In last week's article I talked about Yggdrasil, the world tree, and how it is structured, which includes the nine worlds of Norse mythology. For each world I will give a brief explanation and any information closely tied to it. Once again I will be referencing the Penguin Classics version of the "Prose Edda" by Snorri Sturluson, translated by Jesse L. Byock (indicated by a citation of Byock and a page number) and the Dover Books edition of the "Poetic Edda," translated by Henry Adams Bellows (indicated by a citation of Bellows and a page number). As well, here is the same illustration of Yggdrasil and the nine worlds.
Asgard
Asgard is the fortress home of the gods, surrounded by a great wall. More specifically, it is the home of the Aesir and a few Vanir. Asgard is basically the heaven of Norse mythology, analogous to Mount Olympus of the Greek gods. Valhalla, the seat of Odin's power, is in Asgard, along with Folkvangr. Both of these areas are where the honored dead go when chosen. Asgard is connected to Midgard by Bifrost, the rainbow bridge. In the "Prose Edda," Snorri asserts that Asgard is an earthly place, as the gods "made a stronghold for themselves in the middle of the world, and it was called Asgard. We call it Troy" (Byock 18). Other texts and the development of Snorri's own idea of Asgard go back and forth between it being a solely heavenly place and one on earth.
Vanaheim
Not much is mentioned about Vanaheim in the Eddas. Vanaheim is the homeland of the Vanir, the lesser clan of gods. In the "Prose Edda" Vanaheim is more implied than directly mentioned; however, when the god Njord's background is being described, he is said to be "not of the Aesir family. He was brought up in Vanaheim, but the Vanir sent him as a hostage to the gods" (Byock 33).
Midgard
This is the most important world of all, at least for you and me. Midgard is the land of humans, literally the "Middle land." During creation "Bur's sons lifted the level land / [Midgard] the mighty there they made" (Bellows 4). Midgard shares its border with Jotunheim, the land of giants; "It is circular around the edge and surrounding it lies the deep sea ... [and] further inland they built a fortress wall around the world to protect against the hostility of the giants" (Byock 17). It is said that "as material for the wall, they used the eyelashes of the giant Ymir and called this stronghold Midgard" (Byock 17). The Midgard Serpent, Jormungandr, lies in the seas around Midgard, surrounding it and swallowing its own tail. Odin's ravens, Hugin and Munin, "O'er [Midgard] ... both / Each day set forth to fly" to gather information for him (Bellows 92).
Alfheim
In Alfheim "the people called the light elves live there" and these light elves are "more beautiful than the sun" (Byock 28). Think of Galadriel and other Tolkien elves. Alfheim was even given to the god Freyr as a teething present; "And Alfheim the gods to Freyr once gave / As a tooth-gift in ancient times" (Bellows 88).
Svartalfheim
This is the world that I really wanted to get to. In my breakdown of Yggdrasil I mentioned that sometimes the dwarves are included in Svartalfheim and others in their own realm called Nidavellir. Nidavellir is mentioned in the "Poetic Edda"; "Northward a hall in Nithavellir / Of gold there rose for Sindri's race" (Bellows 16). Sindri is a famous dwarf known for his goldsmithing skills, so it is referring to dwarves. But, northward implies being closer to Niflheim, whereas Svartalfheim is underground. This is the only time Nidavellir comes up in the Eddas, a lot less than Svartalfheim. Svartalfheim and dwarves are mentioned a few times in the "Prose Edda," once during the story of the Fenris wolf and again in Otter's Ransom. While thinking of ways to bind the wolf Fenrir, "All-Father (Odin) sent Skirnir, Freyr's messenger, down to Svartalfheim, and there he had some dwarves make the fetter called Gleipnir" (Byock 40). And in the story of Otter's Ransom, "Odin sent Loki into Svartalfheim, and there he found the dwarf called Andvari" (Byock 95). So, as far as I am concerned, Svartalfheim is the home of the dwarves and the dark elves. Nidavellir may just be a place where other dwarves have settled.
