Mercury (planet) 2015. The "BepiColombo" spacecraft will arrive at Mercury in 2025. Mercury appears to have a solid silicate crust and mantle overlying a solid, iron sulfide outer core layer, a deeper liquid core layer, and possibly a solid inner core. Mercury is one of four terrestrial planets in the Solar System, and is a rocky body like Earth. It is the smallest planet in the Solar System, with an equatorial radius of . Mercury is also smaller—albeit more massive—than the largest natural satellites in the Solar System, Ganymede and Titan. Mercury consists of approximately 70% metallic and 30% silicate material. Mercury's
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