# "Up" and "down" in Space [closed]

From my understanding, "up" and "down" in space is going towards (down) an object's gravitational pull or (up) which is going away from it. I get confused with this explanation, and I believe simply because of how we perceive up and down here on earth.

My question(s) is this: Can we go in all directions in space with the "Earth" interpretation of up, down, left, right, north west, south east, etc if we can get past gravitational pulls of objects in space?

Looking at my Gimp version of the universe, I have the Earth and stars. So going up would essentially be go towards any of the stars in the picture that has the strongest gravitational pull, although each object are on different planes?

In relation to my question above, I have imagined Earth in space as to like the 10 floor on an infinite elevator that can go in all directions. Say we can somehow go through star A and escape it's gravitational pull, we would be essentially "going down" right?

Now my other question: Are there objects in every single direction is space? How about in the Bootes void? Since it's such a massive void and there isn't much objects around to pull you in "down" or go away from "up", essentially can't we go in any direction?

I think that one thing confusing you, is that up/down is a 2 dimensions concept (just like your image by the way), but the Universe is in 3 physical dimensions (let's not talk about time here).

So when you say « going up from Earth is extracting from it's gravity », it can be in many direction. If two persons are in North Pole and South Pole of Earth, and if they are both going up. They are in fact going in opposite directions.

The second point is that you need a frame of reference. You go up/down « to » or « from » something. For example, you go up (going away) from the North Pole, but from Sun's or Moon's point of view, it's not going up at all.

The up/down/left/right concepts always need a reference. See this very simple example: If we are facing each other, what is on my left, is on your right. Your question here is exactly like asking : « What is on my left in the universe ? ». There is no real answer to that.

Hope I could help.

Your confusion is that you are treating gravity from all those objects as a bunch of discrete 'pulls' - but it doesn't manifest itself like that. Gravity from all bodies in the universe effects you as one force (I'm simplifying and excluding getting close to black holes etc where you have dramatically changing gravitational potential over the length of your body)

Add up all those gravitational forces and you will be pulled in a direction. It will not feel like up or down as you will just accelerate.

If you are in a rocket with the engine running, "down" will be the direction opposite to thrust. In the same way that the Earth is down, because it is pushing upwards against your feet.

Acceleration from your rocket engine works a lot like acceleration from the gravitational pull from a planet or star. It affects your velocity. You can go any direction - some will just be easier than others - but that is a much bigger set of questions. Read some of the posts on Space Exploration Stack Exchange on changing orbits, travelling between planets etc.

It is not only about up and down, there are deeper dimensions to this. Like infront and behind.

The Moon seems to be "behind" us, as in expressions like: "Going BACK to the Moon". Although it does go all around and never gets anywhere, much like ones own bottom, actually. Even Ptolemy didn't argue with that fact. Might this be a clue to this geometric puzzle?

Your grandparents might argue against this and say that they definitely remember that the Moon was the horizon in front of them. How little they knew about what would become our behind!