Summary

In “Dark Matter,” MacFarlane travels into a tunnel system near Boulby, Yorkshire where researchers study dark matter and a company mines for potash. He opens the chapter by explaining dark matter, a presence that refuses to interact with light and so is only theorized to exist. We can only infer that dark matter exists. He mentions Fritz Zwicky, the Swiss astronomer who noticed something unseen was influencing speed of revolving galaxies. MacFarlane also explains that only about five percent of the universe’s mass is made up of matter we can touch, see or measure. We cannot see dark matter, but it appears to be foundational to the universe. Scientists attempt to infer the presence of dark matter by studying particles called WIMPs, weakly interacting massive particles or ghost particles.

The guide for this chapter turns out to be the mine safety specialist of...