Can anyone answer this???
Anyone?
Crudely put in the form of a brief internet chat board posting:
Imagine a 2-dimensional universe (well, 2D as far as the inhabitants can imagine) existing on the surface of a balloon. (Go read “Flatland” and “Sphereland” and “Planiverse” right now if you haven’t. Ok, at least go order them from Amazon.com when you finish reading this post.) An inhabitant shoots an arrow, and it goes out of his “solar system”, and continues on traveling, on and on. Eventually it will go around the balloon, and come back and strike him in the back of the head.
Now raise the dimension of the given universe from 2D to 3D (ours). Same idea. In theory, if you shoot that arrow into space, it should go “around” the universe (existing on the surface of a 4D balloon), and eventually come back to you from the other direction. Likewise, the photons bouncing off the back of your head should go “around” the universe, and eventually come back to your eyes - so you could, in oversimplified theory, see the back of your own head.
Of course, the reality is probably a lot more complex, but that’s the basic idea. One of the first complications (sheer staggeringly huge size aside), is that the “balloon” our universe may exist on seems to be expanding - it started really small, then (a la “Big Bang”) started expanding really fast, and is still expanding. So long as it’s expanding slower than the speed of light, and the speed of your arrow, your arrow may take a long time but it should still come back to you. Actual shape remains in debate, seeing as we’re trying to see evidence of higher-dimensional shapes in something several billion light years wide and billions of years old, and doing so with quarter-inch pupils attached to two-pound brains on a small planet in a mere 200-million-mile-radius orbit - so pardon us while we still don’t have the answer exactly nailed down.
Fun to think about though. Good insightful question, which starts you off into the fascinating realm of cosmology.
Love, Curley Howard
The outcome of the flight of an imaginary Arrow is unknowable.
However, if an arrow were launched into space, the arrow would not travel through a void. It would encounter particles and dust. These would act on the arrow. Over time it would scour and pit the surface and erode it away, wood first, later metal. It might erode, with time, into its consitutant atoms.
Gravity, as far as we know, acts on all things. At some point it would act to capture the arrow—if it had not yet been scoured to particles— and pull it toward a galaxy, a sun, a planet. It might become a satellite around a Sun. It might land on a planet and become part of its mass, it might dissipate and become part of a dust cloud....
The outcome of the flight of an imaginary Arrow is unknowable.
However, if an arrow were launched into space, the arrow would not travel through a void. It would encounter particles and dust. These would act on the arrow. Over time it would scour and pit the surface and erode it away, wood first, later metal. It might erode, with time, into its consitutant atoms.
Gravity, as far as we know, acts on all things. At some point it would act to capture the arrow—if it had not yet been scoured to particles— and pull it toward a galaxy, a sun, a planet. It might become a satellite around a Sun. It might land on a planet and become part of its mass, it might dissipate and become part of a dust cloud....
There was an intelligent race in another solar system that were honest and full of virtue. Their scientists devised a rocket ship to explore the next planet in their solar system. They selected the brightest among them to explore the next planet. The rocket ship launched on a beautiful pink morning and was working as expected after one month into the three month travel. Then an arrow hit the space ship and it exploded. The civilization took this as a message from their creator and never tried another rocket ship launch.