Extraterrestrial liquid water Extraterrestrial liquid water Extraterrestrial liquid water (from the Latin words: "extra" ["outside of, beyond"] and "terrestris" ["of or belonging to Earth"]) is water in its liquid state that naturally occurs outside Earth. It is a subject of wide interest because it is recognized as one of the key prerequisites for life as we know it and thus surmised as essential for extraterrestrial life. With oceanic water covering 71% of its surface, Earth is the only planet known to have stable bodies of liquid water on its surface, and liquid water is essential to all known life forms on Earth. The
Solar power in Maryland of S.B. 791, solar hot water systems. Solar hot water systems have a 5 SREC limit. The passage of H.B. 1187, also on May 22, 2012, accelerates the state's Renewable Energy Portfolio Standard with a target of 20% by 2020, of which 2% must be solar. Currently, there is no limit on the system size for a photovoltaic system. In the state of Maryland, one SREC is equal to one MWh of electricity production, and is redeemable for three years. As of January 2017, an SREC is valued at $18, and if the RPS is not increased is expected to