The fading of the star Betelgeuse and the myths of ancient Ireland

The fading of the star Betelgeuse and the myths of ancient Ireland

The recent fluctuation and fading in the brightness of the star Betelgeuse in Orion prompted me to have a look at ancient Irish myths which might pertain to this constellation and its bright red star.

I was thinking about the recent fading of the red giant star Betelgeuse in the shoulder of Orion. The star is known to fluctuate, in short cycles of 14 months and longer cycles lasting about six years, according to the New York Times.

A view of Orion taken in 2013. Betelgeuse, the upper left "shoulder" star, is clearly brighter than the right shoulder star Bellatrix.

However, since October 2019 it has faded dramatically, and is now dimmer than it has ever been recorded. In the space of a couple of months, it has fallen down the list of brightest stars from 10th position to 21st. It generally glows at magnitude +0.5, but is now at +1.5. This drop makes it equivalent in brightness, or close to equivalent, with Bellatrix, the “other shoulder” star in Orion.

A close-up photo of Orion taken 15th January 2020. Betelgeuse is now only the same brightness as Bellatrix.


The effect of all this is that Betelgeuse is noticeably fainter than usual. I first noticed this in December while looking at the constellation on a clear night when it was in the southeast. I thought that Betelgeuse appeared strangely dim and so when I returned to the house, I performed an internet search and quickly saw that there were some news articles online which referred to its recent decline in brightness.

One of the attendant risks associated with this considerable fall in brilliance is that Betelgeuse, being a red giant star and thereby being near to the end of its life, could be on the verge of exploding and becoming what astronomers call a supernova. This is the dramatic conclusion that will come to many stars, including our own sun, at some point. But even though it is closer to death, Betelgeuse could still have as much as 100,000 years left before the inevitable conclusion of its life in a fiery, explosive demise.

Orion with the Dog Star, Sirius, in the sky over Mellifont, Co. Louth. Betelgeuse is prominent in this photo, taken a number of years ago.


Although we have little direct reference to constellation names in old Irish mythology, it is likely that Orion held the same illustrious stature as one of the great star groupings of the night sky for the ancient Irish as it did, for example, with the Sumerians, Babylonians and Egyptians. The name Orion derives from the legendary hunter of Greek myth.

I have written about some of the likely identities of Orion in ancient Irish mythology in some of my books, most notably in Island of the Setting Sun: In Search of Ireland’s Ancient Astronomers, and in Newgrange: Monument to Immortality.

In the former, I suggested that the constellation we know as Orion today might have provided the inspiration for great deities or characters of Irish mythology such as the Tuatha Dé Danann sky god Lugh/Lug, the great warrior of the Ulster Cycle mythology, Cúchulainn, and others, including Amergin Glúngeal (Amergin of the bright-knee, perhaps Rigel?) and Núadu Airgetlam (the Tuatha Dé Danann king Núadu of the Silver Arm).

Núadu Airgetlam

The latter was brutally mutilated in the first battle of Moytura, when Sreng son of Sengann cut his arm off. Because of this great blemish, Núadu was duty-bound to abdicate the kingship. The sovereign could only rule unblemished, and any disfigurement of the king would be deemed a stain on the land. Núadu yielded the kingship of the Tuatha Dé Danann to Bres, whose lineage was tained with Fomorian blood and whose reign was disastrous for the Tuatha Dé Danann.

One scholar aptly summarises the dire reign of the Fomorian interloper: “…Bres’s reign offers a paradigm of incompetent kingship. Seeking only his own profit and having no concern for the well-being of his people, Bres ignores his subjects’ proper social roles and status: practitioners of the arts receive no recognition from him, and the warrior Ogma is forced to serve as a supplier of firewood. The Dagda, master of druidry, becomes Bres’s rath-builder, and is faced not only with his assigned task but with the loss of his food to the extortionate satirist Cridenbél.”(1)

Bres is responsible for plundering his own people. The Tuatha Dé Danann, fed up with his Bres, meet him and declare that he is no longer fit to rule. He asks them to allow him to remain for a further seven years, which they agree to. Bres flees to his father, Elatha, to ask him for an army of warriors, because he wants to take Ireland by force. Elatha agrees, and asks the dreadful Balor, King of the Fomorians, to lead a vast army against the Tuatha Dé Danann.

Behind the scenes, efforts at the reinstatement of Núadu’s arm, and hence his restoration to completeness, were – excuse the pun – “in hand”. The Tuatha Dé Danann healer, Dian Cécht, through the workings of his magical craft, would fashion a new arm for the flawed sovereign, made from silver!

