Travelling In A Straight Line In Space

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Discussion Overview

The discussion revolves around the possibility of a rocket or spacecraft traveling in a straight line in space, considering the implications of orbits, forces, and the geometry of spacetime. It touches on theoretical concepts from general relativity and the nature of motion in space.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that while objects in space typically have orbits, a spacecraft can travel in a straight line if it continuously fires its rockets.
  • Others suggest that once the rockets are off, the spacecraft can only travel in a straight line if it is moving "straight up or down."
  • A participant questions the concept of traveling straight, asking "straight with respect to what?"
  • Another participant introduces the idea from general relativity that in a spacetime with complex geometry, there may not be a true straight line, as objects travel along geodesics when not influenced by external forces.
  • It is noted that in flat Minkowski spacetime, the principle of inertia corresponds to straight lines, suggesting a more general understanding of motion.

Areas of Agreement / Disagreement

Participants express differing views on the nature of straight-line travel in space, with no consensus reached regarding the definitions and implications of such motion.

Contextual Notes

The discussion includes assumptions about the nature of motion in space and the effects of forces, as well as the implications of general relativity on the concept of straight lines in spacetime.

Sammyg
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I know all object in space have orbits and orbits can be changed but is it possible for rocket or a spacecraft to travel in a straight line.
 
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Sammyg said:
I know all object in space have orbits and orbits can be changed but is it possible for rocket or a spacecraft to travel in a straight line.

Hi Sammyg! :smile:

If it keeps firing its rockets, then it can follow any curve it likes, including a straight line.

but once the rockets are off, it can only travel in a straight line if it's going "straight up or down". :wink:
 
Sammyg said:
I know all object in space have orbits and orbits can be changed but is it possible for rocket or a spacecraft to travel in a straight line.

Travel straight with respect to what?
 
In general rel, there may not be such a thing as a straight line in a spacetime with a funny geometry. When not under the action of external forces, things travel along geodesics. In flat "minkowski" spacetime, this principle corresponds to straight lines and is simply a more general form of the principle of inertia.
 

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