3^rd Trumpet:  And the third angel sounded the blast of a trumpet; and there fell down from the air of the sky, a great and mighty star, as stretching across the sky of heaven, burning as set on fire, as if it were a lamp or torch and it fell down upon the third part of the streams and rivers and upon the fountains, that is, the supply of waters; And the name and character of the star is called Wormwood or a calamity of bitterness; and the third part of the rainy waters became wormwood or a calamity of bitterness; and an abundant and a great many human beings began to die off, because of the rainy waters, because they were made bitter. [Revelation 8:10-11].

Phase Three:  6^th Seal, 3^rd Trumpet, 3^rd Vial

[Rev. 6:13] And the stars of heaven fell unto the earth, even as a fig tree casteth her untimely figs, when she is shaken of a mighty wind.

[Rev. 8:10-11] And the third angel sounded, and there fell a great star from heaven, burning as it were a lamp, and it fell upon the third part of the rivers, and upon the fountains of waters; And the name of the star is called Wormwood: and the third part of the waters became wormwood; and many men died of the waters, because they were made bitter.

[Rev. 16:4] And the third angel poured out his vial upon the rivers and fountains of waters; and they became blood.

Most meteoroids disintegrate before reaching the earth. But some leave a trail that lasts several minutes. Meteoroids that reach the earth are called meteorites.

Millions of meteors occur in the earth's atmosphere every day. Most meteoroids that cause meteors are about the size of a pebble. They become visible between about 40 and 75 miles (65 and 120 kilometers) above the earth. They disintegrate at altitudes of 30 to 60 miles (50 to 95 kilometers).

Meteoroids travel around the sun in a variety of orbits and at various velocities. The fastest ones move at about 26 miles per second (42 kilometers per second). The earth travels at about 18 miles per second (29 kilometers per second). Thus, when meteoroids meet the earth's atmosphere head-on, the combined speed may reach about 44 miles per second (71 kilometers per second).

Meteor showers

The earth meets a number of streams (trails) or swarms (clusters) of tiny meteoroids at certain times every year. At such times, the sky seems filled with a shower of sparks. Streams and swarms have orbits like those of comets and are believed to be fragments of comets.

The most brilliant meteor shower known took place on Nov. 12-13, 1833. It was one of the Leonid showers, which occur every November and seem to come from the direction of the constellation Leo.

Meteorites

There are three kinds of meteorites, stony, iron, and stony-iron. Stony meteorites consist of minerals rich in silicon and oxygen, with smaller amounts of iron, magnesium, and other elements. One group of stony meteorites, called chondrites, are pieces of the same material from which the planets formed. Another group of stony meteorites, the achondrites, were once part of a parent body, such as an asteroid, that was large enough to have melted and separated into an iron-rich core and a stony crust. Achondrites come from the outer crust; stony-iron meteorites, from the inner crust; and iron meteorites, from the metallic core. Iron meteorites consist mostly of iron and nickel. Stony-iron meteorites have nearly equal amounts of silicon-based stone and iron-nickel metal.

The size of meteorites varies greatly. Most of them are relatively small. The largest meteorite ever found weighs about 66 short tons (60 metric tons). It fell at Hoba West, a farm near Grootfontein, Namibia. However, much larger bodies, such as asteroids and comets, can also strike the earth and become meteorites.

Meteorites reach the earth's surface because they are the right size to travel through the atmosphere. If they are too small, they will disintegrate in the atmosphere. If they are too large, they may explode before reaching the earth's surface. One such object exploded about 6 miles (10 kilometers) above the Tunguska River in Siberia in 1908, leaving a 20-mile (32-kilometer) area of felled and scorched trees.

Thousands of small meteorites have been found in Antarctica, providing a rich supply of specimens for scientists to study. Scientists study meteorites for clues to the types of material that formed the planets.

Impact craters and basins

When large bodies such as asteroids and comets strike a planet, they produce an impact crater or impact basin. Impact craters are bowl-shaped depressions that measure up to about 10 miles (25 kilometers) in diameter. They have shallow, flat floors and uplifted centers. Impact basins are larger, and inside their rims there are one or more rings on the planet's surface.

Scientists have found more than 120 impact craters and basins on the earth. One of the most famous, the Meteor Crater in Arizona, is about 4,180 feet (1,275 meters) across and 570 feet (175 meters) deep. It formed nearly 50,000 years ago when an iron meteorite weighing 330,000 short tons (300,000 metric tons) struck the earth.

Contributor: Virgil L. Sharpton, Ph.D., President's Professor, Geophysical Institute, University of Alaska Fairbanks.

How to cite this article:To cite this article, World Book recommends the following format: Sharpton, Virgil L. "Meteor." World Book Online Reference Center. 2005. World Book, Inc. http://www.worldbookonline.com/wb/Article?id=ar358140.