Do gravitons exist? What are blazars? How did our universe begin? To grapple with questions on a cosmological scale, Dr. Charles Liu and co-host Allen Liu welcome Dr. Ron Gamble, a theoretical astrophysicist at the NASA Goddard Space Flight Center. As always, though, we start off with the day’s joyfully cool cosmic thing, the gravitational wave background. Luckily, we have the “cosmological - gravitational wave - black hole meister dude” Ron on board as our expert to unpack the concept. Ron’s explanation involves pulsars, pulsar timing arrays, and gravitational waves. You’ll hear about how ripples in spacetime can help us date the age. Ron compares the gravitational wave background to the cosmic microwave background, how both compare to sound waves, and how we decipher them. We interrupt Ron’s flow for an audience question from Kelly for Dr. Gamble: Do gravitons exist? Ron explains why gravitons should exist for the force of gravity the same way that particles exist for each of the other fundamental forces. (And yes, bosons and fermions get discussed.) Next, Chuck asks Ron about his journey to NASA, a path that began when he was 4 years old with a question and continued as a search for answers to this day. You’ll hear how he learned grad school level math 2 years before grad school so he’d be ready when he needed it to study non-linear gravitational wave theory. He explains why he had to relearn how to learn math and science, and how, after that, everything else was just like “building Legos.” He's currently studying little understood objects called “black hole lasers” – relativistic black hole jets, or blazars. You’ll hear all about them, as well as learning about the work of Roger Penrose and Dr. Reva Kay Williams, the first black woman to get a PhD in theoretical astrophysics in the U.S. which lead to a Nobel Prize in Physics –unfortunately awarded only to Penrose, as Chuck and Ron discuss. Our next cosmological question comes from Nicholas, who asks, “Is the big bang theory in trouble?” Not in trouble, Ron says, but incomplete. We have a pretty good idea of cosmology, but we’re still testing it, and we don’t know exactly what happened or what we might find. Ron is also a wide-ranging artist, and he shows off some of his work on the walls of his office, from artistic depictions of equations to visions of urban decay. (Sorry, podcast listeners – but Chuck does his best to describe what they look like!) If you’re interested in his work, you can find it in his new online store at www.theartoftheory.com . Finally, Chuck asks about what it’s like to be an artist and a NASA scientist. Ron talks about his role as the Director of the NASA Cosmic Pathfinders Program. You can keep up with Ron on TikTok, Instagram and Twitter (X) at @dr_gamble21. Or you can visit his website at www.theoreticallydrgamble.com . We hope you enjoy this episode of The LIUniverse, and, if you do, please support us on Patreon . Credits for Images Used in this Episode: – Animation of a Pulsar – NASA SVS, Public domain – The planned Laser Interferometer Space Antenna (LISA) – NASA, Public Domain – The four fundamental forces – NASA, Public Domain – A 4x4 matrix representing a tensor – Public Domain text – A Christoffel Symbol – Public Domain text – Illustration of a black hole jet – NASA/JPL-Caltech, Public Domain – Dr. Reva Kay Williams – (Fair Use) – A cosmology timeline of the universe – NASA/WMAP Science Team, Public Domain
