Uploaded November 2021 | Updated September 2026, 2 weeks ago
Our Socratica Astronomy series is back! Bookmark the playlist here:
✷ socratica.link/Astro_Playlist
We also ask you join our STELLAR email list so we can notify you when new videos go live:
✷ snu.socratica.com/astronomy
(Don’t rely on the YT algorithm to show you what you’re really interested in!)
✵✵✵✵✵ Units of Distance in Astronomy
Light Years, Parsecs, AU (Astronomical Units) and kilometers
We’re familiar with kilometers (and miles) as measures of distance here on Earth. But when it comes time to measure distances of heavenly objects, it makes more sense to use the units AU, LY, and PC. That is, Astronomical Units, Light Years, and Parsecs. That’s because space is REALLY big!
Today we’ll examine these units that are most commonly used to measure distances in space, and when it makes more sense to use one rather than another. For instance, did you know that astronomical units (AU) are typically used for within our Solar System? But the distance to our nearest star, Proxima Centauri, is so huge that we really do need to jump up to using either Light Years or Parsecs. You'll even hear the terms megaparsec and gigaparsec!
✵✵✵✵✵ CHAPTERS
You can jump to chapters in the video here:
0:00 Introduction to AU Astronomical Units
0:33 AU Distances to planets in our Solar System
0:49 Using Light Years (LY)
1:05 LY in km
1:28 Proxima Centauri
1:37 Orion Nebula
1:52 Using Parsecs (PC)
1:57 PC in LY
2:07 Parsec name explanation
2:22 Parallax demonstration
3:23 What is an arc-second
4:15 d = 1/p
5:35 Challenge Question
You can check your work on the Challenge Question on our website:
socratica.com/lesson/astronomical-distances-problems
✵✵✵✵✵ THANKS TO OUR SOCRATICA FRIENDS
This video was made possible by the generous support of our VIP Patrons on Patreon. What a blessing it is to have support from people who care about education! Let's take a moment to recognize these lovely souls:
Alvin Khaled, Carlos Araujo, Charles Southerland, Chris Kunstt, Christopher Kemsley, Colin Negrych, Deeptanshu Malik, Eric Eccleston, Israel Scott Grogin, Jeremy Shimanek, John Krawiec, Justin Fritz, Kavon Johnson, Kevin B, Marcos Silveira, MdeG, Michael Shebanow, Nunya Beezwax, Philip Rice, Rob Neal, Scott Dreblow, Tracy Karin Prell, and Umar Khan.
Many thanks go out to @LaunchPadAstronomy ! Liliana and Kimberly attended the annual Launchpad Astronomy Workshop for writers, led by astronomy professors Mike Brotherton and Christian Ready. Read more about our experience here:
✷ launchpadworkshop.org
✷ socratica.com/the-socratica-method/launchies
Christian generously reviewed this script and offered advice. Be sure to check out his channel “Launchpad Astronomy” where your friendly neighborhood astronomer keeps you up to date on all the latest in the astro world.
✷ youtube.com/c/ChristianReady/videos
✵✵✵✵✵ SUPPORT SOCRATICA
You can support our channel by making purchases using our affiliate links. These are books and other resources we have used ourselves, and can personally recommend. A small percent of your purchase (usually 1-2%) will be shared with Socratica by the vendor.
We highly recommend the Astronomy textbook “Universe” by Roger Freedman et al:
✷ 9th Edition amzn.to/2so6Ums
✷ 10th Edition amzn.to/2tfBjUe
✷ 11th Edition amzn.to/3mhxqvv
Moon Globe with explorations
✷ amzn.to/3me3kZM
Celestron 6-inch computerized telescope
✷ amzn.to/3mhdysk
Our STUDY TIPS BOOK is now available!
How To Be a Great Student
✷ e-book: amzn.to/2Lh3XSP
✷ Paperback: amzn.to/3t5jeH3
Or read for free when you sign up for Kindle Unlimited:
✷ amzn.to/3atr8TJ
Shop Amazon Used Textbooks - Save up to 90%
✷ amzn.to/2pllk4B
✵✵✵✵✵ MORE WAYS TO SUPPORT SOCRATICA
JOIN this channel for cute owl badges:
✷ bit.ly/SocraticaBadges
SUBSCRIBE to Socratica:
✷ bit.ly/SocraticaSubscribe
SUPPORT Socratica on Patreon:
✷ patreon.com/socratica
DONATE with Paypal:
✷ paypal.me/socratica
GIFT CRYPTO with Bitcoin:
✷ Our address is bc1qda47tgfyk67lxa7yqn8y5m02hjcglghsd5c58n
✵✵✵✵✵ CREDITS
Presented by Liliana De Castro
Written by Kimberly Hatch Harrison
Produced by Kimberly Hatch Harrison & Michael Harrison
Picture Credits
ESA/Hubble & NASA Proxima Centauri from Hubble Space Telescope
nasa.gov/sites/default/files/styles/1920x1080_autoletterbox/public/potw1343a.jpg?itok=Ceuxv-GP
Orion Nebula - Spitzer Space Telescope
images-assets.nasa.gov/image/PIA08653/PIA08653~orig.jpg
NGC 6717
Globular star cluster from Hubble Space Telescope
ESA/Hubble and NASA, A. Sarajedini
Meditations F8LKFUP3ZHZBPIZR
Keeping On SMGDBQIF83RWQWEQ
#Astronomy #LightYear #Parsec
Our Socratica Astronomy series is back! Bookmark the playlist here:
✷ socratica.link/Astro_Playlist
We also ask you join our STELLAR email list so we can notify you when new videos go live:
✷ snu.socratica.com/astronomy
(Don’t rely on the YT algorithm to show you what you’re really interested in!)
