'Shooting Star' Trails Narrower Than A Pencil Lead
Two meteor trails, shown as dark streaks.
Credit: Subaru Telescope

Tiny meteors, typically no larger than a grain of sand, frequently bore hot tunnels through Earth's air to leave behind thin, glowing trails of gas. We sometimes see them as dramatic "shooting stars."

The trails were estimated to be narrower than a meter, but until now, more precise measurements have been impossible to make.

Turns out they are amazingly thin compared to the light show they create.

Meteor trails begin about 75 miles (120 km) above Earth's surface, a region that is not typically focused on by ground-based telescopes or satellites.

Using detailed images, snapped by the Subaru Telescope at the Mauna Kea Observatory in Hawaii and focused on this region of the upper atmosphere, astronomers measured the streaks to discover that they can be as thin as a few millimeters across, or about as thin as a pencil lead. The measurements mark the first time a meteor track's width has been precisely measured solely using light emitted from the event.

The results of this study are detailed in a recent issue of the Publications of the Astronomical Society of Japan.