One of the newcomers was Dr. Sarah Wellington, the chair of Geology and Geophysics at Yale University, with a research focus on geophysics. The other was a younger woman named Rachel Holms. She was doing doctoral research in the area of climatology under the supervision of Dr. Wellington.
The president greeted each of the participants, reminded them of the top-secret status of the Peregrinus file, and asked Dr. Wayman to begin.
“Mr. President,” Eli began, “I am going to ask our various experts to cover most of the briefing. We promised a month ago that by now we would have better answers to your questions than we did at that time. We now do have those answers, which isn’t to say that there’s no further testing and refinement still left to do. I am pleased and relieved to confirm, as I mentioned in my recent note, that it appears mankind does not face a catastrophic event, though we will face some major challenges. I’d like to begin today’s discussion by having Ms. Ahmadi and Dr. Galletsia give an update on Peregrinus’s expected path and the resulting astrophysical picture.”
Darya Ahmadi began, “President Rushton, Dr. Rigby and I have been keeping a close eye on Peregrinus as it rises up through the bottom of the solar system. It’s not hard to do with the LSST observatory when you know where to look. As expected, during the last four weeks Peregrinus has moved about two astronomical units along its path, getting closer to the plane of the ecliptic, so now it is about forty-seven AU away, still well beyond the orbit of Pluto. We have confirmed our estimate of the Peregrinus’s diameter to be one hundred and twenty-eight thousand miles, which is 1.44 times larger than Jupiter. That means a volume, which is proportional to the cube of the diameter, of three times that of Jupiter. We still can’t measure its density because it hasn’t come close enough to another known object for us to be able to measure gravitational effects. However, it has a fairly high albedo, or light reflectivity, like Jupiter. So, it is likely a gas giant with a similar low density to that of Jupiter. That’s good news because a denser planet would have a higher mass and greater potential to wreak havoc on its way through the solar system. Three times the mass of Jupiter is already plenty big enough. However, we’re just the data gathering part of the team. The data all goes to Dr. Galletsia for analysis.”
Tony Galletsia was pleased to be the only spokesperson present from the JPL. His boss, Eleanor Appleton, had requested administrative leave as it became increasingly obvious that she had downplayed the risk from an unknown transient object with several sorts of unusual characteristics, initially overruling Tony’s concerns. “Sir, as we advised last time, what we clearly have here is a wandering or rogue planet. There are thought to be many millions of these knocking about in our galaxy, but this is the first we know of that has passed through our solar system.
“When I last spoke with you there was a distinct risk of a direct collision with the Earth, or a near miss that would have been just about as bad as a collision given the size of Peregrinus. However, with the new data provided by Ms. Ahmadi, we have been able to refine our estimate of Peregrinus’s path as it intersects the plane of the ecliptic and continues on into the upward or northern reaches of our solar system. It is going to come a little closer to us than it first looked like it might, but we have also been able to tighten up our error bands around the most probable path. In combination, I am confident in saying that there is no risk of a collision or even a close call. Peregrinus’s nearest approach to Earth’s orbit will be about ten million miles, plus or minus about two million miles. That’s about one-fifth of the way from Earth’s orbit to that of Mars. The error band of two million miles may seem like a lot, but it’s actually less than one twentieth of one percent of the distance Peregrinus is away from us. We’ll be able to tighten up the accuracy even further in another month. The diagram on the screen depicts this, though, as before, it is not to scale.
“So, we will escape the complete doom of a direct collision, as expected, though Peregrinus will be quite a spectacular sight as it sails by, initially appearing to be about the size of a peppercorn held at arm’s length at about two and a half weeks before its closest approach, then growing rapidly to appear to be bigger than the Moon even though it will be forty times farther away than the Moon at that point. Next is the question you posed about tidal waves, eruptions and earthquakes. Your intuition that those could result from a near miss was correct. In this case, ten million miles of separation is not really a near miss. It is more than enough spacing to avoid any such secondary consequences. It would be a different story if Peregrinus was going to go hurtling by at five million miles. That is still a good clean miss, but the resulting tidal forces would be very significant.
“The tidal forces we are familiar with are those exerted by the Sun and the Moon. They are the result of the fact that the gravitational attraction between each of these and the Earth is stronger on the side of Earth closest to each of them, and weakest on the opposite side. This differential in gravity stretches the Earth’s crust, but especially the oceans, toward the Sun and the Moon causing the tides and also causing small movements of the Earth’s crust as the Sun and the Moon move relative to the Earth.
“Fortunately, at ten million miles of spacing no catastrophic tidal effects are in store. Tidal forces actually diminish in proportion to the cube of the distance of separation — so despite the much greater mass of Peregrinus, we are looking at a tidal force about equal to that of the Moon for the few days surrounding the point of closest approach. That could result in some local flooding in places where the Peregrinus tidal effect and the lunar tidal effect occur at the same time on top of each other, but it is unlikely to be very serious. Likewise, the slight additional rolling distortion of the Earth’s crust could possibly be the trigger for a significant earthquake or volcanic eruption but only if one was already imminent and likely to occur within a few years anyway.
