What is a shooting star?
At one time people thought that shooting stars were a sign of coming disasters. Now we make wishes when we see them and hope they will come true. In both cases the reality behind shooting stars is less exciting.
Although we call them stars, they are really no more than bits of space dust which burn up as they enter the earth’s atmosphere. Great heat is generated by the friction of their flight through the atmosphere and this causes them to flare up into a brief streak of light as they race across the sky and disintegrate.
On average you can see a shooting star every ten minutes on a clear night. From time to time the earth passes through a cloud of dust left by a comet, and when this happens shooting stars occur much more frequently.
Exactly for the same reason, spacecraft returning to earth have to be fitted with special heat shields to protect them as they enter the earth’s atmosphere. The American space shuttle, for instance, has heat-reflecting tiles, without these it would burn up on re-entry.
