The planet Earth can sometimes be referred to as terra firma, macrocosm, globe, big blue marble and terrestrial sphere. It is believed that life only exists on Earth since no other planet has the right environment to sup... More » Science Astronomy Planets

According to Encyclopædia Britannica, Earth is classified as a terrestrial planet. A terrestrial planet is rocky, in contrast to the predominantly gas planets found in the outer solar system. More » Science Astronomy Planets

Earth is known as "The Blue Planet" because of its massive oceans and other bodies of water. The University of Michigan website indicates that 71 percent of the Earth is covered by deep oceans. Views of Earth from space ... More » Science Astronomy Planets
similar articles

Ptolemy’s theory of the solar system placed the Earth at the center with each planet on an orbit around it and the stars on a celestial sphere. Ptolemy believed that astronomical elements existed in circular, rotating mo... More » Science Astronomy Planets

From Earth, the planet Saturn looks like a tannish-beige colored sphere famously girdled by rings substantial enough to be seen through a small telescope. Its apparent magnitude of between +1.47 to ?0.24 makes Saturn a f... More » Science Astronomy Planets

As the only known planet that is habitable for human beings, the Earth’s importance is self-evident. Every living organism known to science obtains all of its resources from Earth, and has very few other options availabl... More » Science Astronomy Planets

Earth formed around 4.54 billion years ago and is the third planet from the Sun. It is the fifth largest planet in the solar system and the largest of the terrestrial planets. It is also the densest of all the planets. More » Science Astronomy Planets