In describing different places in the cosmos, the Edda often employs the imprecise word heimr, meaning ‘home’, ‘world’ or ‘land’, and we must guess at the locations of many of the described areas. In addition to the realms of gods, men and giants, the Edda, speaks of geographically disparate regions such as Ginnungagap in the north, an empty place filled with ice, and Muspell, a burning place of intense heat to the south. So also there are several heavens; one is called Andlang and another, ‘further up’, is where light elves live.
Many elements in Norse cosmology, however, as described in the Edda, fit into a coherent picture derived from the main stories. One is the World Tree, whose trunk remains consistently at the centre of the Norse universe. Another is the heavenly vault which the gods made from the skull of the giant Ymir, and which gives a shape to the upper part of the universe. Four dwarves, one under each of the compass points, hold up this vault. At the skull’s upper reaches shine the heavenly bodies, and some of them – the ones that appear to the naked eye to remain steady – were thought to be furthest up in the heavens, while the heavenly bodies that were visibly moving were thought to be lower in the sky. The sun and the moon were clearly the most important of these moving bodies, and chariots pulled them daily across the sky, just ahead of pursuing hungry wolves. In the sky there is also a giant who, in the guise of an eagle, beats its wings and blows winds across the world.
Rising up into the heavens, the World Tree is a living entity, whose branches spread majestically over all lands. This axis mundi or cosmic pillar at the centre of the world is described as a giant ash, binding together the disparate places of the universe, and it serves as a symbol for a dynamic cosmos.
The concept of a World Tree exists in many mythologies. In the case of the Scandinavian World Tree, the idea may reach back thousands of years and may have an Indo-European origin. Although people in Old Scandinavia probably interpreted the tree in different ways, the name Yggdrasil, a compound word with several layers of meaning, perhaps gives us a clue as to how the tree was understood in symbolic terms. One possible interpretation is that the first part of the name, Ygg, meaning the ‘terrible one’ and one of Odin’s many names, is connected to the aspect of Odin’s persona as god of the hanged. Drasill is an ancient term for ‘horse’. Hence Yggdrasil (Yggdrasill) means Ygg’s (or Odin’s) horse and is a metaphor for a gallows tree. This view assumes that the ancient Scandinavians saw a similarity between how people ride horses and how a hanged person bobs as he ‘rides’ the gallows. The gallows tree was an emotionally significant site for the passage between life and death, and is a fitting symbol for the World Tree as the causeway connecting the heavens and the underworld.
Three roots, spread far apart, support the ash tree. Each root extends into a different world, and each is nourished by a well. Through these wells, the tree draws its life force from the waters of three worlds: those of the gods, the giants and the dead. The root that reaches the highest goes to Asgard, where the Æsir live in different halls. Asgard is located close enough to the branches of the tree for the goat that stands on the roof of Valhalla to eat its leaves. Under the root leading to Asgard is the Well of Urd, near which the Æsir daily hold court and make their decisions. Beside the well live three norns – Urd (Fate), Verdandi (Becoming) and Skuld (Obligation) – who are similar to the weirds or prophetic women of Old English tradition and the witches found in Macbeth.
Asgard is connected to the world below, called Midgard (Middle Enclosure or Middle Earth), by the rainbow bridge, Bifrost. This middle world is conceived as a landmass inhabited by humans, who live towards the centre, and giants, who live at the periphery in the region called Utgard. Midgard does not have a root or a well, but under the root that leads to the frost giants in Utgard is the Well of Mimir. A mysterious figure, Mimir owns the well in which wisdom and intelligence are hidden. Odin went to Mimir’s Well and asked for one drink, but his request was denied until he pledged one of his eyes, plucking it out and placing it in the well. Because of this, Odin became known as the one-eyed god. The poem The Sibyl’s Prophecy tells that each day Mimir drinks ‘mead’, a beverage of inspiration from the well containing Odin’s pledged eye.
Midgard’s geographical relationship to Utgard and its threatening giants is somewhat unclear, in part because the Edda refers to Midgard both as the earth itself and as a central fortress. The lack of clarity is heightened because the Edda also gives several descriptions of the placement of the sea, and it is not clear whether the ocean surrounds Midgard and Utgard together or lies between these two regions. One passage suggests that the ‘earth’s girdle’, as the sea was called, lies at Utgard’s outer edge. Another concept of the placement of the sea, which may not be fully contradictory, is gleaned from the story about Thor’s route on his way to visit the giant Utgarda-Loki. This story leaves Midgard in the centre. Since Thor, however, has to cross water after leaving Midgard and before arriving in Utgard, it implies that the sea, or at least an inlet, lies between Midgard and Utgard. Perhaps the discrepancy is mostly a question of emphasis, because a passage describing the Midgard Serpent tells that the outer sea surrounds all the land, and the huge serpent lies in this outer sea, biting its tail.
Yggdrasil’s third root goes to the underworld, a region guarded by the great hound Garm, and into the dark world called Niflheim and Niflhel. The Edda tells us that the well of the underworld, Hvergelmir, is a seething cauldron of waters that unleash a torrent of underworld rivers. The eddic poem The Lay of Grimnir (Grímnismál, Grimnir being Odin) also speaks of Hvergelmir, saying that all the rivers of the world spring from this well. In the underworld is the huge serpent Nidhogg, lying among smaller, gnawing snakes too numerous to count. Nidhogg is not isolated in its dark home, because a squirrel named Ratatosk runs up and down the trunk of the tree, carrying insults between the serpent and a great eagle, who sits high up in the airy branches of the tree with a hawk between its eyes.
The lower region also contains Hel, the realm of those who die a natural death, in contrast to the warriors who enter Valhalla. Hel is also the name of the goddess overseeing the World of the Dead, and her unlucky charges enter the underworld by passing through the Gates of Hel and then crossing the Gjoll Bridge. Old Scandinavian Hel was a pre-Christian concept and was understood to be a shadowy region much like the Greek Hades. As the realm of those who die undistinguished deaths, Hel is very different from the boisterous Valhalla.
Despite the tree’s inherent strength and the sustenance received from the wells, it faces constant peril from several directions: Nidhogg gnaws its deepest root, and four stags move through its branches, ripping and devouring its foliage. The trunk is also subject to rot, and the great ash would die were it not for the three norns in Asgard who nurture it. To slow the rot, these norns draw water every day from Urd’s Well, mix it with the mud lying beside their spring and then coat this potent salve on to the trunk. In the long run, this attempt at healing will be in vain. The Edda implies that the tree is threatened at Ragnarok. The great ash trembles and groans at the coming of the final battle, but it is not clear that it is destroyed.