We have a lot of sayings that involve the word “up”, Keep your chin up, Buck up, Keep looking up, and so on. But what exactly is up? I suppose we should establish that before my little random rant about it.
1. from a lower to a higher place or position
2. in a high position or place
3. toward the sky or ceiling
There are actually a butt ton of definitions but I grabbed the summary because that’s a horse that doesn’t need a beating. Of these three definitions it is #1 that most interests me. When speaking spatially I would argue that the most accurate definition of up is the “direction opposite to the center of the object.” In our regular life this is the Earth, when we are on the planet we tend to look at up as the direction opposite the center of the Earth. This is probably why you see #3 on that list existing. For us the direction away from the core is the sky or space. Additionally because of gravitation we tend to consider places opposite the core to be “high”.
But when you are in Space is there an up? Astronomers and very smart people would tell you no, but I’m neither of those things which is why I’m going to say yes. That’s right NdGT I’m about to not blow your mind.
If we go off my definition which is functionally the same as the 3 above, we merely need to find the object. What is the focus point for modern Human life? The Earth obviously. But what do we do when there are conflicting objects? We give most of our focus to the Earth because of its gravitation holding us to it. If we are in space we can suddenly start noticing the influences of other celestial bodies on us. If we are atop Mars then it becomes the focus point and the location of the Earth does not matter.
Imagine a future where humans go out so far that the gravitation of the very sun is nothing but a faint memory. Deep space, the final…well you get the picture. Is there an up then? Again, astrophysicists would say no! But why would they say no? The argument is that at any point in space you are the center of all things around you. But how do we know? This is because everything around us is moving away from us. If you know where everything else is going you can divine where it came from. If you teleported to any one of those objects you would still see this going on. This is because the universe is expanding.
Try and envision a loaf of uncooked raisin bread. Each little raisin in the bread is a separate galaxy. This is a little bit poor because the raisin bread is not infinitely large but just imagine the only important bit is the inner core of the raisin bread (because there is presumably no edge to the universe). As the loaf rises each of the raisins will move away from all other raisins. If you were an incredibly small raisin creature and you looked up from your little raisin world/galaxy you would see all other raisin worlds/galaxies moving away from you. This is because the “space” between each of these raisins is expanding. When someone tells you the universe is expanding that is what they mean. The “stuff” that is the universe is spreading apart equally in all directions. This is also why the universe can expand faster than the speed of light. Stuff isn’t “moving “persay”, even though I kind of just made it sound like that, the dough that all that stuff is sitting in is expanding and that dough is not restricting by the laws of relativity.
If it looks like everything around us is moving away from us then surely the answer of “what is up?” is every direction and thus no direction! But I disagree because as we established the universe is infinite but, at least presumably, it did have a point of origin. I’m willing to accept that this might not be the case because we don’t necessarily know how infinity works and perhaps when you crush infinity to an infinitely small point it starts doing weird stuff like speaking German.
That point is our source and all things moving away from that point are up. Just like on the planet Earth our point is the core and all things moving away from that are pointing up. So that, I say, is up. There is always an up, we just don’t know what it is at the intergalactic level. Up to that point there are plenty of analogies to our normal life that fit. Though I do see a problem with figuring out this answer. Lets imagine again!
You are sitting atop an unblown balloon. This is a strange day for you indeed!
There you are. Standing there atop your little deflated balloon. Life is simple and sweet. You know exactly where up is. You look down and see the universe beneath you and you point up. I’m happy for you! But then the universe doubles in size.
Hmmm alright this is still pretty easy. I don’t see the problem. It’s a little bigger but you can handle it. Then the universe doubles in size once more.
Starting to notice a little bit of flatness atop my beautiful sphere and I don’t appreciate that! But I still know where up is!
Ok this is getting mildly problematic.
Once the balloon gets large enough compared to you it will appear flat even though it is still a sphere. Depending on the week you’ll see studies out saying the universe is one thing or another. The most recent article I read suggested the the Universe is flat (again) but there are plenty to say it is round, a donut, inverted, and so on. The problem for finding up is that for everyone in the entire universe this “flatness” could appear to be the case. What does that do to the “up?” Does it create an up that is parallel for all living creatures in the universe? I only doubled the size of that circle once in each frame and in four frames it was perfectly flat, which is partially because I was drawing with a mouse but imagine that same thing happening at the universal scale (he says jokingly because nobody can).
We could be on a spherical universe that still looks flat to absolutely everyone. Just like some people thought the Earth was flat because of the size difference between them and their object.
There is always an Up, I suspect, it is just that sometimes it is so difficult to find that it might as well not exist.