On Earth, we can easily find a location given the longitude and latitude. But, how do we determine, plot, and track the location of objects moving through space?
Is there a grid in which we use? If so, where is coordinate 0,0,0 (assuming x,y,z respectively) and what units of measurement do we use? Where is the core of planet earth based on this grid, if it exists?
Or do we use a different method for plotting objects in space?
Because the earth is constantly rotating, I would assume it may be incredibly difficult to keep track of what is X, Y, and Z, unless we were to use other stars as reference.
Is there a grid in which we use? If so, where is coordinate 0,0,0 (assuming x,y,z respectively) and what units of measurement do we use? Where is the core of planet earth based on this grid, if it exists?
Or do we use a different method for plotting objects in space?
Because the earth is constantly rotating, I would assume it may be incredibly difficult to keep track of what is X, Y, and Z, unless we were to use other stars as reference.
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The objects we actually track are reasonably close to earth and the reason we track them is to assess risk. Therefore we wish to know where they are with respect to Earth and how they might behave. And that requires picking a polar coordinate system (angles and distances) with a reference that is most useful. With earth orbiting objects, the most useful reference line is the axis of the earth. Since a coordinate is needed that is not constantly changing itself, rather than using the line to the sun, a line to a star on the ecliptic plane (where most of the planets are including Earth's orbit) but "straight ahead" (at right angles) to the tilt of Earth axis. Sorry don't recall which star is used - mentioned in orbital dynamics stories.
For non-Earth-orbiting, the line perpendicular to the ecliptic through the middle of the sun and a line perpendicular to that out to a distant star in the direction the solar system is moving.
For non-Earth-orbiting, the line perpendicular to the ecliptic through the middle of the sun and a line perpendicular to that out to a distant star in the direction the solar system is moving.
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Yes, you have to used 3 dimensions, X,Y,Z. You can pick any arbitrary spot as 0,0,0. Commonly the center of mass of the Earth is chosen as the origin at launch and for Earth orbit only flights. Flights to the Moon switch to using the center of mass of the Moon when they get close to the Moon. Interplanetary flights use the Sun as the origin during cruise, and then the center of mass of the destination planet as they get close.
Of course you have to keep track of how those various centers of mass change position with respect to each other as the planets orbit. Nobody said it was easy. It *is* rocket science.
Of course you have to keep track of how those various centers of mass change position with respect to each other as the planets orbit. Nobody said it was easy. It *is* rocket science.