The Inexorable Death of our Planet
There are several scenarios for how our planet would likely perish, but one stands out as having no major conditions. In 7.6 billion years — quite a long time from now — our Sun will expand as a red giant star and engulf the Earth. The Sun’s core will shrink, heat up, and ignite a shell-burning phase. This will inflate the Sun’s outer layers to hundreds of times larger. The expansion will likely engulf Mercury and Venus, along with our planet as well.
The Sun, like all stars, follows a life cycle determined by its mass and composition. Currently, it is in the main sequence phase, where it fuses hydrogen into helium in its core. This process provides the energy that we receive as sunlight. However, this hydrogen fuel will eventually run out. The exhaustion of hydrogen fuel inside the sun will lead to the core contracting under gravity and heating up. The increased core temperature will cause the outer layers of the Sun to expand dramatically, turning it into a red giant.
As the sun expands, its luminosity will increase, resulting in higher temperatures on Earth. This increased heat will likely strip away and damage our atmosphere. This heat is such that surface temperatures will rise to the point where oceans evaporate and life becomes unsustainable.
In the red giant phase, the Sun’s core will start fusing helium into heavier elements like carbon and oxygen. This period will show the instability of the sun, with it shedding its outer layers into space, forming a planetary nebula. The remaining core will eventually cool and contract into a white dwarf, a dense, Earth-sized remnant composed mostly of carbon and oxygen. Over billions of years, the white dwarf will cool and fade, becoming a black dwarf. The planetary nebula will disperse into the interstellar.
Further Implications
The Sun’s transformation into a red giant will not only affect Earth but also the entire solar system. The intense solar wind from the expanding Sun will push the outer planets farther away. The asteroid belt and the Kuiper Belt will also be impacted, with some objects potentially being ejected from the solar system entirely. The gravitational fields throughout the solar system will change drastically, creating a configuration of spacial objects.
Research
The study of the Sun’s life cycle and the red giant phase is a critical area of research in astrophysics. By observing other stars at various stages of their evolution, scientists can gain insights into the processes that will affect our Sun. Telescopes and space observatories play a vital role in collecting data on stellar evolution, helping us refine our models and predictions. This research not only enhances our understanding of the universe but also informs our preparations for future cosmic events. Through this continuous research + abundance of time, it is possible that we can come up with some solution to sustain for longer.
