Solar Systems
Solar SystemsA presentation on stars and their orbitals.
DefinitionsSolar System: Consists of the Sun, and everything
bound to it by gravity. This includes the 8 planets and their
moons, the asteroids, the dwarf planets, all the Kuiper belt
objects, the meteoroids, comets and interplanetary dust.Galaxy:
large system of stars held together by mutual gravitation and
isolated from similar systems by vast regions of space. The Milky
Way measures about 100,000 light-years across, and is thought to
contain 200 billion stars.Universe: the totality of known or
supposed objects and phenomena throughout space; the cosmos;
macrocosm.
In summary.We live on planet Earth which is part of our local
Solar System.Our Solar System includes the Sun and everything that
orbits the Sun.Our Sun, is just one Star in the Milky Way
Galaxy.The Milky Way Galaxy is just one Galaxy in the Universe.
The Sun
The star at the center of our solar system is called the Sun, or
Sol. It is one star in a galaxy of more than 200 billion stars. The
Sun and solar system rotate with the rest of the galaxy at about
175 miles per second. That means it takes about 240 million years
for the Sun and our solar system to rotate all the way around the
galaxy.
Our solar system
Our solar system is made up of a star - the Sun - eight planets,
approximately 146 moons, comets, asteroids and space rocks, ice and
several dwarf planets, such as Pluto.All the planets have there own
path along which they revolve around the sun. This path is called
an orbit. They are represented by white lines in the figure to the
right.
The image above shows the planets and their relative sizes when
compared to each other. Earth is the fourth smallest in the solar
system. All the planets however, are dwarfed by the massiveness of
the sun. It is its huge mass which is responsible for its strong
gravitational pull which keeps all the planetary bodies in their
respective orbits. Over time however, the orbital patterns of each
planets were said to have changed until it attained the stable
pattern we know today.
Solar system facts
After the Sun and the Moon, Venus is the brightest object in
Earth's sky.Many of the planets in the solar system are visible to
the naked eye.It is estimated that at least a third of the 200
billion stars in the Milky Way are orbited by one or more
planets.The Voyager 1 spacecraft is the furthest man-made object in
the solar system, it is around 11 billion miles (18 billion km)
from the sun and is still sending data back to Earth.The solar
system is around 4.6 billion years old.
Beyond our galaxy
Andromeda is the nearest major galaxy to our own Milky Way
Galaxy. Our Galaxy is thought to look much like Andromeda. Together
these two galaxies dominate the Local Group of galaxies. The
diffuse light from Andromeda is caused by the hundreds of billions
of stars that compose it. The several distinct stars that surround
Andromeda's image are actually stars in our Galaxy that are well in
front of the background object. Andromeda is frequently referred to
as M31 since it is the 31st object on Messier's list of diffuse sky
objects. M31 is so distant it takes about two million years for
light to reach us from there. Although visible without aid, the
above image of M31 is a digital mosaic of 20 frames taken with a
small telescope. Much about M31 remains unknown, including how it
acquired its unusual double-peaked center.
