Voyager I has traveled 11 billion miles toward the edge of our solar system and has not reached the boundary yet. Maybe it will be difficult to define where this point is located. Scientists have been looking for a clear break between our solar system and interstellar space, but there may not be something that obviously separates the two.
Certainly, Voyager has detected a substantial increase in the level of galactic cosmic rays, which could be evidence that the spacecraft has crossed through a small zone called the heliopause, into a new zone where plasma bubbles have been blown outward by the solar wind. Think of the tear-drop bubbles blown by children which are captured and then transported by the wind. This might be a good analogy as to what our solar system looks like, but it does not explain the mystery of its edge.
A year ago, Voyager passed the termination shock, where the solar wind of charged particles abruptly slowed down, indicating Voyager’s entry into an outer region called the heliosheath. Then last August, the Voyager entered an unknown “magnetic highway” where magnetic fields inside and outside the heliosphere connect.
However, even though Voyager has penetrated into the Kuiper Belt, it has not reached the Oort Cloud, which might require another 11 billion miles. And who knows what lies ahead for our steadfast traveler. Quite frankly, Homo sapiens may not be around by the time Voyager reaches what could have been considered by our species as the end of our solar system.
One may speculate that the matrix of the universe is such that dark energy and dark matter form the skeletal structure with our solar system connecting to other solar systems like cells in our body, forming galaxies. Then the galaxies will merge into other galaxies so that the entire universe is interconnected. If that is the case, the edge of our solar system and galaxy will have no more meaning than the boundary where one cell in a biological organism touches the next.
Then is there an edge to our universe? There should be if there are no other universes. The edge of the entity that surrounds us, which we call the universe, began with the Big Bang. The universe, which had boundaries early in its existence, still must have these borders. Scientists claim that this universe is expanding, but there can be no increase in diameter unless there is an edge for the diameter. In other words, how can the universe expand unless it has a boundary creating that entity which is increasing in size? If our universe had no edges, then it would be headed toward infinity, not expanding in a finite system.
But it seems quite useless to argue that our universe has no edge since we are aware of something we call the “universe” that contains all the galaxies. And we can mathematically show the amount of mass within this closed universe. And we can show the percentages of dark energy, dark matter, and visible matter within our universe.
We may not know much about our solar system, much less our galaxy, even to a lesser extent our universe, but we do know we are part of its contents and we have edges. At least we appear to be confined within one skin and not floating about. Do you believe that gives us an edge when we speculate that the universe has a boundary?