Locating things in the Sky

Exercise:

You have 10 minutes and a single sheet of A4 paper to draw a scale model of the solar system using the following values:

How did you do? http://www.exploratorium.edu/ronh/solar_system/

This exercise is meant to illustrate the need for a different set of scales in astronomy. The numbers here are simply getting too big.

Instead of using metres or even kilometers, we use the Astronomical Unit (AU), the Parsec (pc) and the light year (ly).

Questions:

1. How many AU is Jupiter from the Earth?

2. How many parsecs is it to the edge of the solar system?

3. How far is a light year in AU and pc?

We also have a need for a different co-ordinate system in astronomy to describe where things are in the sky...

We use a system called Right Ascention (RA) and Declination (dec). RA is like longitute and describes how far round an object is, and declination is like latitude and describes how far up or down an object is. We can use these measurements to determine the location of all things in the sky.

Example:

Use sky globe to find the coordinates of the galaxy 'Andromeda'.

Now finding a pretty picture of Andromeda using Google Sky, and it's coordinates in RA and dec.

Exercise:

Repeat the above example for 5 important objects in the night sky. For each record the co-ordinates, date of observation, and any other information you can find out about it which you think is relevent. Why do you think each is considered important in astronomy?

Extension Tasks:

Try and find a bright star (magnitude 3 or above), find out its name, which constellation it is in, what is it's age, chemical composition, distance from Earth, etc.

Now do the same thing for a prominent galaxy.

What is the difference between a constellation and a galaxy? Aren't they both collections of stars?

Why do the stars look different when we use the infra-red or microwave functions in Google Sky?

Worksheet that covers the tasks and questions for this lesson

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Telescopes and Astronomical Observations

There are basically two types of telescope: Reflecting and Refracting- draw a ray diagram for each to show how it's optics work (link: http://www.schoolsobservatory.org.uk/astro/tels/raydiag.shtml)

Most telescopes now fall into one of the following catagories: Refracting Telescope , Prime Focus Telescope, Newtonian Focus Telescope, Cassegrain Focus Telescope

During this course we will use data gained from the National School's Observatory (NSO) Telescope in La Palma.

Tasks:

Draw ray diagrams for each of the four main catagories of telescope.

Find out what type the NSO telescope in LaParma, and the Hubble Space Telescope are. What specific advantages does each offer?

Astronomical Images are very pretty but we need to be able to make measurements from them in order to be able to learn lots about the unverse. We usually use computer programs to enable us to do this. LTImage is a simplified version of software used by professional astronomers to analyse the data they collect using telescopes.

Task:

You will need to learn to use the data analysis software LTImage to analyse images. Work through the LTImage workshop, (the program LTImage will be installed on your computer and you can get the downloaded files you need quicky from Teachers4Students/Science/Space Elective/LTImage wshop1 data).

To complete this task you may need a username: bangkokp000s and password: yarruat

Research Task:

How can we use images taken in different regions of the electromagnetic spectrum to find out more about objects in the sky?

Worksheet that covers the tasks and questions for this lesson

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Hunting for Asteroids

Asteroids are dusty, rocky, metallic objects that orbit the Sun, but are too small to be considered as planets. They range in size from small pebbles up to the largest asteroid, Ceres, which is about 1000km in diameter.

When asteriods are on collision course with Earth they are called meteoroids, and as they crash into the Earth they become meteorites. Some suggest that this is how life started on Earth! But these could also cause the end of life on Earth.

Video: Space episode 2 (Staying Alive)

Exercise:

Introductory Powerpoint

Extension:

Calculate the speed of an asteroid worksheet

Once you have done this, use your answer to make an estimate of an asteroids likely kinetic energy, and what sort of temperature rise that could bring about in the Pacific Ocean if it were to crash into it.

(NB:To complete this task you will need a username: bangkokp000s and password: yarruat)

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Planets and Extra Terrestrial Life

The Solar System- What is it?

How was the solar system made?

When the Sun was made not all the material available was used up- Star formation is a messy business! The remaining matter was held close to the Sun by it's gravity, and orbits it as a result of angular momentum conservation (you'll learn about this at university!). Slowly this material gathered together into clumps, which because of their gravity pulled in more material. Eventually there were 9 main clumps, which are the planets we know of today, and an area of planetary material which never quite turned into a planet (yet), called the asteriod or Kuiper belt.

Discussion Points:

Does this mean there are likely to be other planets orbiting other stars? How could we discover them? Youtube clip

How can we find out about the surface conditions on these planets?

Has life evolved on these planets?

Task:

Using data you find for an extra solar planet ( http://exoplanet.eu/catalog-all.php ), use the calculator to determine it's approximate surface temperature. Can you find a planet with conditions that may have allowed life to start there?

Does ET exist? Watch BBC Space: Episode 4 (Are we Alone?), and decide for yourselves. What is the likelihood of us ever being able to communicate with life elsewhere if it does exist? What would you say, and how would you say it? What problems would the distances involved have for communications between us? Task: Work through the Drake Equation, and determine the liklihood of us finding and communicating with another civilization

Extension Activity:NOVA- Spectral fingerprinting

You will search for life in other parts of the galaxy by looking at the light emitted by planets to see if it contains signs that life may exist there.

You need to read the following research papers, and then complete the tasks as you go through.

