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

The Solar System - Problems of Scale One of the problems of diagrams relating to the structure of the solar system is that of scale. In this diagram the planets are drawn to scale to allow easy comparison of size. Although the planets are drawn to scale, the distances from the Sun have had to be ignored in order to fit the image on the page.

The Solar System Drag each planet to its correct position in the solar system... Pluto has been included in this exercise although it is now officially classed as a planetoid.

So How far to the next star? In 1 year there are 365¼ x 24 x 60 x 60 seconds = 31,557,600 seconds Distance = Speed x Time Distance = 300,000 x 31,557,600 km Distance = 9,467,280,000,000 km Distance = 9,467,280 million km Our scale was 1 cm = 15 million km Proxima Centauri is 9,467,280 ÷ 15 = cm Or m ~ 6.3km away That’s from here to Hirwaun!

Where are we in the Universe? We are on 1 small planet near to 1 average star The nearest star is 9,467,280 million km away Our star is one star in a galaxy of approximately 200,000,000,000 stars. Our galaxy is one galaxy in the universe containing approximately 100,000,000,000 galaxies. So number of stars = 20,000,000,000,000,000,000,000 Or 20 thousand, million, million, million stars. That’s an awful lot!

Objective - Review Understand that distances in Space are very, very, very big. Examine the distance between the Earth and the Moon – our nearest heavenly body. Construct a scale model of our Solar System.

Are We Alone? There’s a lot of Space in the universe and who knows how many planets, so I think it is unlikely!

Hubble Space Telescope The Hubble Space Telescope is not affected by atmospheric distortions or light pollution.

The Hubble Space Telescope was put into orbit using the Shuttle. When placed in orbit, one of the telescope’s mirrors had a defect.

The Hubble Telescope was very expensive to put in orbit, and is very difficult to maintain. To repair the problem with the telescope’s mirror, shuttle astronauts had to first capture the telescope, without damaging it.

How did the Solar System form ? 4500 million years ago a shock wave, in a spiral arm of our galaxy, triggered the collapse of a gas cloud into a doughnut shape which flattened out.

How did the Solar System form ? Enough hydrogen gathered in the centre for fusion to start in the Sun. Solid particles began to strike each other and stick together. This debris eventually formed planets and their moons.

How did the Solar System form ? Eventually most of the gas and dust in the Solar System became attached to a planet. Left over dust and frozen gases formed the comets.

Recognising Celestial Bodies From the time of Galileo’s observations of the rings around Saturn, to today’s telescopes like Hubble, scientists have been studying the Universe in ever increasing detail. For each of the following slides, try to guess the name of the celestial object before reading the information...

Mars is often called the ‘red planet’ because its surface gives the planet a reddish appearance. It is a rocky planet which has a surface temperature of approximately -55ºC. Mars

Jupiter is a giant gas planet. On its surface, the most recognisable characteristic is a giant storm called the Red Spot, which has been raging for 300 years. Jupiter The surface temperature on Jupiter is approximately -123 ºC. Red Spot

Saturn is one of the most easily recognisable planets because of its ring structure, which is made up of billions of rock particles and ice crystals, some of them centimetres or metres in diameter. Saturn The surface temperature on Saturn is approximately -180 ºC.

Neptune is a gaseous planet, composed largely of hydrogen and helium. Its blue colour cannot be explained by scientists. Neptune The surface temperature on Neptune is approximately -220 ºC.