1. Earth
By Omar Roman

2. Basic Facts Third planet from the Sun
Diameter: 12,753 km (7,926 miles)
Rotation Period with respect to Sun (Length of Day): 24 hrs
Mass: 5.98x10^24 kilograms (6.5e21 tons)
Rotation Period with respect to stars (Sidereal Day): 23 hrs 56 min
Revolution Period about the Sun (Length of a Year): 365 days 5 hrs
Minimum Distance from Sun: 146 million km (91 million miles)
Tilt of Axis: 23o 27"
Maximum Distance from Sun: 152 million km (94.5 million miles)
Temperature: -89o C to 57.7o C (-128o F to 136o F)
Average Surface Temperature (K): 287K
Satellites: 1 (the Moon)

3. Earth’s History Earth is 4.54 billion years old
The Earth has experienced 5 mass extinctions throughout its lifetime

4. Earth Compared to the Sun
Earth is very small compared to the Sun
1,300,000 Earths can fit inside of the Sun
The Earth’s core is hotter than the surface of the Sun
Surface of the Sun=5,778 K
Earth’s Core=7,500 K

5. Earth Fun Facts
Earth is the only planet with life that we know of so far.
Earth’s name does not come from Greek/Roman mythology like the other planets
We did not have maps of the entire planet until the 20th century
It’s the densest major body in the solar system

6. Earth’s Layers 0- 40 km-Crust 40- 400 km-Upper mantle
km-Transition region
km-Lower mantle
km-D'' layer
km-Outer core
km-Inner core

7. Earth’s Atmosphere and Water
Earth’s atmosphere contains 77% nitrogen and 21% oxygen with a mixture of argon, carbon dioxide and water
71% of the Earth is water
97.5% of all the water on Earth is saltwater
2.5% is freshwater
Less than 1% (about 0.007%) of that 2.5% is accessible for human use

8. Problems Earth is Facing
Population-More than 7,214,000,000 people inhabit the planet today and by 2050 it should reach about 9.5 billion people
Climate Change- Our current activities have affected the climate so much that the damage is irreversible.
Ozone Layer Depletion-In some areas 20% of the ozone layer has depleted since the mid-1980s
Water 2.6 billion people lack adequate sanitation
1.1 billion people live without water

9. Bibliography
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