Irrationally, humans use the expression forever lightly. “We’ll be together forever”, “Class today took forever”. But nothing is forever, not even all of the stars and galaxies in the universe. Last week, I was on Youtube when a video titled, “The Terrifying way our Universe will Die” was presented in my recommended feed. Intrigued by the eye catching and cynical headline, which was great pathos on the part of the video’s author, I watched the video and was fascinated by the fleeting nature of time relative to the universe. The video used theories and logic to put forth a realistic and practical timeline to how the universe could end. The video theorized that in billion years, the sun will increase drastically in temperature and in size, evaporating the Earth’s oceans and ending all life on Earth. Next, in 4-5 billion years, the Milky Way Galaxy and neighboring galaxy, the Andromeda, will collide into each other. Even now at this present moment, these two galaxies are racing towards each other at 250,000 miles per hour. When this galactic collision happens, our solar system will remain intact but both galaxies will not survive in same capacity they are present in now. In 5-8 Billion years, the sun’s nuclear furnace will become unstable, and eventually swell to such an astronomical size, that it will engulf Mercury, Venus, and Earth. It is important to note that while all of these events are taking place, the universe will be rapidly expanding. Because of this, in 100 billion years, the expansion will have been so drastic that galaxies beyond our cosmic neighborhood will be billions of light years away from each other. This distance is so vast, that light from other galaxies will not reach us. In a trillion years, gravity will eventually combine our cosmic neighborhood, which is made up of about 50 galaxies, into one single “super galaxy”. This will be just one of billions of super galaxies. In 100 trillion years, our universe will enter what astronomers have already coined a little in advance “The Degenerate Era”. Over time in this era, all stars in the universe will die, leaving only behind cool, dim remnants of their former selves. In 10-100 quintillion years, the remnants of all of these stars will either have escaped their respective gravities’ pull, or will be consumed by the massive black hole that will have formed. A decillion years later, black holes will be present in astonishing numbers, essentially dominating our universe. After hearing this portion of the video, I assumed it would be over. I had always assumed that black holes were forever, and once they were created, they were there to stay, but alas, there was 1 minute and 30 seconds left in the video. In this time period, I learned that even black holes eventually die, which I found unnerving due to my previous lack of awareness for of black hole’s mortality. They eventually die through a phenomenon called Hawking Radiation, in which they slowly lose mass by emitting radiation. That is a gross simplification but I’m not STEM major. In a googol years, which I had to look up because I thought it was a made up number, the last black hole in the universe will die, leaving behind nothing but emptiness. The universe will continue to expand, but will not have enough energy to produce new stars or galaxies. This video was fascinating, yet unsettling. It is already difficult enough to picture the number of galaxies in the universe and stars in those galaxies. In my opinion, it is even more difficult to imagine all of those stars and galaxies wiped from existence never to return. It is relatively easy to comprehend human mortality, although we try not to think about it, cosmic mortality is even more seldomly thought of, not because we choose not to think about it, but because few people even know that the universe as we know it is not forever.
Side note, if anyone is wondering what a googol years looks like its this: 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.