What’s in the dark? Countless generations have gazed up at the night sky and asked this question—the same question that cosmologists ask themselves as they study the universe. The answer turns out to be surprising and rich. The space between stars is filled with an exotic substance called “dark matter” that exerts gravity but does not emit, absorb, or reflect light. The space between galaxies is rife with “dark energy” that creates a sort of cosmic antigravity causing the expansion of the universe to accelerate. Together, dark matter and dark energy account for 95 percent of the content of the universe. News reporters and science journalists routinely talk about these findings using terms that they assume we have a working knowledge of, but do you really understand how astronomers arrive at their findings or what it all means? Cosmologists face a conundrum: how can we study substances we cannot see, let alone manipulate? A powerful approach is to observe objects whose motion is influenced by gravity. Einstein predicted that gravity can act like a lens to bend light. Today we see hundreds of cases of this—instances where the gravity of a distant galaxy distorts our view of a more distant object, creating multiple images or spectacular arcs on the sky. Gravitational lensing is now a key part of the international quest to understand the invisible substance that surrounds us, penetrates us, and binds the universe together. A Ray of Light in a Sea of Dark Matter offers readers a concise, accessible explanation of how astronomers probe dark matter. Readers quickly gain an understanding of what might be out there, how scientists arrive at their findings, and why this research is important to us. Engaging and insightful, Charles Keeton gives everyone an opportunity to be an active learner and listener in our ever-expanding universe. Watch a video with Charles Keeton: Watch video now. (http://www.youtube.com/watch?v=Uc3byXNS1G0).

The universe literally encompasses everything we were, are and will be, everything we knew, know and can know. When we decide to understand the universe as a whole, new truths come to light, and unexpected perspectives illuminate our take on life. 30-Second Universe explains all the tantalising concepts, principles and theories that make up our knowledge - the Higgs particle, gluons, quarks, the multiverse, how certainty itself can be uncertain, and of course, where our world came from, and where we're going and what will happen in the end - and it explains these astrophysical answers succinctly, each entry taking only 30 seconds to read, with further exploration flagged, and key scientists noted. This one small book sheds light on the biggest ideas, concepts and discoveries in life, in the universe, in everything.

Tracing the possible origins of the Magi's star, the author uses an ancient Roman coin as a starting point to investigate the possibility that the legendary star may in fact have been an eclipse of Jupiter and the star Aries.

Putting physics into the historical context of the Industrial Revolution and the European nation-state, Purrington traces the main figures, including Faraday, Maxwell, Kelvin, and Helmholtz, as well as their interactions, experiments, discoveries, and debates. The success of nineteenth-century physics laid the foundation for quantum theory and relativity in the twentieth. Robert D. Purrington is a professor of physics at Tulane University and coauthor of Frame of the Universe.

A BBC Sky at Night Best Astronomy and Space Book of the Year “[A] luminous guide to the cosmos...Jo Dunkley swoops from Earth to the observable limits, then explores stellar life cycles, dark matter, cosmic evolution and the soup-to-nuts history of the Universe.” —Nature “A grand tour of space and time, from our nearest planetary neighbors to the edge of the observable Universe...If you feel like refreshing your background knowledge...this little gem certainly won’t disappoint.” —Govert Schilling, BBC Sky at Night Most of us have heard of black holes and supernovas, galaxies and the Big Bang. But few understand more than the bare facts about the universe we call home. What is really out there? How did it all begin? Where are we going? Jo Dunkley begins in Earth’s neighborhood, explaining the nature of the Solar System, the stars in our night sky, and the Milky Way. She traces the evolution of the universe from the Big Bang fourteen billion years ago, past the birth of the Sun and our planets, to today and beyond. She then explains cutting-edge debates about such perplexing phenomena as the accelerating expansion of the universe and the possibility that our universe is only one of many. Our Universe conveys with authority and grace the thrill of scientific discovery and a contagious enthusiasm for the endless wonders of space-time.