Imagine that an advanced alien race, bent on keeping humans from escaping into the galaxy, places an opaque spherical force field around the solar system. The force field is 6 light-hours in radius, is centered on the sun, and is formed in a single instant of time as measured by synchronized clocks in an inertial frame attached to the sun. That instant corresponds to 9pm on a certain night in your time zone. When does the opaque sphere appear to start blocking light from the stars from your vantage point on earth (8.33 light-minutes from the sun)? Does the opaque sphere appear all at once? If not, how long does it take for the sphere to appear, and what does it look like as it appears? Describe things as completely as you can.