Everyone’s heard of the Butterfly Effect nowadays of course but people tend to get it wrong. The initial idea, which I’ve mentioned before on here, was that a single flap of a butterfly’s wings in the Amazon can cause a hurricane in Africa, something which is very relevant to us right now in these days of hurricanes and climate change denial. It’s often taken the wrong way. Whereas it does mean that tiny differences can lead to enormous changes in the long run, it definitely does not mean that all tiny differences will. They have to be in the right place at the right time.
In this vein, something which has been going through my head a lot recently is the question of what would have happened if the year had been slightly longer, for instance by a second. There are actually massive problems with this idea. If the year had been a second longer for the past 4600 million years, the estimated age of the planet, it would have orbited the sun a total of a hundred and forty-five times fewer. There is a major problem with this though, specifically the extinction of the (non-avian) dinosaurs. In fact, it would take an incredibly tiny difference for the asteroid to miss the Earth in this respect. If the year were more than a hundred nanoseconds longer or shorter, the extinction of the dinosaurs wouldn’t have happened and the chances are we wouldn’t exist. This is a good example of the butterfly effect. However, it should also be noted that if the year had been that bit longer so that Earth ended up in exactly the same position, for instance if it had been exactly 6.8 milliseconds shorter or longer, which would add up to exactly a year over its whole history, the asteroid would have hit and the situation would be as it is now. There is another factor in this to which I’ll return, but before I do that I also want to mention that the solar system is chaotic in nature. It is in fact impossible to predict over a period of many millions of years exactly where any of the bodies in the solar system will or have been because they all pull on each other very slightly, which is how Neptune was discovered – Uranus wasn’t in the right place so another planet had to be changing its orbit slightly. Therefore all of this is rather artificial.
The other issue is of course that as well as dodging an asteroid, Earth would also have been hit by other asteroids and meteorites which in reality it wasn’t, so for all we know in this scenario we might have been about to bang the rocks together when we got hit by a completely different asteroid which wiped us all out a couple of million years ago.
Since even a hardly measurable difference in the length of the year would completely change the history of the past 66 million years, it’s not possible to have the length of the year have been different since the very beginning of the world. What is possible, though, is for it to have been altered by the asteroid which wiped out the dinosaurs itself. It’s known as the Chicxulub Impactor, because it hit the Mexican town of Chicxulub in the Yucatan Peninsula. Although it’s not essential for the future evolution of the human race for the object, which may have been a comet, hence the name, it clearly would have to hit the planet somewhere at about that time. The question is, then, how do I get the year to take slightly longer and still have the Chicxulub Impactor hit the planet?
My first thought was to have the object itself hit the planet so hard that it actually changed its velocity by enough to lengthen the year by twenty seconds, which incidentally adds up to around forty-two years in the past 66 million. It might be thought that this would require the planet to be slowed down but in fact the opposite would be needed. In order to move a planet into a slower orbit, it has to be sped up. Hitting it from behind could do this. It would then move into a wider orbit taking longer to go around the Sun.
However, a scenario as simple as this wouldn’t work because of the energy involved to change the velocity of this planet by even a millionth. Earth’s mass is about 5 972 000 000 000 000 000 000 tonnes and moves around the Sun at thirty kilometres per second. Considering the energy of a rifle bullet of twelve grammes travelling at 370 metres a second already sounds quite large, or a Saturn V rocket with a mass of 1000 tonnes travelling at 40 000 km/hr is almost unimaginable, anything which could alter the velocity of this planet by that much would have to exert an unfeasibly immense force even to increase the orbital velocity of this planet by a millionth. The Chicxulub Impactor was ten to fifteen kilometres in diameter and may have been of a class of meteors known as carbonaceous chondrites, which have a maximum density of 3.7 kg per cubic decimetre. Assuming it to be a cube, which it wasn’t of course, its mass would have been up to 12 487 500 000 000 tonnes, and assuming it to have a head-on collision with the Earth, orbiting at the same speed but in the opposite direction, it would have hit us at 59 kilometres per second. Given that its mass would have been two billionths that of Earth’s, hitting it head on at twice its velocity would have slowed us by four billionths of a year, which by now would have added up to about three months, although a slower planet ultimately means a shorter year as its orbit would’ve moved inwards. So this is not a solution. Four billionths of a year is about an eighth of a second, so ultimately one hundred and sixty times that force is needed. This could of course be provided by a body a hundred and sixty times more massive, which given the same density amounts to something, again assuming it’s cube shaped which it wouldn’t be, the size of a dwarf planet. Such an impact would probably do the job of slowing the year down by twenty seconds but it would also wipe out all life on Earth, so that’s a non-starter.
