THE SOLAR SYSTEM

OVERVIEW The Solar System consists of • • • • • •

The Sun is the star of the system Eight planets, circling around the Sun Moons Asteroids Meteorites Comets

OUR PLACE IN THE GALAXY • Our Solar System is located about 2/3 of the way out from the galaxy’s center. •The Sun is the only star in the SOLAR SYSTEM, but it is one of over 100 billion stars in our galaxy, the Milky Way.

THE SOLAR SYSTEM

THE PLANETS  The path each planet travels around the Sun is called orbit.  The planets are kept in their orbits due to the pulling force of the Sun’s gravity.  The time a planet makes one trip around the Sun is called a Year.  Each planet spins around itself and around the Sun. The face of the planet towards the Sun, receives the light, the other is in the dark The planets have Night and Day.

THE MOONS • Moons are ‘natural satellites’ • Moons orbit around a planet • The moon stays in its orbit due to the gravitational pull of the planet • Our moon has a circular orbit • We see the moon because it reflects the Sun’s light

ASTEROIDS, METEORITE AND COMETS • Asteroids - minor planets found in their thousands between Mars and Jupiter • Meteorites - probably fragments of asteroids that broke up

• Comets - These are lumps of ‘dirty ice’ a few km across that travel close and far around the Sun. As they near the Sun they warm up. This causes a tail of dust and cloud.

THE SUN  The sun is a big ball of hot gases, mainly hydrogen and helium.  The gases are converted into energy in the Sun's center and is released into the Solar System as heat and light.

THE SUNSPOTS  Sunspots are darker, cooler areas on the surface of the Sun.

MERCURY • The smallest planet, closest to the Sun • Dry and rocky, very hot days and very cold nights • Rotates slowly – the day 176 Earth days, the night 176 Earth nights • One Mercury-year is a quarter Earth-year • Mercury is very difficult to be spotted with the naked eye • Mercury has no moons • Mercury has no atmosphere • Named after the God of Speed

MERCURY CROSSING THE SUN

VENUS • Venus is the second nearest to the Sun • Is a medium sized planet, almost the same size as Earth. • Thick atmosphere of carbon dioxide traps the Sun‘s heat inside. • The rain is sulphuric acid and the presure on the surface 90 times than on Earth. • Venus is very well visible to the naked eye, always close to the sun before sunrise or after sunset • Venus has no moons

EARTH • Our planet, the only planet were life, as we know it, is possible. • Medium sized planet, a bit larger than Venus, third from the Sun. • Has atmosphere, and deep underground is magma - melted rock. Has active volcanos and is covered 75% with water • The Earth has one natural satelite – the Moon

EARTHRISE FROM APOLLO 8

MARS • It is a small size planet, half as large as Earth, the fourth from the Sun. • Mars is well visible to the naked eye, redish because of the rusted iron in the soil. • Mars has canyons, volcanos, dust storms, fog, polar caps and craters. • The carbon dioxide atmosphere is too thin to keep the heat in, which makes it really cold on the surface. • Mars has two small, potato shaped, moons Phobos and Deimos

PHOBOS AND DEIMOS • Phobos and Deimos are Mars‘s companions. Phobos means “fear“, Deimos means “panic“. Mars itself has been named for the Roman God of War. • They are quite small (