Earth, our home
planet, is the only planet in our solar system known to harbor life - life
that is incredibly diverse. All of the things we need to survive are provided
under a thin layer of atmosphere that separates us from the uninhabitable
void of space. Earth is made up of complex, interactive systems that are
often unpredictable. Air, water, land, and life - including humans - combine
forces to create a constantly changing world that we are striving to understand.
Where Is It?
Our home
planet is the third planet out from the Sun, located in between Venus and
Mars. The orbit, or path we follow around the Sun is nearly a perfect circle.
The closest we come to the Sun is a little over 91 million miles, and the
furthest away we get is a little less than 94 million miles. Our average
distance from the Sun is about 93 million miles. By the way, our average
distance from the Sun is called an astronomical unit
(or a.u.).
How Big Is
It?
Our home
planet is a little over 7,600 miles in diameter, or about 24,000 miles
around the equator. On a size basis, we are right in the middle of
our planetary family, with four planets, Pluto, Mercury, Venus and Mars,
being smaller, and four planets, Jupiter, Saturn, Uranus and Neptune,
being larger.
How Many Moons
Does It Have?
one-fourth
the size of Earth, with a diameter of a little over 2,000 miles. Earth
is the only planet in the solar system that has solar eclipses, which
happen when the Moon hides the Sun.
How Did It
Get Its Name?
Earth is
the only planet that does not have a name from either Greek or Roman mythology.
The name that most of the people on Earth use for our home
planet comes from German/English roots.
What Is It
Made Of?
They way
Earth is put together makes our home planet very unusual. Earth has a core,
or center, that is solid and made up mostly of iron. The large
amount of iron in our planet is what creates the magnetic field that makes
compasses work. On top of the solid core is a very thick layer of
molten, or almost liquid, rock. This layer is called the "mantle" and is
responsible for the many eruptions of volcanoes that happened in the past
and are continuing to happen now. On top of the mantle is the layer
where we live. The solid layer that makes up the continents and the oceans
is actually very thin,
averaging
less than thirty miles thick. The continents actually float around on this
top layer, a lot like crackers do in a bowl of soup!
What's It Like
On The Surface?
The weather
on Earth varies a great deal, from very cold at either the north or south
poles, and keeps getting warmer until you get to the equator, or center,
of our planet. What causes the "seasons" that most of us are familiar with
is the fact the Earth "wobbles" on its axis, like a spinning top, as it
goes around the Sun. If you live north of the equator, you have warm weather
from April through August. This is because that is the time when your half
of the planet is tilted towards the Sun. It is cooler during the rest of
the year when the southern half of the planet is tilted towards the Sun.