“Sir, that brings me to the last matter that I, as the orbital mechanic on the team, can address. While the tidal forces Peregrinus will impose on us will be small, the direct gravitational forces will be substantial for a period of time, even from ten million miles away. Gravitational force is proportional to the product of the masses of the two bodies, the same as tidal forces, and it is inversely proportional to the square of the distance between the two, whereas the tidal force is inversely proportional to the cube of the distance. So while the tidal force is minor at ten million miles, the gravitational attraction of a body as large as Peregrinus is still powerful even at that distance — about one quarter of that of the Sun, albeit for a fairly short interval of time.
“This will result in a tug-of-war between Peregrinus and the Sun. The result of this tug-of-war is that the Earth’s orbit will expand somewhat outward away from the Sun, with its current circumference of five hundred and eighty-five million miles expanding by about 2.3 percent to a circumference of about six hundred million miles. Our average distance from the Sun will likewise increase from ninety-three million miles to ninety-five million miles. Our orbit will be drawn into a more elliptical shape than the current almost perfect circle. Our year will be longer by nearly thirteen full days. We will need to establish a new calendar with an extra day in each month, and leap years with a thirtieth day in February in two years out of three, rather than our current one leap year in four.
“To wrap up, Mr. President, as Professor Wayman said to begin with, we will escape a catastrophic collision with Peregrinus and we won’t be devastated by tidal waves, earthquakes or eruptions, but we aren’t going to escape totally scot-free. There will be some significant consequences from the new orbit; however, the assessment of those consequences is beyond my area of expertise.”
The president turned to Dr. Wellington. “Dr. Wellington, I think you are going to explain the consequences of this new orbit. It doesn’t seem like all that much of a change.”
“Yes, sir,” began the Yale professor, “Rachel and I will lay out what we see, but I am afraid that the change in Earth’s orbit that Dr. Gallet
sia is predicting will be far from benign for our global climate, despite the seemingly minor magnitude of that change. Mr. President, it is a cold universe out there, an extremely cold universe. Out in the far reaches of our solar system, several billion miles out and beyond the reach of the Sun’s warming rays, the temperature is nearly four hundred and sixty degrees Fahrenheit below zero. Even at the much closer distance that the Earth is to the Sun, only ninety-three million miles, the Sun doesn’t radiate enough energy to the Earth to warm it to a habitable temperature absent the greenhouse gas effect, which traps and holds much of that energy in our lower atmosphere.”
“Based on Dr. Galletsia’s work, the Earth’s average distance from the Sun will increase by about 2.3 percent. The warmth that any object gets from the Sun is inversely proportional to the square root of its distance from the Sun, when temperatures are measured on the Kelvin scale. So, a 2.3 percent increase in distance will result in about a 1.1 percent reduction in average temperature. This may seem like a small decrease, but it is 1.1 percent of the Earth’s temperature as measured on the Kelvin scale, not the more familiar Fahrenheit scale. So that will mean a decrease in our current effective average temperature of 288 degrees Kelvin down to about 284.7 degrees. On the Fahrenheit scale that we use in everyday life, this means our global average will drop from its current 59 degrees, which is a couple of degrees warmer than fifty years ago, down to about 53 degrees. A decrease of even that amount will have a profound effect on the Earth.
“Sir, when it gets that much colder, the other factor we have to consider is the Earth’s albedo, which is the term for how much of the Sun’s radiant energy gets reflected back from the Earth’s surface. Apart from that which is captured by our greenhouse effect, the solar energy that is reflected from the Earth’s surface escapes back out into space and doesn’t help protect us from the cold. Our current albedo is 0.30, which means 30 percent of the Sun’s energy is reflected back by the Earth. This is due to the effect of clouds and polar ice. However, at the colder temperatures resulting from our more distant orbit, the polar ice caps will expand. We will have lots of ice and snow lasting year-round in the northern latitudes beyond the sixtieth parallel, which will increase the Earth’s albedo. If we lose only another 3 percent of the Sun’s warmth, this will drop the average temperature down by another six degrees Fahrenheit to 47 degrees. Sir, I am afraid that is likely a best-case scenario without some sort of intervention.
“Mr. President, I am sorry that we geoscientists are the bearers of this bad news, but we have a little more to put on the table. Rachel, it’s your turn.”
The young doctoral student felt a little intimidated, but she sat up straighter and spoke with confidence. “Mr. President, we are sure that you would want as complete a picture as possible. The global average temperature impacts that Professor Wellington has described are fairly straightforward to estimate, but they are global averages. Different parts of the world are going to be affected differently.
