Can we travel in time? Can we find a portal to the past or a shortcut to the future? These questions have been asked by millions of curious minds. But how many are actually close to reality? Is time travel possible?
Well, this is a relatively vast area to discuss and a fairly difficult one to understand. So lets view it form a different perspective. There are known 3 dimensions. We all know everything exists in length, width and a height. But are people aware of the fourth dimension, length in time itself? Every thing has a length in time. So basically travelling in time is travelling through the fourth dimension.
Time travel to the past is proven not possible as it creates paradoxes, if we go to the past we might alter the future which would violate an important rule of physics ; Cause happens before effect. But there is one thing possible:
Time travel to the future.
Time flows like a river and it seems as if each of us is carried relentlessly along by time's current. But time is like a river in another way. It flows at diff erent speeds in diff erent places and that is the key to travelling into the future. This idea was first proposed by Albert Einstein over 100 years ago. He realised that there should be places where time slows down, and others where time speeds up. He was absolutely right. And the proof is right above our heads. Up in space.
This is the Global Positioning System, or GPS. A network of satellites is in orbit around Earth. The satellites make satellite navigation possible. But they also reveal that time runs faster in space than it does down on Earth. Inside each spacecraft is a very precise clock. But despite being so accurate, they all gain around a third of a billionth of a second every day. The system has to correct for the drift, otherwise that tiny di fference would upset the whole system, causing every GPS device on Earth to go out by about six miles a day.
The problem doesn't lie with the clocks. They run fast because time itself runs faster in space than it does down below. And the reason for this extraordinary e ffect is the mass of the Earth. Einstein realised that matter drags on time and slows it down like the slow part of a river. The heavier the object, the more it drags on time. And this startling reality is what opens the door to the possibility of time travel to the future.
Right in the centre of the Milky Way, 26,000 light years from us, lies the heaviest object in the galaxy. It is a supermassive black hole containing the mass of four million suns crushed down into a single point by its own gravity. The closer you get to the black hole, the stronger the gravity. Get really close and not even light can escape. A black hole like this one has a dramatic e ffect on time, slowing it down far more than anything else in the galaxy. That makes it a natural time machine. There is another safer way to travel into space without the fear of getting sucked in a black hole.
You just have to travel very, very fast. Much faster even than the speed required to avoid being sucked into a black hole. This is due to another strange fact about the universe. There's a cosmic speed limit, 186,000 miles per second, also known as the speed of light. Nothing can exceed that speed. It's one of the best established principles in science. Travelling at near the speed of light transports you to the future.
To approach the speed of light means circling the Earth pretty fast. Seven times a second. But no matter how much power a vehicle has, it can never quite reach the speed of light, since the laws of physics forbid it. Instead, let's say it gets close to the ultimate speed. Now something extraordinary happens. Time starts flowing slowly on board relative to the rest of the world, just like near the black hole, only more so.
The live example is the world's largest particle accelerator at CERN in Geneva, Switzerland.
Deep underground, in a circular tunnel 16 miles long, is a stream of trillions of tiny particles. When the power is turned on they accelerate from zero to 60,000mph in a fraction of a second. Increase the power and the particles go faster and faster, until they're whizzing around the tunnel 11,000 times a second, which is almost the speed of light. But just like the train, they never quite reach that ultimate speed. They can only get to 99.99 per cent of the limit. When that happens, they too start to travel in time. We know this because of some extremely short-lived particles, called pi-mesons. Ordinarily, they disintegrate after just 25 billionths of a second. But when they are accelerated to near-light speed they last 30 times longer.
So I say time travel is possible!