Sand and Stars

Pondering Time with Horologium


2 Sep 2016

I have a gorgeous old antique mantel clock (circa 1930s). I love my clock for the way its beautiful, melodious chimes add beauty to the hours, marking time. They marked life for somebody else, somebody before me. And they mark my life now. I love the old clock for its masterful mechanics and hand-craftsmanship that has allowed it to enjoy almost a century of timekeeping, with nothing but its key winding it up every few days. And above all I love it because it uses a pendulum as its timekeeping element…

… which of course, brings me to the wonderful constellations that the French astronomer, Nicolas Louis de Lacaille, put into our southern skies in 1752… Horologium… the clock.

He originally named the constellation Horologium Oscillitorium, to honour the Dutch polymath Christiaan Huygens who invented the first pendulum clock in 1656. The time-pieces previously in use had been balance-clocks, Huygens’ pendulum clock was regulated by a mechanism with a ‘natural’ period of oscillation and had an error of less than 1 minute a day, the first time such accuracy had been achieved.

Christiaan Huygens’ clock, in the Rijksmuseum, Amsterdam

Sadly, somewhere along the line, the constellation’s name lost its Oscillitorium, which is a real pity because with it went a pretty cool bit of astronomical history.

Now I will agree… Holorlogium isn’t a prepossessing constellation. Apart from its lucida, Alpha Horologii, it is but a sprinkle of 5th and 6th magnitude stars. But it’s what its namesake measures that makes it such a monumental constellation in my book… time.

No-one can stargaze and not ponder time. How could one not ponder time when you are sitting out there in the dark, looking up, conscious that you’re actually seeing the history of the universe brought to you by ancient photons? (And in some almost sci-fi convoluted time-thing, being able to look back into time and see a planetary nebula with its small dead sun-sized star wrapped in its nebulous death shroud… while at the same time knowing you’re seeing a vision of our own sun’s demise, five billion years hence.) 

When I am sitting out there, observing and focused, I’m used to the enormity of the astronomical time scales we are spanning in our telescopes. “Ahh… 70 million light-years to this galaxy… my goodness… but what a little beauty it is!” But when I step back and try to work out how to relate it to our human scales of time – time really is a very strange thing.

The Pleiades

Image credit Hubble Space Telescope
Pleiades. Image credit Hubble 
The gorgeous Pleiades that are grace our summer skies lie 411 light years away… their light set out right around the time Galileo was looking through the first telescope. 

M42, the Orion Nebula

Image credit ESA/Hubble
Image credit ESA/Hubble

The Orion Nebula’s light is 1500 years old and left Orion when Europe was in the Dark Ages, more than a thousand years before the invention of the telescope.

Omega Centauri

Image credit Hubble
Image credit Hubble

When the light left the magnificent globular cluster Omega Centauri, around 15,800 years ago, the walls of the complex of caves at Lascaux in France had been covered with a vast number of paintings of animals and, astonishingly, the stars of the Pleiades.

The Large Magellanic Cloud

Image credit Karl Henize, 1956

When the light left the Large Magellanic Cloud over 160,000 years ago, primitive hominids were beginning to evolve into homo sapiens. The facial features of modern humans were beginning to evolve – the skulls have a prominent forehead, flattened face and reduced brow that contrasts with the older hominids’ projecting, heavy-browed skulls. 

Andromeda Galaxy

Image credit ESO/Hubble

The hominid, Homo habilis, had established its fragile foothold on planet Earth when the light we see from the Andromeda Galaxy left over 2 ½ million years ago. These hominids had a brain volume of around 600 cubic centimeters, and had started to use stone tools regularly, created by splitting pebbles (hence their name).

Centaurus A 

Image credit NASA/ESA/Hubble
Image credit NASA/ESA/Hubble

That supernova that popped off in the galaxy Centaurus A in February this year? We’re talking geological timescales here on Earth… that star blew itself to smithereens while Earth was enjoying its chilly Middle Miocene Epoch, about 16 million years ago… and the titanic explosion’s light only arrived on our doorstep a few months ago.

NGC 1300

Image credit Hubble
Image credit ESO/Hubble

And then there’s beautiful galaxy, NGC 1300… its light left 70 million years ago, when Tyrannosaurus Rex still had another 5 million years to call himself the king of the planet.

Quasar 3C 273

Image credit NASA/ESA/Hubble
Image credit ESA/Hubble

I observed the quasar 3C 273 in Virgo through my 16” Dobsonian last year; a faint pinprick of stellar light. But when those photons left the quasar 3.2 billion years ago, our planet was just getting its first whiff of oxygen as photosynthesis kicked in thanks to cyanobacteria – blue-green algae. And knowing that pinprick of light is pure energy radiating from the intensely powerful centre of a distant, active galaxy, powered by a supermassive black hole feeding on gas was something to think about, let me tell you.   

And then there’s the other astronomical complexity with time – one that you are always aware of when out there peering at the universe through a telescope…

Pillars of Creation in the Eagle Nebulae

Image credit Hubble
Image credit ESO/Hubble

Take those iconic Pillars of Creation in the Eagle Nebulae, probably Hubble’s most famous photo. In the photo, we see them as they were 6,500 years ago. Astronomers have spotted shock waves moving through the system, suggesting that the Pillars have crumpled under the onslaught of these shock waves. We are looking at structures that no longer exist… in real time they’ve long since joined the dinosaurs… yet, in our time, there they are, still visible…

So yes, it was a visionary masterpiece for Lacaille to have stuck a clock up there.

Our Time

Lucius Annaeus Seneca(4BC-65AD)

Here is a philosophic pearl from the Roman philosopher Seneca (4BC-65AD) on our use of our life’s time:

“…You live as though you will live for ever. It never occurs to you how poorly provided you are. You squander time as though you had it in plenty, although the very day you devote to someone or something may be your last. You fear everything like creatures that must die, yet hanker after everything as though you could live for ever… Just as travellers are beguiled by a conversation or a book until they suddenly notice to their astonishment that they have arrived, so busy men never notice their uninterrupted and remarkably swift journey through life until they have reached their destination. … Time runs out inaudibly, intangibly, noiselessly, unrecognised and unfamiliar. Yet it is the most precious commodity and the only real treasure we possess. Your lifetime will make no sound. It will not remind you of its haste. Silently it will flow away… There is no more difficult art than that of living. But you must learn how to live while you live…”

Copyright © Susan Young 2016