365DaysDate: February 14, 2009


Title: Astronomical References in Shakespeare

Podcaster: Robert Knop

Organization: The Meta Institute of Computational Astronomy

Description: Shakespeare’s plays are full of the occasional astronomical reference.  Whether it is a reference to “the stars”, a specific referenced to the number of stars in the Pleiades, or even a veiled reference to a famous historical supernova, you hear many of his characters invoking the sky throughout his plays.  In this podcast, I’ll discuss several of the references that are found in Shakespeare’s tragedies.

Bio: Rob Knop obtained his PhD from Caltech in 1997, doing infrared observations of Seyfert Galaxies.  He then worked with the Supernova Cosmology Project, and was a co-recipient of the Gruber Prize in Cosmology for the discovery that the expansion of the Universe is accelerating.  From 2001 to 2007, he was an assistant professor at
Vanderbilt University.  Today, he works for Linden Lab, the creators of Second Life.  He continues his astronomy avocation with MICA, the organization of professional astronomers and other interested people that is based entirely in virtual worlds, including Second Life.  His occasional blog is at

Today’s Sponsor: This episode of “365 Days of Astronomy” is sponsored by Jeff Pollock, who would like to dedicate this podcast to his beautiful wife, Janell who works as a planetarium lecturer at the University of Wisconsin, Stevens Point and his 3 children Payton, Julian and Maesyn who listen to this podcast every night at bedtime. Daddy loves all of you and hopes you have sweet dreams each and every night.  “Happy Valentines day Janell you are the love of my life.”


Two households, both alike in dignity,
In fair Verona, where we lay our scene,
From ancient grudge break to new mutiny,
Where civil blood makes civil hands unclean.
From forth the fatal loins of these two foes
A pair of star-cross’d lovers take their life;

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Happy Valentine’s day!  I am Rob Knop, associated with MICA, the Meta Institute of Computational Astronomy.  You can find us on the web at, and in Second Life in the StellaNova region.

The lines I quoted at the beginning of this podcast are the opening lines from the prologue of Shakespeare’s Romeo and Juliet.  The description of “star-crossed lovers” is but one of many astronomical references that are scattered  throughout the works of the Bard.  Of course, strictly speaking, this reference is more astrological than
astronomical.  The notion that the positions of the stars could have an influence on our destiny was taken more seriously in Shakespeare’s day.

Today, of course, we know that there is nothing to astrology.  However, given that another famous person of  Shakespeare’s era, one Johannes Kepler– who gave us laws of planetary motion that we still use today–
also made money as an astrologer, I think we can excuse a scholar of a few centuries back for mixing his astronomical references with astrology.

There are two ways in which Romeo and Juliet are “star-crossed.”  First, coming from two rival families, they are not likely to come together in the first place… but it was their destiny that their paths should cross.  However, as we know, the play does not end well for these fine lovers, and the term “star-crossed” also suggests that these lovers have
a destiny that curses them.

There are of course numerous other locations in Shakespeare’s plays where he seems to suggest the now-outmoded notion that our destinies are somehow controlled by the stars.  Consider what the Earl of Kent says in the play “King Lear”:

It is the stars,
The stars above us, govern our conditions;

In fact there is one star which is very important to the conditions of those of us who live on the Earth; that star, of course is the Sun. Ultimately, it is the energy of the light that shines from the Sun that powers most of the processes that life on Earth depends on.  It is the tilt of the Earth’s axis relative to its orbit around the Sun that
governs whether we are in spring, summer, fall or winter.

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Then again, you can also find quotes from Shakespeare which directly reject the notion that our destinies are controlled by the stars.  The most famous one is probably this quote, spoken by Cassius, in the play “Julius Caesar”:

Men at some time are masters of their fates:
The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings.

Of course, usually when you hear this quoted, it sounds much more humble.  If you stop after “but in ourselves,” the fundamental ambition of Cassius, revealed by “that we are underlings,” is not at all clear. But, indeed, for each of us today, whether or not we are the complete the masters of our own fates, the fault does not lie in our stars.

