Sunfall

by Jim Al-Khalili

  ‘A typical CME carries a total amount of energy one hundred times greater than that produced by the giant asteroid impact that wiped out the dinosaurs sixty-five million years ago.’

  Several people stared at her incredulously as this statistic sank in.

  ‘So, how have we managed to survive so long under this onslaught from our sun? Well, throughout its history, our planet has always had its magnetic field to cushion the impact of coronal ejections – think of it as planet-sized bubble-wrap. But … if that magnetic field is severely weakened then … well … well, no one really knows what the implications are.’

  An immaculately dressed, grey-haired man with a trim beard sitting across the table from her cut in. ‘Ah, come now, Dr Maitlin, please do not lecture us.’ He had addressed her in English, she realized; her United Nations-issue AR informed her that he was Ashraf al-Magribi, the Egyptian Minister of the Interior. He spoke in a clear, confident voice, as though accustomed to being listened to. ‘We already know all we need to about these coronal ejections and how and why they are formed. That is not why you have been asked onto this committee.’

  Sarah felt momentarily winded, not quite knowing how to respond to this sudden hostility. A woman sitting next to the Egyptian turned to admonish him. She looked about the same age as Sarah, but even from across the table Sarah could tell that she’d had extensive tissue-engineering work and skin nano-implants. However, it was her voice that betrayed the decades her face was hiding. ‘There’s no need for such an insulting tone, Mr Magribi. We have invited Dr Maitlin to join our committee, so at least do her the courtesy of listening without interrupting.’ Her voice was soft, yet commanded immediate respect and al-Magribi sniffed and stroked his beard, trying not to look as though he’d just been put in his place.

  Sarah’s AR informed her that the woman was Filomena Crespo, the immensely powerful Brazilian vice-president of Samsung, and she wondered whether her representing a multinational company rather than a nation state meant she was less encumbered by politics and thus more likely to be sympathetic. Maybe she just felt it necessary to defend a fellow woman – after all, Ms Crespo would have started her career back at a time when women needed to work twice as hard to prove their worth in reaching the very top of the career ladder. Whatever the reason, Sarah was grateful.

  She guessed that an Egyptian representing a population of a hundred and twenty million would be particularly keen to have some reassurances. After all, his country’s agricultural infrastructure was in tatters since the disappearance of much of the Nile Delta a decade ago, one of the first regions to fall victim to the rising sea levels, which had put an almost unbearable strain on an already fragile economy.

  She resumed her presentation: ‘Of course, not all Earth-bound CMEs are dangerous. We think about one in five would cause us major concern. The issue is that everyone is probably looking in the wrong place.’

  Now she had their full attention. This is it. This is where I get to shake them from their smug complacency. ‘You see, you’ve been worried about the coronal ejection’s impact on the magnetic field itself, causing a geomagnetic storm.’

  ‘You’re still not telling us anything new, Dr Maitlin,’ the Chinese ambassador said coldly.

  Sarah felt her face get hot as anger suddenly rose inside her again. For fuck’s sake, it’s not like I asked to come onto this bloody committee. What would they do if I just stood up and walked out? She took a deep breath and composed herself. ‘My point, Ambassador, is that geomagnetic storms are not necessarily what should be concerning us right now. The communication satellites taken out last week that caused the crash of Flight AI-231 were fried by the direct impact of high-energy particles in the ejection itself and not, as everyone seems to think, by a geomagnetic storm.

  ‘Catastrophic though they can be, our focus now should not be on the more predictable problems of disruption to power grids or disturbance to radio signals that we’ve had to worry about during geomagnetic storms in the past, but rather the threat of direct exposure to the burst of CME radiation hitting the Earth.’

  She flicked on to the next holo image. It showed an animation of the Earth with its surrounding magnetic field, which was represented by flux lines emanating from the Earth’s poles and curving round in ever larger loops. The shape of the field was shown compressed on the Earth’s Sunward side to a distance of about ten Earth radii. ‘The reason the side of the Earth’s magnetosphere – its magnetic field – facing the Sun is squashed is the pressure of the solar wind. But on the night side of the Earth you can see how the field lines are stretched out so that the magnetosphere extends like a tail behind us.

