Transcript Objects in the Solar System Powerpoint File

Our Solar System
Earths orbit around the sun
The Sun – our star
Our star makes up 99% of all the mass in the Solar System. Its core is so
dense and hot that normally repellent nuclei fuse together in nuclear
reactions that produce vast quantities of energy. The Sun is mostly
hydrogen (its main fuel) and helium, and radiates charged particles
called solar wind across the Solar System. Phenomena such as solar flares
and sunspots are evidence of the Sun's strong magnetic field, which
changes on a roughly 11-year cycle.
Photo: The Sun taken by the SOHO probe (ESA/NASA)
Vid 2.43 mins
Moons
In addition to the Earth, the planets Mars,
Jupiter, Saturn, Uranus and Neptune have
moons. Since the Voyager 1 and 2 probes began
returning images of Saturn and Jupiter's moons
in the late 1970s and early 1980s, scientists have
become more interested in planetary satellites.
Europa and Titan are considered to be potential
locations where life could exist and have
recently been studied with unmanned probes.
Photo: Image of Io created from data gathered by the Galileo probe (NASA/JPL)
Amalthea
Jupiter's moon is the
reddest object in the
Solar System
Callisto
Jupiter's second
largest moon has
an ancient
surface
Rhea
Saturn's most
heavily cratered
moon was
discovered in 1672
Ariel
This heavily fractured Deimos
moon was visited by One of Mars' tiny
moons, Deimos was
Voyager 2.
discovered in 1877
Tethys
Saturn's moon has a
huge canyon.
Enceladus
Saturn's bright
moon is home to ice
fountains.
Moon
Earth's satellite
had a turbulent
birth.
Titan
Titan is the
only moon
with a dense
atmosphere.
Ganymede
The Solar System's
largest moon orbits
Jupiter.
Io
Jupiter's moon is the
Solar System's most
volcanically active
body
Miranda
Uranus's moon has a
patchy face.
Phobos
Are Mars's moons
Titania
really captured
Triton
Voyager 2 showed
asteroids?
astronomers close-up views Triton's unusual orbit is an
important clue about its past.
of Titania.
Europa
Jupiter's smooth
moon may have
subsurface oceans
Iapetus
This moon of
Saturn has a dark
side.
Mimas
Saturn's small moon
is home to a very
large crater.
Phoebe
An oddball moon
orbits Saturn.
Mercury
The innermost planet in the Solar
System is a dense, heavily cratered
world that takes about 59 Earth days
to fully rotate on its own axis as it
travels on its 88-day journey around the
Sun. It is possible to see Mercury from
the Earth without a telescope or
binoculars though its closeness to the
Sun's bright light can make it difficult to
spot. Photographed and studied at
close range by the Mariner 10 and
Messenger probes, Mercury is blasted by
solar radiation and is not thought to be
a likely place for life to flourish.
Photo: Mercury taken by the
Messenger probe (NASA/JHU Applied
Physics Laboratory/Carnegie Institution)
Vid 1.53 mins
Venus
The second planet from the Sun is an
extreme place - hot and dry with surface
pressures over 90 times higher than the
Earth's and a super thick atmosphere
composed mainly of carbon dioxide.
Because the surface is hidden by
sulphuric acid clouds and the planet is
similar to the Earth in size, astronomers
speculated for many years that Venus
might be a lush world full of life. It is now
thought possible that the Sun's heat
boiled away early oceans on the planet
triggering a planet-warming runaway
greenhouse effect that turned Venus into
a hellish place.
Photo: Venus taken by the Galileo
probe (NASA/JPL)
Vid 6.35 mins
Earth
The third planet from the Sun is
unique in the Universe as it is
currently the only planet known
to support life. It has a single
natural satellite called the Moon
and is the fifth largest planet in
the Solar System. Earth's distance
from the Sun is thought to be one
of the key reasons why it is home
to widespread life. Our planet
occupies what astronomers call
the Goldilocks zone. Its distance
from our star means it's neither
too hot, nor too cold for living
creatures. Astronomers are
searching for rocky planets like
ours in the Goldilocks zones of
other stars.
Vid 2.14 mins
Photo: The Earth rising behind the Moon
taken by the Apollo 16 crew (NASA)
Mars
The fourth planet from the Sun is
easily visible from the Earth and was
among the first bodies in the Solar
System to be viewed through a
telescope. Early astronomers could
see faint surface features along with
evidence of changing seasons and
speculated about an advanced
Martian civilisation. NASA's Mariner
and Viking probes in the 1960s and
1970s found a cold, apparently lifeless
planet with intriguing geology that
hinted at past surface floods. More
recently, six-wheeled rovers have
confirmed that water ice exists below
the surface and looked for evidence
of past microbial life.
Photo: Victoria Crater on Mars taken
by the Mars Reconnaissance Orbiter probe
(NASA/JPL-Caltech/University of Arizona
/Cornell/Ohio State University)
Vid 2.02 mins
Asteroids
Asteroids are objects composed of rocky or metallic materials and are mainly found orbiting the Sun in a
region called the asteroid belt between Mars and Jupiter. Some are large - the biggest is Ceres with a
diameter of nearly 600 miles (966km) - and are sometimes called minor planets or planetoids. There are
millions of small asteroids. The smallest are sometimes called meteoroids. Objects falling through the
Earth's atmosphere are called meteors. If they survive and hit the Earth's surface they are called
meteorites. It's thought that asteroids are material leftover from the time that the planets formed.