Spectral fingerprinting student project

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The Sun and the Stars

Our Sun is just a very normal start, doing a very normal stellar process.

Video: Space episode 1 (Star Stuff)

Task:

Produce a 5 minute presentation to answer  the following questions. In answering these questions you should not just say what we know, but also, more importantly, how we know it.

• How old is the Sun? How and when was it formed?
• What is the Sun made of? How does it fuel itself, and why can’t we do this on Earth?
• How is the Sun’s composition linked to it’s age and lifetime?
• Why is the magnetic field of the Sun important? Why is it so difficult to map?
• What will happen to the Sun in the future? What implications does this have on us?

You will be assessed by your peers on the content and quality of your presentations.

Lesson 2: Other Stars

The Magnitude Scale:

Astronomers classify objects in the sky according to how bright they are. They assign each object a brightness or magnitude, according to the apparent magnitude scale. We also use tha Apsolute Magnitude Scale

The Hertsprung Russell Diagram

We can find out a lot about stars that are too far away to measure by plotting them on a Hertsprung Russell diagram, and comparing them with stars that we have been able to measure.

Task:

Use the spreadsheet to Plot HR diagrams to compare the Sun with other, local and prominent stars.

The Evolutionary Sequence of Stars

The way that stars evolve, and how quickly they do so, depends mainly on the mass of the star. The mass of the star will define its other characteristics, such as temperature, composition, lifespan and ultimate fate.

The following animations take you through the evolution of typical low and high mass stars.

http://www.valdosta.edu/~cbarnbau/astro_demos/stellar_evol/home_stellar.html

Tasks:

Complete the diagram to show the evolutionary sequence of typical stars.

Find out about and complete the writing frames for ONE of these stages in the evolutionary sequence.

Write a summary of the ultimate fate of our Sun.

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The Big Bang and the Future of the Universe

Link to Mr Roff's powerpoint

Task:

This is a University style lecture. I want you to take notes as I talk, then try and write up a set of notes that detail my main important points.

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Galaxies

Galaxies are collections of billions of stars. Gravity means that stars tend to clump together to form galaxies, and galaxies tend to clup togther to form clusters of galaxies.

Wierdly there appear to be two types of galaxies:

• Spirals (of which our Milky Way is a member)

• And Ellipticals

It is easy to see the difference in these images, but some galaxies are lessly easy to classify.

Task:

Galaxy Zoo is an onlione collaboration to classify all the known galaxies into one of these classes. You must qualify as a classifier, and then carry out 10 classifications.

This will raise some questions. Write down what they are.

It is really difficult to explain the different shapes of the galaxies we see because we don't have much to go on. We can only determine the shape of the Milky Way from measurements we make within it and based on observations of other galaxies we can see. We cannot send a space craft off to take the plan view you see in the picture above- the distances are astronomical!

So what about ellipticals? Some scientists have suggested that there is an evolution sequence of galaxies...

Hubble was the first scientist to try and map the Universe using observations of galaxies. He made some truely remarkable discoveries during this work...

• He discovered that most of the Galaxies he observed are moving away from us.
• He said that if they are all moving apart, then once they must have been in the same place.
• He was able to measure the speed that they were moving by reading their Doppler shift.
• He said that if he knew the distance to the galaxies, and their speeds he could work out how long they had been moving for...

The Age of the Universe!

Task:

Plot a Hubble Graph with the data in the worksheet for different galaxies to determine the age of the Uninverse.

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Cepheid Variables to Determine the Age of the Universe

Project:

You will follow through a European Space Agency developed project to determine the age of the Universe. You will need to learn to manipulate astronomical data using SalsaJ- ESA's version of LTImage.

Lots of the calculations that you are asked to do are beyond the scope of what we are trying to achieve here, so use the spreadsheet to record your data, and the maths will be done for you.

Remember, before you do anything, read, the accompanying information.

To complete the project you will need:

Project instructions and information and the astronomical toolkit

Excel spreadsheet to record and analyse your data

Image data for the 3 cepheid variables you will be analysing.

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Dark Matter to Explain the Missing Mass

The Possible Fates of the Universe

A graph of Universe diameter against time, develops the idea of 2 possible fates for the Universe

Open Universe - As we look at the sky we see everything moving away from us according to Hubble's Law. This suggests that the edges of the universe are accelerating. Gravity isn't working! The Universe will expand forever. What are the problems with this?

Closed Universe - If there is enough mass in the Universe, then we have to assume that gravity will kick in, and pull everything back together into the big crunch. As a theory this is attractive because it concludes the Universe in a similar state to that in which it started. Problem: we are missing about 90% of the mass that the Universe needs to have in order to do this

The missing matter problem- Dark Matter and DM Candidates

Task:

Using bungs on strings attached to Newtonmeters investigate how force changes with radius of orbit, and speed of orbit.

Your answer to the investigation is critical to demonstrating how Rubin inferred that there must be some matter unseen inside galaxies. – Dark Matter

Watch the video ‘The Mystery of Dark Matter'

Task:

Complete worksheets on the video to consolidate your understanding of Dark Matter and DM Candidates: MACHOS, WIMPS, Brown Dwarfs and Black Holes.

Question:

What is your prediction (informed by research) about the fate of the universe: Open, Closed or marginally bound?

Watch the short movie clip of Dr Chris Lintott.

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anrophysics 2007