  ‘But … this is what the magnetosphere should look like at full strength. Now watch what happens in the event of a direct hit from a CME.’ As she spoke, the animation showed an approaching coronal mass ejection, a colourful cloud of plasma far larger than the Earth. When it slammed into the magnetosphere it caused the field lines to distort and stretch, compressing even more on the side that took the full impact. ‘The high-energy particles in the CME are deflected around the Earth by the field, like water parting around a rock in the middle of a fast-moving stream.

  ‘Even though the majority of these particles don’t get through to us, the highly charged plasma of the CME sets off a geomagnetic storm – a disturbance in the magnetosphere that causes powerful electromagnetic currents to flow around the planet.

  ‘Now then, you might expect that a weaker magnetic field would mean less violent geomagnetic storms. And you’d be right. But …’ She ran the animation again, but this time there were fewer field lines surrounding the Earth. ‘… a weaker field is also less effective at stopping the high-energy bombardment of the subatomic particles. So, instead of them being deflected around the Earth by the magnetosphere, more of them can punch through it.’

  She paused briefly to see the reaction on the committee’s faces. Yes, she certainly had their complete attention now.

  She added, ‘Maybe this is something new, or does everyone know this already? In which case, I really don’t know what my role is here today.’

  She realized that she had probably raised her voice a little too much, but so what? They wanted the truth, and they’d got it, with no sugar coating.

  The room suddenly erupted in a hubbub of questions, mostly directly to her, and Senator Hogan needed to call the meeting to order. ‘I think, ladies and gentlemen, that the point Dr Maitlin makes is very important, and can potentially be seen as encouraging news.’

  ‘Encouraging? In what possible way can it be encouraging? Or have I just completely misheard Dr Maitlin?’ said the Finnish delegate, a slim woman with cropped white hair sitting off to Sarah’s left.

  Hogan smiled. ‘The reason we asked Dr Maitlin onto this committee was so that she could tell us just how precisely she and her team could forecast the arrival time of a CME, so that the world can take the necessary precautions. If the main threat is therefore from the initial CME impact, then I would guess that is a far more reliable thing to predict than any subsequent geomagnetic storm it might cause. Am I right, Dr Maitlin?’

  Sarah had a sinking feeling. OK, here it comes. Clearly, she had already not endeared herself to most of the committee, and they sure as hell weren’t going to like what she had to tell them next.

  She decided to just give them the facts as calmly as she could. She took a deep breath. ‘Ejections aimed at the Earth are called “halo events” because of the way they look to us. As the approaching cloud of an ejection looms larger and larger it appears to envelop the Sun, forming a halo around it. This means that, unlike with one heading off, say, at right angles to the line between the Sun and the Earth, predicting its speed is difficult, because we can’t see it moving from a side-on view. With something coming straight at us, we just can’t predict precisely when it will hit us.’

  It was Aguda’s turn to interrupt her. ‘But don’t we have solar orbiting satellites that can give us enough of a side-on v
iew? They’d be beyond the path of the ejection – outside of the line of fire – and therefore safe from being fried. They can track the ejection and give us an accurate approach velocity.’ To illustrate his point, he extended his arms, pointing his two index fingers towards a point in front of him, and brought them together.

  On cue, Sarah clicked to the next image, which showed the Earth in its orbit around the Sun and the location of two satellites in the same orbit, one ahead of Earth and the other lagging behind. ‘That’s true,’ she said. ‘We have the STEREO2 spacecraft that give us just this view, but by the time the CME is close enough for this to be useful, it’s too late and the ejection is almost upon us.’

  Even though she was having to relay unpalatable news, she nevertheless felt on much firmer ground now, science she’d spent her entire career working on.

