Monday 14 October 2013

Andromeda Reloaded


It's getting to that time of year again when the 'Clash of the Titans' constellations fill the eastern night's sky; Pegasus, Perseus, Cassiopeia and of course Andromeda. Last night was a beautifully clear one and I managed to get a marginally better view of the Andromeda galaxy than I did last year before moving on to an utterly fruitless attempt to see Neptune through my plucky little telescope. So I thought I would repost this blog from last year on the history of its observation.

Andromeda Galaxy as photographed by  Isaac Roberts 1888
Enjoy:

Winter is coming as they say in Westeros and with the return of dark evenings I found myself on Saturday night scurrying back and forth from the garden where the trusty scope had been trained on the patch of sky above the neighbour’s fence, frowning at the scudding clouds.

At last the sky cleared at least for a while and I cranked, swivelled and twiddled my way through the rising constellation of Andromeda until finally I beheld a cloud-like entity amongst the stars. Having repeatedly checked that the object of interest was neither a rogue regular cloud drifting across my field of view nor a greasy spot on the eyepiece, I pronounced myself satisfied that I had indeed eyeballed the Andromeda galaxy and wished as usual that I had invested in a larger telescope. Even so, it was still another tottering step forward in my astronomical adventures and one has to start somewhere. 
Just then the clouds closed in once more and ended my observations for the evening and I retired to the comfort of the living room. Whenever I feel like grumbling about the limitations of my present technology I remind myself that the pioneers of astronomy would have killed to have a telescope as good my much disparaged 76mm and that they made incredible discoveries and deductions using far more primitive instruments.

The first man known to have observed the Andromeda galaxy did not even have a telescope. Abd al-Rahman al-Sufi, known in the west as Azophi, was a Persian astronomer living in Isfahan during the Tenth Century. Having studied and augmented the works of Ptolemy, Al Sufi compiled his own Book of Fixed Stars, which was completed in 962 AD. Within it he describes a small cloud located within the constellation of Andromeda.

The Constellation of Andromeda as pictured in the
Bodleian Library's copy of Al Sufi's Book of Fixed Stars
 
It was not until 1612 that the Andromeda galaxy was observed by a European astronomer; Simon Marius, who is best known for infuriating Galileo by claiming to have observed the moons of Jupiter prior to Galileo’s own discovery which he announced in his seminal Sidereus Nuncius of 1610. Marius’ claim to have been the first was largely discredited but his re-discovery of Andromeda stands as his signal achievement.

Andromeda, designated M31, is flanked by two satellite dwarf galaxies. The first of these M32 was discovered by French astronomer Guillaume le Gentil , who was perhaps the unluckiest man in the history of astronomy.

Le Gentil set out in 1760 to observe the 1761 transit of Venus from Pondicherry, India. Prevented from reaching his destination by the outbreak of war between England and France, Le Gentil was at sea at the time of the transit and his efforts to observe it from the deck of the ship in rough weather were hopeless. Undeterred, he determined to wait for the next transit in eight years’ time. He spent the intervening years fruitfully, travelling the Indian Ocean on mapmaking expeditions, carrying out astronomical observations and recording details of flora and fauna. When the time came around for the next transit, Le Gentil returned to Pondicherry only to be thwarted once more by storm clouds. His frustration can only be imagined. When at last he returned to France he found that he had been given up for dead and his relatives were squabbling over his estate.

That is the fate that often awaits astronomers. I had gone more than ten thousand leagues; it seemed that I had crossed such a great expanse of seas, exiling myself from my native land, only to be the spectator of a fatal cloud which came to place itself before the Sun at the precise moment of my observation, to carry off from me the fruits of my pains and of my fatigue.
Guillaume le Gentil 1769

Caroline Herschel
 
The second satellite galaxy of Andromeda, designated M110, was discovered in 1783 by Caroline Herschel, sister of William, who through the course of assisting her more celebrated brother became an accomplished astronomer in her own right. Caroline blazed a trail by becoming the first woman to receive a state salary for undertaking scientific endeavours.  As she moved from under her brother’s shadow and began to make her own independent discoveries Caroline identified eight new comets as well as the galaxy M110. Following her brother’s death Caroline, who never married, returned to Germany and lived to the ripe old age of 97, receiving a gold medal from the King of Prussia for her scientific efforts.