Photo: Asteroid Ida taken by the Galileo probe (NASA/JPL)
Vid 6.19 mins
Comets
Comets are icy objects that release gas and dust as they orbit the Sun. The solid part of a
comet is called the nucleus and is mainly made of frozen water, dust and sometimes other
frozen substances such as ammonia. Solar radiation heats the nucleus and gives it an
atmosphere of gas and dust called the coma. A comet's distinctive tail is caused by solar
radiation and a stream of charged particles that constantly jets away from the Sun called
the solar wind. It is thought that comets are material leftover from the formation of the
outer planets.
Photo: Comet Holmes taken by the Spitzer Space Telescope (NASA)
Vid 1.40 mins
Jupiter
The largest planet in the Solar
System has a volume equal to
more than 1,000 Earths. The fifth
planet from the Sun is called a
'gas giant' because it has no solid
surface, being mainly composed
of hydrogen and helium. It is
believed to have a liquid metallic
hydrogen core that generates the
planet's intense magnetic field.
Powerful storms such as the
centuries-old Great Red Spot
travel in bands across Jupiter. Its
many satellites include the moons
Io, Europa, Ganymede and
Callisto.
Vid 3.56 mins
Photo: A true colour mosaic of Jupiter taken by
the Cassini probe (NASA/JPL/Space Science Institute)
Saturn
Saturn's complex ring system of ice particles sets it apart from the
other planets. The sixth planet from the Sun is the second largest
in the Solar System yet it is the least dense - it would float in
water if there were a bathtub large enough to hold it. The
planet is composed mainly of hydrogen and helium and doesn't
have a solid surface. Saturn has 25 satellites that measure at
least 6 miles (10km) in diameter. The largest of these is Titan, the
only moon in the Solar System to have a substantial atmosphere.
Photo: Saturn taken by the Cassini probe (NASA/JPL/Space Science Institute)
Vid 3.07 mins
Uranus
The seventh planet from the Sun was first correctly identified as a planet in 1781
by William Herschel. Uranus may have been struck by a planet-sized object
early in its life and knocked onto its side. Consequently, Uranus's axis is tilted 98
degrees compared with the Earth's 23.5 degrees. Like the other gas giant
planets, Uranus has no solid surface. It gets its bluish surface colour from tiny
frozen ammonia crystals. The atmosphere is thought to be mainly hydrogen
and helium. Uranus has only been visited once, by the Voyager 2 probe.
Photo: Uranus taken by the Voyager 2 probe (NASA)
Vid 4.38 mins
Neptune
The outermost planet in the Solar System
can't be seen from Earth without a
telescope or binoculars. It is covered by icy,
bright blue methane clouds that whip
around the globe at speeds of more than
700mph (1,100km/h). Though its diameter
is four times that of the Earth's and it is 17
times as massive, it is less dense and doesn't
have a solid surface. Eleven moons orbit
Neptune, the largest of which is Triton.
Vid 1.23 mins
Photo: View of Neptune composed of images taken by the Voyager 2 probe (NASA)
Pluto
Pluto held its position as the outermost
planet in the Solar System for 76 years until
it was reclassified as a dwarf planet in
2006. Discovered by the American
astronomer Clyde Tombaugh in 1930,
Pluto's existence was first predicted by the
astronomer Percival Lowell in 1915. Pluto is
now thought to be an object in the Kuiper
Belt, a disc-shaped area of icy, dark objects
beyond Neptune. Pluto has one large
moon, Charon, which is almost half its size
and two much smaller moons, Nix and
Hydra. The NASA New Horizon's mission is
scheduled to reach Pluto in 2015.
Photo: Pluto and its moons taken by the Hubble Space Telescope
(NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI), and the HST
Pluto Companion Search Team)
Vid 2.26 mins
Kuiper Belt
Orbiting the Sun beyond Neptune,
the outermost planet, hundreds of
millions of icy Kuiper Belt objects
are thought to be the source of
some of the Solar System's comets.
Pluto is now considered to be a
large Kuiper Belt object and is
classed as a dwarf planet. The
Kuiper Belt objects may be leftover
material from the formation of the
outer planets and are arranged in
a large flat disc.
Photo: Artist's impression of the Kuiper Belt object Quaoar (NASA)
Vid 1.12 mins
Oort Cloud
The Oort Cloud is made up of a vast number of icy objects that are predicted to envelope the Solar
System far beyond the orbit of Neptune and the Kuiper Belt. The cloud has been estimated to extend
out to a distance of 50,000 astronomical units (about 4.6 trillion miles) from the Sun and marks the
edge of the Solar System. The Oort Cloud is so far away from the Sun's gravitational influence that
passing stars can change the orbits of the objects within the cloud, sending them into the inner Solar
System as long-period comets (those that take at least 200 years to orbit the Sun) or out into interstellar
space.
Vid 3.10 mins
Photo: Comet Hale-Bopp, a long-period comet believed to have come from the outer Solar System (NASA/JPL/STScI)