  ‘So, instead, we have to make predictions based on simulations. These can take into account everything our AIs can learn about an ejection, from the Sun’s own magnetic field to the solar wind, to the size and strength of the ejection itself. All this just so we can get one number out at the end: the SAT, or Shock Arrival Time.’

  The Chinese ambassador interrupted her again. ‘But of course, the number we all want from you, Dr Maitlin, is a different one, and is based on the accuracy of this prediction. How wide is the arrival-time window? How much advance warning do we get?’

  Sarah took another deep breath. ‘Since CMEs can travel at a wide range of speeds – anything from a few hundred to several thousand kilometres per second – our best estimate, based on a combination of computer predictions and satellite data … is a window of eight hours.’

  Everyone stared at Sarah. Al-Magribi broke the silence. ‘Do you mean to tell us we will know we’re going to be hit, but not when? This means it could hit anywhere?’

  ‘That’s correct, I’m afraid. We must face up to the fact that the population of entire continents will need to stay indoors if they are to avoid a potentially fatal dose of radiation. And that’s not to mention the damage done to animal and plant life. No single country will know if it’ll be hit until it is too late to act. And this is something that is likely to happen again and again in the coming months.’ Once again, everyone started talking at once. Her uncompromising assessment had clearly been both unexpected and unwelcome.

  ‘But I still don’t understand,’ cut in the Finnish delegate loudly. ‘How does this eight-hour uncertainty come in?’

  Sarah manipulated her fingers on the touch-sensitive section of the table in front of her to retrieve the very first holo image she had shown of the Earth slowly rotating about its axis. ‘Our planet takes twenty-four hours to complete a full revolution, right? So, over the space of eight hours one whole third of the planet’s surface could be exposed to the impact.’

  An uneasy ripple of conversation spread around the table. This was as good a time as any to hit them with the coup de grâce.

  ‘And I’m afraid there’s one more thing.’ She had to raise her voice to be heard. ‘Before the CME even reaches Earth, we’ll be bombarded by a stream of high-energy protons, the vanguard of the pulse. Because these particles will be travelling at near light speed, they’ll reach us about ten minutes after the CME is ejected by the Sun. Normally, they’d be deflected by the magnetosphere, but in its weakened state some will get through and pose a serious radiation risk.’

  This new revelation left everyone stunned. After a few seconds, Hogan was the first to speak. ‘None of this really changes anything. We already knew we would have to put in place various emergency strategies and procedures in the event of a direct hit. All this means is that more individual governments are going to have to do this than we thought.’

  ‘And even if there is a strong chance a CME will miss us,’ continued Aguda. There were a few reluctant nods around the table.

  ‘But,’ continued the senator, ‘we still need to write our report and agree on a united plan of action.’

  Sarah felt a wave of relief that she’d finally got this off her chest. The world was in peril, but at least it was no longer just her worry.

  13

  Saturday, 9 February – Princeton, New Jersey

  Qiang Lee had arrived early at McCosh Hall on Princeton University Campus, where the dark-matter conference was being held. He felt relieved to have made it at all as so many flights into New York had been cancelled due to fears of what Hurricane Jerome might do next. The superstorm was all anyone seemed to be talking about at the moment and was certainly the only topic on all the AR news feeds.

  His name badge read ‘Prof. Lee, Qiang (IHEP)’, which made him smile. The Institute for High Energy Physics in Beijing now had a strong enough international reputation that its rather generic acronym was sufficient to place the wearer. After turning away from the registration desk with his conference bag, he took a look inside it. There was a time when it would have been filled with useless pieces of paper: maps, leaflets listing the best pizza restaurants in town and glossy brochures of ‘Things to do while in Princeton’ – mostly open markets, art exhibitions and community amateur dramatics events. By contrast this one was almost empty, but he was pleased to see that along with a folded plastic e-pad containing the programme and the rest of the conference information there was a pad of notepaper and pen. Hardly any delegates used such pads any more, but Qiang liked to doodle or work on dense algebraic derivations while only half listening to the talks.

