Highlight details that led scientists to draw a conclusion. 2000: Meanwhile, a team led by American scientist Andrea Ghez announces an extraordinary finding: some amazing force is whipping stars faster and faster around the center of the Milky Way. Each year the stars' speeds increase by about 250,000 miles (more than 400,000 kilometers) per hour! The team concludes that a supermassive black hole can explain this -- but not everyone else agrees.

—A Black Hole Is NOT a Hole,
Carolyn Cinami DeCristofano

Why did scientists conclude that a black hole is at the center of the Milky Way?

A. Stars near a black hole die.
B. A black hole makes the Earth spin.
C. A black hole produces a strong force.
D. A black hole slows stars down.