Start Getting Noticed

“Roids” and Comet Tails: Get to Know Them

In Universe Project on March 7, 2010 at 9:14 pm

Here is everything you would want to know about the “roids”. You might want to take notes. There will be a quiz.

ASTEROID BELT

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The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets.

More than half the mass of the main belt is contained in the four largest objects: Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea. These have average diameters of more than 400 km (249 miles). The remaining bodies range down to the size of a dust particle.

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ASTEROIDS

Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are smaller than planets but larger than meteoroids.

The physical composition of asteroids is varied and in most cases poorly understood. Many, perhaps most, of the smaller asteroids are piles of rubble held together loosely by gravity.

Asteroids contain traces of amino-acids and other organic compounds, and some speculate that asteroid impacts may have seeded the early Earth with the chemicals necessary to initiate life, or may have even brought life itself to Earth.

On the flip-side, most scientists believe that an asteroid is what wiped out a lot of life on this plant – namely dinosaurs. In an article published on March 5, 2010, in the journal Science, 41 geologists, paleontologists and other researchers concluded that a giant asteroid (Chicxulub) slammed into Earth in Yucatan, Mexico, blasting a cloud around the world, that led to the end of the dinosaurs.

Below is a map that shows where the asteroid hit – leaving the Chicxulub Crater.

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METEOROIDS

A meteoroid is a sand- to boulder-sized particle of debris in the Solar System. The visible path of a meteoroid that enters Earth’s (or another body’s) atmosphere is called a meteor, or what some call a shooting star. If a meteor reaches the ground and survives impact, then it is called a meteorite.

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The composition of meteoroids can be determined as they pass through Earth’s atmosphere from their trajectories and the light spectra of the resulting meteor. Meteoroids have been found to have many different orbits. Meteoroids can be as fragile as snowball-like objects with density about a quarter that of ice to nickel-iron rich dense rocks.

Meteoroids travel around the sun in a variety of orbits and at various velocities. The fastest ones move at about 26 miles per second through space in the vicinity of Earth’s orbit.

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METEORITES

Doctors Office in Virginia Hit by Falling Meteorite

On January 18, 2010 a baseball-sized meteorite crashed into a Lorton, Va., family medical practice. Around 5:45 p.m., two doctors were in their offices when they heard what sounded like bookshelves crashing to the floor. One of the doctors found a trail of debris in the hallway. Inside the exam room were fallen insulation and three small pieces of rock.

What they found was a chrondrite meteorite. According to NASA it likely originated from a small asteroid measuring approximately one meter across before it entered the Earth’s atmosphere, where it started to burn up and disintegrate.

Tons of space material from asteroids and comets rain down on Earth every day. According to NASA, most of it falls as dust, but space objects similar in size to the Virginia meteorite strike Earth once a month, typically landing in oceans or uninhabited areas.

Crashing into a building — and an occupied one at that — makes this meteorite landing unusual, but not a one-of-a-kind occurrence. For example, in 1954, a meteorite crashed through the roof of a Sylacauga, Ala., house, badly bruising the woman inside.

Media reports said the Virginia meteorite was the first to strike a building in the United States since September 2003, when a 44-pound rock smashed through the roof of a New Orleans home.

For now, the rock resides with the Smithsonian Institution’s National Museum of Natural History, where scientists have conducted experiments on it.

Meteorite That Hit Doctors Office


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COMETS: ION TAILS VS. DUST TAILS

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Comets are small asteroid-like bodies when they are far from the Sun, traveling in highly ellipical orbits about the Sun. When they sweep in close to the Sun, dramatic changes occur as they brighten and develop an extended tail. The nucleus is widely described as a “dirty snowball” composed of ice and some rocky debris.

There is considerable vaporization as they approach the Sun and they develop ion tails and dust tails. The ion tails are almost straight streamers from the nucleus while the usually brighter dust tails are broad and diffuse and curve slightly, lagging behind the radial direction.

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