This experience is optimized for Internet Explorer version 9 and above.

Please upgrade your browser

Send the Gift of Lifelong Learning!

The Inexplicable Universe: Unsolved Mysteries

The Inexplicable Universe: Unsolved Mysteries

Neil deGrasse Tyson, Ph.D.
Hayden Planetarium

Gifting Information


To send your gift, please complete the form below. An email will be sent immediately to notify the recipient of your gift and provide them with instructions to redeem it.

  • 500 characters remaining.

Frequently Asked Questions

With an eGift, you can instantly send a Great Course to a friend or loved one via email. It's simple:
1. Find the course you would like to eGift.
2. Under "Choose a Format", click on Video Download or Audio Download.
3. Click 'Send e-Gift'
4. Fill out the details on the next page. You will need to the email address of your friend or family member.
5. Proceed with the checkout process as usual.
Q: Why do I need to specify the email of the recipient?
A: We will send that person an email to notify them of your gift. If they are already a customer, they will be able to add the gift to their My Digital Library and mobile apps. If they are not yet a customer, we will help them set up a new account so they can enjoy their course in their My Digital Library or via our free mobile apps.
Q: How will my friend or family member know they have a gift?
A: They will receive an email from The Great Courses notifying them of your eGift. The email will direct them to If they are already a customer, they will be able to add the gift to their My Digital Library and mobile apps. If they are not yet a customer, we will help them set up a new account so they can enjoy their course in their My Digital Library or via our free mobile apps.
Q: What if my friend or family member does not receive the email?
A: If the email notification is missing, first check your Spam folder. Depending on your email provider, it may have mistakenly been flagged as spam. If it is not found, please email customer service at ( or call 1-800-832-2412 for assistance.
Q: How will I know they have received my eGift?
A: When the recipient clicks on their email and redeems their eGift, you will automatically receive an email notification.
Q: What if I do not receive the notification that the eGift has been redeemed?
A: If the email notification is missing, first check your Spam folder. Depending on your email provider, it may have mistakenly been flagged as spam. If it is not found, please email customer service at ( or call customer service at 1-800-832-2412 for assistance.
Q: I don't want to send downloads. How do I gift DVDs or CDs?
A: eGifting only covers digital products. To purchase a DVD or CD version of a course and mail it to a friend, please call customer service at 1-800-832-2412 for assistance.
Q: Oops! The recipient already owns the course I gifted. What now?
A: Great minds think alike! We can exchange the eGifted course for another course of equal value. Please call customer service at 1-800-832-2412 for assistance.
Q: Can I update or change my email address?
A: Yes, you can. Go to My Account to change your email address.
Q: Can I select a date in the future to send my eGift?
A: Sorry, this feature is not available yet. We are working on adding it in the future.
Q: What if the email associated with eGift is not for my regular Great Course account?
A: Please please email customer service at ( or call our customer service team at 1-800-832-2412 for assistance. They have the ability to update the email address so you can put in your correct account.
Q: When purchasing a gift for someone, why do I have to create an account?
A: This is done for two reasons. One is so you can track the purchase of the order in your ‘order history’ section as well as being able to let our customer service team track your purchase and the person who received it if the need arises.
Q: Can I return or Exchange a gift after I purchase it?
A: Because the gift is sent immediately, it cannot be returned or exchanged by the person giving the gift. The recipient can exchange the gift for another course of equal or lesser value, or pay the difference on a more expensive item
Video title

Priority Code


The Inexplicable Universe: Unsolved Mysteries

Course No. 1816
Neil deGrasse Tyson, Ph.D.
Hayden Planetarium
Share This Course
Course No. 1816
Streaming Included Free

Course Overview

Everything we now know about the universe—from the behavior of quarks to the birth of entire galaxies—has stemmed from scientists who’ve been willing to ponder the unanswerable. And with the advent of modern science, great minds have turned to testing and experimentation rather than mere thought as a way of approaching and grappling with some of the universe’s most pressing and vexing dilemmas.

So what is our latest picture of some of the most inexplicable features of the universe? What still remains to be uncovered? What are some of the next avenues of exploration for today’s chemists, physicists, biologists, and astronomers?

Pondering the answers to these and other questions is a great way to

  • appreciate the grandeur and complexity of the world around you,
  • better understand and discuss news and developments in science, and
  • spark further interest in some of science’s many exciting areas of study.

“We know a lot about the universe. But there’s even more that we don’t know,” says astrophysicist and Professor Neil deGrasse Tyson, director of the Hayden Planetarium, an award-winning lecturer, and one of the world’s foremost experts on the secrets of the universe. And his course The Inexplicable Universe: Unsolved Mysteries is the perfect gateway into this mind-bending and eye-opening subject. This visually stunning course, which has been honored with a 2013 Telly Award for Outstanding Educational Program, features six self-contained lectures that transport you on a marvelous journey to the frontiers of the known (and unknown) universe and introduce you to tantalizing questions being addressed by the world’s top scientists. Undeniably engaging and fascinating, this lecture series is a wonderful entrée to scientific pursuits that lie at the very heart of the history and nature of our universe.

