What does the sky look like from the center of a globular cluster?


Here are some numbers. A typical globular cluster core region has about 100,000 stars in a volume of space about 10 parsecs in radius. This works out to a spherical volume of about 4000 cubic parsecs or about 25 stars per cubic parsec. This means that the typical distance between these stars is about (25)^-1/3 or about 1/3 parsec. These stars are mostly evolved giants with a luminosity of about 100 times the Sun, so at 10 parsecs, such a star would have an apparent visual magnitude near zero, and at 1/3 parsec it would have a magnitude near -6 making it as bright as Venus or Jupiter at their maximum brilliance. There would be about a dozen or so of these very bright stars, as bright as Venus, spread across the sky. The most distant stars would be near 10 parsecs and there would be many thousands of these, and each one would have a magnitude near zero...so the sky would be filled with 100,000 stars each brighter than the star Sirius, and a handful brighter than Venus at its maximum brilliance. There are 42,000 square degrees in the sky, so there would be one of these stars in every patch of the sky about the size of the full moon ( 1/2 degree)!!! It would be very difficult to see faint stars with the naked eye because your eye would constantly be flooded by the light from these numerous red giant stars.

This is my best estimate for what it is worth.