Asteroids, Comets, Meteroids,and Moons

Comets

Moon Appearance

Comets are icy bodies in space that release gas and/or dust. They are made of dust, ice, carbon dioxide, ammonia, methane, and possibly more. Orbiting from the Oort Cloud beyond Pluto, comets orbit the sun and sometimes fly into the solar system. Some comets only come around every few centuries, but others regularly complete an orbit.

Io

Halley's Comet, which can only be seen from Earth every 75 to 76 years. It's very famous as a short-period comet. Halley's Comet is named after its discoverer, Edmond G. Halley in 1705, and was last seen from Earth in 1986.Some say Halley's Comet has been orbiting since 240 B.C.

Comet Cores and Tails

Not all moons are fully spherical, like Earth's moon. Some moons are lopsided. Mars's two moons, Phobos and Deimos, have nearly round orbits, but are lumpy and imperfect. Uranus's inner moons are about half watery ice and half rock. Its strangest moon, Miranda, has a scarred complexion of many collisions from rocky bodies.

Europa

Jupiter's four largest moons, Io, Europa, Ganymede, and Callisto, were discovered by Galileo Galilei around January 1610. They are among the largest bodies in our solar system.

Comet cores are formed of ice (made of frozen water and possibly carbon dioxide,methane,ammonia,and carbon monoxide) and dust covered in dark, organic material.This core could also have its own smaller core of rock. When a comet nears the sun, the ice on its surface turns into gas and makes the coma, a cloud. The sun's radiation pushes dust particles away from the coma and makes a dust tail. The light particles from the sun make some of the comet's gases into ions, forming an ion tail.Because a comet tail is made up of solar wind and sunlight, a comet's tail never points to the sun.

Moon Orbits

Meteoroids

Ganymede

Life Cycle of a Comet

Most moons have customary orbits, round and close to their planet, but other moons have abnormal orbits. Most of Jupiter's moons have more elliptical and reversed (opposite to Jupiter's spin) orbits. Uranus, Saturn, and Neptune also have irregular moons that orbit far away from them.

Summary

Callisto

Galileo of NASA encountered the asteroid Ida and its moon Dactyl en route to Jupiter on August 28, 1993. Ida and Dactyl's official asteroid names are 243 Ida & Dactyl.

A meteoroid is a small piece of debris,stone or metal-like, in the solar system. Most are about the size of a small pebble. Large meteoroids are supposed to be from the main asteroid belt. If medium-size, those meteoroids could have been from the Moon or Mars.

* Astronomers believe that comets are left over from gas, ice, rocks, and dust that made our solar system.

* The beginning of a comet's life is its departure, when it starts its orbit. Some comets have very short orbits, and can often be seen from Earth. Others,like Halley's Comet,have very long obits that take years to complete.Some comets have orbits that take them out of the solar system.

* When a comet goes near the sun, it loses ice and dust and leaves it behind as debris. After many orbits, comets can lose all of their ice and dust, becoming asteroid-like rocks or dust clouds instead. Also, some comets' orbits lead them to planets, where the comets crash. Many craters you see on Earth and other planets were made by comets.

Ida

Dactyl

Moons and Planets

Moons

The asteroid Ida and its moon, Dactyl.

* Many moons have Earth-like characteristics, such as volcanoes, atmospheres, and oceans.

* The difference between a moon and a planet is that planets orbit the sun and moons orbit other bodies.

Moons

Mercury-0

Venus-0

Earth-1

Mars-2

Jupiter-50

Saturn-53

Uranus-27

Neptune-13

Asteroids

* A moon is a natural satellite that orbits a bigger body (ex. planet, asteroid, etc.)

* Some planets have none, others have more than 50. Our solar system's eight planets have many moons. There are 146 natural moons orbiting planets discovered in our solar system.

* Since we've used NASA's 2003 research and space technology, the number of moons discovered has nearly doubled.

History

Meteoroids, Meteors, or Meteorites: Which One?

Naming Moons

Size

* The largest moon in our solar system, Ganymede of Jupiter, is even larger than Mercury and is the only moon known to have its own magnetic field.

* Small rocks, not big enough to be planets

The largest meteorite discovered at 66 tons, is the Hoba meteorite near Grootfontein,Namibia. Not moved since it hit about 80,000 years ago, the iron Hoba meteorite was discovered in 1920 It remained intact because Earth's atmosphere slowed it down.

* Vary in size, Ceres is 583 miles across, but 1991 BA is only 20 feet in circumference.. Ceres is the largest asteroid discovered, 1991 BA is the smallest

When a meteoroid is in space, away from Earth it's simply known as a meteoroid. Once it gets near our planet, meteoroid terms get a little more tricky.Meteoroids are called meteors if they enter Earth's atmosphere, which is what happens when you see a "falling" or "shooting" star. When that happens, most of the meteor burns up, and the leftover is called a meteorite. That meteorite can make a gap, also known as a crater, in Earth's surface.The size of the crater depends on the meteorite's size.

Many of the moons in our solar system are named after mythological gods and godesses from many culture, such as Metis and Callisto of Jupiter. However, all of Uranus's moons are named after characters from Shakespeare's plays and from Alexander Pope's poem "Rape of the Lock"

The first asteroid, Ceres, was discovered January 1st, 1801, by Giuseppe Piazzi, while making a star map. At first, he thought Ceres was a comet, but Piazzi later dubbed it a small planet. Giuseppe named the planet, later confirmed as an asteroid, Ceres, after the Roman goddess of grain.

* Also known as planetoids or minor planets

More Meteoroid and Meteorite Facts

Location

* Since meteoroids burn in the atmosphere and turn into dust, it is estimated that about 3,000 tons of space dust fall to Earth every day

* The largest meteorite discovered is the Hoba meteorite, about 66 tons in weight. Being iron,it has rusted, and was believed to once have been about 100 tons.

* The largest meteorite discovered in America is the Willamette (Oregon) iron meteorite, discovered in 1902 and weighing 15 tons.

* Most lie in an outer ring between Mars and Jupiter; this belt has 200+ asteroids 60+ miles in diameter

Citations

www.space.com/53-comets-formation-discovery-and-exploration.html

* Other asteroids in the same belt may number more than 750k, and are larger than 3 fifths of a mile.

In later years, Pallas, Vesta, and Juno, more asteroids, were discovered.

www.space.com/51-asteroids/discovery-and-exploration.html

www.nineplanets.org/asteroids.html

* There are,however,asteroids outside the main belt, such as the Trojans, which are along Jupiter's orbital path

www.starchild.gsfc.gv/docs/StarChild/solar_system_level1/meteoroids.html

Research

www.starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/meteoroids.html

http://www.universetoday.com/15516/how-many-moons-are-in-the-solar-system/

https://solarsystem.nasa.gov/planets/index.cfm

A comparison of Earth (right), the moon (upper left), and Ceres (lower left).

* * * * *

http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)

http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-asteroids.html

Photos

http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-comets.html

http://es.wikipedia.org/wiki/Meteorito_Hoba

Asteroids, Meteoroids, Comets, and Moons

By Diane Bao, with Grant Durow, Audrey Edwards, and Hannah Hansen