Do more meteorites fall at low latitudes? (Intermediate)

Do more, or less, meteorites fall at different latitudes? i.e. do more fall at the equator than at the poles? When I was in Vietnam, I seemed to see many more "shooting stars" than anywhere else I have lived (Alaska to Australia).

I did some reading, and I found that meteor rates do vary by a number of effects, some of which are dependent on latitude.

The first is a daily effect. There are more meteorites in the morning than in the evening, because the morning hemisphere is the part that leads the Earth in its orbit (so, it is 'running into' the meteoroids) and the evening hemisphere is the trailing one. That's why meteor showers are at their best after midnight.

The second is seasonal, due to the fact that meteoroids come from 'streams' of material. The strongest produce distinct meteor showers, but some of the weaker ones all added together mean there's an uneven 'background' of sporadic meteors. This also changes by latitude, since different latitudes would sample different parts of the cloud. However, that's a small effect -- 6000 km (the radius of the Earth) isn't that much.

The third is affected by latitude. At high latitudes, parts of the Earth are always part of the leading or trailing hemisphere, so they always get the benefit of the first effect I mentioned. Think of it as another thing related to the 'midnight sun' effect. During the spring, the high latitudes of the Earth are shielded, like they are during the evening. It's mostly a big deal for places like Alaska (near the pole), and wouldn't be noticeable at all near the equator (like Vietnam).

Also, living in a city (or somewhere else with light pollution) will mean you see less meteors, for the same reason that you see less stars. The more stars you see, the easier it is to see meteors.

In a related matter, Antarctica is a good place to collect meteorites, but not because of the latitude, but because most of the continent's natural rock is buried under the ice, so any rock found is much more likely to have come from above than below.

 

Updated on February 10, 2016

About the Author

Rebecca Harbison

Rebecca is a eighth-year graduate student in astronomy, with an interest in Saturn's rings.

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