xkcd xkcd.com xkcd.com: A webcomic of romance and math humor.Planetary Ringson October 17, 2025 at 04:00 Physics Pathson October 15, 2025 at 04:00 Physics Insighton October 13, 2025 at 04:00 Hot Water Balloonon October 10, 2025 at 04:00 Planetary RingsPhysics PathsPhysics InsightHot Water Balloon