Reva Haymore, age 9, of Douglas, Arizona, for her question:

How far is Mercury from the sun?

Mercury's average distance from the sun is about 36 million miles. The little planet gets almost seven times more heat and light from the sun than we do. To be more accurate, just one half of Mercury gets all this heat and. light. For the little planet orbits around with the same side always facing the sun.

On the sun side, Mercury is hot enough to melt lead. The opposite side is in eternal shadow and may be close to absolute zero. Mercury whizzes around its orbit at 23 to 36 miles a second. It takes 88 earth days to make one complete trip, which means that a year on Mercury is equal to about 88 days on earth. Here are some interesting statistics on Mercury:

Mercury Statistics

Planetary Symbol: Name in Roman/Greek Mythology: Mercury/Hermes

Diameter: 4,878 km (3,030 miles)

Rotation Period about Axis: 58.65 days

Mass: 0.33x10^24 kilograms (0.06 x Earth's)

Revolution Period about the Sun: 0.24 years

Density: 5,427 kg/m^3    Tilt of Axis: 0o

Minimum Distance from Sun: 46.0 million km (28.6 million miles)

Surface Gravity: 3.7 m/s^2 (0.38 x Earth's)

Maximum Distance from Sun: 69.8 million km (43.4 million miles)

Temperature Range on Mercury: -184o C to 427o C (-300o F to 800o F)

Orbital Semimajor Axis: 0.387 AU (Earth=1 AU)

Average Surface Temperature (K): 440K

Minimum Distance from Earth: 77.3 million km (48.0 million miles)

Satellites: 0