The 365 Days of Astronomy

https://spacescoop.org/en/scoops/2609/why-does-jupiter-have-bigger-moons-than-saturn/
Hosted by our editor, Richard Drumm.
Jupiter and Saturn are the gas giants in our Solar System. Ummm… Uranus & Neptune are now called ice giants. But back to Jupiter & Saturn.
They are the largest planets, have the most moons compared to the other planets, and if that isn't cool enough, they're home to some of the largest moons in the Solar System. Saturn has 280 or more moons in total, a total that seems to be changing daily. Jupiter has over 100 known moons so far. 
As for me, I don't even try to keep count any more.
 
Here's where things get really interesting: Jupiter has four big moons, including Ganymede, the biggest one in the whole Solar System. Jupiter's Galilean moons from closest to farthest are Io, Europa, Ganymede & Callisto. 
 
The first 3 are in a 1:2:4 orbital resonance with Io making 4 orbits, Europa 2 and Ganymede 1. It's been calculated that Ganymede & Callisto were in a 7:3 resonance a couple million years ago but are slipping toward a 6:3 which is a nice, stable 2:1 resonance. Callisto will likely fall into that resonance in a billion and a half years making the system 1:2:4:8. Nice & stable.
 
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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 info@365DaysOfAstronomy.org.

Paul Hill & Dr. Jenifer "Dr. Dust" Millard host. 
Damien Phillips, John Wildridge and Dustin Ruoff produce.
This month it appears cosmology is saved, Swift maybe saved and exoplanets have their magnetosphere measured. Jeni has been in the States where she may have been turned into an android visiting Silicon Valley.
 
We've added a new way to donate to 365 Days of Astronomy to support editing, hosting, and production costs. 
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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 info@365DaysOfAstronomy.org.

Hosted by Dr. Paul M. Sutter.
What are the weaknesses of inflation theory? How did the ekpyrotic theory attempt to improve it? How did it open up its own can of worms? I discuss these questions and more in today's Ask a Spaceman!
 
Support the show: http://www.patreon.com/pmsutter
All episodes: http://www.AskASpaceman.com
Watch on YouTube: http://www.youtube.com/PaulMSutter
Read a book: https://www.pmsutter.com/books
 
Keep those questions about space, science, astronomy, astrophysics, physics, and cosmology coming to #AskASpaceman for COMPLETE KNOWLEDGE OF TIME AND SPACE!
 
Big thanks to my top Patreon supporters this month: Justin G, Chris L, Alberto M, Duncan M, Corey D, Michael P, Naila, Sam R, Joshua, Scott M, Rob H, Scott M, Louis M, John W, Alexis, Gilbert M, Rob W, Jessica M, Jules R, Jim L, David S, Scott R, Heather, Mike S, Pete H, Steve S, Lisa R, Kevin B, Aileen G, Deb A, Michael J, Phillip L, Steven B, Mark R, Alan B, Craig B, Richard K, Joe R, David P, Justin, Tracy F, Thomas K, James C, Syamkumar M, Homer V, Mark D, Bruce A, Tim Z, Linda C, The Tired Jedi, Bob C, Stephen A, James R, Allen E, Michael S, Sheryl, David W, Chris, Michael S, Erlend A, James D, Karl W, Den K, Edward K, Scott K, Vivek D, M0PPET, Brad, Azra K, Steve R, M D Malahy, Brian O, Alonna M, Joseph B, and Anders J!
 
We've added a new way to donate to 365 Days of Astronomy to support editing, hosting, and production costs. 
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Every bit helps! Thank you!
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------------------------------------
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 info@365DaysOfAstronomy.org.

Mon 06: Astronomy Cast Ep. 6: Ep. 6: More Evidence For the Big Bang
http://www.astronomycast.com/archive/
From October 16, 2006.
Last week's episode started out with a bang… a Big Bang. This week we continue our discussion into the beginning of everything. We present three additional lines of evidence that have led astronomers to the conclusion that our Universe started out as a singularity 13.7 billion years ago, and has been expanding ever since.
 
Fraser Cain: So Pamela, last week we started out with the big bang and discussed the cosmic microwave background radiation. Now, if people still aren't convinced that the universe began as a singularity 13.7 billion years ago, and has been expanding ever since, fine. We've got more evidence: take your pick.
Okay Pamela, continue convincing us!
 
We've added a new way to donate to 365 Days of Astronomy to support editing, hosting, and production costs. 
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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 info@365DaysOfAstronomy.org.

Dr. Al Grauer hosts. Dr. Albert D. Grauer ( @Nmcanopus ) is an observational asteroid hunting astronomer. Dr. Grauer retired from the University of Arkansas at Little Rock in 2006. travelersinthenight.org
From April 2026.
Today's 2 topics:
- According to NASA an average of one catalogued piece of space junk per day has come down to Earth over the past 50 years. Research is described which can track space junk in the atmosphere and provide the starting location and altitude for tracking clouds of environmentally problematic toxic chemical and/or nuclear contaminants released by the disintegration of reentering spacecraft.
 
- My Catalina Sky Survey teammate Greg Leonard was asteroid hunting with our 60 inch telescope on Mt. Lemmon, Arizona when he came across an unknown moving point of light in the night sky. After Greg reported his observations to the Minor Planet Center his discovery was tracked by telescopes in California, Romania, Germany, New Mexico, Arizona, Bavaria, and Japan. Astronomers used these data to calculate that Greg's discovery orbits the sun between Venus and Earth, estimate its size to be approximately twice the length of a football field, and give it the name 2026 BX4. 
 
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 info@365DaysOfAstronomy.org.