So how many stars are there in the Universe? It is easy to ask this question, but difficult for scientists to give a fair answer! Stars are not scattered randomly through space, they are gathered together into vast groups known as galaxies. The Sun belongs to a galaxy called the Milky Way.
Reverse osmosis. Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove ions, molecules, and larger particles from drinking water.
Warnings. 1  Reverse osmosis (RO) filters will only soften water for a short time before the mineral buildup ruins them. 2  It's best to use an ion exchange filter to soften the water, followed by an RO filter to remove other mineral contaminants. 3  You can find devices that include both of these filters.