We did last year (2012), with my classmates Gloriele and Abegail for a report. Anyone can get information from it, but if you plan to use ALL OF IT, make sure to site the source, okay????! That's all! :D
3. The Solar System
• The Solar Systemconsists of the Sun and
its planetary system of eight
planets, their moons, and other non-stellar
objects.
• It formed 4.6 billion years ago from the
gravitational collapse of a giant molecular
cloud.
4. For thousands of years, humans, with a few notable
exceptions, did not recognize the existence of the Solar System.
People believed the Earth to be stationary at the centre of
the universe and categorically different from the divine or
ethereal objects that moved through the sky. Although
the Greek philosopher Aristarchus of Samos had speculated on
a heliocentric reordering of the cosmos, Nicolaus Copernicus
was the first to develop a mathematically predictive
heliocentric system. His 17th-century successors, Galileo
Galilei, Johannes Kepler and Isaac Newton, developed an
understanding of physics that led to the gradual acceptance of
the idea that the Earth moves around the Sun and that the
planets are governed by the same physical laws that governed
the Earth.
6. .
Sun
The Sun is the star at the center of the Solar System.
It is almost perfectly spherical and consists of
hot plasma interwoven with magnetic fields. It has
a diameter of about 1,392,684 km, about 109 times
that of Earth, and its mass (about
2×1030 kilograms, 330,000 times that of Earth)
accounts for about 99.86% of the total mass of the
Solar System. Chemically, about three quarters of the
Sun's mass consists of hydrogen, while the rest is
mostly helium.
The Sun formed about 4.6 billion years ago from the
gravitational collapse of a region within a
large molecular cloud. Most of the matter gathered in
the center, while the rest flattened into an orbiting
disk that would become the Solar System. The
central mass became increasingly hot and
dense, eventually initiating thermonuclear fusion in
its core.. The Sun's classification, is designated as
a yellow dwarf, because its visible radiation is most
intense in the yellow-green portion of the spectrum.
8. .
Mercury
Mercury is the innermost planet in the Solar System.
It is also the smallest, and its orbit is the
most eccentric (that is, the least perfectly circular) of
the eight planets. It orbits the Sun once in about
88 Earth days, completing three rotations about its
axis for every two orbits. The planet is named after
the Roman god Mercury, the messenger to the gods.
Mercury's surface is heavily cratered and similar in
appearance to Earth's Moon, indicating that it has
been geologically inactive for billions of years. Due
to its near lack of an atmosphere to retain heat,
Mercury's surface experiences the steepest
temperature gradient of all the planets, ranging from
a very cold 100 K at night to a very hot 700 K during
the day. Mercury's axis has the smallest tilt of any of
the Solar System's planets, but Mercury's orbital
eccentricity is the largest.
9. .
Parts of Mercury
Internal structure of Mercury:
1. Crust: 100–300 km thick
2. Mantle: 600 km thick
3. Core: 1,800 km radius
10. .
VenusVenus is the second planet from the Sun, orbiting
it every 224.7 Earth days. The planet is named
after the Roman goddess of love and beauty. After
the Moon, it is the brightest natural object in the
night sky, reaching an apparent magnitude of
−4.6. Its elongation reaches a maximum of 47.8°.
Venus reaches its maximum brightness shortly
before sunrise or shortly after sunset, for which
reason it has been referred to by ancient cultures
as the Morning Star or Evening Star.
Venus is one of the four solar terrestrial
planets The diameter of Venus is 12,092 km
(only 650 km less than the Earth's) and its mass
is 81.5% of the Earth's. Conditions on the
Venusian surface differ radically from those on
Earth, owing to its dense carbon dioxide
atmosphere. The mass of the atmosphere of
Venus is 96.5% carbon dioxide, with most of the
remaining 3.5% being nitrogen.
12. .
Earth is the third planet from the Sun, and
the densest and fifth-largest of the eight
planets in the Solar System. It is also the
largest of the Solar System's four terrestrial
planets. It is sometimes referred to as
the world, the Blue Planet, or by its Latin
name, Terra.
