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. Each of these six self-contained lectures is a marvelous journey to the frontiers of the known (and unknown) universe and introduces 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.

Due to its unique subject matter The Inexplicable Universe takes a highly visual approach. Many of the fascinating subjects in the course, such as black holes, string theory, and multiple universes are best demonstrated visually and Professor Tyson's lectures feature expertly crafted computer animations, explanatory diagrams, high resolution photographs, and other instructive visual elements. In order to better explain to you some of the grand, intricate ideas being discussed, Professor Tyson personally interacts with many of these animations and graphics using greenscreen technology.

Please note that, due to the highly visual nature of The Inexplicable Universe, the course does not come with a guidebook. We did not believe a simple book could adequately convey the information in the course, and rather than make a guidebook that did not do the course justice, we decided to not offer one. However, we believe that you will be very excited by how we produced this course and will find it to be an enriching and fulfilling experience in your educational journey.