However, all is not lost. It’s been suggested that the Chicxulub Impactor was actually formed by an impact event in the asteroid belt in the Jurassic period, which is interesting to contemplate because it means there was a rock with the dinosaurs’ names on it from quite early in their history. Thinking on the same scale, if there is even now an asteroid fated to wipe out humanity in the same way, that would have been around since the dinosaurs themselves were at their height. Hence Chicxulub needn’t be a one-shot job. It could accelerate our orbit over a period of about 100 million years if need be. How though?
In order to answer that question, the moons Janus, Epimetheus and Phobos can help. Here’s a picture of Janus and Epimetheus, which are co-orbital moons of Saturn:
The remarkable thing about these moons is that they share orbits. One takes only thirty seconds longer to orbit Saturn than the other, and they regularly slow down and speed each other up, leading to them swapping orbits. If the Chicxulub Impactor did this with Earth, it would be a very unequal tug of war and over time it could alter the orbital velocity of this planet. What it means, effectively, is that rather than needing to provide a massive jolt of energy in one go, the object concerned can do it over a period of 100 million years, meaning that it would only need to exert one hundred millionth of the force required each year to change Earth’s orbit. This could be achieved by a highly eccentric orbit in the approximate direction of the Earth’s movement, with Earth at the focus in the same direction as its orbit. From the perspective of the Sun, the orbits would be braided, and from ours we would have another small but eccentric moon.
A slightly similar situation exists with this right now:
This is Phobos, which is slightly larger than the Chicxulub Impactor but is also a carbonaceous chondrite. The streaks visible on its surface in this picture are caused by the gravity of Mars tearing at it and in about 40 million years it will break up and form rings around the planet, which themselves will be gone some time afterward.
On first thinking about this, I was given to wonder whether in fact the Chicxulub Impactor was, at least temporarily, a minor moon of this planet which collided with it, and to me that does seem quite plausible, particularly in view of the fact that a very similar situation pertains on Mars right now. However, clearly Earth has no rings so its fate would have been much more violent. Incidentally, when Phobos does get broken up by Mars, some of it will probably hit the planet but it may not slow it down much because the angular momentum of the whole system will remain the same. Angular momentum is the quantity of rotation of a body, given by multiplying the velocity of its rotation by its moment of inertia, which in turn is a body’s resistence to angular acceleration – speeding up its spin in other words. An actual impact would donate the energy of the moon to Mars, but rings won’t. This is also the flaw with Chicxulub. Whereas it is feasible for the object to change the length of the year, it would have changed straight back again when it hit us, unless parts of it broke off and were slung into space carrying their angular momentum with them. Hence I’m going to assume that would happen.
Now it may look as if I’ve done the maths here but in fact I haven’t. However, I ignorantly assume that this is still possible – that if the Chicxulub Impactor had entered into a co-orbital relationship with us in the early Jurassic period, it could have accelerated the Earth-Moon system enough to give us a year twenty seconds longer by the time it hit us 66 million years ago. However, in a way this is too big a change because a year twenty seconds longer would be detectable as time went by. The lengths of the year (there is no one official year length, but that’s another story) are known to within a hundred microseconds, and a year twenty seconds longer would be out by a day compared to ours after only 4320 years, which is shorter than the length of recorded human history so far. Although this sounds trivial, it would be neater to assume that in the process of lengthening the year, the day was also lengthened in proportion to that year. This brings up a couple of issues.
As it is, the Moon gradually slows the rotation of the Earth by tides, both in the rocks and in the oceans, slightly decelerating. At the time the Chicxulub crater formed, there were approximately 370 days a year, meaning that the 24-hour day we have right now would have been around half an hour shorter. It is, however, entirely feasible that the Chicxulub Impactor itself could slow the rotation of the planet by the requisite interval to preserve the exact same number of days per year as there are now. This would require a day only 54.7 milliseconds longer by today. That would be one heck of a coincidence of course, but as far as I can tell the same object could do both in the same orbit. Incidentally, just as there is no one definitive year length, there is no one definitive day length at any particular time, for the same reasons which I’m not mentioning here because it would make all this more complicated than it already is.
