Skip to main content

The History of Earth


The history of Earth concerns the development of the planet Earth from its formation to the present day.Nearly all branches of natural science have contributed to the understanding of the main events of the Earth's past. The age of Earth is approximately one-third of the age of the universe. An immense amount of biological and geological change has occurred in that time span.

 Earth formed around 4.54 billion years ago by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and ocean, but the atmosphere contained almost no oxygen and would have been toxic to humans and most modern life. Much of the Earth was molten because of frequent collisions with other bodies which led to extreme volcanism. One very large collision is thought to have been responsible for forming the Moon. Over time, the planet cooled and formed a solid crust, allowing liquid water to exist on the surface.

 The first life forms appeared between 3.8 and 3.5 billion years ago. The earliest evidences for life on Earth are graphite found to be biogenic in 3.7-billion-year-old metasedimentary rocks discovered in Western Greenland[6] and microbial mat fossils found in 3.48-billion-year-old sandstone discovered in Western Australia.Photosynthetic life appeared around 2 billion years ago, enriching the atmosphere with oxygen. Life remained mostly small and microscopic until about 580 million years ago, when complex multicellular life arose. During the Cambrian period it experienced a rapid diversification into most major phyla. More than 99 percent of all species, amounting to over five billion species,that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.

 Geological change has been constantly occurring on Earth since the time of its formation and biological change since the first appearance of life. Species continuously evolve, taking on new forms, splitting into daughter species, or going extinct in response to an ever-changing planet. The process of plate tectonics has played a major role in the shaping of Earth's oceans and continents, as well as the life they harbor. The biosphere, in turn, has had a significant effect on the atmosphere and other abiotic conditions on the planet, such as the formation of the ozone layer, the proliferation of oxygen, and the creation of soil.

Comments

Post a Comment

Popular posts from this blog

Sardar Hari singh Nalwa

Sardar Hari Singh Nalwa (1791–1837) was Commander-in-chief of the Khalsa, the army of the Sikh Empire. He is known for his role in the conquests of Kasur, Sialkot, Attock, Multan, Kashmir, Peshawar and Jamrud.He is also a founder Haripur, Pakistan city. Hari Singh Nalwa was responsible for expanding the frontier of Sikh Empire to beyond the Indus River right up to the mouth of the Khyber Pass. In 1831, he opposed moves by Ranjit Singh to appoint Kharak Singh as his successor as Maharaja of the Sikh Empire.[citation needed] At the time of his death, the western boundary of the empire was Jamrud. He served as governor of Kashmir, Peshawar and Hazara. He established a mint on behalf of the Sikh Empire to facilitate revenue collection in Kashmir and Peshawar. Hari Singh Nalwa was born in Gujranwala, Punjab to Gurdial Singh and Dharam Kaur, who were Uppal , Khatri by caste. After his father died in 1798, he was raised by his mother. In 1801, at age ten, he took Amrit Sanchar and w...
Post a Comment
Read more

Starting Mobile Phones

A mobile phone (also known as a cellular phone, cell phone, hand phone, or simply a phone) is a  phone  that can make and receive  telephone calls  over a  radio link  while moving around a wide geographic area. It does so by connecting to a  cellular network  provided by a  mobile phone operator , allowing access to the  public telephone network . By contrast, a  cordless telephone  is used only within the short range of a single, private base station. In addition to telephony, modern mobile phones also support a wide variety of other  services  such as  text messaging ,  MMS ,  email , Internet access, short-range wireless communications ( infrared ,  Bluetooth ), business applications, gaming, and photography. Mobile phones that offer these and more general computing capabilities are referred to as  smartphones . The first hand-held cell phone was demonst...
Post a Comment
Read more

Latest Scientific Invention

Sci-Fi Cloaking Device Could Protect Soldiers from Shock Waves A researcher at the defense company Boeing has filed a patent for a sci-fi-esque cloaking device that would protect soldiers from intense shock waves generated by explosions. The just-issued patent (No. 8,981,261) to Boeing envisions stopping shock waves using a veil of heated, ionized air. Such a "shield" would damp  the force of explosions . It doesn't build an invisible wall of force, but rather makes shock waves bend around objects, just as some high-tech materials bend light and make things invisible. Brian J. Tillotson, a senior research fellow at Boeing, said the idea occurred to him after noticing the kinds of injuries suffered by soldiers who served in Iraq and Afghanistan. "We were doing a much better job of stopping shrapnel," Tillotson told Live Science. "But they were  coming home with brain injuries ."
Post a Comment
Read more