Comedians Jessica Michelle Singleton (@JMScomedy) and Christina Walkinshaw (@walkinsauce) join Matt and Andy to discuss bachelor parties, dating, Alaska, super coffee, Google’s April Fools, Microsoft AI, a scientifically impossible Indiegogo, Edx.org's free learning, Vasalgel in rabbits, butt stuff, bunnies in wine glasses, rabbit kidneys, long term good drug effects and fracking-induced earthquakes.

Tom Bell (@tombellforever) of The Leisure Class/Project Greenlight and comedy duo Tommy and the Weeks joins Matt and Andy for a bedroom recording involving a call from a private investigator, Boaty McBoatface, Diana and Mother Teresa, Bob the Robot and Horrible Science, following our robot overlords to disaster, unscrambling eggs to cure cancer, an academic paper that cites The Creator, a video game ProbSci shoutout, eagles vs. drones, Janna Levin's new book and spider boners in amber.

Original Probably Science co-hosts Jesse Case (@jessecase) and Brooks Wheelan (@brookswheelan) return to the show to celebrate Episode 200!

Rick Rosner (@dumbassgenius) has the second-highest IQ score in the world, and his resume includes stints as a bouncer, a stripper, a nude art model and a writer on numerous TV shows. Rick joins Matt, Andy and returning guest Dax Jordan (@daxjordan) to discuss What3Words, xkcd's take on passwords, IQ tests, Rick's Errol Morris interview, spending ten years in high school, stupid California tax rules, Rick's informational theory of the universe, Olbers’ Paradox, The Singularity, Ray Kurzweil, being Borg-ed up, Alcor freezing heads, taking 70 vitamins per day, Rick's gym obsession, writing for MTV's Remote Control, doing nude art modeling with shingles, Rick's Who Wants To Be A Millionaire controversy and his books on Amazon.

Alice Wetterlund (@alicewetterlund) of Silicon Valley and Girl Code joins Matt and Andy to discuss Equinox, aliens, Star Trek, why humans have chins, navigating in Ghana, space lasers and exploding e-cigarettes.

Dr. Chiara Mingarelli (@gravitate_to_me), a Marie Curie Fellow in gravitational wave astrophysics at Caltech, joins the proceedings to talk about low-frequency gravitational waves, pulsar timings arrays and black hole binary systems with masses that are billions of times that of the Sun. This episode was recorded before LIGO's recent announcements confirming the detection of gravitational waves.

One of the biggest scientific breakthroughs of our time calls for an emergency special episode featuring returning guests Dr. Jamie Rollins and Dr. Larry Price, both of whom worked on LIGO, the device that for the first time in history confirmed the existence of gravitational waves, along with theoretical astrophysicist and black hole expert Dr. Janna Levin. Topics discussed include Matt's surprising illness, science fluff, Marco Drago's discovery?, How LIGO works, 30 solar mass black holes, test signals, the actual paper explaining the recent gravitational wave findings, Janna's new book, Relativity 101, BICEP's failure, new black holes, Scorpion!, our T-shirts, Apple vs. the FBI and what the point of all this is.

Visit LIGO.org or LIGO.caltech.edu for all your gravitational wave needs!

Ingrid Oliver (@ingridoliver100) of Watson & Oliver and Doctor Who joins Matt and Andy to discuss pengwings, Germans who can't pronounce squirrel, umlaut words, plastination, bees and weather, sniffer bees, a stupid new drug law, first class flight, anti-aging, the Zika virus, how we’ll all die, and ball-packing and avalanches.

Maude Garrett (@maudegarrett) of SourceFedNERD and Geek Bomb joins Andy (@andytwood) and Matt (@mattkirshen) to discuss the weather, Marge, the rains are here, Foley artists, weird childhood memorization, geek vs. nerd diagrams, the ending of Grease and Jurassic Park, a computer that beat a Go champion, E-sports, a new planet, a new HIV treatment, how quickly conspiracies would reveal themselves, and a monkey head transplant. Also, we realize sound cuts out intermittently in the last half of the episode and for that we apologize!

Matt and Andy welcome comedy's Maria Shehata (@MariaShehata) and Nick Dixon (@nickdixxon) to the show to talk about the discovery of penicillin, vaginal steaming, poop transplant pills, autism and gut flora, standing on escalators, man/woman flu, why hangovers get worse as you age, and bringing a tortoise species back to life.