Surveying the Solar System The Grand Tour

The Solar System  As more powerful telescopes scanned the skies astronomers needed to know more about the celestial bodies that made up our Solar System.

The Solar System  The distances we are speaking of are astronomical.  The diameter of the Solar System (the orbit of Neptune) is 9 billion kilometers.

The Solar System  On our tour we will visit the following:  The Sun  The eight major planets of our Solar System  The asteroid belt  The Kuiper Belt  The Oort Cloud  Comets

The Sun  Made up of mostly hydrogen (70%) it is the largest body in our solar system.

The Sun  The Sun creates its energy by converting this hydrogen into helium through a process called nuclear fusion.

The Sun  At the surface its temperature is °Kelvin. (°K)  At its core it is much hotter, °K.  100 °C = 373 °K.

The Sun  There are cooler areas on the surface.  These are called sunspots.  Only °K.

The Sun  Near the sunspots massive outbursts of energy called solar flares occur.  These flares can interfere with radio communication and electrical grids here on Earth.

Solar Flare Videos  mazca.com/ / _x- flare.jpg&imgrefurl= 7/2006/06/sounds-and-sights-of- sun.htm&h=539&w=576&sz=59&hl=en&start=3 &usg=__ZOzs6zttOSVbhmPnSK5H5H_qXfo=& tbnid=ld7lC_ruAHaLTM:&tbnh=125&tbnw=134 &prev=/images%3Fq%3Dsolar%2Bflare%2Bvi deo%26gbv%3D2%26hl%3Den%26safe%3Da ctive

Layers of the Sun  There are three layers of the Sun:  The Photosphere  The Chromosphere  The Corona

The Photosphere  The Photosphere is the apparent surface of the Sun.  It has a temperature of about 6000 °C.

The Chromosphere  Between 6000 and °C, it is the thick layer of gas just above the photosphere.

The Corona  Only visible during an eclipse, the corona is the uppermost layer of the Sun.  It is also the hottest layer at °C, but scientists do not know why.

Mercury  Heavily cratered, very old and less than half the size of Earth, Mercury is the closest planet to our sun.

Mercury  It has a very thin atmosphere and experiences huge swings in temperature.  Daytime temperature can reach 430°C, but at night will drop to -180°C.

Venus  Named for the goddess of love and beauty, Venus is anything but.  It is enveloped in a thick atmosphere made up mostly of CO 2.

Venus  The atmosphere is so thick that pressures are crushing.  It also has a cloud cover of sulphuric acid.  These photos were taken by two Russian spacecrafts, neither one of which lasted more than 65 minutes on the surface.

Earth and the Moon  Earth, our home, is the only planet capable of supporting intelligent life.  An oxygen rich atmosphere, water and liveable climate make it habitable.

Earth and Moon  The Moon is the only other celestial body visited by humans.  Virtually no atmosphere and much smaller than Earth, there is some evidence to suggest frozen liquid water under the surface.

Mars  Reddish-orange in colour (because of iron-oxide) Mars was long thought to harbour “little green men”.

Mars  Visits to the planet show no intelligent life.  Atmosphere is mostly CO 2 with trace amounts of O 2.  Recent expeditions have shown frozen water at the poles.

Asteroid Belt  Located between Mars and Jupiter, the belt consists of large chunks of rock, some as big as 950 km across.  Thought to be the remnants of a failed planet.

Jupiter  The largest planet in our solar system, Jupiter is a gas giant.  It is composed of mostly hydrogen, much of it in a liquid state, but has a rocky core.

Jupiter  It has an extremely violent atmosphere.  The Great Red Spot is a giant storm (twice the size of Earth) that has been churning for over 300 years.

Jupiter  Jupiter has 63 known moons.  The four largest are Io, Ganymede, Europa and Callisto.

Saturn  Famous for its rings, Saturn is smaller but very similar in make- up to Jupiter.

Saturn  The rings are made up of countless particles of rock, ice and dust less than 1 km thick.

Saturn  It’s largest moon, Titan, has an atmosphere made up mostly of nitrogen.

Uranus  Third of the gas giants Uranus is ringed like Saturn and Jupiter.  It is also unique in that it sits on its side relative to its orbit.

Neptune  The last of the gas giants little is known about it because it is so far away.  It has a ring system and a huge storm (The Great Dark Spot) similar to Jupiter.

Dwarf Planets  A dwarf planet…  orbits the Sun,  has sufficient mass for gravity and has a nearly round shape,  has not cleared the neighbourhood around its orbit, and  is not a satellite.

Dwarf Planet  The former planet Pluto, the asteroid Ceres and Eris are all dwarf planets.

Kuiper Belt  The Kuiper Belt is a region of space that exists beyond the orbit of Neptune.  It was discovered in  Like the asteroid belt (only much larger), it is home to many smaller planet like objects.

Kuiper Belt  Many of the objects are no bigger than large meteors.  Others are as big or bigger than Pluto.

Oort Cloud  The Oort Cloud is a hypothetical region of space surrounding our solar system.  It lies nearly a light year beyond out of our solar system.

The Oort Cloud  It is thought that objects in the cloud are composed primarily of ices (water, ammonia and methane).  Other celestial bodies’ gravity can affect these ices, sending them towards the inner solar systems as comets.

Comets  A comet is a small body in our solar system that orbits the Sun.  They are made up primarily of ice, dust and small particles of rock.

Comets  As they get close to the sun the ice begins to melt, forming a distinctive tail of gas.

Homework  Please read section 13.4, p , p.454 and p.456.  Answer questions 1-5 on p.456.  Vocabulary  Solar Wind  Inner Planets  Outer Planets  Meteors  Meteorites