Earth
Earth is the name for the planet on which humankind lives. It is the third planet from the Sun.
It orbits at an average distance of about 93 million miles (150 million km) in an almost circular orbit. It takes light (and other forms of electromagnetic radiation) approximately 500 seconds to travel from the Sun to the Earth, i.e. the distance can also be stated as "500 light-seconds." The distance to nearby stars is made by measuring the stellar parallax between observations when the earth is at opposite ends of its orbit, so the earth's orbit itself is a measuring stick for astronomical distances, and is known as the astronomical unit (A. U.)
The Earth is approximately 8000 miles (13000 km) in diameter, so its circumference is approximately 8000·π = about 25,000 miles (40,000 km). Its surface area is approximately 4·π (4000 mi)2 = 200 million square miles (510 million km2). It has been said that Earth should really be called "water:" most of the Earth's surface, about 70%, is covered by water. In fact, the Pacific and Indian oceans alone cover about half of the Earth.
Estimates by non-creationist geologists of the age of the Earth have varied over the years; currently, mainstream scientists believe the age of the Earth to be about 4.5 billion years.
Bible scholars have also estimated the age of the earth based on the Creation account in Genesis and the genealogical accounts in Numbers and other books of the Pentateuch. One famous estimate was published in 1650 by R. B. Knox, James Ussher Archbishop of Armagh (usually referred to as Archbishop Ussher) in a book called Annals of the World, in which he estimated the Creation to have occurred in 4004 B.C. Other Biblical scholars maintain that there are possible gaps in the genealogies, often using the ideas of the 19th century Calvinist theologian Benjamin Warfield on the issue. [1]