An Informed Scientific Conversation

Central to The Inexplicable Universe is the way it takes you deep into hidden layers of the universe in a manner that is extremely accessible. Rather than a stern lecture given before a podium complete with confusing mathematics, Professor Tyson’s lectures have the feel of an informed conversation that manages to be both thorough and easy to grasp.

With each of the inexplicable mysteries he lays bare for you, Professor Tyson

  • introduces you to the history behind it,
  • lays out the science that has helped us grasp it,
  • explains what researchers have discovered to date, and
  • reveals what we have yet to discover.

And while the topics explore subjects in everything from quantum mechanics to cosmology to string theory, you’ll never feel overwhelmed by what you’re learning. In fact, you’re more likely to find yourself intrigued by just how much we know—and curious about what the near future will possibly reveal.

Explore Fascinating Territory

So what territory will you chart in this course? Here are some of the inexplicable ideas you’ll investigate in these lectures.

  • Neutrinos: Discovered in 1956, these fast-moving, ghostlike particles are made in abundance in the sun’s core. They hardly interact with matter; it takes a light-year’s worth of lead (5.8 trillion miles) to stop a neutrino. Not only that, but 65 billion neutrinos pass through every centimeter of your body that’s facing the sun every second of every day.
  • String theory: This astounding theory offers the hope of unifying all the particles and forces of physics. In the past several decades since the dawn of string theory, it’s been imagined that all the fundamental particles we see and measure are just the manifestation in our dimension of strings vibrating in higher dimensions and at different frequencies.
  • Quantum foam: This idea posits that when the fabric of space and time is so tightly curved on itself, space-time is less a smooth curve and more like the froth on a latte. In this state of matter and energy, quantum fluctuations can spawn entire universes, each with slightly different laws of physics within them!

In addition, you’ll also

  • get a peek at what it would be like to travel through a black hole,
  • ponder the possibility that life on Earth originated in debris from Mars,
  • probe the supposed existence of multiple universes, and
  • even imagine the possible end of the universe itself.

A One-on-One Chat with a Renowned Science Educator

Professor Tyson is renowned throughout the scientific community and the media for his vast knowledge, his penetrating insights, and his amazing ability to make even the most intimidating areas of science accessible, engaging, and—most of all—enjoyable. He brings the same inviting tone and sharp intellect to The Inexplicable Universe as he does to his range of media appearances on popular television programs, including The Daily Show with Jon Stewart, The Tonight Show with Jay Leno, and Real Time with Bill Maher.

Professor Tyson’s lectures also feature expertly crafted animations, explanatory graphics, and other instructive visual elements designed to better explain to you some of the grand, intricate ideas being discussed.

With The Inexplicable Universe, you’ll feel as if you’re participating in an exclusive chance to sit one-on-one with this renowned science educator and have a provocative, intriguing, and illuminating conversation. No other learning experience—including the most detailed science textbook—can bring you this close to interacting with an expert about the mysteries of the universe around you.

Hide Full Description
6 lectures
 |  31 minutes each
Year Released: 2012
  • 1
    History’s Mysteries
    Science history is filled with puzzling mysteries that were only solved with modern science’s focus on experimentation instead of thought. Here, take a closer look at concepts that were once unexplainable but, thanks to modern physics, are now better understood. You’ll focus on two such former mysteries: the existence of an invisible “aether” through which light and sound were believed to travel and the orbit of Mercury, which seemed (to earlier scientists) to violate Newton’s fundamental laws of motion. x
  • 2
    The Spooky Universe
    Did you know that electrons, discovered in 1897, have never actually been observed by scientists? Or that quarks can only be studied in pairs? Or that as you travel faster or find yourself in a higher gravity, time ticks more slowly for you? Delve into these and other mind-warping facts and insights about the fundamentals of matter in a lecture that covers everything from particle physics to quantum tunneling to thermonuclear fusion. x
  • 3
    Inexplicable Life
    Join Professor Tyson on a fascinating investigation of the possible origins of life in the universe. Why was Jupiter believed to be a good environment for life in the 17th century? Why is there only one single “tree of life” on Earth instead of multiple ones? How do extremophiles help scientists study life’s genesis? Could life have come to Earth from another planet? And what do we mean when we hope to find examples of life that is “intelligent”? x
  • 4
    Inexplicable Physics
    Among the many topics you’ll learn about in this lecture are the discovery of more elements on the periodic table; muon neutrinos, tao particles, and the three regimes of matter; the secrets of string theory (which offers the hope of unifying all the particles and forces of physics); and even the hypothetical experience of traveling through a black hole. x
  • 5
    Inexplicable Space
    Scientists have made astounding progress in their grasp of the universe. But what remains to be understood? Investigate some perplexing aspects of space that science has uncovered in the last half-century. Learn about the mysterious trajectory of the Pioneer spacecraft (known as the “Pioneer anomaly”). Explore two of the longest-standing problems in astrophysics: dark matter and dark energy. And even try to map the shape of space-time. x
  • 6
    Inexplicable Cosmology
    Take a fascinating trip through dimensions higher than our own. You’ll discover how quantum physics and string theory have opened our eyes to the possibilities of quantum foam, the multiverse, antimatter, and tachyons. Also, join Dr. Tyson for a preview of the long-term fate of the universe (including the collision of galaxies, the burning out of stars, and the decay of orbits into black holes). x

