Q:
I have a question about falling stars, I want to know if they really exist. The stars are the most distant objects. The light takes approx. 8 sec to reach Earth so when you see a star falling how can it travel the short distance and yet be visible when it is almost 10,000 cross light years away?
A:
Despite what their name suggests, "shooting stars" or "falling stars" are not stars at all, but bits of space debris called meteors. Meteors, which are usually between the size of a grain of sand and a pebble, create a brief streak of light when they enter the Earth’s atmosphere at high speeds and burn up.
Meteors are produced in large quantities when the Earth's orbit takes it through an area of space filled with rocks and dust in the tail of a comet. For example, the Leonid meteor shower – so-called because the meteors appear to come from the direction of the constellation Leo – is due to a trail of debris left by Comet Tempel-Tuttle on its 33-year orbit of the Sun. When the Earth passes through this stream of rocks, dust grains, and gas every November, observers on Earth can be treated to a wonderful show. The passage can also be a hazard to spacecraft. For a description of how Chandra’s team dealt with the latest encounter, see http://chandra.harvard.edu/chronicle/0401/leonids.html.
Revised: September 15, 2008