Solar SystemSolar System

MILKY WAY200 billion stars Diameter 100 000 LY

Height at center 10 000 LYSolar System is 25 000 LY from center

in 1999 the Hubble Space Telescope in 1999 the Hubble Space Telescope estimated that there were estimated that there were 125 billion125 billion galaxiesgalaxies in the universe, and recently with in the universe, and recently with the new camera HST has observedthe new camera HST has observed 3,0003,000 visible galaxies. galaxies.

The The Local GroupLocal Group is the is the group of of galaxies that includes our that includes our galaxy, the galaxy, the Milky Way. The group comprises over 30 galaxies, . The group comprises over 30 galaxies,

with its gravitational center located somewhere between the Milky with its gravitational center located somewhere between the Milky Way and the Way and the Andromeda Galaxy

Our solar system consists of:Our solar system consists of:– an average star: the an average star: the Sun,,– the planets the planets Mercury, Venus, Earth, Mars,Mercury, Venus, Earth, Mars,

Jupiter, Saturn, Uranus, Neptune, and PlutoJupiter, Saturn, Uranus, Neptune, and Pluto. . – satellites of the planets.satellites of the planets.– comets (coma, tail) (coma, tail)مذنباتمذنبات – asteroids (minor planets, larger than (minor planets, larger than

meteoroids but smaller than planets)meteoroids but smaller than planets)كويكباتكويكبات – meteoroids (small rocks in space)meteoroids (small rocks in space) ونيازك ونيازك شهب شهب– the interplanetary medium (energy, dust, gas)the interplanetary medium (energy, dust, gas)

ComparisonComparison

Composition Of The Solar Composition Of The Solar SystemSystem

Sun: 99.85% Sun: 99.85%

Planets: 0.135% Planets: 0.135%

Comets: 0.01% ? Comets: 0.01% ?

Satellites: 0.00005% Satellites: 0.00005%

asteroids : 0.0000002% ? asteroids : 0.0000002% ?

Meteoroids: 0.0000001% ? Meteoroids: 0.0000001% ?

Interplanetary Medium: 0.0000001% ? Interplanetary Medium: 0.0000001% ?

The Terrestrial Planets The Terrestrial Planets

the four innermost planets in the solar system, the four innermost planets in the solar system, Mercury, , Venus, , Earth and and Mars. .

They are called terrestrial because they have a They are called terrestrial because they have a compact, rocky surface like the Earth's. compact, rocky surface like the Earth's.

The planets, Venus, Earth, and Mars have The planets, Venus, Earth, and Mars have significant atmospheres while Mercury has significant atmospheres while Mercury has almost none.almost none.

The Jovian Planets (Giant Gases) The Jovian Planets (Giant Gases)

Jupiter, , Saturn, , Uranus, and , and Neptune are are known as the Jovian (Jupiter-like) planets, known as the Jovian (Jupiter-like) planets, because they are all gigantic compared because they are all gigantic compared with Earth, and they have a gaseous with Earth, and they have a gaseous nature like Jupiter's. nature like Jupiter's.

The Jovian planets are also referred to as The Jovian planets are also referred to as the the gas giantsgas giants, although some or all of , although some or all of them might have small solid cores.them might have small solid cores.

RevolutionRevolution

The motion of planets around the sun in The motion of planets around the sun in their orbits.their orbits.

RotationRotation

The spinning of the planet.The spinning of the planet.

eclipticecliptic

The plane of Earth's orbit about the Sun The plane of Earth's orbit about the Sun

inclinationinclination

The inclination of a planet's orbit is the The inclination of a planet's orbit is the angle between the plane of its orbit and angle between the plane of its orbit and the ecliptic. the ecliptic.

Distance

(AU)

Radius(Earth's)

Mass(Earth

's)

Rotation

(Earth's)

# Moons

OrbitalInclination

OrbitalEccentricity

Obliquity Density(g/cm3)

Sun 0 109 332,800

25-36*

9 --- --- --- 1.410

Mercury 0.39 0.38 0.05 58.8 0 7 0.2056 0.1° 5.43

Venus 0.72 0.95 0.89 244 0 3.394 0.0068 177.4° 5.25

Earth 1.0 1.00 1.00 1.00 1 0.000 0.0167 23.45° 5.52

Mars 1.5 0.53 0.11 1.029 2 1.850 0.0934 25.19° 3.95

Jupiter 5.2 11 318 0.411 16 1.308 0.0483 3.12° 1.33

Saturn 9.5 9 95 0.428 18 2.488 0.0560 26.73° 0.69

Uranus 19.2 4 17 0.748 15 0.774 0.0461 97.86° 1.29

Neptune 30.1 4 17 0.802 8 1.774 0.0097 29.56° 1.64

Pluto 39.5 0.18 0.002 0.267 1 17.15 0.2482 119.6° 2.03

Orbital PeriodEarth years

Avg.Temp.