The translation of Cath Maige Tuired (The Second Battle of Mag Tuired), from the text of a 16th century vellum manuscript which is based on Old Irish materials, says:

Now Núadu was being treated, and Dian Cécht put a silver hand on him which had the movement of any other hand.(2)

Orion, Taurus and the dog constellations, Canis Major and Canis Minor, over Dowth. January 2020.


But Dian Cécht’s son, Míach, did not like this solution, and through his magical incantation he made flesh grow upon the arm so that it appeared like a normal arm. (Through this act, he arouses jealousy in his father, who kills him).

The Fomorians amass a huge army: “No host ever came to Ireland which was more terrifying or dreadful than that host of the Fomoire.”(3)

However, Núadu, now being restored to perfection and his blemish removed, regains the kingship of the Tuatha Dé Danann, and a great feast is held for the TDD at the Hill of Tara.

Lug Samildánach

At this point, a mysterious warrior called Lug – the son of Cían son of Dian Cécht and of Ethne daughter of Balor – arrives at the door of Tara.

Lug “claims the right to enter the feast, which is restricted to practitioners of different arts, because he is the unique master of every art”.(4) Hearing that he is a true Samildánach, gifted in diverse skills and arts, Núadu invites Lug to enter, and empowers him with responsibility for co-ordinating the preparations of the Tuatha Dé Danann for their looming battle with the Fomoire. In fact, Núadu vacates his seat at the head of the feast and exchanges it with Lug until 13 days have passed.

Orion over Síd in Broga (Newgrange). February 2013. Betelgeuse is noticeably brighter than Bellatrix.


Lug’s role in the battle is decisive. The TDD are outnumbered, but his skill in marshalling the TDD warriors and in coordinating their expertise for the battle proves crucial.

“…the quality of Lug’s leadership and the effect of their unmatched abilities in the arts ultimately bring victory to the outnumbered Túatha Dé Danann”, and all this in spite of the loss of their king, Núadu, who is killed in the battle at the hands of the Fomorian king Balor.

“Although the Tuatha Dé Danann attempt to keep Lug from the battle for his protection, he escapes to join the fighting, encouraging his host with chanted spells; and at a turning point in the conflict, he faces his maternal grandfather in single combat, destroying Balor by casting a sling-stone at his evil eye, and thereby avenging the fallen Núadu.”(5)

The link with Orion

There are several aspects of the story of Núadu that make him an interesting candidate, in my view, for the constellation we know today as Orion. His name, I wrote in Island of the Setting Sun, might have meant “catcher”.(6)  Incidentally, a British cognate of Núadu was Nodons, to whom a temple was dedicated at Lydney in Gloucestershire. Ó hÓgáin says several representations of dogs were found at the temple, which suggest that Nodons was envisaged as a hunter.(7)

I visualised the constellation Orion with his upraised arm “controlling” or “throwing” the sun, moon and planets along the ecliptic or the path that these heavenly bodies appear to follow through the Zodiac. I saw Lug in a similar role to Núadu.(8) The only thing that changed was the epithet. In Núadu’s case it was Airgetlam “silver arm”. In Lug’s case, one of his epithets was Lámfada, “long arm”. I had an interesting explanation for this too. I suggested that “long arm” could portray the notion that Lug’s weapons had a long range rather than the concept of him having a long limb.

After Núadu’s wounding by Sreng, his armpit would have been red with blood, hence the reddish colour of the star Betelgeuse. His “silver arm” was affixed by Dian Cécht. I speculated in Island of the Setting Sun that the arm of Orion raised into the Milky Way above Betelgeuse was the silver arm of Núadu because there are several mentions in Irish mythology of silver chains and silver rivers which may refer to the Milky Way galaxy. A name given for the Boyne river in the Dindshenchas is Mór-Chuing Argait,(9) which means “Great Silver Yoke”, and might have also been a poetic kenning for the Milky Way. 

Two rivers of the white cow ... the Boyne river (below) and the Milky Way (above).


The link between the Boyne and the Milky Way becomes obvious through the respective etymologies of their names. The name of the Boyne river and one of the Irish names for the Milky Way have the same derivation. The Boyne is from Bó Fhinne, meaning the river of the “white cow”. Bealach na Bó Fhinne (Way of the White Cow) and Bóthar na Bó Finne (Road of the White Cow) are two old Irish names for the Milky Way.(10) 

It is interesting too that Núadu yields the throne to Lug (also spelt Lugh), who is pivotal to the success of the TDD in the Second Battle of Moytura. Lug wore the Milky Way as a silver chain around his neck.(11) He hurls a giant, grotesque weapon at Balor to win the war – the Tathlum, a huge ball made from the brains of his enemies hardened with lime. 

