Isaac Arthur
Science-based futurism: megastructures, terraforming, and space colonization.
I mostly listen to this as a podcast. Generally the content is the audio with the video not really being neccisary.
Isaac Arthur explores the future as presented in science and science fiction — megastructures, terraforming, interstellar travel, and the hard engineering constraints behind them — with a weekly upload schedule and a companion podcast. He’s President of the National Space Society and a Hugo Award finalist. The channel’s been at this for a decade; recent uploads keep the format steady (“The Future of…,” “Science of…” episodes). The SFIA handle is the main channel; there’s also a secondary channel for extras.