Re: who (m) is given credit for naming our planet the Earth?

Three of the nine planets in our solar system were discovered in modern 
times with the aid of a telescope:  Uranus, Neptune, and Pluto.  Their 
names were chosen to conform with the pattern of Roman gods used for the 
five planets known since ancient times.

So where does the Earth fit into this great naming scheme?  For most of 
recorded history, the Earth wasn't even thought of as a planet.  The word 
planet means wanderer, and refers to the way that the planets appear to 
move slowly against the backdrop of the stars.  For example, Saturn might 
appear one night to be in front of the constellation Aquarius, and on a 
different night might be in front of Libra.  The Greeks (who were one of 
the first to record their observations about the planets) no more thought 
of the Earth as a planet than we would think of a boulder as a firefly.

That began to change in the early years of the Renaissance.  Several Greek 
philosophers had proposed that instead of the Sun moving around the Earth, 
that the Earth moved around the Sun--a heliocentric system.  In 1444 
Nicholas of Cusa resurrected the idea, and Nicolaus Copernicus developed 
it into a full fledged theory.  

In 1609, Galileo improved the design of the telescope to the point where 
it was possible to see that the planets were not just lights in the sky, 
but spherical objects in their own right, just like the Earth.  Soon after 
the word planet gained its current meaning "a large object that travels 
around the sun" and the Earth became merely the third of six (later to be 
third of nine).

The word used for the planet Earth in English was the same word used all 
along for the ground, a word derived from the Old English word earth.  No 
one knows the precise origin of the word.  The earliest writing we have 
that use a variant of it is the epic of Beowulf, probably written in the 
8th century.

So the short answer is, no one really named our planet the Earth, it just 
grew naturally out of the explosion of scientific thought triggered by the 
Renaissance.