how come it’s never mentioned that one can (presumably) move up, down, left and right in outer space? i have always worked under the assumption that our galaxy was more or less flat. do objects lie above and below Earth and the greater Milky Way?
Yes, they do.
What do you mean? From a NASA page on the Space Shuttle:
Heck, even Star Trek: The Wrath of Khan mentioned that. (“Admiral, Khan’s intelligence cannot make up for his lack of experience. All the maneuvering Reliant has done, bold though it may be, has occurred in a single plane. He takes advantage neither of the full abilities of his ship nor of the possibilities inherent in three degrees of freedom.”)
Both the Solar System and the Milky Way Galaxy are both more or less flat, yes. While most of the matter in the Solar System is fairly close to the solar ecliptic–the flat plane which most of the orbits of the planets lie near (which we rather arrogantly define based on the orbit of our own planet)–even the major planets have minor deviations from this, and there is plenty of other junk which is nowhere near the ecliptic. This is especially true of comets; I believe the Oort Cloud, the deep space reservoir of comets way beyond the orbit of Pluto, is thought to be essentially spherical.
The plane of the solar ecliptic doesn’t line up with the galactic plane, either. And our galaxy, while much flatter than it is wide, is still thousands of light-years thick. There are thus other stars within our galaxy in every direction from Earth, including straight up from either pole. Furthermore, our galaxy is surrounded by spherical haloes of globular clusters–groups of ordinary stars–and “dark matter”. Finally, there is no “universal ecliptic”; other galaxies are scattered through the universe in every direction.
2nd star to the right and straight on till morning.
I think right now it’s not something we really need to worry about. We can deal with pretty much all of our needs with an angle, angle, length coordinate system centered on Earth, and moving to the sun when we deal with interplanetary calculations.
There must be a zero point I don’t know what that is. Does anybody? Where you would say that Star Y is 195º44’14" west, 3º21’18" north. Thus you could find it in the sky. Then the third coordinate we’d rarely have to use which would be the distance from us to it.
Later, when we need it, we can move to a solar based one. And then if we ever get to interstellar space we could move to a galactic based one.
But that’s ok, we’d have to change other things as well. 365 days per year wouldn’t make much sense if you live on Mars.
Many things in the universe are flat because they spin. The solar system started out as a lot of stuff (gas, dust and bigger lumps of matter) orbiting around the sun. You can’t have a lot of stuff orbiting around in random directions - pretty soon the ones going in different directions collide, and in the end everything is orbiting around the sun in the same direction. Same with galaxies, I think (sorry, I’m not an expert there) and gas falling onto massive bodies (black holes, neutron stars, etc).
Once you get to a scale larger than galaxies, I don’t think there is any flattening going on. The distribution of galaxies seems pretty random in 3 dimentions. (OK, there are definite patterns, but no flat patterns)
When Mork was describing how to get to his home planet, I believe he said that you have to “hang an up.”
Sort of. The Milky Way is much wider than it is thick so it has a disk-shape when you view it as a whole*. But out where we are (about 30,000 light years from the center of the galaxy), that disk is still several (16?) thousand light years thick (i.e., several thousand trillion miles thick).
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- yes, I know we can’t do this since we’re inside the galaxy…but we can view other galaxies that are similar in structure to the Milky Way.
[Ender]
The Enemy’s gate is down.
[/Ender]
That venerable RPG “Traveller” had sort of a co-ordinate system. The x-y plane was the plane of the galaxy.
“Corewards” was in the direction of the galactic core. “Rimwards” was in the opposite direction.
“Spinward” was in the direction of galactic rotation, and "Trailing was in the opposite direction.
I don’t think they ever made it clear what defined the X axis, other than one end was anchored on the galactic core.
[hijack]
So, in most space TV / Movies (e.g. StarTrek, StarWars, etc.) do the ships always … always … approach each other with the same “up” orientation? Even in the “Wrath of Khan” scene cited above, Kirk’s ship stayed in the same trim, but went up and down like an elevator.
[/hijack]
The Star Trek Universe has Quadrants and Sectors, and a reckoning system of “degrees” and “marks” (horizontal and vertical?)
There are coordinates used in space. Commonest is to refer to positions with respect to the Earth, according to how far they are from Earth, how far they are angularly from Earth’s north pole (which is near Polaris), and how far around the sky in “Right Ascension” from a zero reference direction (which is in the direciton of Aries, and I think is the vernal equinox or the direction from Earth to Sun at the moment the equatorial plane of Earth sweeps through the Sun). This coordinate system was defined in terms of the celestial motions as of 1/1/1950 and redefined in terms of 1/1/2000. For things not part of the solar system, this coordinate system is accurate enough even if you blur the distinction between Earth’s position at some moment versus its average position ie the Sun.
Another coordinate system is similar but based on the rotation of our galaxy.
I don’t think you could have longitudes >180º. Instead of 181º West longitude, you would have to say 179º East.