Mercury is the planet nearest to the sun and the smallest
planet in the solar system. It is difficult to see from the
earth without a telescope. At certain items of the year,
Mercury can be seen low in the western sky just after
sunset. At other times, it can be seen low in the eastern
sky just before sunrise.
Mercury orbits around the sun in an elliptical line, faster
than any other planet. It travels about 30 miles per
second, and goes around the sun once every 88 eath-days. It
is about 29 million miles from the sun at its closest
point, and more than 43 million miles from the sun at its
Mercury's surface appears to be much like that of the moon.
It reflects about 6 per cent of the sunlight it receives,
about the same as the moon's surface reflects. The planet
is dry, extremely hot, and almost airless. The sun's rays
are about seven times as strong on Mercury as they are on
the earth. Since it does not have enough gases in its
atmosphere to reduce the amount of heat and light it
receives from the sun, the temperature on the planet is
about 625 degrees F. during the day, and lower than 80
degrees F. at night. The plant and animal life of the earth
could not live on Mercury, because of the lack of oxygen
and the intense heat. Astronomers do not know whether the
planet has any form of life.
The Romans named it Mercury in honor of the swift messenger
of their gods.