If we look into a reflection in space 0.5 light years away from Earth, we should see 1 year ago (given zero motion relative to earth, and 0.5+0.5=1 year.)
Where there is relative motion with photons at least isn't there a Redshift and the Doppler effect (edit: and a different parametric or chaotic convolution over large distances without e.g. helical polarization to shield the signal)
Magnetic fields reportedly have a maximum propagation speed that is also the speed of light c in a vacuum.
So, to recall Earth's magnetic field from 41,000 years ago with such a method would presumably require a reflection (41,000/2 = 20,500) light years away
I wish they'd gone into more detail about how they generated those sounds. It's not just sine waves, obviously, and there's also a stereo component there.
Agree. A visualization (or in this case a "sound-alization"?) is just some mapping of an abstract data set into a form more convenient for our evolved senses.
Without understanding the nature of the mapping, you don't really know if you're gaining some insight into the underlying process or just looking at (listening to) a cheap clickbait chartjunk.
From the youtube video description:
> Scientists at the Technical University of Denmark and the German Research Centre for Geosciences used data from ESA’s Swarm mission, along with other sources, to create a sounded visualisation of the Laschamp event. They mapped the movement of Earth’s magnetic field lines during the event and created a stereo sound version which is what you can hear in the video.
The soundscape was made using recordings of natural noises like wood creaking and rocks falling, blending them into familiar and strange, almost alien-like, sounds. The process of transforming the sounds with data is similar to composing music from a score.
So it sounds like this one is more interpretative and meant for popular engagement rather than scientific insight. There's probably some scientific insight to be had, but the level of depth is probably on the order of the accompanying usatoday pop-news text.
"The soundscape incorporates natural sounds such as creaking wood, falling rocks and other sounds which were then blended together in an "alien-like" sounds."
I was thoroughly disappointed with that. Why not use synthesizers, guitars, drums to just make shit up at that point?
There have been some very interesting things done with taking frequencies way too high for human hearing, but just scaling them all down in proportion to a range humans can hear. Even turning the signals from Voyagers crossing the heliopause makes for interesting sounds.
To me, what they've done here is some artsy thing which is fine, but I was hoping to be more sciency.
Where there is relative motion with photons at least isn't there a Redshift and the Doppler effect (edit: and a different parametric or chaotic convolution over large distances without e.g. helical polarization to shield the signal)
Magnetic fields reportedly have a maximum propagation speed that is also the speed of light c in a vacuum.
So, to recall Earth's magnetic field from 41,000 years ago with such a method would presumably require a reflection (41,000/2 = 20,500) light years away