Donaldosaurus

Doctor Who is the longest running science fiction show in the world, first airing on November 23rd 1963. There have been significant gaps between series (the biggest being the 9 years between the mostly forgettable TV movie that was Paul McGann’s only filmed outing as the Doctor, and its triumphant return in 2005 with Christopher Eccleston), but the majority of adults in the UK will have grown up in a time when stomping Cybermen, whirring sonic screwdrivers, and the wheezing groan of a dematerialising TARDIS would have been regularly broadcast into the nation’s living rooms. My mother informs me that my brother and I would literally hide behind the sofa (if I recall correctly we had to push it out about a foot from the wall to provide ample cowering space) whenever Sylvester McCoy’s Seventh Doctor would run into the Daleks, a manoeuvre so commonplace it has become inextricably linked with the show.

A terrifying alien war machine, totally not made of ply wood and kitchen utensils

Looking back objectively on those earlier episodes with adult eyes, the Daleks seem no more threatening than a runaway shopping trolley in a supermarket carpark, but to my 10-year old eyes they were terrifying. They were slow and ungainly, but they never stopped, couldn’t be destroyed, and wanted nothing more than to kill anything that wasn’t Dalek. The look and sound of them was so firmly imprinted on my mind that when one appeared for the first time in the rebooted series, my reaction to it was primal. This was a half-remembered thing from my childhood that scared me then, and scares me now. The Daleks’ frequent outings in subsequent series has diluted the impact somewhat (hearing one rasp WOULD YOU LIKE SOME TEA? In ‘Victory of the Daleks’ probably most so), but thanks to its incredibly long run the show can continually reintroduce semi-forgotten elements that feel all the more vivid because they have such a history in the show.

If it just rehashed old monsters and ideas then the renewed show would likely have died along with Eccleston’s incarnation, but every series has boasted some incredibly well written episodes. The unlimited scope of Doctor Who, having the entirety of time and space to play with (a whole continuum, if you will) means that it can do an unparalleled range of ‘Monster of the Week’ episodes, and has birthed several new and inventive foes for the Doctor such as the Weeping Angels and the Silence.

Taken at the Doctor Who 50th Anniversary celebration in London, though I don't remember seeing this guy for some reason.

But for me what elevates Doctor Who above other equally well-written shows is how it weaves into almost every episode an overarching story arc that establishes an epic mythology for the character. Earlier Doctors occasionally hinted at a dark and troubled personality, but were mostly played as carefree and clowning. The post-reboot Doctors were damaged however, and their cracks showed much more frequently. Eccleston’s Nine was wracked with guilt at the genocide he had committed to end the Time War. David Tennant’s Ten showed what could happen to the Doctor when he was without the moderating influence of a companion, nearly exterminating a brood of Racnoss young in fury in ‘The Runaway Bride’, and declaring himself the  Timelord Victorious and above the laws of his own people in ‘The Waters of Mars’. In ‘Amy’s Choice’, Matt Smith’s eleventh Doctor deduces the identity of the mysterious figure tormenting him, saying to him ‘there’s only one person in the Universe who hates me as much as you’. The figure later turns out to be the manifestation of the Doctor’s own subconscious. Epithets like ‘The Oncoming Storm’ and ‘The Lonely God’ hint at an epic mythology surrounding the Doctor in the show’s universe. It’s this mythology that most appeals to me, and pulls me towards Doctor Who rather than something like Star Trek, probably the nearest sci-fi equivalent. Like the TARDIS, the Enterprise has had many different faces at the helm, and travels through space (and occasionally time) to meet strange aliens and visit bizarre planets, but Kirk et al are still constrained by laws and limits that Doctor Who gleefully oversteps, limited only by the imagination (and the BBC’s budget, admittedly a much tighter leash).

The problem with epic and apocalyptic storylines is that it’s hard to top the previous series’ events. Series finales have seen the Doctor preventing schemes to destroy Earth, then humanity, then reality, and eventually time itself by the end of David Tennant’s tenure. Matt Smith’s story arc centred around the answer to the question “Doctor Who?“, and tangled itself in knots regarding universes ending and being reborn, getting married to someone travelling in the opposite direction in time, and entering his own timeline (at the site of his own tomb) and meeting other Doctors from his past, to the extent that the only way to fully visualise the plot would involve a massive corkboard, coloured string and lots of pins. The show was in danger of collapsing under the weight of its own complexity and forming a black hole – something not helped by the aneurism-inducing anniversary episode at the weekend. I found I enjoyed it far more after I decided to stop worrying about why Doctor’s couldn’t remember the actions of their previous selves and just go with it.

