Uploaded January 2026 | Updated September 2026, 2 weeks ago

---

In this documentary, we explore how ancient photons from stars billions of light-years away allow us to look back to the dawn of time. Featuring astronaut Ulrich Walter and astrophysicist Susanna Randall, we examine the paradox of light: how it can act as both a wave and a particle, and how it links space and time through Einstein’s Special Relativity.

Subscribe to Spark for more amazing science, tech & engineering videos: goo.gl/LIrlur 🚀

Join the Spark Channel Membership to get access to perks:
youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join

You can now become a History Hit member right here on YouTube! Join for access to a new exclusive documentary every week, and access to over 160+ of our documentaries presented by world renowned historians like Dan Snow, Eleanor Janega, Tristan Hughes, Mary Beard, Matt Lewis and more.
Get an exclusive release every week by signing up here: bit.ly/4pyExyn

Any queries, please contact us at: owned-enquiries@littledotstudios.com

#Spark