Today, on Boston Public Radio:

We opened lines to callers to hear your thoughts on Tuesday night’s Democratic presidential debate.

Boston Globe columnist Alex Beam discussed the passing of Alexi Leonov, the first man to walk in space.

National security expert Juliette Kayyem discussed the repercussions of Trump’s decision to pull troops from Northeast Syria, along with the latest on the House impeachment inquiry.

Former Suffolk County Sheriff and Secretary of Public Safety Andrea Cabral stopped by to talk about an appeal by attorneys representing Boston Marathon bomber Dzhokhar Tsarnaev.

Author and naturalist Sy Montgomery discussed a recent study indicating that dog ownership may lead to a longer life, along well as a “karaoke parlor” phenomenon among Humpback whales.

WGBH Arts Editor Jared Bowen reviewed “Rosencrantz & Guildenstern Are Dead,” now showing at the Huntington Theater. He also discussed A24’s upcoming film “The Lighthouse,” and a documentary on the Cocoanut Cove fire called “Six Locked Doors."