Earth
Earth formed approximately 4.54 billion
years ago, and life appeared on its surface
within one billion years Earth's biosphere then
significantly altered the atmospheric and
other basic physical conditions, which enabled
the proliferation of organisms as well as the
formation of the ozone layer and permitted
formerly ocean-confined life to move safely to
land. The physical properties of the Earth
have allowed life to persist
16. .
Jupiter
Jupiter is the fifth planet from the Sun and
the largest planet in the Solar System. It is a gas
giant with mass one-thousandth that of the Sun
but is two and a half times the mass of all the
other planets in the Solar System combined.
Jupiter is classified as a gas giant along
with Saturn, Uranus and Neptune. Together, these
four planets are sometimes referred to as
the Jovian or outer planets. The planet was
known by astronomers of ancient times, and was
associated with the mythology and religious
beliefs of many cultures. The Romans named the
planet after the Roman god Jupiter
Jupiter is composed primarily
of gaseous and liquid matter. It is the largest of
four gas giants as well as the largest planet in
the Solar System with a diameter of 142,984 km.
The density of Jupiter, 1.326 g/cm3, is the second
highest of the gas giant planets.
18. .
SaturnSaturn is the sixth planet from the Sun and
the second largest planet in the Solar
System, after Jupiter. Named after
the Roman god Saturn, its astronomical
symbol (♄) represents the god's sickle.
Saturn is a gas giant with an average
radius about nine times that of Earth, While
only one-eighth the average density of
Earth, with its larger volume Saturn is just
over 95 times more massive than Earth.
Saturn is classified as a gas giant planet
because the exterior is predominantly
composed of gas and it lacks a definite
surface, although it may have a solid core.
The rotation of the planet causes it to take the
shape of an oblate spheroid; that is, it is
flattened at the poles and bulges at the
equator. Its equatorial and polar radii differ by
almost 10%—60,268 km versus 54,364 km.
20. .
Uranus is the seventh planet from the Sun. It has
the third-largest planetary radius and fourth-largest
planetary mass in the Solar System. Uranus is
similar in composition to Neptune, and both are of
different chemical composition than the larger gas
giants Jupiter and Saturn. For this
reason, astronomers sometimes place them in a
separate category called "ice giants". Uranus's
atmosphere, while similar to Jupiter's and Saturn's
in its primary composition
of hydrogen and helium, contains more "ices" such
as water ,ammonia, and methane, along with traces
of hydrocarbons. It is the coldest planetary
atmosphere in the Solar System, with a minimum
temperature of 49 K (−224 °C). It has a
complex, layered cloud structure, with water thought
to make up the lowest clouds, and methane thought
to make up the uppermost layer of clouds. In
contrast, the interior of Uranus is mainly composed
of ices and rock.
Uranus
22. . Neptune
Neptune is the eighth and
farthest planet from the Sun in the Solar
System. It is the fourth-largest planet by
diameter and the third-largest by mass.
Neptune is 17 times the mass of Earth and
is somewhat more massive than its near-
twin Uranus, which is 15 times the mass of
Earth but not as dense. On
average, Neptune orbits the Sun at a
distance of 30.1 AU, approximately 30
times the Earth–Sun distance. Named for
the Roman god of the sea, its astronomical
symbol is ♆, a stylised version of the god
Neptune's trident.
Neptune's atmosphere, while similar to
Jupiter's and Saturn's in that it is composed
primarily of hydrogen and helium, along with
traces of hydrocarbons and
possibly nitrogen, contains a higher
proportion of "ices" such as
water, ammonia, and methane.
25. According to the new definition, a full-fledged planet is an object
that orbits the sun and is large enough to have become round due to
the force of its own gravity. In addition, a planet has to dominate the
neighborhood around its orbit.
Pluto has been demoted because it does not dominate its
neighborhood. Charon, its large "moon," is only about half the size of
Pluto, while all the true planets are far larger than their moons.
