Stephen Ramsey, age 9  of Tulsa, Okla for question:

How long is a year on the planet Mercury?

Mercury is the planet closest to the sun, It keeps an average distance of about 36 million miles, Its orbit is the smallest of planet orbits, for it has the inside track around the sun, It therefore has the shortest distance to travel to make one yearly journey, We would expect Mercury to have the shortest year of all the planets  and so it has.

It takes the little planet 88 earth days to travel once around its orbit, Our earth travels on its yearly orbit about 182 miles a second. Meroury travels much faster, It dashes around the sun at about 30 miles a second. There is evidence that Mercury travels around with the same face always toward the sun, If this is so its day and night period is also equal to 88 earth days,