In the last issue of Nature, two studies came out looking for this elusive piece of evidence. Both groups used spectroscopy. This is where you break down light into its different colors. When you do this each element and molecule has a distinctive fingerprint. Using this teqnuqie one group thinks they found sodium in the water, and another says it's not there.
The group from the Cassini spacecraft team says that they have found sodium. The other group was using two of the best ground based telescopes in the world. They say that sodium is absent from the water. So what do we do? Rarely in science do you get opposite results published at the same time. Both sides have strong evidence, and are both in one of the most prestigious science journals. Really, the only thing we can do is wait for more evidence.
Cutting edge science is thrilling. We are always learning new things, and those things always manage to surprise us. I just can't wait to see what happens.
The suspense is killing me!
Sources - NASA