Mercury is the closest planet to the Sun. It orbits in a highly elliptical orbit ranging from 46 million km (29 million miles) from the Sun out to 70 million km (43.5 million miles). It takes about 88 Earth days to orbit the Sun but rotates on its axis once every 59 Earth days. Because of the slow rotation, a single day on Mercury (mid day to mid day) takes 176 Earth days. Its axial tilt is remarkably small at 3/100ths of a degree. Much smaller than any other planet.

1. Mercury is the closest planet to the Sun.
It orbits in a highly elliptical orbit ranging
from 46 million km (29 million miles)
from the Sun out to 70 million km (43.5
million miles).
It takes about 88 Earth days to orbit the
Sun but rotates on its axis once every 59
Earth days. Because of the slow rotation,
a single day on Mercury (mid day to mid
day) takes 176 Earth days. Its axial tilt is
remarkably small at 3/100ths of a de-
gree. Much smaller than any other plan-
et.
Venus
Venus is the second closest planet to the
Sun and orbits in an almost circular orbit
at 108 million km. As it orbits, Venus
comes closer to Earth than any other
planet in the solar system and can come
to within about 40 million km.
Venus takes about 225 Earth days to or-
bit the Sun and rotates at the incredibly
slow rate of once every 243 days - and in
a clockwise direction (as seen from look-
ing down on the Suns north pole). Only
Uranus (which almost spins on its side)
also has a clockwise spin. A day on Venus
(sunrise to sunrise) lasts 117 Earth days.
Earth and the Moon
The third closest planet to the Sun is
Earth and is the largest and densest of
the inner planets. Earth orbits in a rea-
sonably circular at 150 million km and is
the first of the planets to have a moon.
Earth is of course the only place that we
know of that has life.
Mars is the fourth closest planet to the
Sun and orbits in an fairly eccentric or-
bit at around 230 (+-20) million km.
Mars takes about 686 Earth days to
orbit the Sun. It has a tilt (25.1 degrees)
and rotational period (24 hour 37
minutes) which are both similar to the
Earth with a day (sunrise to sunrise)
lasting 24 hours, 39 mins. Because of
the tilt it also has seasons in the same
way as the Earth does.
JUPITER
Jupiter is the fifth closest planet to
the Sun and is the first of what are
called the outer planets (being out-
side the asteroid belt). It is by far
the largest planet in the solar sys-
tem having two and a half times as
much mass as all the other planets
put together and one thousandth
the mass of the Sun. This is so large
that the Sun and Jupiter actually
orbit each other about a point just
outside of the Suns surface.
Saturn
Saturn is the sixth closest planet to the
Sun. It is the second largest planet in
the solar system having a radius 9
times that of Earth (57,000 km) and a
mass 95 times that of Earth.
Saturn orbits the Sun once very 29
years (at about 1400 million km) and is
mainly comprised of gas .
Uranus
Uranus is the seventh closest planet to
the Sun and the third largest and fourth
heaviest of the planets. It diameter
(50,000km) is four times that of Earth
with a mass over 14 times that of
Earth.
Uranus orbits the Sun once very 84
years (at about 2900 million km) but is
unusual in that it spins on its side (with
an axial tilt of 97 degrees). This means
that its moons and also its faint ring
system also orbit in plane perpendicu-
lar to the plane of the ecliptic.
It is believed to be comprised of a small
rocky core surrounded by a deep man-
tle of water, ammonia and methane.
This is in turn surrounded by an atmos-
phere of hydrogen, helium and me-
thane with an upper cloud layer.
NEPTUNE
Neptune is the eighth closest planet to
the Sun and is (since the relegation of
Pluto) the last Planet in the Solar System.
It is similar in size and composition to
Uranus with a diameter of 49,000km and
a mass of over 17 times that of Earth.
Uranus orbits the Sun once very 165
years at about 4500 million km. This is 30
times the distance from the Sun to the
Earth which means that the strength of
sunlight at Neptune is 1% of its strength
at Earth. Neptune spins on an axis with a
tilt of 28 degrees, which is quite similar
to that of the Earth, every 16 hours.