I was interested to learn that the reason all deep sky objects are given a number with a prefix M, is due to one Charles Messier - 1730-1817 - another good innings! Messier was a prodigious hunter of comets, indeed he discovered thirteen of the things and to aid fellow comet hunters he helpfully created a catalogue of nebulous objects in the night's sky. It is for Messier therefore that M31 and all other nebulous celestial phenomena are so named. For his achievements Messier received the Legion d'Honeur. He is buried in Pere Lachaise cemetery.

Charles Messier

Andromeda’s beautiful spiral structure was first elucidated by Welsh astrophotography pioneer Isaac Roberts whose magnificent long exposure photograph appears at the top of this post. It was taken in 1888 by mounting a photographic plate in the prime focus position within his twenty inch telescope housed in a purpose built observatory at the bottom of his garden.

Roberts had shown the  Andromeda galaxy  in detail but it was still thought to be a nebula within the Milky Way rather than an entirely separate and far more distant galaxy. The debate was soon raging however as to whether  our own galaxy comprised the universe entire or whether it was just one of many galaxies in an infinitely larger ‘island universe’. In 1924 Edwin Hubble, by observing the Andromeda Galaxy through the 100 inch Hooker telescope at Mount Wilson Observatory, discovered the means to settle the argument once and for all.
The Hooker Telescope under construction

Hubble identified the presence of Cepheid variable stars within the Andromeda Galaxy, whose brightness varies over time in regular pulses. By measuring their pulsation periods, Hubble was able to calculate their luminosity since the two are relative. By comparing the observed and expected luminosities of the stars, Hubble was able to deduce their distance from the earth at some 900,000 light years. He thus demonstrated that they were so distant that they must lie outside of the Milky Way, the size of which had already been estimated at 100,000 light years.  Hubble had proved that the universe was comprised of many galaxies and was a bigger place than anyone had previously imagined. Indeed he underestimated in his calculations, for Andromeda is now known to be two million light years away.

And when I think about that I am definitely impressed to have seen it at all!

Al Sufi's Book of Fixed Stars
The ordeal of Guillaume le Gentil
Edwin Hubble
You may also enjoy
http://slingsandarrowsblog.blogspot.co.uk/2013/03/by-jove-story-of-jupiter.html
 

 

 

Wednesday 2 October 2013

Turning back the tide - The rule of Julian the Apostate


Of all the rulers of the Roman world one of the most remarkable must be Julian the Apostate;  a man who sought to turn the clock back and restore Rome to a past glory which he believed had been lost with the coming of Christianity. It is difficult not to develop an admiration for Julian, who for a brief time turned the Roman world on its head. Ultimately Julian was unsuccessful in his efforts and has gone down as something of a failure who struggled against the tide of history but nevertheless he was a man of courage and integrity whose misfortune was perhaps to have been born too late.
 
The emperor Julian

Julian was raised to power by his cousin Constantius; last surviving son of the great Christianising emperor Constantine. The sole reign of Constantius over the Roman world began in 351 AD and soon became a reign of terror. Good men met their deaths as a result of vicious court gossip and were on occasion driven to rebel simply because they had been left with no other choice. Most infamous of Constantius’ informants was a man known as Paul the Chain, due to his ability to fabricate such a weight of evidence against even innocent men that it became inescapable. In such an atmosphere of dread then, grew up Constantius’ cousins Gallus and Julian. They had already seen every male member of their family murdered upon the accession of Constantine’s sons in a bloody purge reminiscent of the days of the Julio-Claudians. It must have seemed to them only a matter of time until they would be considered a threat and eliminated. Shortly after taking sole power however Constantius elected to make Gallus his junior colleague; investing him with the rank of Caesar and dispatching him to Antioch to administer the east. The new Caesar promptly embarked upon a reckless course of debauchery and corruption which led inexorably to his downfall. His growing unpopularity soon sparked a whispering campaign in the court of Constantius and Gallus’ days were henceforth numbered. Lured westwards to a conference with Constantius in 354, Gallus was intercepted by his cousin’s henchmen and found himself bound and beheaded like a common criminal. His body was then mutilated and his head sent to Constantius in Milan.

