I’d wager a guess that we are, as a species, rather fond of our home planet (our wanton carbon emissions notwithstanding). But the ugly truth is that the Earth is doomed. Someday, the Sun will enter a stage that will make life impossible on the Earth’s surface and eventually reduce the planet to nothing more than a sad, lonely chunk of iron and nickel. The good news is that if we really put our minds to it—and don’t worry, we’ll have hundreds of millions of years to plan—we can keep our home world hospitable, even long after our Sun goes haywire. A waking nightmare The Sun is slowly but inexorably getting brighter, hotter, and larger with time.