[Q&A+] How Hot Are Black Holes?

BONUS QUESTION STARTS AT 15:12 Watch the video here (with no ads) or on YouTube: https://youtu.be/wusLmLQ5uqA Dr Paul Sutter https://www.pmsutter.com/ How can black holes be hot when all they do is suck in everything around them? Why is the Oort cloud so perfectly spherical? How do astronomical measurements work? And in Q&A+, can small Moon impacts be a threat to Earth? 00:00 Intro 00:23 [@MistSoalar] Why is the Oort cloud spherical? 03:09 [@rJaune] Could we detect the Oort Clouds, or Kuiper Belts of exo-systems? 03:45 [@nephilim20111] How hot black holes are? 08:05 [@d.o.6769] What are the various units and how do they relate to each other? 15:12 [@-Blackberry] Can small Moon impacts be a threat to Earth 17:06 Dr Paul Sutter