This week, Astrophysicist and board member of the Bulletin of the Atomic Scientists, Robert Rosner joins Abby in the classroom to help explain the Doomsday Clock.

Robert reflects on the origins of the Doomsday Clock and how the time is reevaluated at the beginning of every year by members of the Bulletin of Atomic Scientists. Later, Robert emphasizes that the Doomsday Clock operates as a warning, not a confirmed countdown, to the ultimate human catastrophe.

Keep up with Abby after class on Twitter: @AbbyHornacek

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