Lecture Titles

Clone Content from Your Professor tab

What's Included

What Does Each Format Include?

Video DVD
Video Download Includes:
  • Ability to download 6 video lectures from your digital library
Video DVD
DVD Includes:
  • 6 lectures on 1 DVD
  • FREE video streaming of the course from our website and mobile apps

Enjoy This Course On-the-Go with Our Mobile Apps!*

  • App store App store iPhone + iPad
  • Google Play Google Play Android Devices
  • Kindle Fire Kindle Fire Kindle Fire Tablet + Firephone
*Courses can be streamed from anywhere you have an internet connection. Standard carrier data rates may apply in areas that do not have wifi connections pursuant to your carrier contract.

Your professor

Neil deGrasse Tyson

About Your Professor

Neil deGrasse Tyson, Ph.D.
Hayden Planetarium
Dr. Neil deGrasse Tyson is the Frederick P. Rose Director of the Hayden Planetarium at the American Museum of Natural History in New York. He is also a research associate in the Department of Astrophysics at the museum. Professor Tyson earned his undergraduate degree in Physics from Harvard University and his Ph.D. in Astrophysics from Columbia University. Dr. Tyson has written prolifically for the public, including a series...
Learn More About This Professor
Also By This Professor


Rated 4.5 out of 5 by 114 reviewers.
Rated 5 out of 5 by The Inexplicable Universe: Unsolved Mysteries A most excellent view into the world that was never taught to me in school in the 70's. Will wonders never cease. I recomment it for everyone. October 3, 2016
Rated 5 out of 5 by The Inexplicable Universe: Unsolved Mysteries Really remarkable. Includes a myriad of things I never knew or thought about. Visually great -- and in 3D if you have the glasses. September 30, 2016
Rated 5 out of 5 by The Inexplicable Universe: Unsolved Mysteries This "course" covers in amazing detail the history of and the great issues in those parts of science from ancient through modern times relevant to our current understanding of the Universe and its composition and functioning and also includes many hints about its unknowns. The course introduces each subject and then provokes the viewer to deal with the relevance of and the often very complex issues involved in gaining an understanding of what has been AND what may be. This is difficult but rewarding work. Happily because the "course" is a DVD, one can keep repeating any part of it until one is better able to grasp (I don't say "master") the topic. The Professor is very engaging and exceptionally articulate. He manages to clarify some peculiarly difficult concepts. I am deeply grateful for this course and eager to continue with it and to try others. Christine de Fontenay P.S. My other favorite of the "Great Courses" course is the "Science and Religion" one, which is also extraordinarily well done. And I have also the Hubble course (excellent with wondrous photos), the Economics, and the Calculus courses. I may never get time to just read casually again. CCF September 25, 2016
Rated 4 out of 5 by Entertaining Presentation Neil deGrasse Tyson is unfailingly interesting, entertaining, and informative. This short video course is no exception. Dr. Tyson takes us on a whirlwind tour through a number of outstanding questions (framed as mysteries) in science, focusing on astrophysical and cosmological phenomena. The recording was evidently made a number of years ago, although it is copyrighted 2012. For example, one of the mysteries is the Pioneer Anomaly, an apparently unexplained deviation from the expected rate of deceleration of the Pioneer 1 and 2 spacecraft. By 2012, there was a broad consensus that the anomaly was completely accounted for by anisotropic thermal radiation pressure from the geometry of the craft and their on-board radioisotope thermal generators. Such are the risks of developing any instructional material in fields subject to rapid expansion. Dr. Tyson also seems a bit more hesitant and prone to lean on bridge sounds than in more recent and more polished productions. Nonetheless, this course is certainly worth the cost (very low, actually), and thoroughly enjoyable. Try it out! August 16, 2016
  • 2016-10-23 T09:45:09.042-05:00
  • bvseo_lps, prod_bvrr, vn_prr_5.6
  • cp-1, bvpage1
  • co_hasreviews, tv_114, tr_114
  • loc_en_US, sid_1816, prod, sort_default
2 3 4 5 next>>

Questions & Answers

Customers Who Bought This Course Also Bought

Buy together as a Set
Save Up To $168.00
Choose a Set Format