Humanity's desire to explore, discover, and challenge nature is immense, and that desire becomes much greater when we look up and consider everything the universe has to offer. Unfortunately, our technology and current understanding of physics keep us tethered to Earth and the Solar System, but if that tether didn't exist... would we find any limit capable of defeating even human determination? As the folks at Kurzgesagt explain in their new video, the answer is yes.
Let's imagine for a moment that the laws of physics as we know them turn out to be wrong, which opens the door to traveling faster than light, or discovering things like "subspace", "hyperspace", "warp" or something similar that takes us from point A to point B without having to be immortal, frozen, cloned, or transformed at the genetic starting point for dozens of generations that might or might not reach the nearest star.
The Milky Way is about 100,000 light-years in diameter, and in the worst case, there are a hundred billion stars to visit. Now, let's travel even faster: Andromeda is 2.5 million light-years away—our neighbor! The Triangulum Galaxy is a bit farther, 3 million light-years, but still within our supposed reach. These "three ladies" along with about fifty other galaxies (approximately) form the so-called Local Group. Here we're talking about a diameter of ten million light-years, a true monstrosity from every point of view. However, further away is the Maffei Group, which has another sixteen galaxies to explore.
What if we go there?
Well... we can't. Why? The folks at Kurzgesagt provide an extraordinary explanation in a video that's under eight minutes, and in very relaxed terms it boils down to two words: dark energy. We don't know exactly what it is, how to measure it, or what properties it has, but its effects are there. About six billion years ago, dark energy became the cause of the expansion of the universe and the acceleration of that expansion. Over time, dark energy will push further away other groups and clusters that aren't essentially gravitationally bound to the Local Group, at a speed much greater than that of light, and will cause their light to "shift toward the red" until at some point, everything we see will be darkness.
On the contrary, the Local Group will become increasingly compact thanks to the influence of gravity, and will lead to the merging of two or more galaxies. Andromeda is approaching the Milky Way at a speed of 110 kilometers per second, and experts already have a name for this future "collision": Milkdromeda. It's estimated that the encounter between the two galaxies is still about four billion years away, while the final merge of the Local Group will take much, much longer.
The fact that the universe is moving further and further away from us and letting us see less and less might make this whole situation more depressing, but assuming humanity becomes a Type 3 civilization, one thing is certain: there will be much to explore, and much work to do.