There has been a lot of handwaving mathematically up to this point which I haven’t resolved, so anyway, just assume for the sake of argument that the 24-hour day as we understand it now is roughly 54.7 milliseconds longer and the year is exactly twenty seconds longer. What does that mean for this planet?
The first difference is that the centre of the Chicxulub crater would have been around fifteen metres to the east of its actual location. This is because the planet is rotating slightly more slowly, and it means the casualties of the impact would be slightly different, looking at them at an individual level. For instance, this is a Purgatorius unio:
By Nobu Tamura – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=19461292
This is the earliest known primate, close to our direct ancestors, and lived in North America at the time of the impact, so it’s entirely feasible that many members of the species directly ancestral to us were indeed wiped out directly by the incident. The exact individuals ancestral to us would have been different.
Here’s a quote from Ray Bradbury’s classic A Sound Of Thunder, which is a possible origin of the term “Butterfly Effect”, discussing the possibility of killing a single mammal ancestral to humans in the late Cretaceous:
“All right,” Travis continued, “say we accidentally kill one
mouse here. That means all the future families of this one particular
mouse are destroyed, right?”
“And all the families of the families of the families of that
one mouse! With a stamp of your foot, you annihilate first one,
then a dozen, then a thousand, a million, a billion possible
“So they’re dead,” said Eckels. “So what?”
“So what?” Travis snorted quietly. “Well, what about the
foxes that’ll need those mice to survive? For want of ten mice, a
fox dies. For want of ten foxes, a lion starves. For want of a lion,
all manner of insects, vultures, infinite billions of life forms are
thrown into chaos and destruction. Eventually it all boils down to
this: Fifty-nine million years later, a cave man, one of a dozen in
the entire world, goes hunting wild boar or saber-toothed tiger
for food. But you, friend, have stepped on all the tigers in that
region. By stepping on one single mouse. So the cave man starves.
And the cave man, please note, is not just any expendable man,
no! He is an entire future nation. From his loins would have
sprung ten sons. From their loins one hundred sons, and thus
onward to a civilization. Destroy this one man, and you destroy a
race, a people, an entire history of life. It is comparable to slaying
some of Adam’s grandchildren. The stomp of your foot, on one
mouse, could start an earthquake, the effects of which could
shake our earth and destinies down through Time, to their very
foundations. With the death of that one cave man, a billion others
yet unborn are throttled in the womb. Perhaps Rome never
rises on its seven hills. Perhaps Europe is forever a dark forest,
and only Asia waxes healthy and teeming. Step on a mouse and
you crush the Pyramids. Step on a mouse and you leave your
print, like a Grand Canyon, across Eternity. Queen Elizabeth
might never be born, Washington might not cross the Delaware,
there might never be a United States at all. So be careful. Stay on
the Path. Never step off!”
This is, in my opinion, usually incorrect. Whereas there are crucial individuals, even back in prehistoric times, the same mutations would usually arise elsewhere in different individuals of the same species and it’s been calculated that about fifty thousand generations would be sufficient to dampen down such differences in the gene pool. I don’t know how thoroughly that calculation was done, so once again this is sloppy maths. Having said that, although the Butterfly Effect only applies to a few tipping points, the fact that there are so many species on the planet at the moment in question probably does mean there would be a couple of small differences in what managed to survive the initial extinction and what was wiped out, but it would only be noticeable to specialists.
By World Wide Gifts – Flickr: United States – California – Sequoia National Park – General Sherman Tree – Panorama, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=27955967
There are also examples of species with individuals who may be less than fifty thousand generations from the time of the dinosaurs even now, such as redwoods. Anything which can still produce offspring when more than around 1500 years old would be instances, so it might even include yew trees. But for most species any differences would have been dampened down.
This issue is raised by, of all people, Elizabeth Gray! Not this one but a fictional one who appears in what may be one of the stories which ultimately inspired Doctor Who, namely Time Patrol by Poul Anderson. This is part of a series where people are recruited from the entire history of the human race to ensure that history is never altered by slapdash time travellers, and effectively expresses the opposite of Ray Bradbury’s idea.
