4. A solar system is defined as a central sun
with its associated
planets, asteroids, meteors, satellites
(i.e.,moons), and comets that are "captured" in
its orbit. These various celestial bodies are
trapped in a constant orbit around the sun by its
tremendous gravitational pull.
5. The paths that the planets take as they
travel around the sun in the same direction -
from west to east - is not truly circular, but
more of an ellipse, or egg-shape path. Our
solar system is nestled inside a very large
galaxy of stars called the Milky Way. The
outer limit of our solar system extends six
billion kilometers from the sun.
6. Over 4.6 billion years ago our solar system was born when a
nebula consisting of a dense nucleus, or protosun, surrounded by
a thin shell of a gaseous matter and dust began to collapse in on
itself.
As the dense matter in the center of the solar system further
condensed the extreme heat that was generated in the center
began to burn the abundant hydrogen atoms in its core, becoming
a self-sustaining nuclear-fusion reaction that grew to be our sun.
7. As the dust in the nebula
circulated the newly forming
sun, it collapsed and clumped
together to form larger chunks of
space debris. Larger and larger
pieces of space debris collided
with each other to form the solid
planets, and the gaseous matter
condensed to form the gas planets.
8. Ours is not the only solar
system in the universe. Scientists
have learned a lot about how our
solar system was formed by
studying other astronomical
phenomena, like nebulas, that are in
different stages of their life
cycles.
We have yet to learn if there are
any planets in these other solar
systems that support life - or
