I must say that this is a impressively,magnificent, and a excellent piece! The gears at the right hand reminds me of steam punk, and well, I like steam punk! The artist made the Alicorn look in a special way.The artist made her look that she was born in a special place and made her look important.
They made the tree look cool too. It is interesting that the Element of magic shard is right on the tree. I like how they made the place look exotic and not normal. He also added a bit of sunlight on her. Which adds a realistic feeling to it.
Left: The Earth Ponies' plant growth power, nurturing the lifeform within. Right: The Unicorns' affinity for magitek, automating the caretaking process. Above: The Pegasi's weather manipulation, ensuring the sun always shines down. Center: The fruit of the tribes' combined efforts. Life. Autonomy. Power. Celestia.
(How's that for overwrought pseudo-philosophic narration?)
tecnically it still not explain how luna and celestia became alicorns. (Even the journal of the two sister is not this) you see The diary entries cover a fairly short amount of time, and neither princess goes into great detail about what happenedbefore they became rulers of Equestria.
Just by looking at this, a story could be made from this. The ponies are in dire need of a new and pure leader and thus created the alicorn. The synthetic pony that combines the race of a Unicorn, Pegasus, and Earth Ponies to create the master race of the alicorn. The pure a faithful leader that will not fault in leading the 3 ponies. The unicorns use the power of the Tree of Harmony and the Elements of Harmony to create the this leader the ponies have been longing for. Another concept from this could be created. The three races of ponies are at war and the unicorns decide to create a super weapon alicorn to defeat the other pony races but instead created a all powerful pony that will unite the three types of ponies. Maybe they created Luna after seeing Celestia fail to meet their criteria. Regardless, this art is amazing with the gray tone of the colors and the watered down colors blending to create the eerie feeling of despair and depression. But there is a catch in the art work and its the bubble in the middle with the mysterious pony (of course Celestia) that stands out from the dreary surrounding. The shimmering and bright colors purity radiating from the bubble just waiting to escape and express its true color as the color is still watered down. Amazing work and it reminds me of something from Brave New World where a race of humans create the perfect humans and clone them.