Our Sun Is Lighter Than Ever, And The Problem Is Getting Worse
“As time goes on, the amount of mass lost by the Sun will increase, particularly as it enters the giant phase of its life. But even at this relatively steady rate, the growth of helium in the Sun’s core means that we will heat up here on planet Earth. After about 1-to-2 billion years, the Sun will be burning hot enough that Earth’s oceans will boil away entirely, making liquid water impossible on the surface of our planet. As the Sun gets lighter and lighter, it will counterintuitively get hotter and hotter. Our planet has already used up approximately three-quarters of the time we have where Earth is habitable. As the Sun continues to lose mass, humanity and all life on Earth approaches its inevitable fate. Let’s make these last billion-or-so years count.”
As the Sun burns through its nuclear fuel, it loses mass in not one, but two ways. Sure, in its core, it’s fusing hydrogen in a chain reaction into helium, with the reduction in mass corresponding to a gain in energy: the energy that powers the Sun and gives life to all the planets. But it also blows off particles, including electrons, protons, and atomic nuclei, in a phenomenon called the solar wind. Even though more massive stars burn hotter and brighter than less massive ones, the Sun, perhaps paradoxically, will increase in temperature and luminosity as it loses mass to these two processes. The Sun is getting lighter and lighter, and the problem of its increasing energy output will eventually destroy all life on Earth.