Possible Clues:

• Astronomer's find
• Nothing can escape from one
• 'Region of space from which nothing can escape (5,4)'
• Term popularized by physicist John Wheeler
• What one sees at night on golf course is a problem for some stars
• Trunk full of powdered chalk in prison
• There's no escaping this
• Result of a star's collapse
• Massive astronomical body (Kardashian, letters 5-9)
• Chess player with predicament that admits of no escape