Time is always an interesting subject. Everybody in the world experiences time, with the most common use the ability to determine a specific point of time. This is usually prompted by the simple question ‘What is the time?’, and any person with a watch could easily provide us with a value of the current time. For example, according to my laptop it is currently 12.21pm.
Of course we can split time into several sections. From seconds, minutes and hours to days, months and years – even up to decades, centuries and millennia. Using this I could easily arrange to meet someone on the 20th hour of the 23rd day of the 3rd month of the 2013th year (AD), which we would obviously just describe as 8pm on the 23rd March. It is just the way we have decided to describe specific points in time.
We can also use these parameters to measure a specific period of time, more likely in sport than anywhere else. For example, a football game last 90 minutes, a hockey game last 70 minutes, a rugby game last 80 minutes, and an American football game lasts 60 minutes (though they somehow manage to stretch that out into about 3 hours!). Without the ability to determine a specific period of time these games would not exist, or would go on forever!
From a scientific point of view, time is very important in describing the attributes of the universe. Without it we wouldn’t be able to determine the velocity of an object (distance divided by time), or any of the equations of motion in general.
On the other, more complicated end of the scale time has an important use in relativity. If we put two people with a clock each on two separate trains and pushed them up to near light speed, then person 1 would observe that the clock on person 2’s train would be running slower than their clock. Similarly, person 2 would observe that the clock on person 1’s train would be running slower than their clock also. This would tell us that at near light speed, moving clocks run slow to an external observer. This is the basis of time dilation. This is also one possible way of travelling into the future.
Einstein famously said of relativity: ‘When you are courting a girl an hour seems like a second. When you sit on a red hot cinder a second seems like an hour. That’s relativity.’
Time also has important properties in space. If you approached a black hole and somebody was observing you from a safe distance, then to that observer you would appear slower and slower the closer you got to the black hole, until you eventually froze in space. In your time frame though everything would appear as normal, and if you retreated away from the black hole again to the observers position you would find that time would have moved forward much more than you would have experienced by going to the black hole and back again. This is another possible way of time travel, but only into the future.
But what about time travel into the past? Well one theory is to travel faster than the speed of light, however this would technically mean arriving before you had even left, plus would require an infinite amount of energy to break the speed of light. Another theory would be to discover a wormhole which would work in a similar way to traveling at near the speed of light. Another theory also states that if time travel was invented we would only be able to go between the future and the specific point of time, but not before.
There is one way of course that we can look into the past, and everyone is able to do this. It is simply done by looking at the night sky (weather dependant!). The further you look into the night sky, the further you are looking into the past. For all we know many of the stars we see no longer exist and as a result many new ones would have been formed. Even in the daytime if you were to look at the sun (not directly!) then you are actually viewing the sun from 8 minutes ago!
And I’ll finish with a joke…….
Proudly showing off his new apartment to a couple of his friends late one night the drunk led the way to his bedroom where there was a big brass gong. “What’s that big brass gong for?” one of the guests asked. “It’s not a gong. It’s a talking clock” the drunk replied. “A talking clock? Seriously?” asked his astonished friend.
“Yup” replied the drunk. “How’s it work?” the second guest asked, squinting at it. “Watch” the man said. He picked up a hammer, gave it an ear shattering pound and stepped back. The three stood looking at one another for a moment. Suddenly, someone on the other side of the wall screamed “You friggin’ IDIOT!…it’s ten past three in the morning!”