The grand ballroom of the universe

There are a lot of galaxies in the universe, and like people on a crowded dance floor, they sometimes collide. The time it takes for the full collision to unfold is hundreds of millions of years, so what we see when we observe colliding galaxies with our telescopes are really just snapshots of particular moments during the collision. To try to understand the physics of galaxy collisions, astrophysicists often create sophisticated supercomputer simulations that match our observations of different stages of actual collisions; but instead of taking a hundred million years to play out, we can watch the whole thing happen in the space of minutes.

I love watching simulated galaxy collisions, and I think you’ll find them fascinating, too. It’s as though two galaxies decide to become partners in some cosmic ballroom dance. Even though the collisions are destructive, there is something so graceful and elegant about them that I always hear Mozart in my head as I’m watching.

I wanted my astronomy students to appreciate all this, so a few years ago I put together a video compilation of three galaxy collision simulations by astrophysicists at Case Western Reserve University and set them to one of my favorite Mozart symphonies. The simulations are sometimes paused mid-collision so that the “camera” can pan around to give us a look from different angles. Following each simulation there’s an image of an actual galaxy collision of that type so you can see how well the physics of the simulations matches what we observe in the universe.


Astronomy in a nutshell



If a flea paused in his epic journey through
the weave of the homespun trews of an ale-sodden
Hebrides husbandman, and bent its thoughts on the
grand design of the cloth, striving to grasp not just
the mechanics of the warp and weft of the loom,
but the overarching vision of the weaver, would
you be surprised?

If a single note in a symphony, battered and whirled
by woodwinds and violins, paused for a heartbeat
to consider and assemble a vision, not just of
the entire piece of music, but the conductor and
composer behind the oeuvre, would that raise an

Yet, astronomers, the carbon of their cellular
structures the product of some helpless exploding star
aeons ago, look out upon the entire cosmos, and ponder:
niggling away at countless points of light, in
search of a reason for every detail of its component
weave of light and sound; every aspect of its overall
structure bent by their basilisk gaze. All the while,
swept along willy-nilly on a tiny dust-mote planet,
scorched by an incandescent sun, gnawing on other
carbon life-forms for their sustenance, and quenching
their thirst with dihydrogen monoxide and knowledge
(and maybe beer as well).

The cosmos, looking down on this, can only gasp in
amazement at the unmitigated intrepidity, the
sheer audacity, of these tiny beings and their
grandiose goals and dreams. And that courage, that
vision, in a nutshell, is astronomy.

— G. P. Orris

Dwarf galaxy NGC 1569 image credit: NASA/Hubble

Our Earthly Flight


Our Earthly Flight
By  W. Carl Rufus

Our Earth is like a transport plane,
That carries wealth surpassing gold.
It trafficks not for paltry gain:
Its cargoes are not bought nor sold.

It holds its course around the sun;
Nor rolls, nor banks, nor stalls, nor spins.
Its yearly flight is never done;
When winter ends, the spring begins.

At eighteen-miles-per-second speed
Without an instrument in sight,
No stick to hold, no maps to read,
It travels on by day and night.

It bears a load of human freight;
From birth to death, men come and go.
They live and love, they toil and hate,
For good or ill, for weal or woe.

A billion walk its crowded ways:
And billions sleep beneath its sod.
But souls are safe through stormy days:
The unseen Pilot’s name is God.

Image credit: NASA’s Goddard Space Flight Center.


by Valerie Worth

While we
Know they are
Enormous suns,
Gold lashing
Seas of heavy silver flame,

They look as
Though they could
Be swept
Down, and heaped,
Cold crystal
Sparks, in one
Cupped palm.

Never trust an unstable AGB star…

The best passage from The Lord of the Rings and an astronomical reference to kick off the weekend.

An unstable asymptotic giant branch star is a low- to medium-mass star, like our Sun, in its final phase of fusing hydrogen into helium. At this point, it has burned through all of the hydrogen in its core and is only burning hydrogen in an outer layer. It becomes unstable when it begins to pulsate, after which it will puff off its outer layer into what’s called a planetary nebula. This is the fate of our Sun.

Here’s the Stingray Nebula, in case you were curious.

The Stingray Nebula. Credit: NASA, Matt Bobrowsky (Orbital Sciences Corporation).

Cloud City

Sorry, I got nothin’. Meanwhile, here’s one of Ralph McQuarrie’s concept masterpieces for The Empire Strikes Back. Click on the image for the full version.


In Starry Skies


In starry skies, long years ago,
I found my Science. Heart aglow
I watched each night unfold a maze
Of mystic suns and worlds ablaze,
That spoke: “Know us and wiser grow.”