By the end of the Palaeocene, fourteen million years later, any organism with a generation time under about three centuries which exists in this timeline stands a good chance of existing in the other one. Past that point, barring another impact which would have been dodged, things proceed pretty steadily and similarly to how they are “here” until the start of the Pliocene, ten million years ago, because there does turn out to be at least one significant difference, namely Milankovitch Cycles.
There are three of these, and for us they repeat every thousand centuries or so. One is how circular or elliptical the orbit of the planet is, which varies between almost circular and 5% from circular. Since the Sun is always at one focus of the ellipse, this alters its position more than might be thought. Also, over forty-one millenia the planet tilts more or less, between 21 and 24 degrees from right angles to the plane of its orbit. Finally there’s a twenty-three millenium wobble, which is quite widely known, called precession. The three of these together change how much light and heat from the Sun Earth gets, thereby changing the climate, substantially because ice is white and reflects heat. Again, however, the ultimate difference would amount to a few months, so although the onset of the ice ages and the warmer periods between them would be altered, it probably isn’t very significant. The Butterfly Effect loses again.
This brings us to the end of the last Ice Age, happening maybe nine months later, and since ice ages don’t have such rigid timetables this really means nothing. The climate in the Sahara would alter in its usual cycle, so it makes no difference to when the people who left Africa did so or when others crossed the Bering land bridge much later on, during the last Ice Age. All of this still seems inevitable and the fact that by the end of that time the planet happens to have orbited forty-two times less is pretty irrelevant.
One thing which would’ve been happening throughout this period is that in terms of strictly numbered years since the impact, astronomical events have been occurring in different years and different times of year. Eclipses in particular are very different. They occur on different dates and at different times, are of different types and durations and over different parts of the planet. Therefore there’s potential for differences in history. The Chinese astronomers whom the Emperor executed for failing to predict a solar eclipse would not have died. Earth dodged the Arizona meteorite and there is no Meteor Crater in Arizona, but of course there might be another crater elsewhere. There would also be minor differences in Moon craters. For instance, the 22 km wide crater Giordano Bruno appears to have formed in 1178, so that wouldn’t be there either, along with perhaps others, but others would be.
This is where it gets rather hard to think about. Assuming exactly twenty seconds difference over exactly 66 million years, which is spurious accuracy, the difference is not precisely forty-two years but forty-one years, 302 days, 20 hours, 20 minutes and 34.2 seconds according to the solar year, again with spurious accuracy. Over the five thousand years of recorded history the drift would amount to just over a day. The significance of this is that the seasons would be at different times of year if the year is thought of as a trip round the sun. They would in any case be at different times of year because the Milankovitch Cycles would be different. So would the solstices and equinoxes, for the same reasons. Since solar calendars such as our own are based on seasons and day lengths, the actual start of the year would be at a different time in terms of seconds since the extinction of the dinosaurs. Speaking of seconds, since they are 1/86400 of a day, they would be very slightly longer and the year would be the same length. The speed of light would therefore seem to be very slightly slower although in fact it wouldn’t be. The astronomical unit, however, would not be different as it’s rounded off and the difference in the distance of the Earth from the centre of gravity wouldn’t be big enough for it to make any difference. This also means that the parsec would be the same length because measurements can’t be accurate enough. The light year, however, would be longer by twenty light seconds.
It would in fact be forty-two years earlier, but in order to make this show on a calendar the assumption must be made that the date of the beginning Christian Era, along with the points in time for all the other dating systems, is fixed. I have in fact chosen to assume this although it does make it a religious statement. The idea is that the birth of Jesus, which incidentally occurred in 4 BCE rather than 1 BCE/CE because of a mistake by the Venerable Bede who invented this dating system (there is no year zero), occurred at the same time as it would’ve done anyway in absolute terms, so it is in fact now 1975 rather than 2017. Jesus was born during the rule of Caligula rather than Augustus and was crucified not in the time of Tiberius but that of Vespasian. This has several particularly interesting consequences. It means that:
- His ministry began just after the destruction of the Second Temple.
