It has been said that time is an illusion and lunchtime doubly so. But what is time, and how can we best use it, asks Shane Hegarty.
Here's a quick time travel experiment you can try in the comfort of your own home. Stand up from your chair. Walk across the room. Now turn around and walk back to the chair. Congratulations, you have aged a little less than the chair did in those few seconds.
Just the tiniest, most negligible amount, but even the ordinary act of motion is enough to create a time dilation between you and the chair. The faster you move, the bigger it gets. Take a flight across the Atlantic and you'll arrive billionths of a second younger than those you left behind. It's difficult to take it in. You may need to sit back down in that chair.
Here's another experiment. Sit in a traffic jam on a day when you have to be somewhere important, and watch how quickly the minutes pass even as time seems to crawl no quicker than the cars in front of you.
Few things are as perplexing as time, and there are few things with which we are quite so obsessed. Scientists try to understand it, the rest of us try to deal with it. We attempt to manage it better, to carve it into ever smaller portions. We live longer, yet we seem to have less time.
Meanwhile, the older we get, the quicker time passes. We reduce it to cliches, because time is money and time flies and time waits for no man. And we do that because it constantly frustrates us.
"What is time?" pondered Augustine of Hippo. "I know what it is, but when you ask me I don't." Or, as Douglas Adams explained it: "Time is an illusion. Lunchtime doubly so."
Much of which will be discussed at the upcoming Time Event hosted by the Royal Irish Academy (RIA). There, scientist John Barrow, poet Brendan Kennelly and novelist and critic John Banville will speak for 20 minutes each, followed by a panel discussion on the topic. It will deal with time travel and fiction, with science and philosophy. So little time, but so much to say about it.
Perhaps we are so fixated on time because from the moment we are born we have a clock beating in our chests, ticking away until that big day when the alarm goes off but you don't wake up. We don't have to discover time. We may learn how to measure it and read it, but it is something we understand from a very early age. We are aware that time's arrow points in only one direction although this, as one physicist has put it, "stops everything happening at once".
And yet, despite such intimate knowledge, it is elusive for scientists just as it is for the rest of us. There is, as Paul Davies puts it, "no common now", so even the most precise clocks do not measure the motion of time, only intervals. The shortest time interval yet measured is 100 attoseconds. That's an impressively short space of time. If 100 attoseconds were stretched to the length of one second, then one second would last 300 million years on the same scale.
We mightn't have reached such a level, but in daily life we have squeezed our time into ever smaller intervals. Five minutes here or there can make or break your day. That's a fairly recent trend. In the past our sense of time was tied in with the natural rhythms of the day, month and year. Gradually, the clock's hour hand was joined by the minute hand, then the second hand and so on to the attosecond. And yet, while we see it as inexorably stretching out ahead of us and trailing behind us, that might largely be a cultural preconception. It has been discovered that the Aymara people of the Andes perceive the flow of time as a mirror image of ours. For them, the past is ahead and the future behind them. The word for tomorrow is a literal translation of "some day behind one's back."
Only lately has time been measured seriously, since when it has proven not to run like clockwork. Newton thought of time as "flowing equably", that it was the same across the universe. Einstein came along and showed us that it depends on where you are looking at it from. His Theory of Relativity is famously difficult to comprehend, as much because it makes a mockery of our ordered sense of time.
His pivotal thought experiment involved twins, one of whom travels to the stars while the other stays at home. Ten years later, the traveller returns, but has only aged a year. She perceives 12 months as having passed, but to her homebound twin it has been a decade. Both are right. This has been proven several times, because an atomic clock put on an aircraft will run slower than one left behind - although this doesn't make it any easier to accept.
Einstein, thankfully, calmed things with a quip. "When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute and it's longer than any hour. That's relativity." Which is something we can all grasp. Even on a daily basis, time appears to flow at different rates. Sleep contracts it. Boredom stretches it. That it appears to speed up as we get older is a subject tackled in a new book, Why Life Speeds Up As You Get Older. Its author Douwe Draaisma points out that "this is a powerful time illusion and most people experience it". He suggests it is because our individual sense of time is wrapped up in memory, and new experiences make stronger memories than familiar ones. As our lives progress, they become filled with routine and early memories become much more vivid than those of later years because they hold so many first-time experiences. This also explains why holidays, which are filled with original experiences, seem to last longer than a normal working week.
"I would argue that the same holds true on a lifelong scale for youth memories," believes Draaisma. "When these are vivid again in old age, it seems as if the time as a youth has lasted longer than, say, a year during middle age." Fever seems to speed time up, a cold slow it down. Some drugs can do very strange things with it.
While recovering from cardiac surgery in 1996, Brendan Kennelly experienced several visions in which he "walked through history". He later turned his experience into the book, The Man Made of Rain, from which he will read at the RIA event. The visions confirmed for him the malleability of perception. "I understood I was in a situation of time that had nothing to do with the chronological concept of the phenomenon, but which had to do with the bridges between moments of intensity," he says.
We are intimidated by the loss of control over time, increasingly becoming almost slaves to it, he adds. The more we feel the need to break down the day and order it into suitable packets, the more it seems to escape us. We have less time than we used to, we are constantly being told, and have been reduced to scrabbling around for that much sought-after commodity that is "quality time". "Time is so terrifying that you have to wear it on your wrist," says Kennelly.
"You have to put it into an alarm clock at six or seven in the morning. You have to hang it from the wall in the form of a calendar. The only way to cope with time is to impose measurement on it. And I think it's such a mad and wonderfully wild phenomenon. And so impossible to grasp. The only way you can handle it is to measure it. There is a great line in one of Yeats's last poems [ Under Ben Bulben]: 'Measurement began our might'."
The RIA lecture will also look at the tantalising prospect of time travel; whether we can go back and if we would be allowed change things if we could. For the moment, though, this is only allowed through art, memory and imagination. You can travel into your twin's future - or your chair's - but they are one-way tickets. Otherwise, you'll just have to go with the flow. "I wasted time, and now time doth waste me," wrote William Shakespeare. But that is a somewhat gloomy way to end things. Let's listen instead to Thomas Edison, who remarked, "There is time for everything". Obviously, Edison never had to get the kids ready and to the creche in enough time to beat the traffic and get to a vital sales meeting.
The Time Event - Exploration of the Idea of Time, Cosmology & Literature is a free public lecture, taking place in BurkeTheatre, Trinity College Dublin, Apr 20th at 6.30pm. For tickets see www.ria.ie or call 01- 6762570
Timely thoughts...
"We must use time as a tool, not as a crutch." - John F Kennedy
"Half our life is spent trying to find something to do with the time we have rushed through life trying to save." - Will Rogers
"The future is something which everyone reaches at the rate of 60 minutes an hour, whatever he does, whoever he is." - C.S. Lewis
"Time is what prevents everything from happening at once." - John Archibald Wheeler
"Men talk of killing time, while time quietly kills them." - Dion Boucicault
