Time Travel: How can we do it?
- Nikhil Patel
- 2 days ago
- 8 min read
Hundreds of Science Fiction movies talk about Time Travel. But, can we even do it? If yes, how? Turns out that, Albert Einstein and his theory of Relativity figured out a lot about time travel before any of us were even born.
The Dinner Party: Where Time Became a Place
It was a chilly evening in Victorian London, and the guests were gathered around a warm fire, sipping tea and sharing stories. But this wasn’t an ordinary dinner party—because the host, known only as The Time Traveller, was about to reveal something extraordinary.
With a sparkle in his eyes, he stood up and said, “You’ve all heard of length, width, and height. But there’s a fourth dimension—time.” The guests looked puzzled.
“Think about the weather,” he continued. “We can say where a storm is—north, south, up in the clouds—but we also say when it is. Tuesday’s storm. Tomorrow’s sunshine. Time, like space, is just another direction.”
The room fell quiet.
“If time is just another direction,” he said, “shouldn’t we be able to travel through it, just like we walk down a road?”
He pulled back a curtain to reveal a curious machine. It had levers, dials, and a shining crystal at its core. “This,” he said proudly, “is my time machine.”
The guests laughed nervously. Was this a trick? A magic show?
But then, he stepped inside.
With a final nod, he pressed a lever forward— and suddenly, everything around him began to blur. The candles flickered into long streaks of light. The clock on the wall spun wildly. Outside the window, the sun rose and set over and over again, flashing like a heartbeat.
Days turned into weeks. Flowers bloomed and withered in seconds. Buildings aged. The future was flying past.
DID YOU KNOW?
H.G. Wells wrote The Time Machine in 1895—long before Albert Einstein explained how time and space are connected. But Wells imagined time as a direction we could travel, which is pretty close to what modern science says today! Would you get into a time machine if you had the chance?
Over 300 years ago, a young man named Isaac Newton was sitting under an apple tree in his mother’s garden. It was a calm afternoon, and he was deep in thought.
Suddenly—bonk!—an apple fell and hit him on the head.
Now, most people would just rub their head and move on. But Newton was no ordinary thinker. He stared at the apple and asked a question that would change science forever:
“Why did it fall down? Why not up, or sideways?”
Of course, everyone knew that things fall to the ground. But no one had ever asked why. Newton did. He thought: maybe the Earth was somehow pulling the apple down. Just like a magnet pulls metal. He called this invisible pull gravity.
But Newton didn’t stop at ideas—he wanted numbers. He spent years studying motion and eventually came up with a brilliant formula to describe how gravity works:
This looks complicated, but here’s what it means:
F is the force of gravity between two objects.
G is a special number called the gravitational constant.
m 1 & m2 are the masses of the two objects.
r is the distance between their centers.
Basically, the bigger the masses, the stronger the pull. The farther apart they are, the weaker the pull.
So, What Did Newton Discover?
He figured out that everything pulls on everything else—not just apples and Earth, but planets, moons, even you and your pencil (though the pull is too tiny to notice).
Newton didn’t just explain falling apples. He showed that the same force that pulls apples down also moves the planets in the sky. It was one of the greatest scientific leaps in history.
Think About It: If you jumped high enough, could you escape Earth’s gravity? (Answer: You’d need to be going over 11 kilometers per second—that’s 25,000 miles per hour! So… better build a rocket!)
Einstein and Spacetime
Isaac Newton gave the world a big idea: gravity. He showed how apples fall, how the Moon orbits Earth, and how planets move around the Sun. But there was one thing he couldn’t explain:
What is gravity, really?
Newton simply assumed that gravity was a force objects had, like an invisible rope pulling things toward them. He called it a “property” of matter. But he didn’t know why it worked that way.
Fast forward about 200 years, and along comes a wild-haired genius named Albert Einstein. He looked at Newton’s idea and said,
“Hmm… this doesn’t quite add up.”
Einstein wasn’t happy with the idea of gravity as a mysterious pulling force. He believed that the answer had to be deeper—and so he came up with a completely new way to think about space and time.
He called it the Theory of General Relativity, and it changed everything.
The Fabric of Spacetime
Einstein imagined space and time as one thing: spacetime. You can think of spacetime like a giant stretchy sheet—sort of like a trampoline or a big piece of fabric that stretches across the whole universe.
Now, imagine placing a heavy bowling ball (that’s a planet) in the middle of the fabric.
What happens? The fabric sags around it!
If you now roll a smaller ball (like a marble) near the dip, the marble doesn’t go in a straight line—it starts spiraling around the bowling ball, caught in the curve of the fabric.
That’s how Einstein said gravity works. It’s not a pulling force. It’s the curving of spacetime around massive objects like planets, stars, or black holes. The more massive the object, the deeper the sag.
