Given the task definition and input, reply with output. This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: In 2011, Spielberg launched Falling Skies, a science fiction television series, on the TNT network. He developed the series with Robert Rodat and is credited as an executive producer. Spielberg is also producing the Fox TV series Terra Nova. Terra Nova begins in the year 2149 when all life on the planet Earth is threatened with extinction resulting in scientists opening a door that allows people to travel back 85 million years to prehistoric times. Spielberg also produced The River, Smash, Under the Dome, Extant and The Whispers, as well as a TV adaptation of Minority Report. Question: How far back in time do people in 'Terra Nova' travel?
85 million years