I have a question for the astrophysicists and chemists out there.
If you look at a graph showing how well water absorbs different electromagnetic waves of different frequencies you will see a very sharp valley in the graph for the range of frequencies we call visible light. See this page for a graph showing this: http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/watabs.html
The reason for this gap is that as you move across the spectrum from high-frequency to low-frequency waves, the waves interract in different ways with the water molecules. Some cause vibration, some cause rotation, some have a photoelectric effect, etc. and as a result of that interraction their energy gets absorbed by the water. But visible light's frequencies fall "between the cracks", and don't interract with the water molecules much at all and pass through the water far better than all other frequencies.
This explains why water appears transparent to our eyes, and why we have organs called eyes that detect visible light. As organisms evolved in the ocean, those that could detect what we call visible light had an advantage over those who couldn't, so those 'visible light detectors' got better and better until they became what we now call eyes. This is an 'anthropic' explanation which holds water (sorry for the pun).
But now if you look at the spectrum of EM waves emitted by the sun, you'll see that the strongest waves (i.e. those with the greatest flux) are the ones in the visible range. This is also the case for many stars provided they are in a certain temperature range. There's a chart showing this on this page: http://www.windows2universe.org/sun/spectrum/multispectral_sun_overview.html
I find that to be an interesting and surprising correlation: the highest-intensity EM waves coming from the sun are precisely the ones that travel the furthest through liquid water.
Aside from anthropic explanations, can anyone offer any scientific/physical/chemical explanation for this correlation?
Thanks in advance for your help.