Overview

Make the time to really sit and think about what all these years, months, days, hours, minutes, seconds, and nanoseconds mean for us.

Produced in partnership with Scientific American magazine, Examining the Big Questions of Time explains how philosophers, physicists, cosmologists, and neuroscientists have wrestled with the deeper meanings of time and what their research has contributed to our collective understanding of it. With Laura Helmuth, Editor-in-Chief of Scientific American, as your guide, this course challenges you to leave your assumptions about your personal temporal existence at the door and to allow your mind to be pushed to the farthest frontiers of the past and future, to the edge of the universe.

While we’ve exponentially increased our ability to measure time, how much progress have we made in understanding the nature of time itself? Galileo and Newton both worked with the concept of time, but assumed it was an absolute, the same for everyone, everywhere. Einstein’s theories showed that time is relative, dependent on the motion of its observers. In this course, studies from Scientific American will guide you through many of humanity’s most exciting questions about time, including:

• Is time real, or is it an illusion?

• Could the universe have existed before the Big Bang?

• What can the quantum world teach us about time?

• Must time always move from the past to the present?

• Could wormholes help us travel through time?

With the benefit of thought experiments, mathematics, and our increasingly accurate ability to measure time, some of our biggest current questions about time might be answered one day. But with time being as basic to humanity’s existence as it seems to be, new questions will continue to arise, always pushing our thought processes and imaginations to the limit.

Course Structure

01: A Matter of Time

While most of us measure time in hours or days as we plan our activities, these units are not nearly small enough—nor large enough—for those who work at the edges of discovery. Explore how some scientists use attoseconds and others use billion-year increments to study the often baffling revelations of spacetime.

Duration: 27 min

02: The Myth of the Beginning of Time

Just a few decades ago, scientists were absolute in their determination that time began with the Big Bang. But that’s all been turned on its head with the rise of string theory and other fascinating developments in theoretical physics. Learn how those advances brought the pre-Bang universe to the forefront of cosmology.

Duration: 30 min

03: That Mysterious Flow

Right now, you are reading these words. True enough, right? But all that certainty erodes when we look at the concept of “now” through the lens of modern physics. Although we perceive “now” as being unique—our present moment always seeming to separate the knowable past from the unknowable future—you’ll learn why “now” slips from our grasp when we try to actually define it.

Duration: 21 min

04: Is Time an Illusion?

While we’ve all heard that time is money, the two terms might turn out to be more similar than we ever knew. Could time, like money, be just an invented convenience with no fundamental existence in the natural world? Discover the many ways in which philosophers have helped physicists grapple with this question—and the answers they’ve come to so far.

Duration: 31 min

05: Time Travel and the Twin Paradox

In a thought experiment called the twin paradox, Einstein illustrated that two observers moving at different speeds would experience different durations between the same two events. See how this time dilation has been proven and measured since Einstein’s life, and why your GPS wouldn’t work without accounting for it. Time travel, anyone?

Duration: 23 min

06: A Chronicle of Timekeeping

From the ancient Egyptians to the 13th-century inventors of the mechanical clock to the atomic clocks of the last century, people keep striving to measure time more accurately. Understand why accuracy in timekeeping was important for the agriculturists of the Nile and why it still matters for those of us today who use navigation systems, cell phones, and electricity from the power grid.

Duration: 29 min

07: Atomic Clocks

Modern timekeeping has allowed us to measure differences in the passage of time as affected by motion and gravity to such a degree that relativity itself can now be measured in the lab. Learn about the development and precision of atomic clocks—and the myriad ways they benefit us—and about the optical clocks that can keep time to within one second in roughly 3.7 billion years.

Duration: 27 min

08: Times of Our Lives

Our circadian rhythm is hardwired into every cell in our bodies. Even under constant lighting, human cells in a petri dish will continue to follow 24-hour cycles of gene activity, hormone secretion, and energy production. Explore neurologists’ latest thinking about the brain’s internal timekeeping systems, and how those systems affect our health.

Duration: 28 min

09: Remembering When

While our internal clocks regulate our physical processes, our mind has a clock of its own. Explore what scientists mean by “mind time,” and how we organize our thoughts about events in the passage of time. Uncover how mind time is linked to our ability to make and store memories, and reveal the interesting differences between anterograde and retrograde amnesia.

Duration: 21 min

10: Inconstant Constants

Almost all our scientific knowledge is possible because we rely on a few very basic constants—such as the velocity of light and the mass of the electron. Discover how string theory brings the possibility of a vast number of other worlds with different self-consistent laws and constants, and whether or not those worlds could possibly include biological entities like ourselves.

Duration: 25 min

11: Atoms of Space and Time

In the field of quantum mechanics, physicists have suggested for almost a century that light is made of energy packets that can behave like both a particle and a wave, a phenomenon known as photons. But could gravity also be made of discrete packets—gravitons? Explore the concept of loop quantum gravity and learn how physicists use spin networks to gain a deeper understanding of our universe.

Duration: 29 min

12: Could Time End?

As we experience life, time never ends. Even after death, our molecules will be recycled, and both time and matter will continue. But if time can slow down and speed up—as Einstein predicted, and later confirmed by observation—could it also end? Explore what the equations of modern physics tell us about the possibility of an end with no rebirth.

Duration: 25 min