A billion years from now, the sun will begin to swell into a massive red giant, swallowing Earth's oceans and atmosphere and likely engulfing our planet entirely. But here's the remarkable part: we might not need to flee into space to survive. A team of scientists and engineers has mapped out an ambitious, if purely theoretical, plan to keep Earth alive — and it all starts with building a sunshade the size of a small moon.
The idea, explored in detail by researchers working at the intersection of astrophysics and speculative engineering, relies on placing a giant shade at a gravitational "sweet spot" called Lagrange point 1, positioned between the sun and Earth. To fully eclipse a red giant sun, this shade would need to stretch 350,000 kilometers across — roughly half the distance from Earth to the moon. The tether to hold it in place would be 2 million kilometers long, requiring raw materials from Ceres, a dwarf planet in the asteroid belt. Scientists estimate we would need to mine 40 percent of Ceres just to build it.
Blocking the sun solves one problem but creates another: no sunlight means no warmth or energy for life. Here the solar system's gas giants come to the rescue. Jupiter and its siblings are essentially giant balls of fusion fuel. According to the researchers' calculations, they contain enough hydrogen and helium to produce artificial sunlight for Earth for an astonishing 9.1 quadrillion years. The plan calls for floating fusion reactors sunk 6,500 kilometers into Jupiter's atmosphere, generating energy that would be beamed by laser to a relay point and then reflected down to Earth.
Moving Earth itself poses another challenge. As the sun expands, our planet would need to drift farther away to avoid being consumed. Rather than risking dangerous asteroid flybys, the proposal suggests mining oxygen from Jupiter's atmosphere and firing it past Earth as a particle beam — equivalent in mass to half the flow of the Amazon River — to safely push our orbit outward over millions of years. If the beam accidentally struck Earth, researchers note that oxygen is harmless to the environment and would scatter widely.
Even Earth's interior would need help. Plate tectonics — the process that builds mountains, recycles nutrients, and regulates climate — would eventually wind down without extra heat. The solution sounds like science fiction: produce a tiny amount of antimatter, seal it in a container, and drop it into a deliberately opened hole in Earth's crust. The container would sink for two weeks until it reached the planet's core, then release the antimatter to annihilate with matter and release heat. Just 2 kilograms of antimatter per day, produced using solar panels covering an area the size of India, could keep tectonics running.
None of these ideas are anywhere close to possible with today's technology. But the researchers say they prove one thing: the long-term survival of life on Earth may not require fleeing to another star system. We might simply need to rebuild our home, piece by piece, for a billion years to come.