The Norse sun-goddess, far from being some sort of Northern aberration, is very similar to other Indo-European sun deities. This shouldn’t come as a surprise, since “basic” deities like the sky, earth and rivers tend to keep their characteristics across a very wide swathe of Europe and Asia.
Whether you accept the idea that there was originally one people who spoke an IE language, or several who shared a language family, it is clear that their basic mythological concepts did not change.
In fact, the IE sun-deity, whether male or female, is remarkably consistent. (And while feminine ones are common in northern and western Europe, the Anatolian Hittites also worshipped a sun-goddess, who is consistent with the others.)
The chart below puts Sol (Norse) against two other well-known solar deities: Helios (Greece) and Surya (India). (An x means a definite connection, a ? means a possible connection, and —– means no connection found.)
Sun and son (or daughter): all three have a younger version of themselves as a son or daughter. However, the three are very different. Both Sol and Surya have daughters, both rather obscure. Helios has a son, Phaethon, and a father, Hyperion.
Sol’s daughter doesn’t have a name, that we know of, but we know that she will drive the sun’s chariot after the new world emerges from the ashes of Ragnarök. Helios, like Sol, has a younger self of the same gender, but Phaethon famously screwed up when he tried to drive his father’s chariot, and had to be killed by Zeus before he could burn up the earth. Suryaa, the Indian sun-god’s daughter, is the most obscure, as she appears only in one hymn in the Rig Veda, and a few other texts. She functions as a model bride, who is given by her father to the twin Asvins. The Indian version doesn’t keep the gender pattern of the other two.
Wheel: West speculates that before the sun became a chariot driver (before the technology became available), the sun was a wheel, or was symbolized by a wheel. Bronze Age art is the clearest expression of this, showing the sun as disc or wheel, or cross in a circle. (Mary Cahill of the National Museum of Ireland has an interesting article on how solar phenomena may have influenced Bronze Age art.)
There are other remnants of this idea in the various mythologies. The Norse sun-goddess is named fagrhvel, Fair Wheel, in the Eddic poem Alvissmal. The non-Eddic poems Harmsol and Liknarbraut also refer to the sun’s and moon’s wheel. (West: 202)
In the Rig Veda the storm-god Indra triumphs over Surya by stealing or breaking his chariot wheel, which keeps the sun from travelling across the sky. This may make you think of those clocks where the woman and man alternate to tell the weather, but apparently it reflects tensions in Indian society. (Puhvel: 61)
Chariot: most solar deities across the I-E world (and some others) used the most up-to-date status vehicle, the chariot drawn by horses. The Romans, who were a bit literal-minded, and very into racing, made the sun and moon patrons of charioteers, and an ancient temple to Sol and Luna stood the Circus Maximus.
Sometimes the horse(s) that draw the sun are named: Surya has Etasa (Swift) while Sol has Árvakr and Alsviðr (Early-Awake and All-Swift). Surya, too, is described as “possessing swift horses” in the Rig Veda, although the number varies widely, from two to a hundred. Helios, however, had a quadriga, or tethrippon, with four horses. (Although the most famous image of a sun-chariot makes do with just one: the Trundholm Chariot.)
The sun is also often called “swift”, both in the Rig Veda and the Greek writer Mimnermus (West: 198). The Scandinavian Prose Edda puts a slightly different spin on it, implying that the sun goes as fast as she does because of the giant wolf pursuing her across the sky.
Boat: this a less common image, although it does appear in the Rig Veda, which says of the Sun, “O Aditya, thou hast boarded a ship of a hundred oars for well-being”. In Scandinavia, the sun’s boat features mainly in Bronze Age art, especially on bronze razors found in Denmark, two of which show a both a ship and the horse, as well as the sun-disc. (Gelling and Davidson: 133, fig. 58b) Helios, on the other hand, gets back to the east every night in a golden goblet, although some have suggested that it may be a coracle. The early poet Mimnermus says that he sleeps as it carries him back across the river Oceanos every night, which sounds comfy.
All-seeing: Homer in particular refers to Helios as “all-seeing”, and the Homeric Hymn to Demeter also calls him “watcher of gods and men” (62). The Roman PIndar, too, calls Sol/Helios “far-sighted”. (West: 198) Ovid, too, has the sun call himself “the eye of the world”. Surya, too, is “wide of vision”, and “all-seeing”.
Both Helios and Surya have an ethical aspect: as all-seeing gods they watch the behaviour of gods and men – it is because of this that Helios knows that Hades has kidnapped Persephone, and can tell Demeter about it. There is little trace of this in the Norse material, although West finds it in the Old English poem The Phoenix, where the sun woruld geondwlited, “surveys the world”. (199)
Oath-swearing: Swearing oaths by the sun seems to have been common enough in ancient Greece that even cheeky Hermes, after stealing Apollo’s cattle, swears he did not, “I reverence Helios greatly and the other gods”. (Homeric Hymn to Hermes) There are no references in the Vedas to oath-swearing, but Surya is said to keep to cosmic law. (RV 3.30.12)
There are few references to swearing by the sun in Norse literature, although in the Atlakvida, thought to be one of the older Eddic poems, Gudrun reproaches Atli for breaking “the oaths you swore often to Gunnar and pledged long ago by the Sun southward-curving and by Odin’s crag.” The Franks, too, continued to swear by the sun even after conversion to Christianity.
Puhvel, Jaan 1987: Comparative Mythology, John Hopkins University Press.
West, M. L. 2007: Indo-European Poetry and Myth, OUP.