What is the origin of the word Earth?
The Modern English word Earth developed from an Old English noun most often spelled ertha. This term has cognates in every Germanic language, tracing back to a reconstructed root that meant the ground or soil.
Questions about Earth
Short answers, pulled from the story.
How old is the planet Earth according to scientific estimates?
By 4.5 billion years ago, the primordial Earth had formed from gas and dust in the early Solar System. The oldest material found in the Solar System is dated to 4.568 billion years ago.
When did the first continental crust form on Earth?
Grains of the mineral zircon of Hadean age found in Eoarchean sedimentary rocks suggest that at least some felsic crust existed as early as 4.0 billion years ago. New continental crust forms as a result of plate tectonics, a process driven by continuous loss of heat from Earth's interior.
Where was the earliest evidence for life discovered on Earth?
Among earliest fossil evidence for life are microbial mat fossils found in 3.48 billion-year-old sandstone in Western Australia. Biogenic graphite found in 3.7 billion-year-old metasedimentary rocks in Western Greenland provides additional early evidence.
What is the average diameter of Earth in kilometers?
Earth has a rounded shape through hydrostatic equilibrium with an average diameter of about 12,742 kilometers making it fifth largest planetary sized object of Solar System. Due to rotation it has ellipsoid shape bulging at equator where diameter is 43 kilometers longer than at poles.