Mercury 0.24 -180 to 430

Venus 0.62 465

Earth 1 -89 to 58

Mars 1.8 -82 to 0

Jupiter 11.9 -150

Saturn 29.5 -170

Uranus 84 -200

Neptune 164 -210

Age In ...You would be ...

years old.

Mercury years 91.36

Venus years 35.77

Earth years 22.00

Mars years 11.70

Jupiter years 1.85

Saturn years 0.75

Uranus years 0.262

Neptune years 0.133

Pluto years 0.089

Your Age on Other Planets

ObliquityObliquity

is the angle between a planet's equatorial is the angle between a planet's equatorial plane and its orbital plane.plane and its orbital plane.

ComparisonsComparisonsMercury: 0.24 daysMercury: 0.24 daysVenus: 0.615 yVenus: 0.615 yEarth: 1 yEarth: 1 yMars: 1.88 yMars: 1.88 yJupiter: 11.8 yJupiter: 11.8 ySaturn: 29.4 ySaturn: 29.4 yUranus: 84 yUranus: 84 yNeptune: 164 yNeptune: 164 yPluto: 248 yPluto: 248 y

Asteroids Asteroids الكويكباتالكويكبات

Asteroids are small rocky objects that Asteroids are small rocky objects that move in elliptical orbits in the asteroid belt move in elliptical orbits in the asteroid belt between the orbits of Mars and Jupiter. between the orbits of Mars and Jupiter.

Their average distance from the Sun is Their average distance from the Sun is about 2.9 astronomical units (A.U.) about 2.9 astronomical units (A.U.)

Asteroids are also called minor planets. Asteroids are also called minor planets.

asteroidsasteroids

Around 200 asteroids have diameters of Around 200 asteroids have diameters of more than 100 km.more than 100 km. There are thousands of smaller asteroids. There are thousands of smaller asteroids. More than 10,000 asteroids have been More than 10,000 asteroids have been cataloged and named so far.cataloged and named so far.All the asteroids in the solar system All the asteroids in the solar system together weigh much less than the Moon.together weigh much less than the Moon.

http://nssdc.gsfc.nasa.gov/planetary/http://nssdc.gsfc.nasa.gov/planetary/factsheet/asteroidfact.htmlfactsheet/asteroidfact.html

Kuiper Belt

Ida: 56 x 24 x 21 kilometres Ida: 56 x 24 x 21 kilometres

video

MeteoroidMeteoroid. When a piece of debris , later . When a piece of debris , later to enter the Earth's atmosphere, is to enter the Earth's atmosphere, is traveling through space towards our traveling through space towards our planet, the object is called a meteoroid.planet, the object is called a meteoroid.

MeteoroidMeteoroid

MeteorMeteor

The brief flash of light we see in the night The brief flash of light we see in the night sky and caused sky and caused notnot by the material by the material "burning" with friction from the "burning" with friction from the atmosphere, but rather from the atoms atmosphere, but rather from the atoms which have been excited in the air from which have been excited in the air from the object's high speed.the object's high speed.

MeteoriteMeteorite

The name given to the relatively small The name given to the relatively small number of objects which are not number of objects which are not completely destroyed in the upper completely destroyed in the upper atmosphere, but survive to the ground.atmosphere, but survive to the ground.

Scientists estimate the impact by an asteroid even as small as 0.5 km could cause a global climate change due to atmospheric debris restricting sunlight.

Impacts by objects 1 to 2 km in size could therefore result in significant loss of life.

CometsCometsThe center or The center or nucleusnucleus is believed to consist of dust and is believed to consist of dust and rock particles held together with ices such as water ice rock particles held together with ices such as water ice and carbon dioxide ice. Far away from the Sun, the comet and carbon dioxide ice. Far away from the Sun, the comet is cold, and to an observer close by it would appear as is cold, and to an observer close by it would appear as nothing more than a fairly small dead chunk of material.nothing more than a fairly small dead chunk of material.

HoweverHowever, as the comet approaches the Sun, it begins to , as the comet approaches the Sun, it begins to heat up. The ices start to melt, and gases begin to escape heat up. The ices start to melt, and gases begin to escape from the body, surrounding the nucleus with a glowing from the body, surrounding the nucleus with a glowing cloud called a cloud called a comacoma, which may measure more than , which may measure more than 100,000 km across (in comparison to the nucleus which 100,000 km across (in comparison to the nucleus which may only be a few km in diameter).may only be a few km in diameter).

What is next?What is next?

The distance from the Sun to Proxima The distance from the Sun to Proxima Centauri is Centauri is 4.224.22 LY. LY.

Our fastest space probes would take Our fastest space probes would take 6000060000 years to travel this distance. years to travel this distance.

Are there any objects between the Are there any objects between the edge of the solar system and the edge of the solar system and the

nearest star? nearest star?

There are certainly many asteroids just There are certainly many asteroids just beyond the orbit of Pluto. This is called the beyond the orbit of Pluto. This is called the Kuiper belt and may contain tens of Kuiper belt and may contain tens of thousands of asteroids.thousands of asteroids.