Could We Ever Move Earth to a New Orbit or Colonize a Habitable World Among the Stars?

Every year, the Sun loses about 6 trillion kilograms of mass through solar wind. As it sheds mass, its gravitational grip on Earth loosens slightly, and Earth drifts outward by about 1.5 centimetres annually. That sounds negligible. Over five billion years, it adds up to almost nothing useful, because the Sun will expand into a red giant long before Earth drifts far enough to be safe. When that happens, it will swell to roughly 200 times its current diameter and swallow Mercury, Venus, and quite possibly Earth. The timescale is enormous, but the physics is not speculative. This is settled stellar evolution.
The uncomfortable version of this fact: humanity either leaves, moves the planet, or ends here. Those are the only three options astronomers and planetary scientists actually discuss.
In 2001, astronomers Don Korycansky, Gregory Laughlin, and Fred Adams published a paper in the journal Astrophysics and Space Science outlining a gravitational slingshot method to shift Earth's orbit outward. The idea: send a large asteroid or Kuiper Belt object on a precisely calculated flyby of Earth. The object's gravity tugs Earth slightly, and Earth's gravity tugs the object back. The object then swings around Jupiter or Saturn to reset its trajectory, and returns for another pass. Repeat this over millions of years, and Earth migrates to a safer orbit.
The numbers are staggering. To push Earth from its current orbit to roughly where Mars sits today, far enough to survive the Sun's expansion, you would need to perform this manoeuvre roughly every 6,000 years, for several million years. Each pass would shift Earth's orbit by a small but compounding fraction. The energy budget required is comparable to the total solar output over thousands of years. The engineering precision needed to avoid flinging Earth into deep space or crashing it into another planet is, to put it plainly, beyond anything humans have built, but not beyond the laws of physics.

A separate proposal, from engineer Stuart Sherwood and others, involves placing a massive solar sail at a specific gravitational balance point to redirect sunlight and apply a continuous, gentle push. This is slower and requires a structure larger than anything ever conceived, but it does not require sending asteroids past a populated planet at close range.
Moving Earth is the conservative option. The more radical answer is leaving it behind. The nearest star system, Alpha Centauri, sits about 4.37 light-years away. At the speed of Voyager 1, currently the fastest human-made object in interstellar space at roughly 17 kilometres per second, that journey would take about 75,000 years. Proposed concepts like laser-propelled lightsails, the Breakthrough Starshot initiative backed by Stephen Hawking before his death, aim to accelerate a small probe to 20 percent of the speed of light, cutting travel time to about 20 years. A crewed ship at that speed remains a different problem by several orders of magnitude.

Within our own solar system, the targets are closer and more credible. Mars is the obvious candidate. NASA's Artemis programme is building toward a lunar return that serves as a proving ground. ISRO's Gaganyaan mission, India's first crewed spaceflight programme, is designed to put Indian astronauts in low-Earth orbit and develop the operational experience that any longer-duration space mission requires. Astronaut Shubhanshu Shukla is scheduled to fly to the International Space Station as part of the AXIOM-4 mission, a step in that chain. Mangalyaan, India's Mars Orbiter Mission launched in 2014, reached Mars on its first attempt and at a fraction of the cost of comparable missions, demonstrating that Indian deep-space engineering is not aspirational, it is operational.
The habitable zone around a star is the band of orbital distances where liquid water can exist on a surface. In our solar system, Earth sits comfortably inside it. Mars sits at the outer edge. Several exoplanets in other star systems, including Proxima Centauri b orbiting our nearest stellar neighbour, sit in their own habitable zones. Whether they have atmospheres, water, or magnetic fields that could protect life is still unknown.

Terraforming Mars, meaning altering its atmosphere and temperature to support human life without suits, is not a plan with a timeline. It is a framework for thinking about what would be needed. Mars has about 1 percent of Earth's atmospheric pressure. Its average surface temperature is minus 60 degrees Celsius. It has no global magnetic field, so solar radiation reaches the surface directly. Proposals include releasing greenhouse gases from the Martian soil, redirecting asteroids rich in ammonia to crash into Mars and thicken its atmosphere, or deploying orbital mirrors to warm the surface. Carl Sagan proposed seeding Mars with photosynthetic bacteria in a 1973 paper in Icarus. Elon Musk has described wanting to detonate nuclear devices above the Martian poles to release frozen CO2. These are not engineering plans. They are starting points for conversations about engineering plans.
A conservative estimate from planetary scientists puts a minimally breathable Martian atmosphere centuries away, assuming continuous, large-scale intervention begins soon. A fully Earth-like Mars is a project measured in geological time.
Some proposals skip planets entirely. O'Neill cylinders, first described by physicist Gerard K. O'Neill in his 1976 book The High Frontier, are rotating space habitats large enough to generate artificial gravity through centrifugal force. A pair of counter-rotating cylinders, each roughly 8 kilometres in diameter and 32 kilometres long, could house several million people under simulated Earth conditions, with sunlight redirected by mirrors. The materials could be mined from the Moon or asteroids, avoiding the enormous energy cost of lifting mass out of Earth's gravity well. O'Neill's calculations were done with 1970s physics and remain structurally sound. What they require is not new science but sustained industrial capacity in space, which is exactly what programmes like Chandrayaan-3's successful south pole landing in 2023 are beginning to build toward, by mapping lunar water ice that could supply both drinking water and rocket propellant for future operations.
The honest answer to whether humanity could ever move Earth or build a home among the stars is: the physics permits it, the timescales are vast, and the first small steps are already underway, not as metaphor, but as actual missions with actual launch dates.
The distance between a Chandrayaan landing and an O'Neill cylinder is not a gap in imagination. It is a gap in accumulated capability, and capability accumulates. Each mission that maps a resource, tests a life-support system, or keeps humans alive a little longer in space adds one more layer to the answer. The planet-moving paper from 2001 and the Gaganyaan launch schedule belong to the same long chain. What makes the question worth taking seriously is that the chain is already being built, one link at a time, by real agencies, with real budgets, pointed at real destinations.