Astronomers theorize that over 4.5 billion years ago, Theia, an object about the size of Mars, collided with Earth to create a tilted axis. This is called "the giant impact theory." Prior to this event, the axis was straight at 180 degrees.
The theory holds that as Theia collided with the Earth, the mantle and elements flew into space, creating the materials for the moon. Scientists named Theia after the Greek god Titan.
The 23.5-degree tilt of the axis sustains life on Earth and produces seasons. Since the Earth rotates on an angle, no portion receives the brunt of the heat from the sun. Agriculture and many species rely upon the season changes from the tilted axis.Learn More
Scientists agree that the Earth formed about 4.6 billion years ago out of accreted matter from the solar nebula. All planets in the solar system formed the same way. Once the proto-Earth was formed, many changes occurred over vast timescales to produce the Earth of the 21st century.Full Answer >
According to Universe Today, the duration of a day on Earth is the time it takes for the planet to complete a rotation around its axis. The Earth’s rotation takes 23 hours, 56 minutes and 4.1 seconds.Full Answer >
While no one knows for certain how the Earth formed, scientists theorize that it formed over 4 million years ago after the sun went through its initial formation, gravity began to draw heavy particles together into a planet and solar winds blew away lighter gases. These heavy particles became the core of the planet. As the mass continued to grow, heavier particles sank to the center, according to Space.com.Full Answer >
Life could not exist on Earth without trees because they produce most of the oxygen that humans and wildlife breathe. Trees absorb carbon dioxide from the atmosphere and release oxygen using the process of photosynthesis. There would also be no rain without trees, since trees absorb water from the soil and release it through evapotranspiration. Water vapor released through evapotranspiration is the major mechanism by which air is remoistened.Full Answer >