Earth

“Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill.”

- Stephen Hawking

General Information

• Earth is made of rocks and land (30% of the surface) and water or oceans (70% of the surface). The land portion of Earth is always changing based on the weather and is seen as mountains, canyons, valleys, and plains. It is made of several elements, perhaps over 200.

• Earth’s atmosphere is made of oxygen, nitrogen, and carbon, which allows for the presence of life since many life forms depend on these elements. The atmosphere also protects us from the sun’s UV rays and meteorites.

• Earth has a slight tilt on its axis that causes sunlight to hit at different amounts in different places. It also rotates once every 24 hours. This creates the different time zones of the world and causes the 4 seasons (spring, fall, summer, and winter) on Earth.

• Earth has one moon, known as the Moon, that rotates around in.

• Earth is the only planet that is known to have life and intelligent beings. There are hundreds of thousands of species on Earth, and some are still yet to be found.

• The Earth is the 3rd planet from the Sun. It is in a position where it is not too far nor too close to the sun, meaning that it receives just the right amount of heat to support life.

• Natural disasters, such as earthquakes, hurricanes, tsunamis, occur on Earth as a result of its weather patterns that are caused by the atmosphere.

• Climate change is the largest environmental issue on Earth at the moment. It is caused by an excess of carbon in the atmosphere, causing heat to get trapped in the atmosphere and warm up the Earth. People encourage climate change to stop by reducing the amount of carbon they produce every day.

Discoveries

• Using radioactive decay, scientists discovered that earth was 4.6 billion years old.

• The ozone layer was discovered in 1913 by French scientists to protect Earth from the sun’s UV rays

• Harry Hess discovered seafloor spreading, or when magma from the sea floor comes out through cracks and cools, causing the seafloor to grow and spread outward.

• The NASA satellite Magsat first measures the Earth’s magnetic field.

• The Hubble Space Telescope explores more about Earth’s structure.

Fun Facts

• Earth is the only planet in the Milky Way Galaxy not named after a Greek God/ Goddess.

• Earth has the highest density of all the planets.

• It is the only planet known to have life.

• The Earth was formed over 4.6 billion years ago and still continues to change.

• Early scientists and astronomers believed that the Earth was the center of the solar system. This theory, known as the geocentric theory, influenced all of the maps of the solar system and calendars created at that time.