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how earth is formed ? |
Planet Earth was formed 4.6 billion years ago from the same nebula cloud of gas and dust that the Sun and the other planets were formed. However, Earth then was very different from Earth now, and it would have been impossible for life to exist on it. In fact, it is only quite recently in the Earth's 4,600,000,000 year long life that life, resembling modern-day life, has been possible, first with the dinosaurs over 200,000,000 years ago and now with humans and other animals. The Earth is still being formed now. It still has a molten centre which causes volcanoes to occasionally erupt, and plates on the surface are constantly swimming meaning that they collide with other plates and cause earthquakes. There are two theories as to how planets in the solar system were created. The first and most widely accepted, core accretion, works well with the formation of the terrestrial planets like Earth but has problems with giant planets. The second, the disk instability method, may account for the creation of giant planets. Scientists are continuing to study planets in and out of the solar system in an effort to better understand which of these methods is most accurate. |