Given the fate of his half-brother, it must have been with some trepidation in the following year that the scholarly Julian, who had been living the laid back life of a student philosopher in Athens, received his call up; being elevated to the purple as Caesar in Gallus’ stead. Unlike his unfortunate sibling  Julian was not to be entrusted by Constantius with control of the east. Unwilling to risk his becoming a second Gallus, Constantius instead dispatched Julian westwards to Gaul whilst himself taking control of matters on the Danube frontier where the Sarmatians were making trouble.

On the face of it, the troops stationed on the Rhine might not have made much of the unassuming twenty four year old bearded intellectual sent to take over their destiny. He would not have seemed like much of a soldier but would prove to be something of a revelation, taking to military life like a duck to water.

In the campaigning season of 357, Julian found himself in command of a small army of thirteen thousand men tasked with taking the fight to the Alamanni who were at this time united under the strong leadership of a king named Chnodomarius. This strongman had extended his authority over seven other principle kings of the Alamanni and a number of lesser ones and had assembled an unusually large force with which he had advanced into Gaul. Julian was supposed to be acting in concert with a larger Roman force of twenty five thousand men under the command of the Master of Soldiers Barbatio, who as the experienced military man in the western theatre was in theory meant to be keeping an eye on the young Caesar. Instead Barbatio was busy doing everything in his power to undermine and hinder Julian, refusing to march to his aid and burning supplies and equipment required by his forces. Julian therefore found himself outnumbered by perhaps as many as three to one as he advanced to confront the Alamanni near Strasbourg.

Unperturbed and encouraged by his officers Julian attacked at dawn and a fierce battle developed. The Alamanni had the best of the early action, routing the Roman cavalry on the right wing. Julian himself rallied the fleeing horsemen and led them back into the battle where the Alamanni, led by their kings, were battering the Roman infantry with sword and axe and the Romans were desperately hanging on. For a time the battle hung in the balance but as the barbarian horde began to lose cohesion, the superior discipline of the Romans began to tell and the Alamanni were driven back against the banks of the Rhine where many drowned attempting to escape. Chnodomarius was captured and sent to Rome where he died a prisoner. It was a glorious victory which shattered Alamannic power for a generation and confirmed Julian’s military reputation whilst cementing the loyalty of his troops. He continued to lead them in punitive expeditions against the Alamanni and the Franks, who were also stepping up their incursions into northern Gaul.

Julian crowned - 19th century engraving depicting the raising on a shield

In the following year the Persians under their new king Shapur II made a serious incursion into Roman territory. Shapur had subjected the city of Amida on the Tigris to a vicious sack after the son of one of his client kings was skewered by a bolt from a Roman catapult, having ridden too close to the walls of the besieged city in order to taunt the defenders. As Constantius prepared to respond, he requested that Julian send him several units of auxillia from his own forces to augment the effort against the Persians. Julian pointed out that these Gallic units had received guarantees as part of their terms of enlistment that they would not be asked to serve beyond the Alps. Constantius nevertheless insisted and Julian had no choice but to comply with the predictable result that his troops rioted. Surrounding his headquarters they demanded that Julian show himself and when he appeared before them they loudly proclaimed him as Augustus. We are told that Julian accepted his elevation only with great reluctance and attempted to placate Constantius with assurances that the army had left him with no choice but to acquiesce to their wishes. An outraged Constantius was having none of it and demanded that his upstart cousin renounce the purple at once, upbraiding him for his ingratitude and reminding him that it was he who had arranged for Julian’s care and education when he had been an orphaned child. This last outrageous statement was too much for Julian who incredulously declared to his troops that it was because of the murderous conduct of Constantius and his brothers that he had been made an orphan in the first place. Now he raised the standard of revolt and marched against his cousin; launching a lightning campaign which saw his troops reach the Danube and lay siege to the city of Sirmium before word reached Constantius that he had even left Gaul. In Rome the Senate acknowledged Julian as their sovereign and were gratified by the respectful tone in which he addressed his communications to them. Constantius at last responded to the threat and began to make his way westward. On his way to confront Julian however he fell ill and died at Tarsus in 361. On his deathbed he acknowledged  Julian as his rightful successor, sparing the empire further bloodshed.

