Imagine this: The year is one billion AD. The Sun has become a much brighter, angrier version of itself, pouring out enough heat to turn Earth into a giant oven. Everything on the surface is scorched, and life as we know it is impossible. This isn’t the premise of a sci-fi movie, although it could be—it’s a future that scientists predict will happen. So, the question becomes: can we escape? Can we give Earth a push, just enough to move it out of harm’s way?
This is exactly the question posed by Manni Frei in reference to the film The Wandering Earth, where humanity decides to pack up and move the whole planet before it’s consumed by the Sun. As outrageous as it sounds, is such a plan even remotely possible? Could we actually shove Earth out of its orbit?
The Lifespan of Stars (and the Earth)
First, a quick crash course in astrophysics: stars, like our Sun, are not eternal. They have life cycles. Stars form in massive gas clouds, where gravity pulls everything together until nuclear fusion kicks off. This fusion process generates energy, and it’s what keeps a star from collapsing under its own weight. In the Sun’s case, it’s been burning hydrogen for billions of years, but this won’t last forever.
As stars age, they increase in brightness and energy output. For example, our Sun is now about 40% brighter than when it first started. In a billion years, that increase will be so extreme that Earth’s surface will resemble a fiery wasteland. The once-comfortable habitable zone—the region around a star where conditions are right for liquid water and life—will shift outward, leaving Earth behind to roast.
So, what’s the plan? Either we pack up and move to another planet, or we figure out a way to keep Earth in the habitable zone by giving it a cosmic nudge.
Option 1: Turn Down the Sun
The first idea might seem like a no-brainer—why not just dim the Sun a little? Keep its brightness in check, and voilà, problem solved! Unfortunately, as cool as it sounds, this plan is about as practical as trying to extinguish a forest fire with a garden hose.
The Sun is a massive ball of gas with 333,000 times the mass of Earth. It’s 700,000 kilometers wide, and its energy production is off the charts. There’s no feasible way to “dial down” the fusion process happening at its core. The sheer scale of the Sun makes any form of manipulation utterly impossible. So, the dream of controlling the Sun’s brightness quickly fades into the realm of bad sci-fi.
Option 2: The Great Galactic Migration
Since we can’t tweak the Sun, how about packing up and leaving Earth behind? This, after all, is the classic human response to trouble—migrate! Our ancestors did it during the Ice Age, and they weren’t even facing a burning planet. So, why not do it again?
The problem is, this time, we’re not talking about crossing continents—we’d need to cross space. A lot of space. Imagine trying to move 10 billion people off Earth to a nearby planet like Mars. Let’s say you could fit 10 people into a spaceship and launch 100 ships per day. At that rate, it would take about 27,000 years to move everyone. And that’s if you can keep things running smoothly for nearly 30 millennia—no breakdowns, no delays.
And where would we even go? Mars? Sure, it’s the closest planet that’s even remotely plausible. But Mars is tiny, with only about a third of Earth’s surface area. If you think Earth feels crowded now, imagine cramming 10 billion people onto Mars. And that’s not even taking into account the fact that Mars has no atmosphere to speak of, no liquid water, and generally looks like the set of a particularly depressing dystopian movie.
Option 3: Earth on the Move
If we can’t leave Earth, maybe we can take Earth with us. What if we turned our planet into a cosmic caravan?
In The Wandering Earth, humanity does just that—they install giant engines on the planet to push it out of the solar system, avoiding the Sun’s fiery expansion. Sounds simple, right? Just strap some rockets to the South Pole, fire them up, and blast away!
Not so fast. The physics of moving an entire planet are, to put it mildly, complicated. To push Earth out of its orbit, you’d need to expel material at speeds greater than escape velocity—11.2 kilometers per second. That means whatever you’re shooting out the back of your giant Earth engine needs to leave fast enough to break free from Earth’s gravity.
Here’s the kicker: rockets only reach a fraction of that speed, and even if they could, you’d need to expel 85% of Earth’s mass just to get it moving. Yes, you read that right. We’d have to shoot most of Earth out the back to move the rest forward. Not exactly the most eco-friendly plan.
Option 4: Solar Sailing (Earth Edition)
What if we took a page out of the sailors’ playbook? When you can’t use engines, you hoist a sail and let the wind do the work. In space, we don’t have wind, but we do have solar radiation—the constant stream of energy from the Sun. Could we attach a giant solar sail to Earth and let the pressure of sunlight push us to safety?
It’s a cool idea, and in theory, it could work. Colin McInnes, a researcher, crunched the numbers and found that to move Earth, we’d need a solar sail 19 times the diameter of the planet—about 240,000 kilometers wide. The sail would need to be incredibly thin, just 9 micrometers thick, and tethered to Earth with cables stretching over 2 million kilometers.
Sounds good so far, right? Just one tiny problem: there’s no material in existence that could withstand the stresses involved. Even if we could build the sail and the cables, they’d collapse under their own weight, leaving us with a pile of very expensive space junk.
Option 5: The Gravity Assist
This next option is a bit more creative. Instead of trying to physically push Earth, why not use gravity? By passing a massive object close to Earth—like an asteroid—we could use its gravitational pull to give Earth a little tug, slowly shifting it out of orbit.
This idea works in theory, but in practice, it’s a logistical nightmare. To have any significant effect, we’d need to fly these objects past Earth at incredibly precise distances—about 10,000 kilometers away. And we wouldn’t need just one flyby; we’d need millions of them.
Imagine every year, humanity holds its collective breath as another asteroid zooms past Earth, hoping it doesn’t crash into us. It’s a bit like playing cosmic roulette, only the stakes are slightly higher.
The Ripple Effect: Messing with the Solar System
Let’s say we do manage to shift Earth out of its orbit, one way or another. Problem solved, right? Not exactly. Moving Earth would have serious consequences for the rest of the solar system.
The planets in our solar system are in a delicate gravitational dance, and changing the orbit of one planet could throw the others out of balance. Mercury, for example, could be knocked out of its orbit entirely, leading to chaos as it careens through the solar system. And don’t even get me started on what might happen if Venus gets pulled out of position. One wrong move, and we could be looking at a domino effect of planetary disasters.
Galactic Survival
In the end, the idea of moving Earth is both fascinating and terrifying. It’s a problem that every advanced civilization in the universe will likely face at some point—what do you do when your star gets too hot? The solution isn’t clear, but one thing is certain: if humanity wants to survive in the long run, we’ll need to think big. Really big.
Whether it’s developing new technologies to move planets or figuring out how to build self-sustaining space colonies, the future of humanity may depend on our ability to solve the ultimate cosmic puzzle. After all, joining the “Galactic Club” of advanced civilizations is going to require more than just physics—we’ll need a little bit of genius, a dash of creativity, and perhaps a giant space sail or two.
