Nanotubes are, by definition, are carbon molecules in the shape of a tube having a fullerene structure and a diameter of 1 to 2 nanometers. A fullerene structure is further defined as any class of allotropes of carbon having hollow molecules. Now let’s figure out what 1 to 2 nanometers are since the nanotubes are that thickness?
To give you and idea, a nanometer is roughly 1 billionth of a meter. In todays world of budget deficits of billions and trillions those words are sometimes said so often they lose their effectiveness. I decided to research how long it would take you to count to 1 billion with each number taking 1 second to count. Counting non-stop, with that 1 second/number rule it would take you 31 years, 251 days, 7 hours, 46 minutes, and 39 seconds to count to 1 billion. If you have some spare time you might want to try this:)
In all seriousness, you can now understand the size values involved in the nanotubes and hopefully it gives you some perspective.