While listening to my younger daughter Jemima singing in Winchester Cathedral with her university choir, I idly picked up the Book of Common Prayer and leafed through it. I came across a section that gives the methodology for calculating the date of Easter, all the way up to the year 2300. I thought that this was optimistic on the part of the bookbinders, that this particular book might last that long, but then again, some books are hundreds of years old, and a few of them are more than a thousand years old.
Anyway, it got me thinking about how long it is sensible to plan into the future, and about events that will inevitably occur in the longer future. In the human world, we all worry about events that are imminent - on the scale of hours, days, weeks or even months. We can easily envisage them on that time-scale, even if we can’t properly forecast them.
However, on longer times-scales, things become much more difficult - who foresaw Mr Putin’s War in Ukraine a year ago? Who knows what the situation will be, one year hence? However, in the non-human world, based on physics and chemistry, things are much more pre-ordained - we know that they will happen, with or without us. One such timeline of the far future1 actually only starts at the end of the year 3000, but then extends to ages that are unimaginably vast - beyond billions, trillions or even quadrillions of years old. Here are some future highlights to look forward to:
By one reckoning, by the year 12,000, humanity has a 95% chance of being extinct;
In any case, by 17,000, it is more likely than not that a ‘civilisation-threatening supervolcano’ will have erupted, spewing out more than 1000 Gigatonnes of material;
In a piece of possibly good news, by around 100,000 years hence, it will have been possible to terraform Mars into a planet habitable by humans;
By around 500,000 years into the future, it is more likely than not that the Earth will have been hit by a meteor of more than 1km in diameter (assuming that it cannot be averted);
Due to the gradual slowing of the Earth’s rotation, by 3 million years’ time, a day will be one minute longer (and by 180 million years hence, a full hour longer);
In 250 - 350 million years, all of the continents on the planet may fuse together into a supercontinent - possibly leading to global cooling;
In 500 - 800 million years, the Sun’s increasing luminosity will ultimately lead to the death of all plants, while the cooling of the Earth’s core will lead to the end of plate tectonics and mountain-building, which will eventually lead to the Earth becoming a more-or-less flat, water-covered ‘Water-world’;
Due to depletion of CO2 in the atmosphere, after about 900 million years, only single-celled life will remain on the planet; In about 2 billion years, the trillion-star Andromeda Galaxy will make a close-pass collision with the perhaps 300 billion-star Milky Way Galaxy - our home galaxy. It’s unlikely that any stars would actually collide; Due to the Sun’s increasing luminosity, by 2.8 billion years, the Earth’s surface temperature will reach 147°C, and all life will have died out;
By 5 billion years’ time, Andromeda and the Milky Way will have fully merged, to form ‘Milkdromeda,’ a giant elliptical galaxy;
In about 7,900,000,000 years, the Sun will expand in size to the diameter of the Earth’s orbit and the planet will be obliterated;
During the period 100 billion to 1 trillion years hence, all 47 galaxies of the local group will coalesce into one big galaxy;
After a very large gap in time, by 1 nonillion years’ time (that’s 1030, or 1 followed by 30 zeros) the supermassive black holes in the heart of all galaxies in the universe will have consumed everything around them;
After an even-larger gap in time, by 30 tredecillion years’ time - 3×1043 - black holes are the only celestial bodies that remain - The Black Hole Era begins;
Through emission of Hawking radiation, black holes decay: By 10104 years hence, even the largest black holes formed from the collision of multiple galaxies, with masses of more than 100 trillion times that of the Sun, will have evaporated: “Beyond this time, if protons do decay, the Universe enters the Dark Era, in which all physical objects have decayed to subatomic particles, gradually winding down to their final energy state in the heat death of the universe.”
Admittedly, this is not a cheery scenario - eventually all life will die, all stars will cease to shine and all points in the universe will be at an equally chilly zero Kelvin - Absolute Zero. However, all this gloom really serves to remind us all of one thing: to ‘live for today.’