Asteroids, comets, meteorites, meteors, and meteoroids... Can you tell the difference between these objects that are found in our solar system?

Introduction

Video

https://www.youtube.com/watch?v=LeRQAYZkFAM

What is an asteroid, you may ask? Asteroids are chunks of rock that are floating around in space. The largest recorded asteroid was named Ceres and was founded in 1801 located between Mars and Jupiter. Considered to be a Dwarf

Planet, Ceres is 940

kilometers wide.

The smallest recorded asteroid was just over 2m wide!

Asteroids

Like Earth, asteroids orbit the sun. Most of the asteroids in our solar system are found in the Asteroid Belt located between Mars and Jupiter. The belt was formed from dust and rocks that were rejected from the formation of the solar system and got sucked in by the gravity

between the two previously

mentioned planets. There are

millions of asteroids floating

around in the Asteroid Belt.

Asteroids do not always appear in the Asteroid Belt. Asteroids that are orbiting around the sun are in danger of colliding with planets and moons. When asteroids come into contact with Earth's atmosphere, they are then called meteors. These will be discussed later in the book!

Asteroids vary greatly in size and shape. Ceres was the largest and extremely round. This is not normally the case, though! Asteroids tend to collide with one another, chipping away at their surfaces and creating irregular shapes.

Asteroids are classified into three different categories:

Carbonaceous (C-type) - grayish in color, found in the outer belt, the most common (~75% of the known asteroids)

Silicaceous (S-type) - greenish or reddish in color, found in the inner belt, appear to be made of nickel-iron (~17% of the known asteroids)

Metallic (M-type) - reddish in color, found towards the middle of the belt, appear to be made up of nickle-iron

C-type Asteroid

M-type Asteroid

S-type Asteroid

Do not be fooled!

Asteroids are not the only thing flying through the starry sky. Comets can also be seen, even with the naked eye.

Comets

Comets were formed in the dawn of our solar system and are referred to as the "dirty snowballs" of space. Comets are chunks of ice and rock that hold a lot of information about the early formation of our solar system. Scientists believe that comets brought organic compounds to Earth and other planets.

Inside each comet is an icy center, called a nucleus. Each nucleus is about a few kilometers across. The nucleus contains icy chunks and frozen gases embedded with dust.

As the comet travels on its orbit, the sun heats the icy nucleus, causing it to expand and create a coma around the comet. The coma may extend to hundreds or thousands of kilometers. This will form a long bright tail. Comets have two tails, one made of dust and the other is made of ion gas.

The average size for most comets is about 16 kilometers or less. However, some comets have comas that can stretch for 1.6 million km and have tails that reach up to 160 million km.

We can see a number of comets with the naked eye when they pass by the sun. This is because a comet's

tail and coma reflect sunlight. However, there are comets that we cannot see with our eyes and must

use a telescope instead.

Beyond the planet Neptune there lies an icy-belt, known as the Kuiper Belt, where a large population of comets orbit around the sun. These icy comets can enter an orbit that puts them closer to the sun. These comets are called short-period comets. These comets take about 200 years to do a full rotation around the sun. Long period comets take over 200 years to orbit the sun, and they come from the Oort cloud far beyond any of our planets. Single-apparition comets are not bound to the sun. They are free to roam

in and out of

our solar system.

As comets orbit the sun their tails get larger in size. Since a comet's tails is made up of particles that reflect sunlight, the tail is always going to be directed away from the sun. The gas tail will point away from the sun, while the dust tail curves in the direction of the comet's orbital path.