A question from a listener leads us into some very tall weeds as we ponder the nature of light: what is it, exactly? It is a wave? Or a particle? Or, somehow, both at once? And photons, the massless particles that apparently make up all light: if they've got no mass, how can they be affected by gravity — like around a black hole, for example? Oh, it's all very tricky stuff, but we have lots of fun unpacking it all. Because in the end, you can't do much astronomy without light, so it's best to understand it properly, really.
Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.
To view the podcast chapter list and artwork in this episode, you could do worse than use the Overcast app on iOS, or Pocket Casts on Android. (Other podcast players are available, though they may not handle mp3 chapters nicely.)
Some of the things we talk about in this episode:
A listener question from Circus Stu! https://www.circusskillsyorkcic.org
James Clerk Maxwell: https://digital.nls.uk/scientists/biographies/james-clerk-maxwell/discoveries.html
Wave-particle duality of light: https://www.youtube.com/watch?v=Iuv6hY6zsd0
Einstein’s Special Theory of Relativity: http://www.einstein-online.info/elementary/specialRT.html
General Theory of Relativity: https://www.newscientist.com/round-up/instant-expert-general-relativity/
Bowling balls and rubber sheets: https://www.youtube.com/watch?v=MTY1Kje0yLg
Brian Cox drops stuff in a vacuum: https://www.youtube.com/watch?v=E43-CfukEgs
Mass is weird: https://www.youtube.com/watch?v=Ztc6QPNUqls
Neutrino astronomy: https://www.space.com/24334-neutrino-telescopes-astronomy-new-era.html
Gravitational waves: https://www.ligo.caltech.edu/page/what-are-gw
Gravitational wave Astronomy: https://www.scientificamerican.com/article/the-future-of-gravitational-wave-astronomy/
- Dark Sky Reserves: http://darksky.org