Type of Planet
Earth is a terrestrial planet, meaning primarily composed of rock and metal. Earth is potentially unique though, as it contains life.
Earth's core is made up of nickel and iron. Earth's mantle is made up of rock, containing; silicon, iron, magnesium, aluminum, oxygen and other minerals.
Size (Diameter), Mass, and Density
Earth is the largest of the Solar System's four terrestrial planets.
In the study of exoplanets, the mass of Earth is used as a unit of measure for smaller rocky terrestrial planets.
The density of Earth is 5.51 grams per cubic centimeter.
The gravity of Earth at the poles is greater than at the equator. Gravity also decreases with altitude, since you're further away from the Earth's center.
The main part of Earth's magnetic field is generated in the core.
Earth's atmosphere is composed of 78 percent nitrogen, 21 percent oxygen, and other elements such as argon and carbon dioxide. Our atmosphere also contains water vapor.
The average temperature on Earth is 7.2 degrees celsius. Temperatures vary greatly around the world depending on the time of year, location, ocean and wind currents and weather.
Length of a Day (Rotation)
A day on Earth lasts 24 hours. In the past however, the Earth spun quicker, making the days shorter. The length of a day has been increasing slowly throughout most of the Earth's 4.5-billion-year history, due to the moon's gravitational pull slowing the rotation of the Earth.
Earth's axis is tilted about 23 degrees. On Earth, that tilt is the primary reason for the differences in weather we observe between summer and winter.
Length of a Year (Orbit)
A year on Earth lasts 365 days.
Distance from the Sun
Earth is the third planet from the Sun at 93 million miles.