There are so many ways Earth could go. It could crash into another planet, be swallowed by a black hole, or get beaten to death by asteroids. There is, in fact, no way to tell which doomsday picture will be the cause of our planet’s death. However, one thing is for sure, even if Earth passes the rest of its years escaping alien attacks, dodging space rocks, and avoiding a nuclear disaster, there will come a day when our own Sun will finally destroy us. As Jillian Scudder, an astrophysicist at the University of Sussex described to Business Insider in an email, the day might come earlier than we think.
The Sun endures by burning hydrogen atoms into helium atoms in its center. In fact, it burns almost 600 million tons of hydrogen every second. And as the Sun’s core turns flooded with this helium, it shrinks, producing a nuclear fusion reaction to speed up, which means that the Sun troughs more energy out. In fact, for every billion years the Sun passes are by burning hydrogen, it gets about 10 percent brighter. And while 10 percent might not seem a lot, that difference could be catastrophic for our planet.
Scudder said,"As the Sun brightens over the upcoming billion years are pretty unreliable. But the overall idea is that the increasing heat from the Sun will produce more water to evaporate off the surface and be detained in the atmosphere instead. The water then acts as a greenhouse gas, which traps more entering heat, which speeds up the evaporation. Before it ever hydrogen vanishes, the Sun’s high-energy light will attack our atmosphere and split apart the molecules and allow the water to discharge as hydrogen and oxygen, ultimately bleed Earth dry of water". .
And it does not end there.
A 10% increase in brightness in each billion years means that 3.5 billion years from today, the Sun will shine nearly 40% brighter, which will melt Earth’s ice caps, boil Earth’s oceans, and will clear all of the moisture from its atmosphere. Our planet, once full of life, will become unbearably hot, dry, and unproductive, like Venus. And as the balanced thump of time drums down on our presence, the condition will only get bleaker.
All good things ultimately come to an end. Every book has the last chapter, every single pizza has one last bite, and every person has a dying breath. And one day, nearly 4 or 5 billion years from now, the Sun will burn through its last breath of hydrogen and start burning helium instead.
Scudder said, “Once hydrogen has stopped burning in the center of the Sun, the star has officially left the main order and can be considered a red giant."
As the Sun sheds its outside layers, its mass will decline, loosening its gravitational grip on all of the planets. So all of the planets revolving the Sun will move a little further away. When the Sun turns full blown red giant, Scudder said, its core will get tremendously hot and dense while its outer layer increases ... a lot. Its atmosphere will stretch out to Mars’ present orbit, absorbing Mercury and Venus. Though the Sun’s atmosphere will touch Mars’ orbit, Mars will escape, as it will have wandered past the reach of the Sun’s increasing atmosphere. Earth, on the other hand, has two choices: either run away from the expanding Sun or be consumed by it. But even if our planet escapes the Sun’s reach, the extreme temperatures will burn it to a sad, dead crispy.
Scudder said, "In each case, our planet will be pretty near to the surface of the red giant, which is not good for life. It will then spend about a billion years expanding and burning helium inside, with a shell around it where hydrogen is still able to fuse into helium."
X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI
Though more massive stars can originate another shell of fusing denser elements when this helium is shattered, the Sun is too delicate to generate the pressure required to begin that layer of fusion, Scudder described. So when the Sun’s helium finishes up, it is pretty much all simple from there.
Once the Sun has collapsed its fuel reserves, it will become unbalanced and start to pulse. With every pulse, the Sun will dismiss layers of its outer atmosphere until all that’s left is a cold, heavy core, bounded by a planetary nebula.
With every day passing this core, called a white dwarf, will cool and fade miserably out of existence as if it did not once swarm the liveliest planet ever found in the far-reaching canvas of the Universe.
But who knows. Perhaps the aliens will get to us first.
This article was originally written by Business Insider.