(As an aside, my biggest disappointment in the episode, which I otherwise loved, was the small scale of the Time War. Previously, when the Time War had been referred to, it was rendered in broad strokes as a vast, Universe-encompassing conflict that by the end had descended into destruction on an unimaginable scale, unleashing such horrors as the Nightmare Child, the Horde of Travesties and the Could’ve Been King with his army of Meanwhiles and Neverweres. Which in the show turned out to be two armies going pew-pew with lasers.)

In that spirit I came up with some thoughts regarding the warp and specifically how it related to Tyranids. The warp is explained as something that is generated and formed by conscious thought. Presumably then it can only exist in any meaningful way where there is sentient life. Life can only exist in large numbers in galaxies, so the warp must exist in isolated pockets separated by the intergalactic spaces. (This might not be true, as the warp corresponds only loosely with realspace, but the spaces between galaxies are big enough that they’d probably be isolated).

As a sentient species (or at least, one that manifests psychic abilities) grows and matures, the emotions and desires of that race coalesce in the warp and inevitably give rise to chaos gods, or strengthen existing ones. The Eldar were all but destroyed when their unchecked hedonistic excess reached critical mass and created the warp entity Slaanesh. Mankind seem to be heading in a similar direction, albeit by strengthening existing gods (possibly because humanity is a more diverse race in terms of emotions and desire compared to the Eldar). Perhaps it is the natural life-cycle of an intelligent species to manifest psychic powers, colonise the majority of their host galaxy, and then in time be wiped out by the warp entities they spawn, leaving clear the stage for a later species to repeat the cycle. The universe is home to 400 billion or so galaxies (that we know of), which conjures the image of a void clustered with little islands of life, each with their own attendant gods formed in their own image; or at least in the image of their own unique and alien desires and predilections.

It is hinted at in the fluff that the Tyranids invading the Milky Way are fleeing something even worse lurking out in the void. The Tyranids evolved or were created in another galaxy and are predisposed to consume, multiply and move on. This singularity of purpose suggests they were engineered, rather than evolved naturally. With their ability to multiply rapidly and strip bare entire planets, it’s not difficult to imagine them expanding beyond the ability of their creators to control. Areas they strip of life would not be able to support their voracious appetites and their numbers would diminish. Areas that were given the chance to replenish would eventually be consumed once more in a never ending cycle of feeding.

This Tyranid hunger is never sated, and over the millennia its manifestation in the warp would grow and grow. With no other life or emotions in the galaxy the resulting god of hunger would be extraordinarily powerful, and its birth would be calamitous for the Tyranid hordes. Ironically, the species that had destroyed their creators with their unchecked hunger would now face a similar fate. Hunger-daemons would invade their realspace and consume trillions, and whole constellations would be pulled into the warp to be feasted on. The survivors would instinctively realise they had to flee, but there would be nowhere in their galaxy safe from the god they had unwittingly created. Their only choice was to abandon their galaxy and strike out into the void.

Denied the use of warp travel through the quiescent gaps between galaxies, the journey would take millennia, pulled along the faint gravitational tether of their nearest neighbouring galaxy by their Narvhal bio-ships. Thousands and thousands of years later the first tendrils of the survivor hive-fleets drift into the outer reaches of a spiral galaxy of some 400 billion stars, and find it teeming with life. The vanguard Tyranid forces are awakened from their slumber, ready to initiate another galaxy-wide holocaust, before they are once again forced to move on.

A black hole forms whenever enough matter is squeezed into a small enough space. The Earth would form one, if you could somehow work out how to squeeze its entire mass into a sphere the size of a cherry tomato. Mass really doesn’t like being squeezed up like that however, and there are various physical impediments to that happening. Something that does have enough squeeze to get past these is a collapsing star.

