I did it because the edge of the Oort Cloud is a lot further out, and more ill defined. If we’re positing the rest of the universe disappearing and a chance to see what the edge of the universe looks like, Pluto’s orbit is a lot closer. We could have something out there to look in a few years rather than several decades.
Quarantine, for anyone following along and interested. The impermeable object obscuring the rest of the Universe was dubbed “The Bubble”, which appeared simultaneously around the entire solar system sometime in the 21st century.
The end twist is that the Bubble was built by aliens trying to keep humans from observing (in the QM sense) the universe outside the solar system, humans somehow having evolved the ability to collapse the waveform of entire galactic-sized QM systems. Only by segregating the human race off into its windowless ghetto can the rest of existence continue in its uncollapsed glory.
Now, in the age of LIGO, we would be able to at least “see” “through” such a bubble, and have some amount of confidence about whether the rest of the universe still existed or not, even if we couldn’t do anything about it.
I often ponder these particular things in my crude layman mind. I consider the centrifugal force one to be more self contained. The difference between the center point and the distance and speed around that point that something is rotating are all that is needed to create/explain centrifugal force? But the velocity of a body in a straight line in a universe that contains nothing else? That befuddles me. I suppose it has added kinetic energy. But how can that ever be measured? Nothing to slam into. It has some relativistic effects? But again, there is nothing to measure it against.
There’s no such thing as the edge of the universe. And the Solar System is not defined by the orbit of Pluto; it’s defined as everything that’s gravitationally bound to the Sun.
The stellar system that Against a Dark Background by Iain Banks takes place in is not in a galaxy. It was ejected so long ago that even the nearest galaxies are not naked-eye visible. I’ve been wondering what changes to human history would be if that had happened to the Sun. Perhaps I should start a separate thread for this.
Likewise Poul Anderson’s “World Without Stars” takes place outside on a world outside of any galaxy (but close enough for an awesome view of the Milky Way)
Which was naked-eye visible, but only for part of their night. That star would likely have been closer than the Large Magellanic Cloud, which is about 160,000 lightyears away. To not be naked-eye visible, the Milky Way would have to be significantly further than the Andromeda Galaxy, which is 2,500,000 ly away.
Yeah.
It there’s no edge, what is the alternative? As far as I can gather, the universe is not infinite in size. If it’s not infinitely large, how can there be no edge?
Let’s consider this thought experiment, in out actual universe. Let’s pick a direction in space, it doesn’t matter which one. Given that the universe is 13.8 billion years old, that’s the furthest we can see in any given direction. Let’s imagine a hypothetical person at that point, who is looking in that same direction, another 13.8 billion light years away. Now we’re talking 27.4 billion light years away. Keep going in that same direction. Presumably the number of observers can’t stretch into infinity, because the universe isn’t infinitely large. If the shape is spherical, then yes, it would wrap around, with the 23rd or 50th or whatever observer looking back at the 1st one, just like a line of people at the equator would eventually wrap around to the first one. But a sphere has a surface / edge. Here on Earth we can head up into space or down into the mantle and core, and thus the surface where we live is, in that sense, the edge of planet Earth. If someone were to ask, “what’s past the edge of Earth” one could point to the various layers of the atmosphere, to our moon, and beyond. It’s not a non-sense question. Unless one were to postulate a fourth (or more) spatial dimension, or a universe of infinite size, I don’t see how else the question can be answered other than to hypothesize that there is a surface / edge.
27.6 billion LY, not 27.4 
The universe may or may not be infinite. Could be either one, but we don’t know which.
If you’re going to consider an analogy to a sphere, you need to drop down a dimension. Think of the sphere as a two dimensional surface. It has no edge; it just wraps around. Inward and outward are not part of the surface and only exist because that sphere is embedded in a higher dimension. But the universe is not thought to be embedded in a higher dimension, so including one does not make a valid model.
The geometry of the universe does not have to be Euclidian. We try to visualise weird topologies by embedding them into our world view of how geometries work. But that is a limitation of our minds, not something that is required of reality. Whilst our minds rebel from attempts to imagine a wrapped universe, there is nothing intrinsic to say it isn’t true.
