Due to the eccentric orbit of Mercury, the closest point to the sun is 47 million kilometers (29 million miles), while the most distant is 70 million kilometers (43 million miles).
The surface temperature of Mercury can reach 430 degrees Celsius (800 degrees Fahrenheit). Since the planet has no atmosphere, the night surface temperatures can drop to -180 degrees Celsius (-290 degrees Fahrenheit).
Mercury orbits the sun for 88 days, speed is almost 50 km (31 miles) per second, faster than any other planet. A day on Mercury equals 175.97 Earth days. Mercury is the second densest planet after Earth, with a large metallic core having a radius of about 2,000 km (1,240 miles), about 80 percent of the planet's radius.