The Big Blue

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Why is it that when you hold up a glass of water it appears colourless, but when you look out onto a beautiful Caribbean vista, the water dances in unbelievable shades of blue? Is there something special about the sea that gives the big blue its name?

There is nothing that makes the ocean more blue than drinking water. Its just that there is so much of it that we see its true colour.

So what is the source of that true blue? One idea is that the ocean reflects the blue of the sky. Another is that there are dissolved ions, like copper, that give the water a blue tinge.

The water, in fact, is not reflecting the sky. I bet if you shone a floodlight on a crystal blue lagoon at night, you would still see that aquamarine colour.

And yes, there are many dissolved ions and other particles that may absorb, reflect, and scatter light, but this just causes variation in colour from sea to sea. But this is not the source of the blue.

In its typical unique style, water gets its colour in a way that is unlike most other molecules.

Colour corresponds to the length of light waves. Molecules will tend to absorb some light waves and reflect others. The wavelengths that are not absorbed are the ones we see, and give a substance its colour. Usually light waves interact with the electrons of the atoms, and not the inner nucleus.

Water, however, gets its hue from the vibrations coming from the nucleus of the atoms. The excited vibrations absorb red waves and not blue ones. This is the only known molecule to get its colour in this way.

As if I needed another reason to revere this gorgeous view...

~Rheanna "just about to put my toes in the" Sand

The Damp Side of the Moon

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Three spacecraft have obtained some astonishing data that completely contradicts a widely held belief in planetary science: there is water on the Moon. And not just a couple of rogue molecules, either. The Moon is actually "painted" with water and hydroxyl (see the blue and orange/green above, respectively).

It's everywhere. And now two enormous mysteries remain: How did it get there? And forgive the phrase, but why on Earth didn't we see it before?

Already scientists are speculating.

The water was discovered by measuring sunlight reflected off the Moon's surface. Researchers observed a dip at the wavelength where water absorbs infrared light, and found that the amount of absorption varied with temperature. According to the researchers:

That suggests the water is being created when protons from the solar wind slam into the lunar surface. The collisions may free oxygen atoms in the minerals and allow them to recombine with protons and electrons to form water.

So why didn't we find it before? Well, we did. Lunar soil brought back from the Apollo mission did show signs of water. But the Apollo scientists, erring on the side of caution, dismissed it as being more likely a result of contamination on re-entry. Which just goes to show you, even skeptics can overdo it.

At an estimated concentration of one quart of water per cubic yard (about a liter per cubic meter), all that remains now is to determine the effect this discovery will have on future attempts to actually colonize and form settlements on the Moon.

For my part, I'm just dying to try a sip.

- Brit Trogen