque: Pubic Outreach
• Research & Recovery: Research old meteorite falls and finds, then follow up with field work
• Prospecting: Find good terrain and search for meteorites
• Serendipity: Meteorites find you

Chicken Little Method

Chicken Little was right – the sky IS falling. Meteoroids strike the earth’s atmosphere every day, the total mass exceeds several tons. However, only a small percentage of meteoroids survive the fall to become meteorites. Of those only a small amount are witnessed by human populations. When a fireball or bolide is seen, often local astronomers and meteorite buffs begin the arduous task of trying to triangulate the incoming meteorite.

There is no guarantee that the fireball will produce a meteorite, but for big fireballs often it does. Daylight fireballs and daylight meteors are very likely to produce meteorites. Once a fresh meteorite is found, then the real search begins. This is because meteorites fragment in their descent to earth and they will fall in a line that is possibly over 10 km long and 3 km wide. Thus, a great deal of walking is involved in hunting the meteorites.

Some meteorites falls are high density and some are low. The November 20, 2008 fireball in Saskatchewan in Canada produced a high density field and I can report first hand, a meteorite was found every 30 minutes of walking. The April 15, 210 Wisconsin meteorite fall was was a very low density fall, perhaps one ever 25 hours of walking. Obviously grass height and terrain will greatly effect recovery rates. In the case of both falls, the average stone found was about the size of a walnut.

The main drawback, is there will be a huge amount of competition at a new meteorite fall, especially one in a first world country.

Niningeresque Method

H.H. Nininger is considered the father of modern meteoritics. He recovered thousands of meteorites, but not by walking and looking for them. He did it via outreach. The outreach was targeted to those who work closely with the earth. Farmers are the main target, they work the earth, disturb the earth, and watch the earth. Ranchers and hunters are also of interest, but they don’t disturb the earth so much as walk over it. These groups are important because more than 50% of all meteorites are found by farmers, ranchers, and hunters.

Nininger’s outreach came at a golden age, as it was a time when the farming equipment was just becoming powered and virgin soil was being busted for the first time. Also, the farmer was slightly elevated and could see the ground easily on the equipment of the era. Now, the farm equipment is much larger, the operator is higher in a cab and the cab is usually enclosed which reduces the chances of odd rocks being spotted.

Outreach should be multi-threaded. For example, writing newspaper articles, giving lectures, and posting education posters at farming supply stores, seed stores, and other likely areas that farmers and ranchers would visit. Part of the success of any outreach is the mention of reward for any meteorite found.

Research & Recovery Method

This method is straight forward, simply research a known meteorite fall or find and try to find more of it. However, the trick is to pick a known meteorite area that gives a good chance to find more. Such as a fall in a desert environment, not in a swarm or forest. Vegetation will quickly bury any meteorite in a matter of a few years. Also, try to pick a meteorite that has many pieces already found. If 10 stones were found, then likely over a hundred are still out there. If one was found, then you don’t have enough information to estimate the main axis of the fall direction and recovery efforts would be blind guesses on direction.

Prospecting Method

Usually a desert or a lake bed is chosen because the terrain is light colored and would easily contrast a dark meteorite. This method does not require that any meteorites be known to exist in the area, it is merely counting on statistics that a meteorite has fallen in the area and can be spotted.

Serendipity Method aka “I was on my way to the bar when…”

This is the pure dumb luck method. It also accounts for the fewest meteorites discovered. On the contrary, it is usually how the first meteorite is found from a fall. An example, the guy asleep in his house in Park Forest when a meteorite crashes through his roof. Or the kid in Mbale, Uganda that has a stone bounce off a tree and smack him in the head. No research needed, no effort taken. But it is really, really, hard to find them this way.

 

After notes:

It does help if you use GIS for your expeditions. I’d recommend taking some online GIS classes, and I’ve found one that is only 8 hours.