  Strolling back outside the building, he wondered how his old friend and collaborator would be. He’d heard about Marc Bruckner’s marriage breakdown, and how he’d fallen out with several people in the Physics Department at Columbia and had finally escaped to his late parents’ summer home in New Zealand for some much-needed convalescence. Having spoken to him last night, Qiang decided he did look and sound a lot better than he had dared to expect. Was that just an act for his benefit? Could sufferers from depression recover so quickly? He doubted it. Maybe it was more to do with the anticipation of seeing his daughter Evie after the conference.

  Their brief online exchange had brought back memories of those heady days in the late twenties when the two men had made the biggest breakthrough in particle physics research since the discovery of the Higgs boson, that dark matter self-interacts, creating normal matter in a burst of high energy.

  He spotted Marc striding purposefully across the grass towards him and waved. Marc waved back and grinned broadly. As soon as he was close enough Qiang extended his hand, but Marc pulled him into a bear hug.

  Qiang smiled, feeling a little awkward. ‘It’s good to see you. And I’m glad you could make this meeting. We’ve got a lot of catching up to do.’

  Both men had long since given up on the idea that a scientific conference was about listening to the talks. They could find out about other people’s research any time and from anywhere. No, conferences were about renewing acquaintances, discussing the politics of academia and, of course, knocking around new ideas in the bar. Qiang wondered whether Marc could still outdrink everyone else.

  The two men walked into the building where thirty or more delegates were milling around greeting each other. There was an audible drop in the level of background chatter as Marc was spotted. He didn’t seem to care and Qiang was relieved, although he felt certain that had it been him on the receiving end, he’d have been devastated. Maybe Marc was just good at hiding his feelings.

  They picked up coffees and wandered into the lecture theatre to claim their seats – not too close to the front or the rear, but always to one side in case they needed an early escape if a talk was particularly boring.

  As soon as they were seated, Marc turned to Qiang. ‘So, how’s Chyou doing? And the kids … they must be school age now?’

  ‘Yup, the boys are both at school and doing well. And Chyou is fine. Although I think she still misses New York.’

  ‘What? Are you crazy? What’s to miss?’

  ‘When were you last in Beijing, Marc?’ chided Qiang.
‘Chyou says she misses Manhattan’s clean air and provincial feel.’ They both laughed.

  ‘How about you? When you said that you’d moved back to New Zealand I expected you to turn into a hermit and shut yourself away from the world.’

  Marc sighed. ‘Yes, I did think about leading a life of solitude and focusing full-time on feeling sorry for myself …’ His eyes took on a distant, glazed look. Then he shrugged and smiled. ‘But, you know what? Fuck it. Life is only as bleak as the lens you look at it through, right? Anyway, did you know Evie turns sixteen next week?’

  ‘Wow, sweet little Evie? I remember babysitting her when she was the same age as my boys are now.’ Qiang thought back to those times when Marc and Charlotte seemed to have the perfect marriage and family life with their young daughter. He looked closely at his old friend.

  Marc smiled self-consciously under Qiang’s scrutiny. ‘Time marches on, my friend,’ he said. ‘I see you’ve got the odd grey hair yourself now.’

  Qiang shrugged. ‘That’s just Chinese bureaucracy for you, and the never-ending writing of grant proposals. Not something I guess you’re too worried about these days.’ As soon as he’d said it, he regretted it and started to apologize. Marc cut him off.

  ‘Hey, don’t be silly; it’s true, I don’t. Anyway, I haven’t decided what to do next. I haven’t entirely ruled out getting back into academia.’

  Other delegates were starting to filter into the hall. ‘So, what’s new with you, Qiang? I saw your last paper before Christmas. What are you working on now?’

  Qiang couldn’t hide his change in demeanour and it was clear Marc had picked up on it. There was no point keeping what he knew to himself any longer, so he dropped his voice to a whisper. ‘That’s why I was so relieved when you told me you’d be here. If you hadn’t come I would have flown down to New Zealand to speak to you.’