In addition, bodies that dominate their neighborhoods, "sweep up"
asteroids, comets, and other debris, clearing a path along their
orbits. By contrast, Pluto's orbit is somewhat untidy.
Originally classified as a planet, Pluto is now considered the largest
member of a distinct population called the Kuiper belt.
Like other members of the Kuiper belt, Pluto is composed primarily of
rock and ice and is relatively small: approximately a fifth the mass of
the Earth's moon and a third its volume. It has a highly eccentric and
highly inclined orbit.
28. Comets
• A comet is an icy small Solar System
body (SSSB) that, when close enough
to the Sun, displays a visible coma (a
thin, fuzzy, temporary atmosphere)
and sometimes also a tail. These
phenomena are both due to the effects
of solar radiation and the solar
wind upon the nucleus of the comet.
Comet nuclei range from a few
hundred meters to tens of kilometers
across and are composed of loose
collections of ice, dust, and small
rocky particles. Comets have been
observed since ancient times.
29. Most Popular
Comet
• Halley's Comet or Comet
Halley , officially
designated 1P/Halley, is the best-
known of the short-period
comets and is visible from
Earth every 75–76 years. Halley is
the only short-period comet that
is clearly visible to the naked
eye from Earth, and thus the only
naked-eye comet that might
appear twice in a human lifetime.
Other naked-eye comets may be
brighter and more
spectacular, but will appear only
once in thousands of years.
30. Meteors
A meteor is a bright streak of
light in the sky (a "shooting star"
or a "falling star") produced by
the entry of a small meteoroid
into the Earth's atmosphere. If
you have a dark clear sky you
will probably see a few per hour
on an average night; during one
of the annual meteor showers you
may see as many as 100/hour.
Very bright meteors are known as
fireballs; if you see one please
report it.
31. Most Popular Meteor
Several "shooting stars" or
meteors per hour can usually be
seen on any given night.
Sometimes the number of
meteors seen increases
dramatically: these are termed
"meteor showers". In fact, some
meteor showers occur annually
or at rather regular intervals.
The number is greater in
autumn and winter. The number
always increases after midnight
and is usually greatest just
before dawn. Perhaps the most
famous are the Perseids which
peak around August 12 every
year.
32. Asteroid
Asteroids are small Solar System
bodies or dwarf planets that are not comets.
The term asteroids historically referred to
objects inside the orbit of Jupiter. They have
also been called planetoids, especially the
larger ones. These terms have historically
been applied to any astronomical object
orbiting the Sun that did not show the disk of
a planet and was not observed to have the
characteristics of an active comet, but as
small objects in the outer Solar
System were discovered, their volatile-
based surfaces were found to more closely
resemble comets, and so were often
distinguished from traditional asteroids.
Thus the term asteroid has come
increasingly to refer specifically to the small
bodies of the inner Solar System within the
orbit of Jupiter, which are usually rocky or
metallic..
33. Biggest Asteroid
Vesta was first discovered on March
29, 1807 by Heinrich Wilhelm Olbers. The
asteroid measures 578 km by 458 km and
has a mass of 2.67 x 1020 kg. It has a
magnitude of +5.4 to +8.5 and can be
easily observed with binoculars on a clear
night. It has been seen with the unaided
eye on several occasions. Vesta rotates
on its axis every 5.342 hours and has an
axial tilt of 29º. Temperatures on the
surface range from a frigid -188ºC (85 K)
to -18ºC (255 K). Hubble images have
revealed ancient lava flows. This is a
direct contradiction of the belief that
asteroids are simple cold, dead rocks
floating in space. There is a gigantic
impact basin so deep that it exposes the
asteroid’s mantle at the South pole. The
mantle is thought to be 10 km below the
asteroid’s surface.
34. Moon
A natural
satellite, moon,
or secondary
planet is a celestial
body that orbits a
planet or smaller
body, which is called
its primary.
35. Mercury’s Moon
31 Crateris was once
mistaken to be a
moon of Mercury but
it is in fact a star
about 1750 light years
away.
Mercury does not
have any moons.