And after a few moments, her therapist tries a new tack, and they start singing together, and Gabby starts to sing through her tears, and you can hear her clearly able to enunciate the words to a song that describe the way she feels, and she sings, in one descending scale, she sings, Let it shine, let it shine, let it shine.

However, comets behave differently, due to their ejection of large amounts of volatile gas which then also reflect sunlight and may also fluoresce.

The dismal science truly shines in this optimistic talk, as economist Alex Tabarrok argues free trade and globalization are shaping our once divided world into a community of idea sharing more healthy, happy and prosperous than anyone's predictions.