What Makes Up Our Solar System? Meteoroids
Space and Astrology 6/22/11
By: Yona Williams
Meteoroids are small bodies of stony and/or metallic materials that travel throughout space. The International Astronomical Union officially designates the title of a meteoroid as "a solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom." The majority of meteoroids are actually quite tiny Ã¢â‚¬â€œ like the size of a pebble. Others see a meteoroid as measuring between 100 Ã‚Âµm and 10 m across.
A meteoroid develops because of several different reasons. The majority of meteoroids come from asteroids that have broken away because they have collided with other asteroids. Other meteoroids originate from comet, the Moon, as well as from the planet Mars.
What is a Meteor?
A meteor is a meteoroid that has entered the Earth's atmosphere. Because of this, it leaves behind a fiery tail as it falls. Meteors are what we sometimes refer to as a 'shooting star' or 'falling star.' Meteors typically take place in what is known as the mesosphere. Most of them range in altitude from 75 km to 100 km.
Every day, millions of meteors occur in the Earth's atmosphere. The reason why you donÃ¢â‚¬â„¢t hear so much about them is because the majority of meteoroids that cause meteors are only about the size of a pebble. They are first visibly detected when they are between about 40 and 75 miles (65 and 120 kilometers) above the Earth. However, they disintegrate at altitudes of 30 to 60 miles (50 to 95 kilometers), which is why they generally do not become a problem for inhabitants on Earth.
Just before a meteor enters the Earth's atmosphere, it is traveling at a speed of about 70 kilometers per second. The act creates intense heat because of the friction between the quick-moving meteor and the gas in the Earth's atmosphere. The heat causes the meteor to glow, and then it starts to burn. Most meteors burn up before they hit Earth. Only large meteors survive travel through the atmosphere.
What is a Fireball?
When a meteor reaches brightness greater than Venus (magnitude Ã¢â‚¬â€œ4), it is called a fireball. The fireball is a meteor that is brighter than usual Ã¢â‚¬â€œ according to the International Astronomical Union Ã¢â‚¬â€œ it is "a meteor brighter than any of the planets."
What are Meteorites?
When a meteor falls to Earth, it is called a meteorite. The fiery entry into the Earth's atmosphere and all of the pressure that comes with it causes a meteor to loss a great deal of its mass. If it survives the travel, it is a rare occurrence. When a meteorite hits the earth, it is comprised of rock and/or metals. Upon impact, it comes in contact with the ground, but it is not destroyed. Impact craters found on the earth are sometimes associated with meteorites. If the collision possesses more energy, the meteorite vaporizes and leaves no trace of a meteorite behind.
A phenomenon that is pretty cool to witness is a meteor shower, which involves the falling of many meteors through the atmosphere in a relatively short period of time. The patterns of the falling meteors are described as parallel trajectories. When a meteor shower is intense, it is called a meteor storm.