The Earth Orbits the Sun Student Question Sheet (Advanced)

Transcription

1 The Earth Orbits the Sun Student Question Sheet (Advanced) Author: Sarah Roberts

2 - Faulkes Telescope Project Introduction This worksheet contains questions and activities which will test your knowledge and understanding of the topic,. This module, The Earth orbits the Sun is one of 4 modules which make up this topic. The remaining 3 modules can be found on the Faulkes Telescope Project website. The Earth Orbits the Sun The following diagram shows how day and night occur on Earth. The line through the centre of the Earth shows the Earth s axis, around which the Earth spins once every day. Sunlight hits half of the Earth s surface - on this half of the world, it is daytime. Only the Sun, possibly the Moon and a couple of planets would be visible in the sky from anywhere on this side of the Earth at this time. On the opposite side of the Earth, which lies in the shadow, it is night. From any location on this side of the Earth, the Moon, planets, other Solar System objects and millions of stars are visible in the sky. If there is a telescope on this side of the planet, other astronomical objects such as planetary nebulae, galaxies and clusters, could also be seen from this side of the Earth. Page 2 of 9

3 - Faulkes Telescope Project Below is a diagram which shows the positions of the Faulkes Telescope North (FTN) and South (FTS) on the Earth. FTN is on the island of Maui in Hawaii. FTS is in New South Wales in Australia. Night and Day 1. Considering the information given above, and looking at the position of the telescopes on the Earth, can you suggest a reason why, for UK schools, the telescopes are perfectly placed? The time difference between Hawaii (where FTN is located) and Greenwich Mean Time (GMT) is -10 hours. GMT is the same as UK time in the winter, but once summer comes, people in the UK put their clocks forward one hour to British Summer Time (BST). This is one hour ahead of GMT, and in some countries, this is called Daylight Saving Time, or DST. It is called DST because it shifts daylight hours so people can make better use of the evenings. BST starts on the last Sunday in March and ends on the last Sunday in October. In 2007, these dates are: BST begins - 25th March Page 3 of 9

4 BST ends - 28th October - Faulkes Telescope Project 2. You have a science lesson in school at 9:00am on Monday 5th February 2007, and would like to use the telescope in Hawaii to image some galaxies. In February, the sun sets in Hawaii around 6:00pm local time. a). By considering the date of your planned session given above, is the UK following GMT or BST? b). Using your answer to part a), state how many hours Hawaii is behind the UK in February. c). What time is it in the UK when the Sun is setting in Hawaii? d). If your session is at 9:00am in the UK, what time is this in Hawaii? Will it be possible to use the telescope at this time? Page 4 of 9

5 - Faulkes Telescope Project The Sun rises in Hawaii at about 7:00am local time in February. e). What time is it in the UK when the Sun is rising in Hawaii? f). Your after-school club meets on a Monday evening until 6:00pm. The club leader wants to use the telescope in Hawaii for 30 minutes between 5:30pm - 6:00pm. Is this possible? Explain your answer. 3. The Faulkes Telescope South is located in New South Wales in Australia. Australia also has DST - beginning in their summer on the last Sunday in October, and ending on the last Sunday in March. During DST in Australia, the time difference between the UK and Australia is +11 hours. At their standard time, from March to October, the time difference between the UK and Australia is + 9 hours. The Sun sets in Australia in February around 8:00pm local time. a). What time is it in the UK when the Sun sets in Australia? Page 5 of 9

6 - Faulkes Telescope Project b). Given that the sky won t be completely dark until a couple of hours after sunset, would it be possible to use Faulkes Telescope South in Australia, during the science lesson at 9:00am on Monday 5th February? Explain your answer. The Sun rises in Australia around 6:30am local time in the beginning of February. c). What is the time in the UK when the Sun rises in Australia? d). Given that the sky will begin to get light about an hour and a half before sunrise, would it be possible to use the Faulkes Telescope in Australia during the after school club mentioned in Question 2? Page 6 of 9

7 - Faulkes Telescope Project Spinning around... If you look up at the sky on a clear night, and watch the stars for any length of time, you will notice that the stars appear to rise in the East, and over the course of the night, travel across the sky, eventually appearing to set in the West. The brightest star in our sky, the Sun, also rises in the East and sets in the West. This is why, for example, Australia, to the East of us, is 11 (or 9) hours ahead of UK time - the Sun rises there before it appears to rise in the UK sky. However, it is not the stars themselves which are moving relative to the Earth - it is the Earth spinning on its axis which makes the stars (including the Sun), appear to travel rapidly across our sky (it is also this spin which give us the day and night cycle). This rotation on the Earth results in the stars appearing to move across our sky, leading to different stars being visible at different times in the night. As the Earth is rotating on its axis, it is also orbiting the Sun, as shown in the diagram below. This results in a more gradual change of which stars appear in the night sky, resulting in different groups of stars, or constellations, only being visible when the Earth is at a certain position with respect to the Sun. We are going to investigate how the positions of the stars vary with time with the following activity. Page 7 of 9

8 - Faulkes Telescope Project IT OPPORTUNITY 1. Download the free planetarium package, Stellarium, and generate sky charts with the constellations labelled, and which give a full 180 degree view of the night sky. Make sure you label the North, South, East and West directions on your sky charts. (Alternatively, use the sky charts given in the document, Worksheets - Sky Charts.pdf linked in this topic). Instructions on how to download and install Stellarium can be found on the Faulkes Telescope website, together with a guide on how to display objects in Stellarium. Generate the following sky charts: 4 hourly intervals for one night e.g. 9pm - 12am. 4 monthly intervals, keeping the date the same. 4 monthly intervals at the same time e.g. Oct 20th - Jan 20th at 9pm for each sky chart. 4 yearly intervals at the same time and the same month e.g. 9pm on Oct 20th each year from season intervals at the same time and in the same year e.g. 9pm on March 20th, June 20th, Oct 20th and Dec 20th (for Spring, Summer, Autumn and WInter) Each of these sky charts can now be used to investigate how star positions move in different time steps, whilst keeping all other variables constant. 1. Compare your nightly sky charts to your sky charts which show the constellations in different months given on the following pages. a). How do the positions of the constellations vary each hour? (Hint: Think about what direction the constellations are moving) b). How do the positions of the constellations vary each month? Comment on how this compares to their positions each hour? Do the star positions vary more during an hour or a month? Page 8 of 9

9 - Faulkes Telescope Project c). What causes the apparent movement of the stars during the night? d). What causes the apparent movement of the stars every month? e). Why do we only see stars at night? f). Can you think of any exceptions to (e) above? Page 9 of 9