Some parts of the sea are saltier than others. The Atlantic Ocean for example has two huge deserts of extra salty water. To see which parts are saltier than the other, NASA's Aquarius instrument aboard Argentina's Aquarius/SAC-D spacecraft released the first year of data.
You can see it in the image above, red and orange areas are very salty, while green and blue areas are less so.
Invisibility is something scientists have been trying to achieve in tech for many years. It looks like the smart folks from the University of Rochester have found a way to hide something from sight. Read more