Basically this is my interest in life; ASTRONOMY. Why? well first it's
interesting,
second it's fun and educational to watch stars move and being formed and
last it's
the FUTURE and INFINITY!!!!
The Sun, together with the planets and moons, comets, asteroids, meteoroid
streams and interplanetary medium held captive by the Sun's gravitational
attraction.
The solar system is presumed to have formed from a rotating disc of gas
and dust
created around the Sun as it contracted to form a star, about five billion
years ago.
The planets and asteroids all travel around the Sun in the same direction
as the Earth,
in orbits close to the plane of the Earth's orbit and the Sun's equator.
The planetary orbits lie within 40 AU of the Sun, though the Sun's sphere
of gravitational influence can be considered to be much greater.
Comets seen in the inner solar system may originate in the Oort cloud,
many
thousands of AU away.
Astronomical unit (AU or a.u.) A unit of measurement used mainly for
distances within the solar system. It is effectively the mean distance
between the
Earth and the Sun, though it now has a formal definition independent
of the Earth's orbit.
Its value is 149,597,870 kilometres (92,955,730 miles), which is
slightly less than the semimajor axis of the Earth's orbit.
There are about 63,240 astronomical units in a light year.