- The Epistle to Titus is called Traian instead, assuming that Titus was named after the emperor.
- The Number of the Beast is 1260 rather than 666, because numerologically the name used appears to have been that of Nero, but in this reality it would’ve been Traian instead because he was on the throne at the appropriate time. This assumes a preterist interpretation of Revelation, where it’s seen as a disguised account of the events of the first Christian century. It so happens that the number 1260 also occurs in Revelation in any case, so this is a world where the Number Of The Beast is mentioned a total of three times and is numerologically the same as the title of one of the books in the New Testament. Someone might use this.
- Although the first pope is called Peter, this is not the Peter of this timeline but someone else. This means there are fewer popes in this timeline. Assuming Alexander I is the second pope, there are four missing popes and the regnal number of the Clements is one lower.
- Assuming that the darkness after the Crucifixion was a real event and a genuine eclipse, which some early texts say it was and for which there is an apparent candidate at the appropriate time, the heavens did not darken after the death of Jesus in this timeline, which makes the gospels one verse shorter for that reason if not others.
Passing beyond the immediate aftermath of the foundation of Christianity, the next issue is Constantine’s conversion and his decision to make Christianity the official religion of the Roman Empire. In order to keep history in step in terms of absolute time since the extinction of the dinosaurs, the Edict Of Milan, which declared the Empire Christian, occurred in 271. Since I believe Christianity was responsible for the fall of the Roman Empire by causing people to focus on the hereafter, this would lead to the Goths sacking Rome in 368, and so it continues forty-two years ahead of us in calendar terms right through history. Easter, all movable feasts and Passover would all be on different dates.
Another set of differences is astronomical. The solstices doe not occur when the Sun enters Capricorn and Cancer, but Aquarius and Leo. Or so it seems. If the hypothesis that the sequence of the Zodiac is named after dominant seasonal incidents, they would be in the same places but these would be at different times. However, for the sake of this idea I assume that this is a merely mnemonic device, since I genuinely believe that Scorpius, for example, does look like a scorpion, meaning that Libra, having been formed from its “claws”, would still be next to it, and this in general suggests that they would have the same locations relative to each other.
Hence there are tropics of Leo and Aquarius rather than Cancer and Capricorn. This means that the books ‘Tropic Of Cancer’ and ‘Tropic Of Capricorn’ by Henry Miller are called something else, possibly ‘Crazy Cock’ and ‘Crazy Hen’. Another literary change is ‘1984’, and this has considerable consequences too. George Orwell will have written it in 1906 and swapping over the last two digits would make it ‘1960’. 1960 is our 2002. This means that the John Hurt ‘1984’ film does not exist, that the Eurhythmics didn’t bring out the album ‘Nineteen Eighty-Four’ and that the influence of ‘1984’ on Terry Gilliam’s ‘Brazil’ is absent. However, Bowie’s ‘The Diamond Dogs’ still refers to ‘1960’. This would’ve made a difference to the careers of Annie Lennox, John Hurt, Richard Burton and Terry Gilliam.
By contrast, ‘2001’ would still be called that but it would be set in a more distant future which we have yet to reach. On that subject, there would have been no Y2K bug in 1958 and presumably the problem would be completely solved by the time the year 2000 came around. ‘1066 And All That’ would be called ‘1024 And All That’ and England would’ve won the World Cup in 1924. Columbus would have sailed the ocean blue in 1450, so that rhyme would have to be different.
Anyone falling asleep here and waking up in the 20 seconds later universe the next day wouldn’t notice much awry other than the date being way out. This would be a 1970s with Donald Trump and social media. The world would’ve been changed by an attack on the Twin Towers on 9/8. There would be a number of trivial differences in popular culture, such as the probable absence of ‘Twelve Monkeys’, the Asian radio station GEM AM being a heavy metal station instead and so on, which nobody would be able to account for easily.
I want to use this scenario as the basis for writing but I don’t know what to do with it. One merit it has, however, is its resemblance to the kind of trivial popular culture differences often associated with the Mandela Effect, and for this reason it also interests me. The trivial results from the year being twenty seconds longer seem inconsequential but in fact would here be caused by such a tiny change. This is like the universe next door, and it illustrates that some unknown detail could be different and lead to such differences.
But mainly I just want to use it as a basis for a story.