As we saw last time, a medium sized star like the Sun will end up as a white dwarf. Even though it is no longer producing fusion, which was the reaction that supported its weight during its lifetime, it doesn’t shrink beyond a certain size. This is because the electrons orbiting its atoms can’t be forced into the same space (technically the same quantum state, a quantum-mechanical phenomenon called ‘electron degeneracy).

Pile enough mass on, however, and the electrons are forced to combine with the protons in the atomic nucleus to form neutrons, and the whole thing collapses into a super-dense nugget with the same density as a nucleus. This is a neutron star; an utterly bizarre object that spins at phenomenal speeds and has such a strong gravitational field that the heights of its ‘mountains’ are measured in atoms. Its weight is prevented from shrinking it any smaller than a few kilometres however by ‘neutron degeneracy’, a similar phenomenon to electron degeneracy.

But even this last bastion can be overrun if the object’s weight is sufficient. Eventually nothing can stop the pull of the star’s weight, and after that point, all bets are off. All of the mass collapses to a single point (the singularity), and a black hole is formed.

A black hole is a singularity surrounded by an event horizon. The event horizon is usually thought of as the boundary of the black hole’s extent. Outside, it’s possible for an object to escape and go about its business. Inside the event horizon, there is only ever one destination, no matter which direction you go and how fast: the singularity. What happens there is anyone’s guess; we don’t currently have the physics to describe it.

  So once you’re past that event horizon, you’re toast: cut off from the rest of the universe, bound for an unknown and almost certainly fatal end. So if you’re whizzing about the universe in your spaceship then, the size of the black hole’s event horizon obviously matters. Most black holes are formed from the deaths of large stars, and are only a few dozen kilometres across.

In principle, tiny black holes a fraction of a millimetre across (but still with a mass similar to the Moon) can be formed from high-energy collisions. These have never been observed however, and in any case would very swiftly evaporate (the rate that a black hole evaporates due to Hawking radiation increases as it gets smaller). These micro-black holes have been blamed for everything from the Tunguska event to the end of the world that didn’t happen when the Large Hadron Collider was turned on.

However, it’s the other end of the size scale that we’re interested in here. A black hole left to itself will shrink as it slowly loses energy through Hawking radiation. However they can also grow by swallowing up matter, and in this way they can grow phenomenally massive. It’s now thought that every galaxy, including our own Milky Way, has at its heart a supermassive black hole, with a mass equal to millions of stars. Due to their enormous density however, these extremely massive objects are still smaller than the solar system.

Recently however, bigger and bigger black holes have been discovered, and last month the biggest yet was found 220 million light years away in the heart of the galaxy NGC 1277. This beast has a mass of 17 billion suns, making up an enormous 14% of the galaxy’s mass. By comparison, the supermassive black hole at the centre of most galaxies counts for about 0.1% of its mass.

What’s really terrifying about it though is its size. The event horizon of this black hole is 11 times wider than the orbit of Neptune, the farthest planet from the Sun. If light were capable of traversing it, it would take 4 days for it to reach one side from the other. Betelgeuse, the largest of the stars we looked at last time, could fit into it more than 3 million times.

Possibly more scary is the thought that if you were an intrepid space explorer, you could fall into this black hole and not immediately notice. For most, smaller black holes, the change in the strength of the gravity the closer you are produces notable tidal forces on an object nearby (think of your feet being pulled down slightly more than your head, and the slight stretching sensation that would cause. Now imagine it much, much stronger). If for some reason you didn’t have your black-hole detector active, that would be a pretty good sign you were approaching the event horizon and you should turn round now. But supermassive black holes, and especially hyper-supermassive black holes like the one at the centre of NGC 1277 have a much shallower gravity slope, initially at least, like the gentle foothills of a sky-piercing peak.. You could quite happily cross the event horizon and be none the wiser. By the time the tidal forces of the singularity alerted you to where you were, it would be far, far too late.

Turning your ship around and going to full speed away from the singularity that you now know is behind you, you notice something unusual – every star you can see, the entire universe seems to be concentrated in a circle in front of you. Everything else is completely black. And the circle is shrinking, no matter what you do. Every path you take, at whatever speed, all accelerate towards the singularity.  Eventually the difference in gravitational pull between one end of the spaceship and the other is so great that it is ripped apart, and some time later, the same happens to you. And the black hole grows by an imperceptible amount.