✵✵✵✵✵ Units of Distance in Astronomy
Light Years, Parsecs, AU (Astronomical Units) and kilometers
We’re familiar with kilometers (and miles) as measures of distance here on Earth. But when it comes time to measure distances of heavenly objects, it makes more sense to use the units AU, LY, and PC. That is, Astronomical Units, Light Years, and Parsecs. That’s because space is REALLY big!
Today we’ll examine these units that are most commonly used to measure distances in space, and when it makes more sense to use one rather than another. For instance, did you know that astronomical units (AU) are typically used for within our Solar System? But the distance to our nearest star, Proxima Centauri, is so huge that we really do need to jump up to using either Light Years or Parsecs. You'll even hear the terms megaparsec and gigaparsec!
✵✵✵✵✵ CHAPTERS
You can jump to chapters in the video here:
0:00 Introduction to AU Astronomical Units
0:33 AU Distances to planets in our Solar System
0:49 Using Light Years (LY)
1:05 LY in km
1:28 Proxima Centauri
1:37 Orion Nebula
1:52 Using Parsecs (PC)
1:57 PC in LY
2:07 Parsec name explanation
2:22 Parallax demonstration
3:23 What is an arc-second
4:15 d = 1/p
5:35 Challenge Question
You can check your work on the Challenge Question on our website:
socratica.com/lesson/astronomical-distances-problems
✵✵✵✵✵ THANKS TO OUR SOCRATICA FRIENDS
This video was made possible by the generous support of our VIP Patrons on Patreon. What a blessing it is to have support from people who care about education! Let's take a moment to recognize these lovely souls:
Alvin Khaled, Carlos Araujo, Charles Southerland, Chris Kunstt, Christopher Kemsley, Colin Negrych, Deeptanshu Malik, Eric Eccleston, Israel Scott Grogin, Jeremy Shimanek, John Krawiec, Justin Fritz, Kavon Johnson, Kevin B, Marcos Silveira, MdeG, Michael Shebanow, Nunya Beezwax, Philip Rice, Rob Neal, Scott Dreblow, Tracy Karin Prell, and Umar Khan.
Many thanks go out to @LaunchPadAstronomy ! Liliana and Kimberly attended the annual Launchpad Astronomy Workshop for writers, led by astronomy professors Mike Brotherton and Christian Ready. Read more about our experience here:
✷ launchpadworkshop.org
✷ socratica.com/the-socratica-method/launchies
Christian generously reviewed this script and offered advice. Be sure to check out his channel “Launchpad Astronomy” where your friendly neighborhood astronomer keeps you up to date on all the latest in the astro world.
✷ youtube.com/c/ChristianReady/videos
✵✵✵✵✵ SUPPORT SOCRATICA
You can support our channel by making purchases using our affiliate links. These are books and other resources we have used ourselves, and can personally recommend. A small percent of your purchase (usually 1-2%) will be shared with Socratica by the vendor.
We highly recommend the Astronomy textbook “Universe” by Roger Freedman et al:
✷ 9th Edition amzn.to/2so6Ums
✷ 10th Edition amzn.to/2tfBjUe
✷ 11th Edition amzn.to/3mhxqvv
Moon Globe with explorations
✷ amzn.to/3me3kZM
Celestron 6-inch computerized telescope
✷ amzn.to/3mhdysk
Our STUDY TIPS BOOK is now available!
How To Be a Great Student
✷ e-book: amzn.to/2Lh3XSP
✷ Paperback: amzn.to/3t5jeH3
Or read for free when you sign up for Kindle Unlimited:
✷ amzn.to/3atr8TJ
Shop Amazon Used Textbooks - Save up to 90%
✷ amzn.to/2pllk4B
✵✵✵✵✵ MORE WAYS TO SUPPORT SOCRATICA
JOIN this channel for cute owl badges:
✷ bit.ly/SocraticaBadges
SUBSCRIBE to Socratica:
✷ bit.ly/SocraticaSubscribe
SUPPORT Socratica on Patreon:
✷ patreon.com/socratica
DONATE with Paypal:
✷ paypal.me/socratica
GIFT CRYPTO with Bitcoin:
✷ Our address is bc1qda47tgfyk67lxa7yqn8y5m02hjcglghsd5c58n
✵✵✵✵✵ CREDITS
Presented by Liliana De Castro
Written by Kimberly Hatch Harrison
Produced by Kimberly Hatch Harrison & Michael Harrison
Picture Credits
ESA/Hubble & NASA Proxima Centauri from Hubble Space Telescope
nasa.gov/sites/default/files/styles/1920x1080_autoletterbox/public/potw1343a.jpg?itok=Ceuxv-GP
Orion Nebula - Spitzer Space Telescope
images-assets.nasa.gov/image/PIA08653/PIA08653~orig.jpg
NGC 6717
Globular star cluster from Hubble Space Telescope
ESA/Hubble and NASA, A. Sarajedini
Meditations F8LKFUP3ZHZBPIZR
Keeping On SMGDBQIF83RWQWEQ
#Astronomy #LightYear #Parsec
