planetsplanets David HigginsDavidHiggins Mercury’s sunny sideMercury’ssunnyside has a temperaturehasatemperature rising to 400risingto400° Celsius°Celsius or 750° fahrenheit.or750°fahrenheit. Mercury is theMercuryisthe clossed to the sun.clossedtothesun. Mercury has noMercuryhasno moons.moons. Mercury’s diameter, the distance right round its middle, is only 3100 miles or 4990 kilometres. When mercury orbits the sun, it travels 36 million miles, or 58 kilometres in the 88 days of the orbit.