A cascade of meteors, which are the dust tracks of a comet’s path,
will be visible in the skies over the United States this weekend.

On Friday, Nov. 17, and Saturday, Nov. 18, Earth will travel through
the tail of dust from Comet Tempel-Tuttle. As the dust particles — tiny
meteoroids — burn up in Earth’s atmosphere, they give the appearance of
“shooting stars,” called meteors. This display, known as the Leonid meteor
shower, may be most visible over North America’s East Coast. That’s because
the constellation Leo, where the meteors seem to come from, will be in a
dark part of the sky high above the eastern horizon.

The Leonids, however, may produce only a minor shower this year —
about one streak per minute. The Moon’s brightness can also reduce the
visibility of the meteors.

“The third-quarter Moon will be in Leo, making the sky bright and the
Leonids a bit difficult to see,” said comet scientist Dr. Don Yeomans of the
Jet Propulsion Laboratory, Pasadena, Calif.

The best way to see the Leonids shower is to block the Moon’s
brightness with a hand or tree. On North America’s West Coast this week,
look in the general direction of the Moon on Friday night from 11:30 p.m.
until after midnight. Some meteor activity may be evident the night before
at the same time. From the East Coast, look in the general direction of the
Moon at about 2:50 a.m. on Saturday, when the showers should be strongest.

Every 33 years, Comet Tempel-Tuttle travels through the inner solar
system. The comet, which is basically a ball of dust and ice, last passed
close to the Sun and was visible from Earth in March 1998. Near the Sun, the
comet’s ices begin to vaporize and the embedded dust particles fall away and
trail the comet in its orbit. Every year, Earth passes through the trail of
debris left behind by the comet, and the comet dust particles plunge into
Earth’s atmosphere at some 71 kilometers (44 miles) per second — fast
enough to travel from Los Angeles to New York in about one minute.