I have also heard the argument that dark elves and dwarves could possibly be the same thing. In the description of the light elves, one of the dark elves is offered too. The dark elves "live down below in the earth" and "are blacker than pitch" (Byock 28). But dwarves are given a much different description as they are being created: "They were maggots at that time, but by a decision of the gods they acquired human understanding and assumed the likeness of men, living in the earth and the rocks" (Byock 22), or more simply put, "There was Motsognir the mightiest made / Of all the dwarfs, and Durin next; / Many a likeness of men they made, / The dwarfs in the earth, as Durin said" (Bellows 6). So dark elves and dwarves may live in the same realm, but they certainly aren't the same beings.
Jotunheim
Pronounced with a soft J, Jotunheim is the home of the giants. Like I said in the description of Midgard, Jotunheim shares a border with the land of men, just beyond the sea; "On these ocean coasts, the sons of Bor gave land to the clans of the giants to live on" (Byock 17). This is why Midgard has fortressed walls. Not too much is said about Jotunheim, though it is the origin of some important mythological characters, such as Utgard-Loki and Hrungnir, both of which are giants who have encounters with the gods.
Muspellheim
Muspellheim is the primordial land of fire and heat. It is the southernmost world, the exact opposite of Niflheim, and "is bright and hot. That region flames and burns and is impassable for foreigners" (Byock 12-13). Muspellheim is one of the two oldest worlds, and I will talk about it more when I cover the creation of the world and Ragnarok. The fire giant Surt defends this land, and "fares from the south with the scourge of branches, / The sun of the battle-gods shone from his sword" (Bellows 22). The demons of this land led by Surt will march against the gods at Ragnarok.
Niflheim
Niflheim is the other half of the primordial worlds. Literally the "land of mists," Niflheim "was made many ages before the earth was created, and at its centre is the spring called Hvergelmir" and "coldness and all things grim came from Niflheim" (Byock 12-13). This realm is often confused with Helheim.
Helheim
Also known as Niflhel or just Hel, Helheim is the realm of the dead. Niflhel is used more than any other name and is described as "The home where dead men dwell" (Bellows 80). It is arguable that Hel and Niflhel are two different places, since "evil men go to Hel and from there into Niflhel, which is below in the ninth world" (Byock 12). This again brings about the question of exactly how many worlds there are.
The ruler of Helheim is Loki's daughter, Hel, which is where the name of the world comes from. But, when Hel was born, Odin "threw [her] down into Niflheim and made her ruler over nine worlds" (Byock 39). This is why Hel, the place, is usually confused with or directly associated with Niflheim. It may be that Helheim is directly, or in some way, below Niflheim (as the picture above places it). A listing of the rivers that flow from Hvergelmir, the well in the middle of Niflheim, ends with "And hence they fall to Hel" (Bellows 95). As well, when the roots of Yggdrasil are being mentioned, "'Neath the first lives Hel" (Bellows 97), which corroborates this idea of Helheim being below Niflheim, since the first root is fed by the well Hvergelmir. But, passages that mix elements from both Niflheim and Helheim are still present, such as this: "I saw there wading through rivers wild / Treacherous men and murderers too, / And workers of ill with the wives of men; / There Nithhogg sucked the blood of the slain, / and the wolf tore men" (Bellows 17). The dishonored dead go to Hel, those treacherous men and murderers too. However, Nidhogg (or Nithhogg) is the dragon-serpent that bites at the root in Nifheim, and the wolf mentioned is likely the bloody Garm, who guards the gates of Hel. So, even though some of the texts allow for a logical placement of the two realms, one atop the other, there is still overlap.
So those are all nine of them. The traditional nine, to be specific. As I have pointed out, it can be hard to tell which ones are which in some cases. Norse cosmology can be confusing, especially since most of the information about the universe comes from one man, Snorri Sturluson. Let's just say he wasn't always as careful with his world(s) as Tolkien was.
Keep thinking, my friends.