Did you ever wish you could go back in time and see how the Egyptians built the pyramids? Or maybe go ahead in time and see where you would be 10 years from now? If time travel were possible history would never be the same again. In fact nothing would be, because events could be manipulated even before they happen. let’s not complicate this already complicated topic.
We’d all love to travel through time, stopping at periods that we want to watch or even see if we could change something (without having serious consequences, of course!). But before we go meddling with the time-space continuum, let’s see whether time travel is actually possible.
To answer the burning question: Yes, time travel is possible. However, not in the way you think. In fact, you’re time travelling right now. As you’re reading this, you’re hurtling through time at the speed of one second per second. You’re constantly travelling through time, even when you’re sitting in that extra-long and dry class and it feels like the clock has stopped.
Unfortunately, time travel isn’t what sci-fi movies and books have told us it is. Who wouldn’t love to sit in a machine and shuttle through time? But many scientists have tried to prove time travel exists and have failed. Noted physicist Stephen Hawking once said, “The best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”
So what’s the big deal about travelling through time one second per second? Well, because we all experience it differently.
Famous scientist Albert Einstein came up with a theory about time and space called relativity. It is, even today, considered to be one of the most basic principles of physics. In the theory, Einstein put forth one very important point: nothing can travel faster than the speed of light. The theory also stated that the faster you travel, the slower you experience time.
This has been proven by many scientists over the years. One experiment had two clocks, one on the ground and one on an aeroplane flying in the same direction that the Earth rotates. After the plane completed a trip around the world, scientists saw that the clock on the ground was slightly faster than the clock on the plane, by a fraction of a second. So, this proved that the clock on the plane was travelling through time slower than one second per second. Today the most accurate clock in the world can spot the minutest of differences in time that was not possible earlier.
You may be wondering what the big deal is if a clock is a fraction of a second slower in an aeroplane. It doesn’t make a difference when you’re travelling, but it does make a difference to a vital part of our daily life: GPS tracking.
GPS satellites, or that tiny app on your phone that maps your location, help us all figure out where we are and where we’re headed. GPS (which stands for Global Positioning System) satellites orbit the Earth at approximately 14,000 kilometres per hour. And just like Einstein’s theory of relativity states, these satellites’ clocks are slower than the ones on Earth by a fraction of a second.
But there’s a twist: Another part of Einstein’s theory states that gravity curves time and space. What this means to time, is that when the GPS satellites are in space, they are orbiting at more than 20,000 kilometres per hour. This translates to the satellites experiencing time slightly faster than one second per second. This would make your navigation map go faster than you would be on Earth.
Thankfully, scientists in NASA and other space agencies, use maths to correct this gap and match our time with that of the satellites.
But we shouldn’t be disappointed. There is another, more technical, way to time travel — by crossing the international date line or IDL. The IDL is an imaginary line that runs from the North Pole to the South Pole, used to mark the end of a day and the start of another. When you cross it, you either lose or gain a day, depending on which direction you are travelling. If you are travelling westward, you gain a day and if you travel eastward, you lose a day. This is why, if you travel from the US to Australia, you tend to go back in time when you land! Speaking of time travel, here is a biographical sketch of Stephen Hawking the man who was noted for his work in the field of general relativity, space, time and blackholes.
Now that you know how we travel through time, which time period would you go to if sci-fi time travel was possible? Let us know in the comments below.
Learn more about space and time with these fascinating articles from Science Feed:
Can Your Cat or Dog Tell What Time It Is? The Answer Will Amaze You!
The time-travelling sneeze: How healers of the old world dealt with a cold
There’s a Traffic Jam in Space and It Could Turn Dangerous
1. Is backwards time travel possible?
Although humans can't hop into a time machine and go back in time, we do know that clocks on airplanes and satellites travel at a different speed than those on Earth.
2. Do time machines exist?
We can't use a time machine to travel hundreds of years into the past or future. That kind of time travel only happens in books and movies. But the math of time travel does affect the things we use every day. For example, we use GPS satellites to help us figure out how to get to new places.
3. Can a wormhole exist?
Einstein's theory of general relativity mathematically predicts the existence of wormholes, but none have been discovered to date.
4. What does Einstein say about time?
Time seems to follow a universal, ticktock rhythm. But it doesn't. In the Special Theory of Relativity, Einstein determined that time is relative—in other words, the rate at which time passes depends on your frame of reference.
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