Astronomy Cast Questions Show: The Source of Atmospheres, the Vanishing Moon, and a Glow After Sunset

From May 7, 2009. How do planets get their atmospheres? What would happen to the Earth if the Moon just disappeared? And what’s that strange glow we see after sunset?   - What would happen if the Moon disappeared — would that change Earth’s orbit? - How do planets get atmospheres? - I see a faint glow after sunset in the East — what could it be? - Can light get stuck in orbit around a black hole? - Where on Earth would I weigh the most? - How much less would I weigh if the moon was directly overhead? - How is ionized hydrogen detected in space? - Do we live in an unbalanced Universe? - Why do some celestial objects form in disks and others don’t? - Could a spacecraft perform a “solar system assist,” in the way we do gravity assists? - If Earth had no axial tilt, how eccentric would its orbit have to be to have  seasons like we have now? - Does light have mass? - The Cosmic Microwave Background is a redshift of the Big Bang.  If one could travel near light speed, would that counteract the redshift? - Is repulsive gravity real?   We've added a new way to donate to 365 Days of Astronomy to support editing, hosting, and production costs.  Just visit: https://www.patreon.com/365DaysOfAstronomy and donate as much as you can! Share the podcast with your friends and send the Patreon link to them too!  Every bit helps! Thank you! ------------------------------------ Do go visit http://www.redbubble.com/people/CosmoQuestX/shop for cool Astronomy Cast and CosmoQuest t-shirts, coffee mugs and other awesomeness! http://cosmoquest.org/Donate This show is made possible through your donations.  Thank you! (Haven't donated? It's not too late! Just click!) ------------------------------------ The 365 Days of Astronomy Podcast is produced by the Planetary Science Institute. http://www.psi.edu Visit us on the web at 365DaysOfAstronomy.org or email us at [email protected].