And with each season’s ebb and flow,
My soul, with faltering steps and slow,
Still wanders up far-glimmering ways
In starry skies.

Nor do I heed Life’s gaudy show,
But onward, upward I shall go,
Until new star-lands meet my gaze,
And where, perhaps in after-days,
I’ll learn the things I long to know
In starry skies.

–Sterling Bunch

Goldsmith vs Williams

When I was a kid in the 1970s–1980s, it was a golden age for movie soundtracks, particularly in science fiction / science fantasy. Jerry Goldsmith and John Williams were giants in the genre, having composed two of the most memorable sci-fi themes of all time. Goldsmith is best known for the theme for Star Trek: The Motion Picture, which later became the theme for the television series, Star Trek: The Next Generation. Williams is known for many popular movie themes, including Raiders of the Lost Ark and Jaws, but is arguably best known for Star Wars. The names of these composers are practically synonymous with science fiction, but these composers could hardly differ more in style.

Goldsmith’s style is grand, remote, cerebral. In my opinion, he’s most responsible for the ‘spacey’ ambiance of hard sci-fi. In this piece from Alien (1979), called “Hypersleep,” there is a vague nautical element—you get the sense of a lonely ship navigating an endless cosmos. Like much of his space-music, it is stark and beautiful. This universe is cold in its beauty—it offers wonder, but no quarter.

In “The Cloud,” a piece from ST:TMP (1979), we get a sense of the enormity of the unknown entity heading for Earth and of the secret it contains. Again, there is a nautical element, highlighted by electronic whooshes that evoke memories of earthly oceans. The music is a little brighter here—the universe of Star Trek is less harsh and hostile than that of Alien, but no less grand and mysterious.

In contrast, Williams’ style is robust, familiar, romantic. It is evocative of adventure, human relationships, and spirituality. Consider this piece from Return of the Jedi (1983), which frames the moment when Luke reveals to Leia that they are brother and sister. This piece, like most of Williams’ compositions, is suffused with warmth and emotion.

“Tales of a Jedi Knight / Learn About the Force” (Star Wars, 1977) is no less filled with awe and mystery than Goldsmith’s “The Cloud,” but it is more optimistic and tinged with a sense of adventure. Here we have the budding relationship between a master and his young apprentice. With Williams, you don’t get the sense of a harsh and hostile universe, but one in which purpose and hope are woven into the fabric of its cosmos, even while it is momentarily under the sway of a dark and oppressive force.

Though Goldsmith and Williams differ in style, they have one element in common—the sense of awe and grandeur they convey through their compositions. It’s impossible to imagine the universes of Alien, Star Trek, and Star Wars without the character and dimension of their music.

Canis Major

Ground-based image of Orion, Canis Minor and Canis major [Credit: Akira Fujii]

Ground-based image of Orion, Canis Minor and Canis Major [Credit: Akira Fujii]

The great Overdog
That heavenly beast
With a star in one eye
Gives a leap in the east.

He dances upright
All the way to the west
And never once drops
On his forefeet to rest.

I’m a poor underdog,
But to-night I will bark
With the great Overdog
That romps through the dark.

–Robert Frost

A Star Wars legend passes away

Legendary graphic artist, Ralph McQuarrie, passed away on Saturday at the age of 82. McQuarrie is best known for the artistic visions he created for the Star Wars movies — from the iconic design for Darth Vader’s helmet to the sweeping vistas of Cloud City, he was responsible for much of the look and feel of the Star Wars universe.

I was introduced to that universe as a very young child, when my parents took me and my brother to see Star Wars during the summer of 1977. But it wasn’t until I saw its stunning sequel, The Empire Strikes Back, that this fictional universe had any significant impact on me. By the summer of 1980 I was old enough to cogitate on the visions before me, and I remember being completely blown away by Empire, particularly the scenes that took place on Cloud City. I saw the movie many times that summer, and I simply could not get those visions out of my head. Not that I wanted to.

It was years later, when I became a collector of Star Wars memorabilia, that I came across several prints of McQuarrie’s concept paintings and realized from whose imagination those stunning visions emerged. So complete were McQuarrie’s concepts for the Star Wars universe, that George Lucas and the other directors didn’t merely use them as guides, but recreated them on the screen with astonishing faithfulness.

The adventures of three young people in a galaxy far, far away had almost nothing to do with astronomy or space science, but I was so swept away by what I had seen that for the first time in my life it got me thinking about outer space in a meaningful way. It was a very short journey from the fictional Star Wars universe to the real universe, and it eventually led to a career as a professional astrophysicist. In a way, I owe my passion for outer space to McQuarrie and his astonishing vision. May the Force be with him.