On 12 July 2011, Neptune was one year old - one Neptunian year that is.

The furthest planet from the sun, it's only now completed one solar orbit since its discovery in 1846, traveling so slowly each Neptunian season lasts 40 Earth years.

Too distant to spot with the naked eye, the ancients could never have known of Neptune's existence.

Nineteenth century astronomers had to climb on the shoulders of scientific giants to see it.

First a tiny blue disc now an ice giant whose strange atmospheric features send shivers down the spines of astronomers today.

What twists and turns of fate, what scientific clues and personality clashes won the race for Neptune's discovery?

Some say Galileo spotted it 200 years earlier, secretly noting its existence in a coded Latin anagram awaiting further proof.

Forensic tests of the ink he used could solve the puzzle along with painstaking studies of his original manuscripts in Florence.

It's late spring, early summer in Neptune today.

It has been for decades now.

Astronomers can only watch and marvel at the quirky movements and sudden shifts and disappearances of the vast 'black spot' amongst its clouds.

What is it?

Where does it come from?

What can you ever know about a world when even the most advanced human telescopes have only studied it for a season?