The Earth is one of the planets orbiting the Sun.  The Sun, the Earth and the other planets that orbit the Sun can be considered as a Solar System that humans call The Solar System.

Physical dimensions and composition

The Earth is about 25,000 miles (approx. 40,000 kilometres) in circumference (although it's not an exact sphere, there's a bit of a flat bit somewhere), which orbits a star called the Sun (not to be confused with the newspaper of the same name) somewhere in space. It's about 93,000,000 miles from the Sun and goes round it about once a year.

The Earth is made of all sorts of stuff, such as rocks, metals, water and other things. It probably has other stuff as well but if it does, we don't know about it yet.


The typical surface temperature on the Earth is roughly 20 Centigrade (C) (about 68 Fahrenheit (F)) but this varies between regions. Some of it goes down to about -50 Centigrade (sorry, can't be bothered to do the conversion), while other bits go up to about 50 C (about 120 F). The hottest it ever got was about 60 C (let's call it 135F).

However, the further into the Earth you go, the hotter it gets.  The core of the Earth is very hot indeed, but probably not as hot as the Sun.  Either way, it's very hot.

Satellites of the Earth

The Earth has one main natural satellite called the Moon, which is made of some sort of rock and orbits the Earth about once a day. It's about 250,000 miles away. A few people went there in the late 1960s and early 1970s, but nobody bothers doing that anymore, because there's nothing much there. But not all people believe that other human people ever went there and all the footage was faked by some guy.

Other satellites of the Earth are man-made and are generally used for one or more of the following:

- Looking at stuff

- Communications

- Spying

- Distribution of porn

What On Earth?

The surface of the Earth has two main sorts of things on it, called "oceans" or "seas" (which are made of water) and "land", which is made of the other stuff. About three-quarters of the surface is water and the rest is land, but the sea doesn't go very deep; even in the places with the most water, it only goes down about five miles. Sometimes there are bits of sea go into the land, which are called rivers. There's other bits of water enclosed by land which can be called seas or lakes, whatever.All of the stuff that is classified as "land" is divided up into lots of other bits. Antarctica is a big bit made of ice that is at the bottom of the Earth; the other bits are generally made out of rocks and stuff and are located elsewhere. The other bits are called Africa, Asia, Europe, North America, South America and Australasia. All of the bits except Antarctica are further subdivided into smaller parts with various names.

The Earth is the only one of the planets within The Solar System that definitely supports life, but nobody really knows why.  Life on Earth is usually based on the chemical elements carbon and hydrogen and bits of other stuff.  Some lifeforms (or "species") are very small, while other ones are very big. Most of the lifeforms live on the land (e.g. humans and giraffes), but some of them live in the water (e.g. sharks and fish).  Some forms of life can live in either water or on land; these are called amphibians. There's some other ones called viruses which aren't really lifeforms at all but they're out there somewhere.

Overall, the apex predator of the Earth is recognised as a species known as "humans". But this wasn't always the case, about 100,000,000 years back, creatures called "dinosaurs" were everywhere and there weren't any humans at all, but then all the dinosaurs disappeared for some reason. Some say it got too cold for them, some say it got too hot; whatever, they all died. Of the species that were left behind after whatever it was that happened, some sort of amphibious creature probably adapted itself to living exclusively on land, that became something like a monkey and then evolved into a human or something.  Whatever, humans ended up on top.

The Ages of the Earth

The Earth is really old but not as old as the Universe or the Sun.  It's about the same age as the Moon or maybe a bit older.  It probably formed at much the same time as The Solar System was getting itself together.

Most of the ages of the Earth have been defined by humans.  These include:

- The Stone Age

- The Iron Age

- The Bronze Age

- The Age of Enlightenment

- The Dark Ages

- The Rennaissance

- The Industrial Age

- The Modern Age

- The Postmodern Age

- The Transhuman Age

It is hypothesised that further ages may follow, but nobody knows what they are yet.

The Ultimate Fate of the Earth

There is widespread disagreement amongst experts as to the future of the Earth.

Some say that humans will somehow contrive to contrive to destroy the Earth prior to its natural cosmological fate (possibly by technological means, or using the Moon as sone sort of giant missile or something), but others take a different view.

Eventually the Sun will blow up or whatever it is that stars do when they get too old, and if the Earth's still around at the time, it won't come out of it well.  But that's not going to happen for quite a while.