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The traceroute utility on any computer connected to the Internet can be used to record the roundtrip time for small Internet packets between major Internet traffic hubs. Some of the routes include transmission over transoceanic fiber optic cable. We report on traceroute’s use by students to quickly and easily estimate the size of the earth. This is an inexpensive and quick way to involve introductory physics students in a hands−on use of scientific notation and to teach them about systematics in data.

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      I have mixed feelings about this paper. On the upside, for introductory students who don’t yet have any sense of the speed of light, or the size of the earth, I could see the traceroute being an interesting classroom activity.

      It’s worth being aware of a few confounding factors that will make this estimation technique unreliable:

      • Undersea cables can’t be laid in a theoretically straight line due to obvious seabed obstructions like coral reefs, volcanoes, etc.
      • traceroute and ping responses are often deprioritized or rate limited by routers
      • routers are usually not located exactly at the undersea cable’s landing site, or even particularly near the center of the metro area that may be suggested by their PTR record.

      BTW, what’s up with all the resources that are listed in the acknowledgements section? Why does it require a NASA grant to run a traceroute on a classroom computer that’s already on the internet?

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        BTW, what’s up with all the resources that are listed in the acknowledgements section? Why does it require a NASA grant to run a traceroute on a classroom computer that’s already on the internet?

        Probably that this guy had a NASA grant for something else, and was required to acknowledge it.