Why do planets orbit in the same plane?

The Urban Astronomer Podcast

In episode 48 of the Urban Astronomer Podcast, we're doing another Science Explainy bit! These segments are where you get to hear my droning voice explain some fundamentals and answer listener questions. Today we get asked why it always is that planets orbit in the same plane, and why the Moon can be seen during daylight. If you like what you hear, don't forget to tell a friend about the show, and make a small donation on our Patreon account. Why do planets orbit in the same plane? 1:50 This question was asked by Matthew du Plessis, one of our Twitter followers. He wants to know why planets always seem to orbit their star in the same direction, and why those orbits are always aligned within the same orbital plane. We take a look at how solar systems are formed in the first place, to show why this alignment is inevitable. I make reference to this video: Why can I sometimes see the Moon during the day? 12:29 This question came from Anzet du Plessis, also on Twitter. She wants to know why it is that the Moon is sometimes visible during the day. I think a bit about how small children never seem to be surprised by this, yet older kids and adults often are. And of course, I also answer the question! Announcements 18:35 This weekend, on Saturday 14 September, I will be at ScopeX, at the Military History Museum in Johannesburg. ScopeX is an astronomy and telescope fair held every year. It is packed with amateur telescope making displays, science shows, commercial telescope vendors. There are also public lectures in the auditorium. I will be presenting a talk on Orbital Mechanics, demonstrated through the medium of Kerbal Space Program. So basically, I'll be playing video games to demonstrate the physics of space travel! Other speakers include Case Rijsdijk, president of the Astronomical Society of South Africa, Dr Pieter Kotze of the Hermanus Magnetic Observatory, Prof Roger Deane of the University of Pretoria, Martin Heigan, who is the section director of ASSA, and David Rogers who will be speaking on "Fifty Years after Apollo - with so much going wrong, how did they get it right?" If you are in the area, please do come along. The museum does charge a small entrance fee, with discounts for students, scholars and pensioners, but it's not much and they need the support. It's a great day out for the family, there's a lot to see and do, there are prizes to be won, including cameras and telescopes, and of course you'll meet fellow space and astronomy enthusiasts who've flown in from all over the country! It's one of the highlights of the local astronomy calendar, and i'm really looking forward to meeting you there! One Last Thing 20:55 I announced last episode that I've joined the team at the Weekly Space Hangout, and I now have a date for my first episode! I'll be on the air, live, on 18 September, with Fraser Cain, Kimberly Cartier, and whoever the special guest will be! Longtime listeners will remember that time I experimented with unscripted content, and if you enjoyed hearing me flounder along speaking from the top of my head, well... you'll love this! Follow my twitter account at @uastronomer for updates closer to the time on who I'll be sharing the mic with, the exact time we'll be broadcasting, and the link to watch it. I'm nervous as all hell, but I also think it's gonna be a ton of fun and I'm looking forward to having you loyal listeners with me, for moral support if nothing else!