From unlikely beginnings the scholar turned soldier had found himself as master of the Roman world. Julian now lost no time in setting about turning the clock back, for in what had become a largely Christian empire, the new emperor was unashamedly pagan.  The old temples were reopened and across the empire smoke rose once more from sacrificial alters. Where pagan temples had been demolished to make way for churches the process was reversed and the Christians made to foot the bill. The Jews too were given permission to rebuild their temple in Jerusalem although this was never accomplished. When Syrian Christians retaliated against these measures by allegedly burning the temple of Apollo at Daphne there were ruthless reprisals but generally Julian sought a return to tolerance rather than persecution. The emperor understood that this was a more sensible policy since oppression would only unite the Christians whereas allowing schismatic groups to practice freely would deepen their divisions. Naturally the emperor favoured fellow pagans over Christians and many who had been appointed to positions of authority now found themselves out of favour. Julian also barred Christians from educating the young since he considered them unfit to do so by virtue of their rejection of the classical past. All of this naturally made the new emperor deeply unpopular with the Christian church although the Senate enjoyed something of a renaissance under Julian, who showed them more respect than any emperor had for generations as he indulged his nostalgia for the old Republic.

Julian the philosopher emperor

In  363 Julian prepared to invade Persia. He was keen to emulate the achievements of Alexander and Trajan whom he greatly admired and hoped that by doing so he could usher in a new golden age in which the gods and the fortunes of Rome would be restored. To this end he assembled a substantial force of perhaps as many as sixty thousand men, to be supplied by a thousand barges which would make their way down the Euphrates and strike at Ctesiphon. A second force of thirty thousand men were to advance from Armenia supported by the Armenian king in order to draw the forces of Shapur northwards whilst Julian swept down upon the poorly defended Persian capital.

At first everything went well as Julian’s army marched down the Euphrates overcoming all opposition and capturing the Persian strongholds that stood in his way. The emperor was conspicuous in his daring to the point of recklessness, missing no opportunity to be at the heart of the action and exposing himself to danger.  On one occasion Julian was surprised by two would-be Persian assassins whilst on a scouting mission and fought them off; felling one of the assailants with a sword thrust.

As the army drew closer to Ctesiphon, Persian resistance stiffened and the pace of advance slowed. The Romans nevertheless continued to clobber their way into the fortified towns along the Euphrates with ram and ballista or sometimes negotiate the garrisons’ surrender through the persuasive eloquence of Hormisdas; an exiled Persian noble with a tenuous claim to the throne who perhaps hoped that Julian would place him upon it.

The defence of the capital had been entrusted to the Surenas; Shapur’s leading general. His forces now began to harass the column and to burn crops in the Roman line of advance but Julian pressed on unperturbed, comfortably supplied from his barges. He made use of a disused canal which had originally been dug by Trajan in order to move his fleet from the Euphrates into the Tigris so that they could continue to support his advance. The approach to Ctesiphon was guarded by a formidable fortress by the name of Maogamalcha to which the Romans laid siege. With the chances of success for a direct assault looking slim, Julian’s engineers commenced digging a tunnel under the walls. Julian’s forces then mounted a diversionary attack on the walls whilst a force of fifteen hundred picked men made their way through the tunnel and emerged in the unsuspecting enemy’s rear, overwhelming the surprised defenders and opening the gates.