It is quite possible (both in theory, and consistent with observations) for our universe to be either infinite in extent, or finite but boundless. In the latter case it would have to be quite large as the curvature, if not zero, is very small.
Worth noting that if the universe is infinite, it always has been, ever since the first moments after the Big Bang. A continuous transition from finite to infinite extent is not possible. So the universe shortly after the Big Bang should not be conceived as very small, but rather very dense.
I was thinking of another SF story - “Nightfall” by Asimov. A planet in perpetual all-encompassing sunlight, except every 2000 years a moon eclipses the suns and the stars are visible. The story begins with this quote from Ralph Waldo Emerson:
“If the stars should appear one night in a thousand years, how would men believe and adore; and preserve for many generations the remembrance of the city of God which had been shown! But every night come out these envoys of beauty, and light the universe with their admonishing smile.”
This doesn’t take the expansion of the universe into account. Thanks to expansion the edge of the observable universe is 46.5 billion light years away and increasingly distant.
I don’t think all the stuff about gravity “rebounding” is correct. Or at least, we don’t have any reason to suppose something like that would happen.
Gravitational waves are very weak; they should not be confused with the gravitational force itself.
Meanwhile the removal of all that mass will certainly have a big effect on the solar system’s velocity, but there would be no way for us to observe the difference.
So, yes, it depends on what magic we used to remove all the matter, but I think the most straightforward interpretations would lead us to say: no difference. The stars could wink out, and apart from the difference of not seeing stars would have on humans and some fauna, it wouldn’t affect Earth.
Biggest consequences would be Earth becoming safer, and very excited scientists.
Extrasolar events that could affect Earth are things like nearby supernovas, black holes passing through, or super energetic cosmic rays. Or relativistic kinetic weapons from aliens in the next system over. So Earth gets safer.
Dark matter/energy, part of their “thing” is their influence is only detectable on a very large (galactic+?) scale. At the solar system level there isn’t enough dark matter to notice.
I think the cleanest method would be a mathematical surface outside Pluto and a Sol-centered inertial frame, everything at the surface is either left at pre-“blink” value or set to zero. My math intuition is that all external forces are either uniform across the volume, and/or too small to matter.
Or maybe not. If our new universe is closed and small, sunlight gets interesting like someone said upthread. If it misses everything in the solar system, it travels across the universe until it comes back and hits something like earth. Global warming. Possible extra side effect: closed universe means light from earth could travel across the universe back to earth. For a small enough universe, I think gravity also loops back: effectively treat the surface as having virtual suns at the right distance beyond the surface, so you get gravity magnification. Which could turn the universe into a black hole.
One interesting effect: if we assume that the sphere of disappearance is centered on the Sun and that the disappearance happens simultaneously in the Sun’s frame of reference, we’d see from Earth stars disappearing from the nighttime sky in an every increasing circle centered on the anti-solar point, and if a solar eclipse happened to be happening at that time, the stars in the daytime sky would disappear, leaving a contracting circle centered on the moon/Sun, which would be as creepy as heck (borrowed this imagery from the Egan novel)
My understanding is that you can’t actually get an “awesome view” of the Milky Way (or most any galaxy, for that matter) with the naked eye. Galaxies are just too dim and too diffuse. Note that this is not helped by getting closer, because the same light is only spread out into a larger area.
Consider that as viewed from the Earth, the Andromeda Galaxy is actually wider than the moon. But all you can see with the naked eye is a star-like blob at the center. You can’t see any of the spiral arms, because they’re simply too dim.
All those beautiful pictures you see of galaxies and nebulae are created with telescopes with large light-gathering ability and/or long exposures.
More info here:
Google and I have determined that the nearest star to us is 4.246 light years away, that’s 24.960.643.334.537 miles away. That’s the NEAREST star. I seriously doubt that our solar system would feel even a slight effect from the disappearance. True, our solar system circles our galaxy so, because of its disappearance, would no longer travel in any specific direction. Since our solar system is a closed system, however, it doesn’t really matter how it meanders around empty space.
Good point. But we have a pretty awesome view of some portions of the Milky Way galaxy - it would be even more impressive from an angle that didn’t hide the really bright parts from view (via dust clouds) and from a location without nearby stars to distract from its glory.