You should now be familiar with the names of the planets, as well as the order that they are in. A useful mnemonic is:-

|||||||||| My Very Expensive Mercedes Just Sped Under North Pier ||||||||||

The letters in bold stand for the planets from the sun outwards so we have

|||||||||||||||||||| Mercury Venus Earth Mars ------ sometimes called the inner planets ||||||||||||||||||||

and

||||||||||| Jupiter Saturn Uranus Neptune Pluto ------ sometimes called the outer planets |||||||||||

Now try the explorer exercise. You must navigate from Pluto to the sun in order to 'traverse' the solar system, watch your spellings, good luck ......