“Julius Caesar” is a play that has quite a number of astronomical references.  Caesar himself uses Polaris, the North Star, and its unwavering position in the sky throughout the night as a metaphor for his own resolve:

But I am constant as the northern star,
Of whose true-fix’d and resting quality
There is no fellow in the firmament.
The skies are painted with unnumber’d sparks,
They are all fire and every one doth shine,
But there’s but one in all doth hold his place:

It would seem that politicians of Caesar’s day– or, at least of Shakespeare’s day– were as afraid of being labelled a flip-flopper as are politicians of today!

In the play “King Lear”, Shakespeare makes another reference to a specific astronomical object.  In this case, Lear’s fool, speaking with the King, makes a reference to the Pleiades:

FOOL  The reason why the
seven stars are no more than seven is a pretty reason.

LEAR   Because they are not eight?

FOOL   Yes, indeed: thou wouldst make a good fool.

The Pleiades is a small sprinkling of stars you can see in the sky northwest of the constellations Orion and Taurus.  To the naked eye, you can see six or seven stars.  However, it turns out while the Fool is correct that there are not eight stars in the cluster, his conclusion that there are seven is not quite right.  With a pair of binoculars or a small telescope, you can see that there are in fact tens or hundreds of stars in the cluster.  All told, down to the dimmest members, the cluster contains more than a thousand stars.  They are all grouped together because they formed together out of a gigantic molecular cloud.  The cluster was formed 100 million years ago; while that sounds like a long time to you or me, it’s not very long compared to the multi-billion year life span of a typical star, including stars like our Sun.

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One of the most intriguing astronomical references in Shakespeare comes in the first scene of “Hamlet”.  The young prince is meeting with his friend Horatio and two castle guards, who are telling him of their having sighted a ghost.  One of the castle guards, describing the time when he last saw the ghost, says:

Last night of all,
When yond same star that’s westward from the pole
Had made his course to illume that part of heaven
Where now it burns, Marcellus and myself,
The bell then beating one, —

In 1998, a collaboration between Physics professors Don Olson and Russell Doescher, and English professor Marilynn Olson, of Southwest Texas State University suggested that the star to which the castle guard refers is in fact Tycho’s supernova which appeared in November of 1572.  A supernova is a tremendous explosion that occurs when a rare type of star dies.  They are very rare, but very bright.  There has only been one supernova that exploded in our galaxy and that was visible to the naked eye on Earth since Tycho’s supernova– and, ironically, that supernova was just a few decades later in 1604.

The 1572 supernova was in the constellation of Cassiopeia… the constellation which, at 1am in November, can be observed to be in the northern sky to west of the pole.  This is exactly where the star in “Hamlet”, called out as particularly noticeable by the castle guard, was seen.  Shortly after the supernova exploded, it would have been nearly as bright as Venus in the sky.  The appearance of this new star, one of the brightest things in the night sky, second only to the Moon and perhaps Venus, doubtless left an impression on the active mind of the child Shakespeare, who would go on to write his masterpiece nearly 30 years later.  It is too bad that the astronomy of Shakespeare’s day did not appreciate that the supernova was in fact not a new star, but rather the death of a star, for that would have made the symbolism all the more appropriate for the play.  After all, it is heralding the death of Hamlet’s father– one whom Hamlet saw as a shining example of a good king– which leads later to the complete collapse of the royal family of Elsinore into the body count that ends Shakespeare’s play.

This is a rather morbid way to end a podcast that started with “Happy Valentine’s Day,” but if you’re going to be talking about astronomical references in Shakespeare’s tragedies, you have to accept that things may not always end all that well.  Thank you for listening!

The excerpts from Tchaikovsky’s “Romeo and Juliet Overture-Fantasy” were performed by the Skidmore College Orchestra, and were provided to the public domain by

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365 Days of Astronomy
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