To the hero Lugh was given
This concrete ball – no soft missile –
In Mag Tuireadh of shrieking wails,
From his hand he threw the tathlum.
Orion pictured with the \'Voyager\' statue at Laytown in Co. Meath. Photo taken January 2020. Betelgeuse is noticeably dim.



If you were looking for meaning in a cataclysmic event like the explosion of Betelgeuse, you might find plenty of meaning in the Moytura legends. It is clear that the loss of Núadu’s arm, a seemingly mystifying episode in the story of the battles, is imbued with a more complex significance associated with sovereignty and the fulfilment of fate. It had long been foretold that Balor would be killed by his own grandson, and Núadu’s willing submission of the top seat at the feast of Tara (symbolic of, if not an implicit reference to, the throne), neatly suits the narrative of the wider storyline and the eventual routing of the Fomorian army by the TDD with Lug as their champion – even though Dé Dananns were vastly outnumbered by the Fomoire.

Núadu, despite being the king of the Tuatha Dé Danann and their trusted sovereign, falls twice in battle – the first time, to Sreng’s blade, losing his arm; the second, to the Fomorian king and overlord Balor, losing his life. 

Orion, with his faded shoulder star, and the Maiden\'s Tower, Mornington, Co. Meath. January 2020.


Balor’s fate was sealed years previously, when he locked away his daughter Eithne in a high tower on Tory Island, with a round-the-clock guard of 12 women. He did this because of a druidic prophecy that foretold that he would be killed by a grandson borne by his daughter. However, in another dramatic twist of fate, and indeed irony, Balor’s own desire for the magical cow Glas Ghaibhleann led to him stealing the animal from Cian. Cian’s revenge was to disguise himself as a woman and enter Eithne’s tower on Tory Island to seduce her. They made love and she bore three children to Cian, one of whom was Lug.

Having found out about the infiltration and the existence of grandchildren, Balor ordered them killed. Two were drowned but Lug alone survived.(12) Only by surviving could Lug fulfil the destiny that lay before him.

Myths of the stars

It may be possible that the Moytura myths were inspired, at least in part, by the night sky. The American doctor and visual astronomer Charles Scribner suggested to me 20 years ago that the numbers of those killed in Cath Maige Tuired “made good sense” in terms of long astronomical cycles.(13) My own thesis, compiled in conjunction with Richard Moore over eight years and published in our book Island of the Setting Sun: In Search of Ireland’s Ancient Astronomers, suggested that a number of Irish myths associated with prehistoric sites were inspired by stars, constellations and heavenly events.

Orion over Síd in Broga (Newgrange), taken March 2019, before the dramatic fading of the red giant star Betelgeuse.


The regular fluctuations in the brightness of Betelgeuse would undoubtedly have been noticed by the ancient astronomers. Were these incorporated into the myths inspired by the constellation that we know today as Orion? We can only guess, of course, and speculate. Given that there are aspects of Betelgeuse’s brightness variations that appear less predictable than its regular nuances (it is over 600 light years from us, so we cannot study it in any great detail), it might be possible that more severe variations in its luminosity cultivated a belief that unusual events in the sky were portents pertaining to human events.

The red star in the armpit of the king bled when Núadu lost his arm, but later the silvery arm embroidered with the glittering stars of the Milky Way was magically added by the healer Dian Cécht. When Núadu was killed by Balor, Lug took over as Orion, and using his upraised arm with its long reach, he hurled the tathlum (moon) at Balor’s baleful eye (the sun) and killed him.


My own hope is that Betelgeuse returns to its former brightness, and that it continues to blaze for my lifetime and for many lifetimes after I am gone. I could not bear to think about the constellation Orion without one of its bright gems, the gleaming red star Betelgeuse, that is the 10th brightest star in all the night sky…

References and footnotes

(1) Gray, Elizabeth (1982), Cath Maige Tuired, The Second Battle of Moytura, Irish Texts Society.
(2) Ibid.
(3) Ibid.
(4) Ibid.
(5) Ibid.
(6) Ó hÓgáin, Dáithí (2006), The Lore of Ireland: An Encyclopaedia of Myth, Legend and Romance, The Collins Press, p. 385. See also Murphy, Anthony and Moore, Richard (2006), Island of the Setting Sun: In Search of Ireland’s Ancient Astronomers, Liffey Press, p. 231.
(7) Ibid., p. 386.
(8) Murphy and Moore (2006), p. 228.
(9) For more about Milky Way names in Irish, see:
(10) McCionnaith, L., Foclóir Béarla agus Gaedhilge,1935, p. 824.
(11) Murphy, Anthony (2017), Mythical Ireland: New Light on the Ancient Past, p. 281.
(12) For more, see MacKillop, James (1998), Dictionary of Celtic Mythology, Oxford University Press.
(13)Personal communication (email), 31st July 2000.

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