$2 - 1 - DO NOT LOOK DIRECTLY AT THE SUN WITHOUT EYE PROTECTION. IF YOU DO, YOU WILL DAMAGE YOUR EYES FOREVER! In this book let we will discuss the transit of Venus, which is when the planet Venus drifts across the face of the Sun as we see it. At Sydney Observatory, we will use filters that block more than 99% of the harmful infra red and ultra violet radiation. Please ensure that everyone, especially children, only use the correct filters to look at the Sun. - 2 - It is possible to safely watch the transit yourself if you have a small telescope or a pair of binoculars. Use the telescope or the binoculars to project the image, as shown in the image above. With your back to the Sun, aim the telescope towards it (this is not as difficult to do as it sounds – use the shadow of the telescope) and focus its image onto a white card held about 200mm behind the eyepiece. Venus will appear as a black spot with a width of 1/33rd of the Sun’s width and should be easily seen. DO NOT LOOK THROUGH THE TELESCOPE OR BINOCULARS! Never leave the telescope unattended and ensure that children are supervised at all times. Viewing the projected image is quite safe, but looking through the telescope or binoculars will cause almost instant and irreversible blindness. For a direct safe view of the Sun, a pair of Sydney Observatory eclipse glasses can be purchased for $5.00 each. - 3 - Where will the 2012 transit of Venus be visible, and what about the weather? Image courtesy of Fred Espanak, NASA The transit of Venus occurs when the planet Venus drifts across the face of the Sun as we see it from Earth. You have to be in just the right position to see it and luckily here in Sydney, we will get a great view if the sky is clear. Yes, of course we are always worried about the weather! In the space below, keep a record of the weather for 6 June. The temperature at _________ (time) today is ______ °C (you will find a large thermometer in the Russell Room) Image courtesy of the Bureau of Meteorology Circle the picture above which best describes the weather today. If it is cloudy, try to identify what type of cloud it is and draw a circle around it. - 4 - Transit animation On the following pages, you will see several slightly different images of the transit. Hold the book in the centre at the top with your left hand and flip through the pages quickly from the front to the back. (The booklet needs to have been printed double-sided for this to work.) You will see a simple animation of Venus drifting across the Sun. We have put north at the top. - 5 - We now know there are about 130 billion galaxies in the observable Universe. The Universe is about 13.7 billion years old. - 6 - A single galaxy like the Milky Way may have 200,000 million stars in it. - 7 - There may be as many as 20,000 stars just like the Sun in the Milky Way. SUN FACTS − 5 billion years old − 1.4 million km diameter − 5,500°C surface temperature − 10 million°C core temperature − Converts 4 million tonnes of hydrogen into energy every second To see the latest videos and images of the Sun from space visit http://www.nasa.gov/mission_pages/soho/ - 8 - (not drawn to scale) The family of objects that travel around the star called the Sun (or “Sol”) is known as the Solar System. Our Solar System has one star, eight planets, nearly 200 moons, eight dwarf planets and millions of comets and asteroids; but do they just wander all over the place? - 9 - Lots of things rotate. This ice skater is rotating in an anticlockwise direction. Have you ever seen the hands of a clock If you can go to Sydney Observatory, look for the models move? If you watch very carefully you will of the Solar System called orreries like the one shown above. see them move but quite slowly. Then look for the planet models. Two spin clockwise and Put an arrowhead on the end of the curved one anticlockwise. line to show which way the hands move. This direction is called “clockwise”. 1. The planet ______________spins anticlockwise. 