The Earth
Rotates anticlockwise as do most of the solar planets.
Just two headings on this page.
1 Formation of the Earth
2 Have fun on the Moon
1 Formation of the Earth
- As the universe expanded, according to current scientific understanding, matter collected into clouds that began to condense and rotate, forming the forerunners of galaxies.
- Within galaxies, including our own Milky Way galaxy, changes in pressure caused gas and dust to form distinct clouds. In some of these clouds, where there was sufficient mass and the right forces, gravitational attraction caused the cloud to collapse.
- If the mass of material in the cloud was sufficiently compressed, nuclear reactions began and a star was born.
- Some proportion of stars, including our sun, formed in the middle of a flattened spinning disk of material.
- In the case of our sun, the gas and dust within this disk collided and aggregated into small grains, and the grains formed into larger bodies called planetesimals ("very small planets"), some of which reached diameters of several hundred kilometers.
- In successive stages these planetesimals coalesced into the nine planets and their numerous satellites.
- The rocky planets, including Earth, were near the sun, and the gaseous planets were in more distant orbits. ........
- The oldest known rocks on Earth occur in northwestern Canada (3.96 billion years), but well-studied rocks nearly as old are also found in other parts of the world.
- In Western Australia, zircon crystals encased within younger rocks have ages as old as 4.3 billion years, making these tiny crystals the oldest materials so far found on Earth.
- The best estimates of Earth's age are obtained by calculating the time required for development of the observed lead isotopes in Earth's oldest lead ores.
- These estimates yield 4.54 billion years as the age of Earth and of meteorites, and hence of the solar system.
- The origins of life cannot be dated as precisely, but there is evidence that bacteria-like organisms lived on Earth 3.5 billion years ago, and they may have existed even earlier, when the first solid crust formed, almost 4 billion years ago.
- source
2 Have fun on the Moon
Use your mouse to push the moon around here