Could you travel to the past and visit Julius Caesar? Could you travel to the year 4000 and see what the future is like? Find out about the possibilities and paradoxes of time travel. Time marches on except in astrophysics. Einstein taught us that time is a coordinate in space, and it’s all relative. Learn about the weird physics of our universe that could make time travel possible. Standing in for Lynne Koplitz this week is J. Richard Gott, III, author of Time Travel in Einstein’s Universe.

Mark Twain said, “Get your facts first, then you can distort them as you please.” Pseudoscience adheres to this adage, but are their distortions deliberate, the result of scientific ignorance, or due to a deep desire for extraordinary possibilities? In our quest to understand the universe, how can we be sure our conclusions are correct? Human beings have evolved to find meaningful patterns in nature, but sometimes the patterns we see are just figments of our imagination — or perhaps the result of wishful thinking.

Space is now big business. Technology originally developed for the space program sometimes ends up in products for use on Earth, often in surprising ways. The 40,000 certified “Space Products” range from mattresses to medical devices, and have turned space into a multi-billion-dollar industry. Inspired by our excursions into the Final Frontier, entrepreneurs and inventors are turning stardust into gold.

Scientists have been searching for aliens in our solar system and beyond, but have not yet found evidence that life exists beyond Earth. SETI, the Search for Extraterrestrial Intelligence, has been scanning the stars for alien radio beacons for 50 years. Radio and TV broadcasts have been leaking from Earth’s atmosphere for over a century, and these traveling time capsules could eventually reach a broader audience than ever imagined. Neil and Lynne review the methods used to locate aliens and discuss what to do if you’re ever abducted.

The Star Trek TV and movie series imagine a bright future for humans in space, one in which we explore alien worlds with the aid of advanced technology. Because the writers tried to include as much realistic science as possible within the fictional framework, the stories have been an inspiration for students, scientists, inventors, and anyone interested in pondering our destiny on Earth and beyond. In this show, Brandon Fibbs reviews a Star Trek movie, and Lawrence Krauss talks about how Star Trek uses science to explore what is possible in our universe.

Starry, starry nights, stormy and sun-filled days. Long summer days of picnics and ballgames are played out under a vast and gorgeous canvas of astronomical and meteorological curiosities. From the stories of the stars told by the ancients, to a recent mammatus cloud over CitiField in New York, learn about the phenomena in the summer skies that keep us looking up.

In this fascinating foray into the centuries-old relationship between science and military power, acclaimed astrophysicist Neil deGrasse Tyson and writer-researcher Avis Lang examine how the methods and tools of astrophysics have been enlisted in the service of war. "The overlap is strong, and the knowledge flows in both directions," say the authors, because astrophysicists and military planners care about many of the same things: multi-spectral detection, ranging, tracking, imaging, high ground, nuclear fusion, and access to space. Tyson and Lang call it a "curiously complicit" alliance.

For decades, beloved astrophysicist Neil deGrasse Tyson has interpreted science with a combination of brainpower and charm that resonates with fans everywhere. This pioneering, provocative audiobook brings together the best of StarTalk, his beloved podcast and television show devoted to solving the most confounding mysteries of Earth, space, and what it means to be human.

Attempts by scientists and artists to reveal deep truths about the universe may take different forms, but they often end up agreeing with the poet John Keats that “truth is beauty”. Geometry, physics, and the other sciences describe the world we live in, and artists often play with these properties in their own imaginative investigations. From the drawings of Leonardo Da Vinci to high tech computer graphics, Neil and Lynne paint a picture of how science has inspired art through the ages.

This year marks the 400th anniversary of Galileo’s use of the first telescope. On this week’s show, we reflect on how telescopes have changed our perception of our place in the universe, how small we are in size, space, and time. Our guests include Dava Sobel, author of The Planets, Vatican Astronomer Father Chris Corbally, and astronaut Paul Richards.