Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 19/02/2016 12:50:02

Title: What happens to the light from the surface in the deep sea?
Post by: thedoc on 19/02/2016 12:50:02

Oscar asked the Naked Scientists:
   What happens to light going down in water untill it gets dark in the deep sea?
What do you think?

Title: Re: What happens to the light from the surface in the deep sea?
Post by: Colin2B on 19/02/2016 23:15:10

Some is reflected at the surface, but mostly it is absorbed by plankton - including algae. There are also minerals in the water which absorb and scatter the light, and even water molecules will absorb energy.
There are some good articles by oceanographic institutes eg Woods Hole, of particular interest to divers if you want to look at the detail.

Title: Re: What happens to the light from the surface in the deep sea?
Post by: guest39538 on 20/02/2016 11:58:51

Maybe something to do with pressure and density of the medium at the lower depths slowing the propagation speed of light down.

Title: Re: What happens to the light from the surface in the deep sea?
Post by: Colin2B on 20/02/2016 18:20:12

Quote from: Thebox on 20/02/2016 11:58:51

Maybe something to do with pressure and density of the medium at the lower depths slowing the propagation speed of light down.

Slowing the light down would merely delay the light getting there by a very, very small period of time.
The questioner asked a serious question, please do not disrespect him by offering an ill considered reply. Take the trouble to learn about light and its behaviour before offering an answer.

Title: Re: What happens to the light from the surface in the deep sea?
Post by: Ethos_ on 20/02/2016 18:41:39

Quote from: Colin2B on 20/02/2016 18:20:12

The questioner asked a serious question, please do not disrespect him by offering an ill considered reply. Take the trouble to learn about light and its behaviour before offering an answer.

I agree Colin.  Infection of the forum with biased views and polluting our discussions with this typical nonsense requires the application of some effective antibiotics. 

Title: Re: What happens to the light from the surface in the deep sea?
Post by: chris on 20/02/2016 19:51:47

The hydrogen bonds in water are strong absorbers of red light; this is why blood looks black underwater. As a result, not much light at the red end of the spectrum penetrates the deep ocean. Absorption of the red also makes the underwater world look bluer.