Isaacs (named after Isaac Newton are a unit of space; they are formed of a similar structure to atoms and fill the space between the atomic nuclei. They are made up of a Tree (which does not grow like any old tree but in fact shrinks) particle in the centre being orbited by a number of Apple particles (which it seems can be eaten however there small size means that it is impossible to tell weather they really taste like cabbage or beef). The Tree particle emits Apples particles like radiation which causes the Apple particles have a spiral orbit slowly moving away from the tree particle in the centre of the Isaac. This result in Isaac’s expanding constantly and so increasing the amount of empty space in the universe, ultimately resulting in the universe expanding.
The Attenborough (Named after David Attenborough) is the measure of Isaacs per a cubic nano meter of a particular element. The Cox (named after physicist Brian Cox not Cox apple) is the force of repulsion between the apple and tree.
One problem with the theory is that the tree particle at the centre emits Apple particles, every time this happens the number of Fruits (these make up a tree and will all be emitted at some point) the tree has left will be decreased and would eventually lead to the tree becoming non existent. This would cause the Apple particles to slow down and eventually stop. The theory suggests that after time two or more apples may collide which would cause a new tree to form.
Another problem is that trees can sometimes emit different particles depending on the situation. E.g. in a black hole all Isaacs with apples are repelled as the tree in the centre of a black hole produces a particle now known as the orange which forms a complicated tri spiral around the tree it is unknown as of yet why this happens and more research has to be done.
The anti matter equivalent is the anti-Isaac. The anti-Isaac it is formed from the Wyrm (named after a type of Dragon) particle which releases small Worms (Not your average common garden Worm these are harmless to humans) as radiation.
This theory was first invented by Steven Dupont and Aidan Boyce. Originally called the apple theory with the unit of space starting with the name newton with the abbreviation ew. However it was renamed after careful consideration and so the names you see today stand strong.