The army moved on to the old capital of Seleucia where they forced a crossing of the Tigris at night. The attack almost met with disaster when the advance party sent across the river was intercepted by the Persians and their boats were set ablaze. Thinking on his feet, the emperor announced to his troops that the fire that they could see across the river was the agreed signal for a successful landing and ordered them all forward. Those who could not make it into a boat swam across using their shields as floats and the Persians were beaten back. The Romans then engaged the forces of the Surenas in battle within sight of the walls of Ctesiphon. The Romans had the best of the battle with Julian fighting in the front line and the Persians fled into the city.

With victory in sight however, the expected troops who were supposed to be advancing from Armenia failed to materialise and without them Julian was not confident of taking the Persian capital. Neither however was the emperor ready to make peace and he rejected envoys from the Surenas. Persuaded instead by Persian deserters who encouraged him to march further into their land with assertions that support for Shapur would crumble in the face of a bold Roman advance, Julian gave orders for the fleet to be burned, since it could not make its way back up the Tigris against the current.

The soldiers were much disheartened by this turn of events as they marched away from the smouldering remains of their fleet, advancing through a land stripped bare of supplies. The Persian deserters, who in reality remained loyal to their king, treacherously led the Romans in circles and then abandoned them as Shapur’s army moved in. Now desperately short of supplies, Julian decided to retreat towards the Tigris. As the Persians harassed the Roman column Julian once again became careless of his personal safety and whilst leading a counter attack was fatally wounded by a javelin. It took the emperor several hours to die, facing death calmly and stoically and declaring that he had no regrets. He named no successor and only expressed his hope that a suitable candidate may be found.

So passed Julian the Apostate, one of the most remarkable men to rule over the Roman world and one whose passing marked the end of an era. His attempts to turn back the tide of Christianity died with him as did his dream of reviving the military glories of the past. From here on in Rome would be on the defensive.
 
Monument of Shapur II thought to depict the fallen Julian
 
Julian left no heir and since he was the last surviving male member of the house of Constantine there was no obvious choice of successor. The army settled on an obscure officer by the name of Jovian who seems to have been elected almost by accident and did little to distinguish himself subsequently. Shapur had the new emperor right where he wanted him and extracted from Jovian a most dishonourable peace in return for the army’s safe passage. And so the army turned for home. The remains of Julian were laid to rest in the city of Tarsus along the way.

Julian has left us one insight into his mind through his comic sketch ‘The Caesars’ in which all the past rulers of Rome attend a banquet with the Gods of Olympus along with Alexander the Great. Whilst some are cast down for their crimes, the greatest amongst them compete for the recognition of the Gods as the foremost of their company. In the end Caesar, Augustus, Trajan, Marcus Aurelius and Constantine make their cases. Caesar and Alexander bicker like schoolboys over the top honours but Julian’s admiration for both shines through. Augustus shows himself to be wise and Trajan is too quick tempered whilst Constantine ends up as a laughing stock. It is Marcus Aurelius however whom the Gods most favour. Of all his predecessors, it was the philosopher emperor whom Julian most admired and most closely sought to emulate. I should like to think that when Julian took his own place amongst the Caesars at the great Olympian banquet, he gave a good account of himself and was not found wanting.

The trial that begins
Awards to him who wins
The fairest prize to-day.
And lo, the hour is here
And summons you. Appear!
Ye may no more delay.
Come hear the herald's call
Ye princes one and all.
Many tribes of men
Submissive to you then!
How keen in war your swords!
But now 'tis wisdom's turn;
Now let your rivals learn
How keen can be your words.
Wisdom, thought some, is bliss
Most sure in life's short span;
Others did hold no less
That power to ban or bless
Is happiness for man.
But some set Pleasure high,
Idleness, feasting, love,
All that delights the eye;
Their raiment soft and fine,
Their hands with jewels shine,
Such bliss did they approve.
But whose the victory won
Shall Zeus decide alone.


The Caesars

Ammianus Marcellinus on Julian

You may also enjoy: Justinian II - Mad, Bad and Dangerous
http://slingsandarrowsblog.blogspot.co.uk/2013/02/justinian-ii-mad-bad-and-dangerous.html


I was lazy for this article and reused material from my own book The Battles are the Best Bits, but if you liked it please check out the book.