2. The planet ______________spins clockwise 3. The planet ______________spins clockwise - 10 - Faster than a speeding … It is sometimes difficult to understand how fast our planets move. Some racing cars can travel at 300km per hour which is about 80m per second. That is nearly the length of a football field every second! Passenger jets are even faster! They can travel at about 900km per hour which is about 250m per second. Both racing cars and jets are slow compared to the planets. Mercury orbits the Sun every 88 days at about 48km per second. Venus orbits the Sun every 225 days at 35km per second. Our Earth orbits the Sun every 365 Can you name the planets days at a slightly slower 30km per on the dais in order? second. - 11 - Many spacecraft have now been to Venus. The first landing on Venus was Venera 3 on 1 March 1966. It was from the former USSR but did not survive the incredible temperature of up to 463 °C and atmospheric pressure 92 times greater than on Earth. Perhaps you can design your own spacecraft to survive the hostile environment of Venus. Sputnik 7 was the first mission to fly by Venus in 1961 - 12 - As the planets orbit the Sun, sometimes they line up and eclipse, transit or block one another’s view. What happened to the Sun in the picture below? Where has it gone? It looks like some of the Sun has been removed, but it is really just the Moon moving between us and the Sun, creating a shadow. Image courtesy of Fred Espanak Did you know some people thought eclipses were caused by dragons eating the Sun and Moon! Sometimes everyday objects or people line up too and can make an unusual sight, like this! - 13 - Here we can see a simplified diagram of the Moon moving between the Earth and the Sun. This is called a solar eclipse. DO NOT LOOK DIRECTLY AT A SOLAR ECLIPSE! (not drawn to scale) - 14 - The Moon orbits the Earth every 29 days but it rarely passes through the Earth’s shadow. It does pass through the Earth’s shadow twice every three years to cause a lunar eclipse. These are safe to look at directly. The next total lunar eclipses that can be seen from Australia are: 1. 15 April 2014 2. 8 October 2014 3. 4 April 2015 4. 31 January 2018 This series of images was taken in December 2011. - 15 - Only three large objects can move between us and the Sun. Choose which three objects and draw a line from each one to its correct position. (not drawn to scale) - 16 - (approximate scale as seen from Earth) The three objects that pass between the Earth and the Sun are: 1. The planet Mercury, 2. The planet Venus, and 3. The Moon. - 17 - Venus is a very hot planet . The atmosphere is so “heavy” or dense it would crush us instantly. There is also a lot of volcanic activity. It is not a nice place compared to Earth. Draw a circle around the different features that you might find on Venus. Draw a cross through the features you wouldn’t find on Venus VENUS FACTS − Second planet from the Sun − Hottest planet in the Solar System, with temperatures reaching up to 463 ºC − Atmospheric pressure 92 times that on Earth − A day on Venus is 243 Earth days − Only 650km smaller than Earth - 18 - Mercury moves between us and the Sun about 13 or 14 times per century, Venus four times every 243 years and the Moon three times every two years. So why are we so interested in the rare transit of Venus? - 19 - In 1768 a famous voyage took the HMB Endeavour from England to Tahiti to see the 1769 transit of Venus. Who was the captain? ____________________________ The Astronomer Royal, Edmond Halley, worked out how to measure the size of the Solar System. The idea was simple but proved difficult to do. Astronomers had to carefully observe the transit of Venus from different locations. They had to record the EXACT times of the four contact points. We’ll talk more about them soon. At Sydney Observatory there is a model of the Endeavour. Internet question: What other famous ship had the same name? S _ _ _ _ S _ _ _ _ _ _ Endeavour - 20 - Captain James Cook 1728-1779 Did you know the cottage where James Cook was born was moved to Melbourne’s Fitzroy Gardens from England in 1934? We now know he took very good measurements of the four contact times: 1st contact is when Venus first touches the edge of the Sun. 2nd contact is when Venus is first fully inside the Sun. 3rd contact is when Venus touches the edge before leaving the Sun. 4th contact is the last touch of Venus on the edge of the Sun. Modern examination of Cook’s data showed his error was just 1.5 seconds! Using his data, the distance from the Earth to the Sun was between 149 and 151 million km. The current value is 149,598,000 km. - 21 - What did Tahiti and the planet Uranus have in common with King George III? Fort Venus At one time, both Tahiti and the planet Uranus were named after King George III, but not any more.