Awesome Facts about Earth #1

  1) The word "planet" comes from the Greek word planetai for "wanderer".

  2) Earth began as sticky dust which clumped, like snowflakes, into a planetesimal, or a body that is about a half mile in diameter.

  3) Earth is made up of hydrogen gas, stardust, and gravity. The gas and dust floating in space were drawn together by gravity and they formed into a spinning disc. As this disc collided with and absorbed rock bodies, the Earth formed. Astronomers believe the formation of Earth was relatively quick.

  4) Orbiting debris smashed into the newly formed Earth, and gravity and radioactive processes heated its interior to nearly 2000 degrees Fahrenheit. A solid inner core formed as iron and nickel were absorbed into the center. This inner core was surrounded by a molten outer core, and then less dense silicates formed the mantle and crust.

  5) The name "Earth" comes from Old English and Old High Germanic words (eorthe and erda, respectively) for "ground" or "soil", and it is the only name for a planet of the solar system that does not come from Greco-Roman mythology.

  6) Earth is called a terrestrial planet because it is made almost entirely of rock and metal. Because Earth formed inside the snow line - meaning it was close enough to the sun that water, carbon, and nitrogen were all in a gaseous state - the elements so essential to supporting life had to be supplied in some other way. They were carried to the Earth by dirty snowballs - asteroids that retained water in hydrated minerals. Later those hydrated minerals were heated and the trapped water was released.

 7) The birth of Earth’s moon is singularly important because it stabilizes Earth’s tilt. Without the moon, Earth would still have wild changes in climate and be uninhabitable. The stabilizing tug of the moon tempers Earth, resulting in the minor tip that causes summer and winter seasons.

   And the most awesome fact!

 8) Earth was originally born as a twin to the planet Theia, which was about half as wide as Earth and roughly the size of Mars. The two planets shared an orbit for several million years until they collided. Earth absorbed Theia, and the remaining debris eventually coagulated into Earth’s moon. The mass donated by Theia gave Earth the gravity necessary to sustain a substantial atmosphere!