Impeding EM waves (split from Supersonic sub (split from Speed limit on earth))

[Charles 3781]

22 hours ago, John Cuthber said:

Only at depths where it could navigate by the stars in the way that sailing ships did.
Attenuation of 1.5GHz GPS signals by water  will be worse than attenuation of light.

Just wondering why water should impede radio-waves.  Water is composed of Hydrogen and Oxygen. 

Neither of these two elements, by themselves, seem to offer much resistance to radio-waves.  For example, the Oxygen in the Earth's atmosphere doesn't prevent terrestrial radio stations from receiving  broadcasts over long distances.   And Hydrogen gas, which is present in large quantities on the planet Jupiter, doesn't prevent random radio-noise from that planet, being received over even longer distances by our radio-telescopes on Earth.

This demonstrates that both elements are transparent to radio-waves.

So why do Oxygen and Hydrogen when combined together in the form  of water,  block radio waves so strongly?

[studiot]

8 hours ago, Charles 3781 said:

Just wondering why water should impede radio-waves.  Water is composed of Hydrogen and Oxygen. 

Neither of these two elements, by themselves, seem to offer much resistance to radio-waves.  For example, the Oxygen in the Earth's atmosphere doesn't prevent terrestrial radio stations from receiving  broadcasts over long distances.   And Hydrogen gas, which is present in large quantities on the planet Jupiter, doesn't prevent random radio-noise from that planet, being received over even longer distances by our radio-telescopes on Earth.

This demonstrates that both elements are transparent to radio-waves.

So why do Oxygen and Hydrogen when combined together in the form  of water,  block radio waves so strongly?

 

There is a substantial electric field within liquid water.

That is why hydrogen bonding is so important in water.

[swansont]

Gas vs liquid is one effect (density). More degrees of freedom is another - more bonds, more opportunities for a resonance.

Oxygen has a very strong absorption peak at 63 GHz, and this peak rises out if a continuum, so to say it doesn’t offer “resistance” to radio waves is a lazy, uninformed claim.

https://www.rfcafe.com/references/electrical/atm-absorption.htm

 

Quote

Hydrogen gas, which is present in large quantities on the planet Jupiter, doesn't prevent random radio-noise from that planet, being received over even longer distances by our radio-telescopes on Earth.

Why would that prevent the noise? Why would it have an effect on the signal after it left the planet (i.e. why does the distance in space matter)?

[MigL]

It is not the atomic element, but the intermolecular bonds that resonate ( stretch/vibrate/bend ) at radio and microwave frequencies.