Which way is up in space? (see deatails)?

For example if 2 space crafts meet in space why would they be the same way up?

The only way that the two ships would have the same orientation or definition of up is if they are using a common reference system. Astronomers use a galactic coordinate system that is based on the fact that most of the galaxies lie close to a plane. In 1959, the galactic coordinate system was defined based on the orientation of the Milky Way creating a common "north" or "up" reference that is used to define the location of astronomical bodies.

When we eventually get to the point that we have multiple spaceships travelling through regions of space away from reference points such as planets, there will likely be a common reference system in place that will tell the ships and their crews which way "up" is.

LOL no there is a galactic sphere, solar sphere, stellar sphere, comic sphere.
But that still doesn't judge. That is our conclusion from Earth of what is up and what is down but we do not know for certain. Report It

Lets say a ball is the galactic measure sphere and from the centre what is up and what is down. So we say for our measures the positional data of what is up and what is down. But for we do not know what is up and what is down as in truth, only god knows. Report It

UP, DOWN, LEFT, RIGHT. To a ball we say which is which but how the ball was made is unknown.
I am an astrophysicist, cosmologist and astronomer. I know from the internal world of space education and carrer. Report It

The is why we create a COMMON reference, albeit man-made. Why is north always at the top of map? Why is the Prime Meridian in England? Why is noon in the middle of the day? Why does the year start on Jan. 1? All so we can have a reference point when we say be at X location at Y time. Report It

they wouldn't be

There is no up in space in the way you mean. Unless the ships are generating a pseudo-gravity by rotating there is no need for a "way up".

There is no up in space, on earth there is due to gravity. For example if you stood on your head the blood would "rush" to your head, because of gravity, but in space this would not happen, Up in space is dependant on the things around you - ie which way up your "spaceship" is at the time is up, when it turns "upside down", then this becomes up!!!

they dnt they jst face the same direction

If two space crafts meet, it wouldn't really matter which direction they are pointing. On the other hand if they wanted to dock with each other, all that would matter is that their ports are properly alligned. When discussing the issue, they wouldn't refer to up or down, they would refer to reference points on the hull, angles, vectors and distances.

if you are refering to Star Trek and the like. They do tend to go with a familar horizon line type of orientation. In effect one of the biggest problems for astronauts is the lack of gravity or horizon to orientate from. They spend a lot of time on simulators training themselves to navigate in all directions when on space stations. In the bigger picture, you could take an imaginary equator line through lined up with the orbits of the bulk of are system's planets and spread it out through the universe. Or you could wait for further results on the shape of our universe and imagine an ups and downs based on that.

If I remember my science correctly, our "north" is relatively analagous, overall, to the north pole of the sun. That north is (I think) roughly analagous to the "north" of the center of the galaxy.

Because we have a bias towards top-down orientation, we would angle any ship by the "north" pole of the galaxy. I imagine any spacecraft would have a bias towards orientation to one pole or the other at the center of the galaxy as well.

So, most spacecraft would (assuming they were approaching an object in space at the same vector) face each other same way up IF other earth-like planets orbit their stars similarly and their inhabitants see up and down the same way we do.

just hold on a minute i will go ask Spock and data!

It is impossible to know!

It is any way you wish it to be until you reach a large celestial body with a great gravitational attraction in which can you would be able to land on it and wherever you stand and look skywards that would be 'up'!

Another example of this would be the Earth, if two people were standing on opposite ends of the Earth (the poles for instance) then to both of them 'up' would be in the opposite direction to the other.

Therefore 'up' is purely relative to your point of view.