Final answer:
The author includes the detail to highlight the time dilation effect experienced by the astronaut near the black hole.
Step-by-step explanation:
The author includes the detail, 'you know we've got to get back to that asteroid within two weeks' to highlight the time dilation effect experienced by the astronaut near the black hole. According to Einstein's theory of relativity, time moves slower in a strong gravitational field, so while the astronaut spent only 2 weeks near the black hole, more than 2000 weeks (40 years) could have passed on Earth. This detail adds to the astronaut's surprise when she realizes that she has arrived in the future.