The planet Earth is the third rock from the Sun and the fifth
largest planet in our solar system. It is the only known
solar system body to harbor life. It's diameter is only
slightly larger than that of Venus. It's atmosphere
shields the inhabitants of the earth, such as human beings, from
the unlivable conditions of deep space. Earth's atmosphere
also protects the planet from harmful radiation from the sun and
from meteors that enter the atmosphere an burn up. At
earth's surface, the atmosphere is comprised of 78% nitrogen,
21% oxygen, and 1% other other various gases.
Earth is made up of a molten nickel-iron inner core, a mantel,
and a crust. The molten core combined with earth's rapid
rotation gives earth a magnetic field. When charged
particles from the sun come racing towards the earth and
interact with air molecules above Earth's magnetic field, they
glow in beautiful auroras known as the Northern or Southern
Lights.
Earth's crust is in constant state of motion. Tectonic
plates move the crust around the surface of the Earth.
Faults, such as the San Andreas Fault pictured on the right, are
cracks in the Earth's surface. Faults are usually a hotbed
of tectonic activity. When two plates collide and rub past
each other, earthquakes can occur. Oceans dominate the
surface of the Earth. In fact, over 70% of earth is
covered by water that is at least 4km. Earth has been
pummeled by asteroids and comets over the millennia, but
geological activity has erased almost all of the impact craters
themselves. There are still some that have not been
eroded, such as Meteor Crater in the Arizona desert.
Earth has one natural satellite, the Moon.
The moon is believed that the Moon was formed when a large
object, possibly the size of Mars, slammed into the Earth
causing debris from Earth's surface and from the object fly into
space and coalesce to form the Moon. The gravity from the
Moon affects the tides of Earth's vast oceans.
| Mass (kg)
| 5.98 x 1024
|
| Diameter (km)
| 12756
|
| Mean density (kg/m3)
| 5520
|
| Escape velocity (m/s)
| 11200
|
| Average distance from Sun
| 1 AU (149,597,890 km)
|
| Rotation period (length of day in Earth days)
| 1 (23.93 hours)
|
| Revolution period (length of year in Earth days)
| 365.26
|
| Obliquity (tilt of axis degrees)
| 23.4
|
| Orbit inclination (degrees)
| 0
|
| Orbit eccentricity (deviation from circular)
| 0.017
|
| Mean surface temperature (K)
| 281
|
| Mean maximum surface temperature (K)
| 310
|
| Mean minimum surface temperature (K)
| 260
|
| Visual geometric albedo (reflectivity)
| 0.39
|
| Highest point on surface
| Mount Everest
(over 8 km above sea-level)
|
| Atmospheric components
| 78% nitrogen,
21% oxygen,
1% argon
|
| Surface materials
| basaltic and
granitic rock and
altered materials
|
|
Image of The Planet
Earth With
The Moon
Photograph of
Earth's San Andreas Fault
Picture of
Meteor Crater
Northern Lights as seen
from the Space Shuttle |
