Документальный фильм "Summer Meteor Shower"



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Summer Meteor Shower

Summer Meteor Shower - presented by Science at NASA.

It's summer. School's out. Camp fires are crackling, marshmallows are roasting, and fireworks are exploding in the night sky. Those fireworks are the Perseid meteor shower.

Starting in late July and continuing through mid-August, scores of meteoroids fly out of the constellation Perseus. They cross the starry Milky Way, bisecting the heavens with vivid streaks of green or yellow light. Fireworks, indeed!

The source of the display is Comet Swift-Tuttle. Every 133 years the huge ball of dirty ice swings through the inner solar system and leaves behind a trail of dust and gravel.

At the moment, Swift-Tuttle is far away, but its debris is nearby, littering the July and August part of Earth's orbit. When our planet passes through the debris zone, specks of comet-stuff hit the atmosphere at 140,000 miles per hour, and disintegrate in flashes of light.

Swift-Tuttle debris zone is so wide, Earth spends weeks inside it. In late July when our planet first enters the outskirts, Perseid rates are low. A camper peering out the door of his or her tent for an hour might spy only a half-a-dozen shooting stars. That's a pretty show, but the real excitement takes place in August. On the morning of August 11th through 13th, Earth will pass through the heart of debris zone. During the dark hours before sunrise, meteor rates could soar - well - meteorically, to more than a hundred per hour. August 11th, 12th and 13th are the dates to plan your summer camping trip

There's just one problem - the Moon. The Moon is full on August 13th, so it will be glaring brightly just as the shower reaches the peak. Many of the fainter Perseids will be overwhelmed by moonlight. It is not a disaster, however, because some Perseids are fireballs, and they will have no trouble piercing the glare.

The debris stream of Comet Swift-Tuttle consists mainly of very tiny meteoroids. These miniscule pieces of comet dust produce meteors of ordinary brightness, easily overwhelmed by the Moon. Fortunately, the debris stream is also spiced with larger chunks, the size of golf balls, baseballs, and so on. When these bigger pieces hit the atmosphere, they turn into fireballs that you can see right through the moonlight. You might spot only a few during a long observing session, but even a single fireball can make the whole camping tip worthwhile, burning an incredible streak into your collection of good summer memories. Enjoy your summer - and the Perseid meteor shower.

For more summer science blockbusters, please visit science.nasa.gov.

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Документальный фильм "Summer Meteor Shower"

















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