{"id":754,"date":"2024-12-31T19:35:21","date_gmt":"2024-12-31T19:35:21","guid":{"rendered":"https:\/\/home-ed-in-a-shed.blog\/?p=754"},"modified":"2024-12-31T19:35:24","modified_gmt":"2024-12-31T19:35:24","slug":"a-time-travellers-guide-to-the-universe","status":"publish","type":"post","link":"https:\/\/home-ed-in-a-shed.blog\/?p=754","title":{"rendered":"A time-traveller’s guide to the universe"},"content":{"rendered":"\n

Hey Blog! As it\u2019s the end of the year, and it seems as if this year has gone even faster than the one before, I started thinking about time \u2013 and therefore, it is \u2018time\u2019 to share it with you!<\/p>\n\n\n\n

Most people do not consciously think too much about time. Animals likewise – apart from knowing when to get up, when to go places, when to eat and drink, or when to go to sleep again, it\u2019s unlikely that animals bother too much consciously considering time. Some animals do need to use time seasonally, of course: mating, migrating, and hibernating, or in humans, cultivating; all are seasonal activities which we need to know the time for. But while almost every animal has an inbuilt body-clock, or sometimes multiple clocks, these are mostly below the level where we can consciously rely on them. Humans are probably the only animal which records time externally, and the best example to start with is a clock.<\/p>\n\n\n\n

A clock doesn\u2019t actually measure the flow of time \u2013 nothing can. All we can measure is how something else is affected by the passage of time. In the case of a battery-powered clock we are using the stored energy in the batteries to turn a second, minute and hour hand, and because the clock\u2019s own mechanism regulates how much energy is released at once, we can set the hands to move at a constant rate which means that, if each hour is the same length, we can measure how much time has passed. If I took your clock off the wall and manually moved the hour hand forwards one hour, it doesn\u2019t mean that the very time of day has changed \u2013 only the time recorded by that clock. Even if I hacked the supercomputers, changed the time on every single time-keeping device in the world, I still wouldn\u2019t have changed time \u2013 though I might have wreaked havoc world-wide as deadlines, emails, meetings and birthday parties would have been moved ahead according to the clock!<\/p>\n\n\n\n

While I can\u2019t literally alter time, I can record its passage in many ways. For instance, grandfather clocks, which have to be wound up, use a complex system of levers, bars and weights to move the hands and prevent the winding weight from falling instantly. Alternatively, quartz clocks are run on the interaction between electrical impulses and quartz crystals. The quartz sends a constant-rate impulse when you put a charge through it, which means we can measure how much is released and how fast and thus run time off that. Ancient Egyptian water clocks had a small hole which the water drained from, and how much drained in a single night meant you could fill it up once a day and determine the time after that from markings on the walls. Candle clocks use a set length of candle and a known length of time it takes to burn, combined with markings on the side like water clocks by which you can read how long it has been burning and thus the time. In theory, you could measure time by any means whereby a constant rate of change has occurred over a long period combined with a scale to mark its passage.<\/p>\n\n\n\n

You will probably have noticed in that last paragraph that time is, quite simply, a rate of how long it takes to do things. As I read in a book once, \u201cWhat is time but motion?” Taking time as a measure of motion, or any process, you could record time by how long it takes for me to write this blog, but since sometimes it takes forty minutes to finish a post and sometimes takes three hours, I don\u2019t think it\u2019s a very consistent scale!<\/p>\n\n\n\n

Time can, as we have seen, be measured by different scales. However, these differ drastically depending on the time we want to reference. Oddly, light years are not a measure of time but of distance, because they are how far light can travel in a year. That is, one Earth year \u2013 a Mercury year is shorter than a Mercury day, for instance \u2013 but a Mercury day is longer than an Earth day. However, this doesn\u2019t even cover how space and time interact. The esteemed Albert Einstein was an expert at this, and he formulated the two Theories of Relativity. Special relativity is, to put it extremely simply, that the laws of physics always apply; that the speed of light in a vacuum is always the same; and the formula E=mc2<\/sup>, which means that essentially, mass and energy are the same thing. However, General <\/em>Relativity is the theory that space and time are intertwined in a universal blanket known as spacetime, which the existence of mass bends to create gravity. Thus, if objects can be spatially affected by gravity, they can also be affected timewise. The discovery of the whole spacetime continuum is an incredible feat of theorising, reasoning, and endless calculations. And it also offers time travel scientists both a possible line of inquiry and a good thing to use to explain everything (like archaeologists and \u201critual\u201d!).<\/p>\n\n\n\n

Speaking of time travel\u2026 this is a very strange field of research. No one has yet proven it is possible \u2013 but absence of evidence does not constitute evidence of absence. It is speculated that were you to circle a black hole, you would see yourself going round on the other side, in the past (or maybe in the future) \u2013 because the immense gravity of the black hole has warped the time element so much that you could see yourself in the past (or the future). I once personally formulated a theory that if you go faster than the speed of light you go either backwards or forwards through time \u2013 but this is impossible, since the speed of light in a vacuum is the fastest thing that can ever be. One clue that someone has developed a time machine is that time travel is illegal in China. Yes, there is a law which means you could go to jail if you used time travel. Admittedly this is unlikely to ever be implemented, but then again\u2026<\/p>\n\n\n\n

Authors have also used this as a major plot device. While I have never watched Doctor Who<\/em> (in fact, the list of movies and TV shows I have watched is very low overall; I primarily devote time to history\/wildlife documentaries) I have read The Dark Is Rising<\/em> and a few similar books. What I have gleaned from this is: time travel is a more complex plot device than you might think. To do it properly and believably (at least to me), I would have to conform to the rules of physics or else blur it over with a lot of sparkly effects. And that is not even incorporating whether going back in time means you can change the past, thus changing the future (the present); or creating a parallel, alternate world; or whether you can\u2019t go back at all, just forwards. Just don\u2019t mess with tales of the fairies \u2013 if they whisk you away, you may return in a hundred years after being away only a few minutes. A bit like me with books, only much, much more severe!<\/p>\n\n\n\n

I will leave you with two paradoxes. Firstly:<\/p>\n\n\n\n

A young man discovers a time machine. He uses it to visit the past, and see his grandparents who he never met. Unfortunately, a tragic series of accidents means he manages to kill his grandfather simply by appearing in the past. By killing him, his parent cannot be born, and thus he cannot be. Therefore, he cannot go back in time and kill his grandfather. Therefore, his grandfather does not die, has a child and subsequent grandchild who finds a time machine, and so on\u2026<\/p>\n\n\n\n

A young woman discovers a time machine. She goes back in time and manages to crash the machine, and is stuck in the past. She meets a young man, and they go on to get married and have a child. This child looks just like her\u2026 then she realises that events are happening just as they were when she was a girl, before she went back to the past. That\u2019s when her daughter disappears, in a time machine, to go back to the past, to become her. So where did she come from? Which time is real?<\/p>\n\n\n\n

Ultimately, if time travel is real, it would mean there is no past, no present and no future. As once written on a sundial, \u201cTime is, time was, time is not.\u201d<\/p>\n\n\n\n