Available on PBS Digital Studios (the network's YouTube Channel), PBS Space Time is a show that "explores the outer reaches of space, the craziness of astrophysics, the possibilities of sci-fi, and anything else you can think of beyond Planet Earth." Hosted by physics and astronomy professor Matthew O'Dowd, this series features short (approximately 10-15 minutes) episodes that explain topics including quantum mechanics, dark energy, and gravitational waves. New episodes are released approximately weekly, and sometimes address astronomy and physics topics in the news. For example, an episode earlier this month examined NASA's July 4th Juno Mission to explore Jupiter. Visitors to this YouTube channel can browse 42 past episodes. One highlight of this series is the ongoing Challenge Question subseries (compiled in a playlist on the channel). These short episodes pose question problems for viewers to answer based on hints provided in the episode.