The Earth is like a big bowling ball sitting on the fabric of spacetime. It creates a dip around it. The Moon, like a marble, is rolling near the edge of that dip. But instead of falling in, it keeps going sideways and ends up orbiting
Earth—always falling, but never crashing.
The same thing happens with planets around the Sun. They’re caught in the Sun’s giant spacetime curve.
Einstein’s idea explained things Newton never could—like why light bends around stars, or why time ticks slower near massive objects (yes, really!).
So, What Did Einstein Do?
He didn’t just tweak Newton’s theory. He rewrote the laws of gravity.
Instead of asking what gravity is, Einstein asked how space and time behave near big masses— and that made all the difference.
Think About It: If you placed a super-heavy object on the fabric of spacetime, like a black hole, what would happen? (Hint: it would make a hole so deep, even light couldn’t escape!)
Einstein showed us that the universe isn’t just filled with stuff—it’s filled with a shape-shifting fabric, and that’s what guides everything, from falling apples to orbiting moons.
Pretty cool, right?
A Thought Experiment
One evening, Albert Einstein was riding a tram through the streets of Bern, Switzerland. As the tram moved away from the famous clock tower, he glanced back and had a strange thought.
“What if this tram was moving as fast as light?”
He imagined racing away at the speed of light—and he realized something odd. If he were moving that fast, the light from the clock tower—the light carrying the image of the clock’s hands—would never catch up to him.
To him, it would look like the clock had frozen. The hands would stop moving.
But for the people still standing near the tower, nothing would seem strange. The clock would keep ticking, second by second, like always.
So what’s going on?
Einstein figured it out: Time itself changes depending on how fast you’re moving. When you move really fast—close to the speed of light—time slows down for you.
He imagined coming back to the clock tower after his super-speed journey. The hands on the tower would show that more time had passed than on his own wristwatch.
That meant only one thing: He had traveled through time.
Not by magic. Not with a machine. Just by moving fast .
The faster you travel in space, the slower you move through time.
This idea became part of Einstein’s Theory of Special Relativity—and it’s not just science fiction. Astronauts on the International Space Station age just a tiny bit slower than we do on Earth.
So, in a way, Einstein proved that time travel is real.
Pretty cool for a tram ride, right?
Light, Sags, and Slower Time A Cosmic Shortcut That Isn’t
Imagine spacetime—the universe’s fabric—as a big, smooth, flat table.
Now, imagine a ray of light traveling straight across it. Since the surface is flat, the light takes the shortest possible path from Point A to Point B. It zips straight across, nice and quick. But now let’s add something big and heavy to the middle of the table—like a bowling ball.
That weight causes the surface to sag, just like massive planets or stars bend spacetime.
Now, if the ray of light wants to go from Point A to Point B, it can’t take the flat, straight route anymore. Instead, it has to curve around the sag, like going around a dip in the road.
The path is now longer—even though the start and end points haven’t changed.
And here’s the important part:
Light always travels at the same speed.
So if the path is longer, it takes more time to get there.
This means that in areas where space is curved—where the universe is “sagging”— light takes longer to pass through. To someone watching from far away, it looks like time is running slower in the sag. It’s like a slow-motion zone.
Real-Life Example The Sun and a Bending Beam
During a solar eclipse in 1919, scientists saw that light from stars behind the Sun appeared slightly out of place. Why? Because the Sun’s mass bent spacetime, and the starlight had to curve around the sag. It traveled a longer path.
That proved Einstein was right: Gravity bends light, and slows time.
How We Know It’s All True? Real-Life Time Travel Examples
Einstein’s ideas weren’t just cool thoughts— they were tested, measured, and proven true. Here are two real-life examples that show time really does move differently depending on gravity and speed:
The ISS and the Slower-Ticking Astronauts
Astronauts on the International Space Station (ISS) are orbiting Earth at around 28,000 kilometers per hour. That’s super fast! And even though they’re a bit farther from Earth’s gravity, their speed causes time to tick slower for them compared to people on Earth.
After spending months in space, an astronaut returns slightly younger—by just a few milliseconds—but still younger! That’s time travel into the future, thanks to relativity.
Airplanes and Atomic Clocks
In an experiment, scientists placed atomic clocks (which are super precise) on fast-moving Airbus planes, while keeping other clocks on the ground.
After the flight, they compared the clocks— and found that the ones on the airplane had ticked a tiny bit slower than the ones on Earth. Einstein was right again: the faster you go, the slower time moves.
So... Could a Time Machine Work?
If time slows down with speed or gravity, then a time machine doesn’t have to be magic. It could be:
A super-fast spaceship, traveling near the speed of light (time slows down for you).
A trip near a black hole, where gravity is extreme (time moves slower near it).
Or a future technology that bends spacetime itself—like creating a tunnel through space and time (a wormhole).
Einstein showed us that time is not fixed. It can stretch, bend, and even freeze under the right conditions.
So while we don’t have a time machine yet, the science behind it is real.
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