Science A Physics – P1 Science A Physics – P1 Topic 7c : The Solar System & its place in an evolving Universe Topic 7c : The Solar System & its place in an evolving Universe

Distances in Space - Astronomical Unit One astronomical unit is the average distance from the Earth to the Sun - 150,000,000 kilometres. 1 AU Planet Mean distance from the Sun AU(million km) Mercury Venus Earth1150 Mars Jupiter Saturn Uranus Neptune Pluto

A light year (ly) is the distance travelled by light in one year. The distance is equivalent to 9,460,730,472,580.8 km. Distances in Space - Light Year Distances from the Earth to the stars are too great to be expressed in Astronomical Units and so the Light Year is used.

Proxima Centauri is 4.22 light years away - about forty trillion (4 x ) kilometres). After our Sun, the nearest star to the Earth is Proxima Centauri, one of the 3 stars in the Alpha Centauri star system. Proxima Centauri

The Eagle Nebula, which is a giant gas cloud, is believed to contain newly forming stars. Eagle Nebula It is 7,000 light years away from the Earth.

Galaxy NGC 4414 The central region is composed of older yellow and red stars, while the spiral arms contain younger blue stars. This spiral galaxy is approximately 60 million light years from the Earth.

On July 16 th 1969, Apollo 11 was launched, with the aim of putting the first men on the surface of the Moon. In the 1960’s, America planned to send astronauts to the Moon, as part of their space exploration programme. Moon Landings

On July 20 th Neil Armstrong set foot on the surface of the Moon. His first words from the surface were... “That's one small step for man, one giant leap for mankind.”

The Moon was later further explored by using roving vehicles.

It is still only the moon landings that have allowed humans to personally make observations of the Earth from the surface of another celestial body.

There are two types of probe (unmanned flights) that are used to investigate the solar system: Probing The Solar System Fly-bys These are probes that fly close by to a celestial body or go into orbit around one, e.g. Voyager I and II. Landers These are daughter probes released form a parent probe and which land on the surface of a celestial body, e.g. the Rover landings on Mars.

In 1977, Voyager I and Voyager II were launched to study the outer planets and eventually to leave the Solar System, travelling into outer space. Fly-bys (Voyager I and Voyager II)

As they passed by planets, Voyager I and II sent back amazing photographs revealing great detail. Fly-bys (Voyager I and Voyager II)

Fly-bys (Getting Close To A Comet) Unmanned probes have now been able to get close to comets and provide valuable data.

In 2003, NASA (National Aeronautics and Space Administration) launched the Mars Exploration Rover Mission, which placed two robots on the surface of the planet Mars. Landers - Mars Exploration Rover Mission

The purpose of the mission was to study the surface of Mars, and to gain a greater understanding of the origins of both Mars and the Solar System. Landers - Mars Exploration Rover Mission

Landers - Destroying a NEO In January 2005 NASA successfully launched a probe called ‘Deep Impact’ which had a smaller lander probe that was designed to impact with comet Tempel 1 in July of that year. The mother probe will return to Earth in January The impactor (lander) probe formed a crater and provided information as to the makeup of a comet. However, the impactor could well have carried a nuclear warhead to shatter or realign the comet.

Moons of the Solar System All moons are drawn to the scale of the Earth’s moon. More recently unmanned probes have visited the outer reaches of the solar system and new moons have been discovered...