caustics on the sea shore

User avatar
Graeme
Cosmic Lounger
Posts: 1500
Joined: 11 Feb 2010, 12:23
Location: Medway, Kent, UK

Re: caustics on the sea shore

Post by Graeme »

ChrisGreaves wrote:
29 Jan 2025, 21:01
John Gray wrote:
27 Jan 2025, 10:32
Clarity would result were you to look on Wikipedia... https://en.wikipedia.org/wiki/Caustic_(optics)
Well, yes, but ...
In optics we are talking about bending/refraction/focusing of light, waves of light.
And I think that I can see how fluctuations in (in Ken's case) the lake water produce chaotic shapes as a result.

But if this is true for light rays/waves passing through a fluid (water), might it not also be true for, say, radio waves passing through air? A radio-photographer ought to be able to duplicate Ken's result with radio images.

And then some smarty-pants will jump in with a similar question about gravity waves. :grin:
Cheers, Chris

Or some smarty pants will jump in and say that radio waves are light waves!

Gravitational waves are not though.
_______________________________________

http://www.averywayobservatory.co.uk/

User avatar
stuck
Panoramic Lounger
Posts: 8704
Joined: 25 Jan 2010, 09:09
Location: retirement

Re: caustics on the sea shore

Post by stuck »

Graeme wrote:
31 Jan 2025, 16:04
...and say that radio waves are light waves!
:laugh: I nearly did just that.

Ken

User avatar
ChrisGreaves
PlutoniumLounger
Posts: 16789
Joined: 24 Jan 2010, 23:23
Location: brings.slot.perky

Re: caustics on the sea shore

Post by ChrisGreaves »

Graeme wrote:
31 Jan 2025, 16:04
Or some smarty pants will jump in and say that radio waves are light waves! Gravitational waves are not though.
Seriously: Have I interpreted this correctly?
You are agreeing that Radio/light/heat waves are all electromagnetic waves, but that gravitational waves are NOT electromagnetic waves?
Thanks. Chris
Fill your face with laughter, then there will be no room for tears.

User avatar
ChrisGreaves
PlutoniumLounger
Posts: 16789
Joined: 24 Jan 2010, 23:23
Location: brings.slot.perky

Re: caustics on the sea shore

Post by ChrisGreaves »

stuck wrote:
31 Jan 2025, 16:28
Graeme wrote:
31 Jan 2025, 16:04
...and say that radio waves are light waves!
:laugh: I nearly did just that. Ken
Er, Ken, I think that with that post you just did!
Cheers, Chris
Fill your face with laughter, then there will be no room for tears.

User avatar
stuck
Panoramic Lounger
Posts: 8704
Joined: 25 Jan 2010, 09:09
Location: retirement

Re: caustics on the sea shore

Post by stuck »

Yes. The EM spectrum goes from very short wavelengths / high frequency waves like gamma rays, through X-rays, UV, visible, IR and on to very long wavelengths / low frequency waves like radio waves:
    https://en.wikipedia.org/wiki/Electroma ... s_edit.svg
Yes, I know, the diagram goes the other way, long to short.

Gravitational waves are not EM radiation, they are ripples in spacetime:
    https://www.ligo.caltech.edu/page/what-are-gw

Ken

User avatar
ChrisGreaves
PlutoniumLounger
Posts: 16789
Joined: 24 Jan 2010, 23:23
Location: brings.slot.perky

Re: caustics on the sea shore

Post by ChrisGreaves »

stuck wrote:
31 Jan 2025, 19:08
Yes, I know, the diagram goes the other way, long to short.
Ken, You're not having a good day with back-to-front posts, are you? :laugh:
Gravitational waves are not EM radiation, they are ripples in spacetime:
I suppose that this means that any argument based on "Gravity means mass and mass is energy and energy is EM radiation" is not going to get much traction here, is it?
Cheers, Chris
Fill your face with laughter, then there will be no room for tears.

User avatar
Graeme
Cosmic Lounger
Posts: 1500
Joined: 11 Feb 2010, 12:23
Location: Medway, Kent, UK

Re: caustics on the sea shore

Post by Graeme »

ChrisGreaves wrote:
01 Feb 2025, 00:10
I suppose that this means that any argument based on "Gravity means mass and mass is energy and energy is EM radiation" is not going to get much traction here, is it?
“Spacetime tells matter how to move; matter tells spacetime how to curve.”
― John Archibald Wheeler, Geons, Black Holes and Quantum Foam: A Life in Physics
_______________________________________

http://www.averywayobservatory.co.uk/