ᚦᛁᛅᛋᛅ ᛅᚢᚴᚢ þiasa auku

Þjazi's eyes: two stars thrown into the sky

To make peace with the giantess Skaði, the gods threw her father Þjazi's eyes into the sky as two stars. Which two, no source says.

Þjazi's eyes became two stars: Medieval source The two stars are Castor and Pollux: Modern guess

What the sources say

It is so said, that Odin did this by way of atonement to Skadi: he took Thjazi's eyes and cast them up into the heavens, and made of them two stars.
Skáldskaparmál, ch. 1, tr. Brodeur (1916)

Thjazi I felled, the giant fierce, / And I hurled the eyes of Alvaldi's son / To the heavens hot above; / Of my deeds the mightiest marks are these, / That all men since can see.
Harbarthsljoth 19, tr. Bellows (1923)

The names

ᚦᛁᛅᛋᛁÞjazi: a giant, killed by the gods after he stole the goddess Iðunn and her apples
ᛋᚴᛅᚦᛁSkaði: his daughter, who came to Ásgarðr armed to avenge him
ᛅᛚᚢᛅᛚᛏᛁAlvaldi: Þjazi's father (Hárbarðsljóð calls Þjazi 'Alvaldi's son')

Runes: our letter-by-letter spelling in the Viking-age Younger Futhark; these names come down to us in manuscripts written in the Latin alphabet. How we write runes.

The story and what it means

The giant Þjazi, in the shape of an eagle, forced Loki to lure the goddess Iðunn out of Ásgarðr with her apples of youth. Without them the gods grew old and grey, so they made Loki bring her back, and when Þjazi chased him home the gods lit a fire on the walls that burned the eagle's wings, and killed him. His daughter Skaði then came to Ásgarðr in helmet and mail to take revenge, and the gods paid compensation instead: she could choose a husband, though only by his feet, they had to make her laugh, which Loki managed with a goat and a rope, and her father's eyes were set in the sky.

The two sources disagree about who threw them. In Snorri's Skáldskaparmál it is Óðinn; in the poem Hárbarðsljóð Þórr boasts that he did it himself, and that the eyes are among the greatest marks of his deeds, that all men since can see. Both agree on two stars, and neither says which.

Modern books and websites usually name Castor and Pollux, the two bright stars of Gemini, the Twins. The idea goes back to Jacob Grimm, who suggested in his Deutsche Mythologie (1835) that the eyes were most likely two stars close together and of equal brightness, perhaps the Twins?; Cleasby and Vigfusson's dictionary (1874) repeated it as 'probably'. They are an obvious pair, 4.5° apart and high in the winter sky of the north. But it is a scholar's guess, not a tradition: nothing in Old Norse or later Icelandic sources links Þjazi's eyes to Gemini. On this site's charts Castor and Pollux carry the name with a question mark.

How sure are we?

Claim	Grade	Basis
Þjazi's eyes became two stars	Medieval source	Skáldskaparmál (Óðinn) and Hárbarðsljóð 19 (Þórr), 13th-century manuscripts.
The two stars are Castor and Pollux	Modern guess	Suggested by Jacob Grimm (1835) and repeated by Cleasby-Vigfusson (1874, s.v. auga); no medieval or folk source names the stars.

See it tonight

Castor and Pollux are best placed in the evening sky around February; in the evening from December to April.

City	Tonight, Mon 26 Oct (local time)
Reykjavík	Clear of the northeast horizon from about 21:45, highest around 06:45 (56° S)
Oslo	Clear of the northeast horizon from about 21:15, highest around 05:30 (60° S)
Stockholm	Clear of the northeast horizon from about 21:00, highest around 05:00 (61° S)
London	Clear of the northeast horizon from about 21:45, highest around 05:15 (68° S)
New York	Clear of the east-northeast horizon from about 23:30, highest around 06:15 (79° S)
Sydney	Clear of the northeast horizon from about 03:00, 25° up in the north-northeast as dawn comes

Castor is the slightly fainter of the two (magnitude 1.6, white); Pollux is brighter and orange-tinted (magnitude 1.2). Seen through a small telescope, Castor splits into a double star.

Sources

Texts: Skáldskaparmál ch. 1 (Brodeur; the story of Iðunn and Þjazi is told in Bragaræður, printed with Skáldskaparmál); Hárbarðsljóð 19; Haustlöng by Þjóðólfr of Hvinir (skaldic poem on Þjazi, quoted by Snorri). Quotations from the public-domain translations of the Poetic Edda by Henry Adams Bellows (1923) and the Prose Edda by Arthur Gilchrist Brodeur (1916); Brodeur's chapter numbers. Identification: J. Grimm, Deutsche Mythologie (1835; English tr. Teutonic Mythology, ch. XXII); Cleasby-Vigfusson s.v. auga and stjarna.