“For one thing, the southern hemisphere has a lot more ocean-covered surface than the northern hemisphere, which has much more land-covered surface. Land heats up more quickly than oceans do, but it also cools down more quickly. So, the northern hemisphere temperature decline resulting from the new orbit will be much quicker than in the south, especially the inland areas of the north. At the same time, the more elliptical shape of the new orbit means that we will experience a much more pronounced drop in temperature in our summer season than in winter, the converse in the southern hemisphere. In the parts of the north where we have always had a winter season with snow, the usual spring melting will occur later and later. Because of the combination of these two effects, the increase in albedo caused by ice formation with be more pronounced in the north.
“Mr. President, I am unhappy to have to tell you that the northern hemisphere is going to experience temperature declines even somewhat greater than what we’ve estimated for the decline in the global average. The southern hemisphere will be colder than at present during the peak of its winter, but summer will be about the same as it is now, and will melt the winter snow accumulation and prevent much increase in local albedo, except in the very southernmost latitudes. There is some fairly complex modeling to determine these location-specific temperature impacts, which is under way, but directionally that’s what we can expect.”
“Sir, a drop in the global average temperature of twelve degrees but with the albedo component of that decline more pronounced in the northern hemisphere means a significant ice age in the north with ice eventually covering all of Canada and the northern United States as well as Russia and northern Europe. The southern hemisphere will fare much better. Even as far down as the south island of New Zealand and the southern coast of Australia will remain relatively hospitable.”
Most of the group were hearing the details of the climate impacts for the first time. They were all absorbing the information, including the president who mused out loud, “I feel a little like a yo-yo. At first, I feared maybe we would be totally obliterated by a collision, and the difficulties posed by any other outcome seemed to pale in comparison. Once you took the collision risk off the table I was only relieved for a moment before I started to worry about the potential destruction and desolation from what you described as the tidal forces resulting from a close pass, but then you ruled that out as well. Then it sounded like maybe the Sun would lose the tug-of-war with Peregrinus and we would be dragged along in the thing’s wake, but once again I felt like we dodged the bullet when you explained the minor change to the Earth’s orbit, which is all that would result from the tug-of-war. Now I am told that even what seems to be a small change in Earth’s orbit will have unfavorable climate effects that will make much of the world unlivable. It is still an enormously better outcome than some of the alternatives, but that’s little consolation.”
Eli responded, “Sir, your mixed emotions are completely understandable. I think we are all feeling much the same. I don’t want to downplay the seriousness of the climate effects at all. They will be the greatest challenge man will have ever faced, at least since the Great Flood. However, Sir, like Noah, we are getting some time to prepare.
“We have two years before the temperature will start to drop. Then it will take quite a while for the atmosphere to cool off, maybe another year — we are working on this. At first there will be no change to the albedo so we will not face the full cooling impact. It will take many years, possibly thousands of years, for the polar ice cap to cover the northern third of the globe. During the early part of that period, it will still be livable in much of the north and, importantly, it will still be possible to grow crops. It will be a colder existence, with winters even more bitter than those experienced by the early Icelandic settlers on the shores of Lake Winnipeg in Canada. However, we have much better technology for coping with the cold than back in that day. So, we will have time to plan how we are going to respond and time to execute that plan. It is a challenging outlook for sure, but not an insurmountable one if we rise to the challenge.
“Mr. President, I think we should brief a few of General Montgomery’s staff on the Peregrinus file to at least map out the broad outline of a response plan, including options for your consideration. That may include additional energy infrastructure. It may include long-term relocation plans, though that can likely wait for many years and be undertaken on a phased basis. Mr. President, I think we will also need to consider the geoengineering possibilities. I touched on that subject when we discussed options to curtail global warming, but there are also strategies that would act in the opposite direction, to reinforce the greenhouse effect and curtail global cooling.”
“Eli, of course you are right,” replied the president, “I was just feeling sorry for myself, or maybe for mankind, for a moment. We need to turn all our ingenuity and effort toward mitigating this galactic event and preserving the quality of life on Earth as best we can. Yes, let’s start to develop the response plan and options. I’ll
want a preliminary look at that within a week. We should identify which departments within our government are best suited to refining the plan and implementing the actions.
“Eli and Will, I would like to have this team brief the full cabinet on the Peregrinus file in a couple of weeks and to have the response plan far enough progressed that it will provide some comfort and a point for us all to rally around. I am also going to invite the congressional leadership to sit in on that briefing, still all under the top-secret strictures. The following day I will communicate privately with the leaders of our key allies and two days later I will address the American people. Can the two of you organize all this, please?
“Thanks to all of you for your work on this file. Because of you we know what we are facing and we have time to prepare for it. Please continue your efforts on every scientific front.”
Chapter 23
Saturday, March 11, 2028
Washington, DC
President James Rushton sat with his wife, Julia, and children in the family room of the White House, watching CNN. The president had returned moments ago from the White House studio where he had announced to the American public, and the world at large, the news of Peregrinus. He had then participated for about half an hour in the media scrum that followed, leaving Eli Wayman and General Isaac Montgomery to field the remaining questions. CNN was carrying a live feed of the question and answer session.
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