The 365 Days of Astronomy

Cheap Astronomy investigates why light moves at light speed in a vacuum.
Hosted by Steve Nerlich.
Shining a light!
Dear Cheap Astronomy – Why does a photon travel at speed c, part1
It may sound a bit strange to ask why light travels at the speed of light, but that's because c isn't really the speed of light – it's really a measure of the relationship between distance (or space) and time. It's become customary to call c the speed of light, but in reality light moves at different and slower speeds through air, water or glass, it only moves at c in a vacuum.
 
Dear Cheap Astronomy – Why does a photon travel at speed c, part1
Last week we grappled with the issue of why light is able to move at the speed c, which is around 300,000 km/sec in a vacuum. Some key points we landed were that c is actually the fastest speed that anything can move and that light isn't the only thing that moves at c, gravity does too. The constant c is perhaps better thought of as defining the fundamental relationship between space (or distance) and time, where it must take at least one second to cross 300,000 kilometers – meaning it must take at least 0.000000033 second to cross one meter, and you can add even more zeros to cross centimeters and then nanometers.
 
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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 [email protected].

https://www.youtube.com/watch?v=JBHzV4y7G5A
Hosted by Tony Darnell.
From May 23, 2025.
The COSMOS-Web dataset represents the deepest look into our universe done by #JWST.  
 
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].

http://www.astronomycast.com/archive/
From October 26, 2009.
Launching a rocket into space requires a big effort on the ground. Space agencies have built up huge infrastructures to store, prepare and launch rockets. Let's take a look at what's involved on the ground at a place like Cape Canaveral. What happens before, during and after a launch.
 
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].

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 October 2025.
Today's 2 topics:
- The Lagrange point L4 is 60° ahead of Mars whereas L5 is 60° behind Mars on the red planet's orbital path about the Sun. An object placed at either of these locations is trapped gravitationally and is likely to remain there indefinitely. The Mars L4 and L5 locations could provide a permanent place for staging and resupply missions to Mars and would give humans a different view of space weather and its effects on our home planet.
 
- Obtaining accurate data on the Earth's climate and how it is changing is vital to inform agriculture , insurance risks, business planning, disaster preparedness, financial investments, wild fire mitigation, and national security. The USA should not be flying blind and relying on Europe and China for the data we need.
 
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].

Astronomers have discovered one of the most chemically primitive stars ever identified — an ancient stellar relic that preserves the chemical imprint of the very first stars in the Universe. In this podcast, Dr. Ani Chiti discusses the discovery of this ancient star and what it tells us about star formation in the early Universe. 
 
Bios: 
- Rob Sparks is in the Communications, Education and Engagement group at NSF's NOIRLab in Tucson, Arizona.
- Dr. Anirudh Chiti is a Brinson Prize Fellow at Stanford University, interested in the formation of the first stars and galaxies, the early production of heavy elements, the early Milky Way, and local tracers of dark matter. He observes and characterizes nearby stars and galaxies that formed at early times to understand these topics, in an approach known as "Near-field Cosmology" or "Galactic Archaeology".
 
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].