Telescopes are, in a way, time-travel machines to the distant past & faraway galaxies. The speed of light is the Universe’s speed limit.

Forget that 55 MPH thing.

186,000 miles per second is more like it!

Lightspeed is also the speed of gravity and electricity, so there’s that.

 

For example, it takes light from the Sun over 8 minutes to reach Earth, so the sunlight we feel on our faces is, on average, actually 8 minutes 25 seconds old. When astronomers use telescopes to look at galaxies in space, they find some that are close by and some that are farther away—that is, some that are younger and some that are very much older. 

 

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].