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.

As the force field is centered on the sun, the earth is displaced from its center by 8.33 light-minutes. This means, the closest point to Earth is at a distance

When the sphere is placed, the light that is inside the sphere must reach Earth before we can observe the light from the stars being blocked. So, from the closest point, the light must travel:

So, if the sphere is placed at 9 pm, this must mean the opaque sphere starts to appear at 2:51:40.2 am of the following day.

The sphere wont appear all at one, as the earth is at different distance for different points.

The farthest point from earth is at :

This means, that it will be observed blocking light at  3:08:19.8 am of the following day.

Between this two events, it will appear that from the closest point a sphere grows enlarging, wrapping earth in the process.