World Wide Telescope Script
Edited by Sadie on 30th March, for Uni Genius event. Introducing A-level students to WWT. Total session length 30 mins including – 10 min Intro of programme and 20 min .wwt tutorial.
Main jist of talk
1. Introduce WWT, yourself and helpers
2. Give quick tutorial of WWT, make sure all users are in programme.
…..Look in more detail and stuff discussed in the dome show.
3. Orion & Orions Nebula & Star birth
4. Star Death, Crab Nebula & Neutron stars and Pulsars
5. M101 a recent supernovae
6. X-ray Binary black holes & Cygnus X-1 (Look in X-ray)
7. Sagittarius A* our supermassive black hole, diff Wavelength (Look in Infrared) Galactic Centre
8. NGC 4051 looking in optical and X-ray bands explain my PhD research
9. M87, elliptical galaxies, mergers, part black holes play in galaxy formation?
10. Hubble Deep field get an idea for how massive the universe is…
11. The End, Any questions
1. World Wide Telescope this is a Microsoft program which you can download for you own computers for free, you do need a good internet connection, because all the images are downloaded as you zoom into them. Explain top and bottom menu bars and the search bar.
2. (Get them to do this within software as you explain it!). Now by Clicking on your favourite image in bottom ‘Look at’ menu, I’ve chosen the Pleiades which is a group of stars in Taurus. By right clicking on the images you can see the ‘Finder Scope’ this shows you the RA and DEC of the object which is basically the co-ordinate system astronomers use to assign positions to objects like stars and galaxies. You will notice the Alt and Az , which is another co-ordinate system is moving. This is because the stars move across our sky. The Magnitude is the measure of brightness and the distance to the stars is given in Ly, where a light year is equivalent to about 6 trillion miles, that’s a 6 with 12 zeros! If you want to know more about a specific object select ‘Research’ and there are loads of other options which allow you to explore information about the object. Including the Simbad database which is used by astronomers like myself. Choose ‘lookup on Simbad’, as you can see these is a lot of information here and lots of ways you can look at it. So the best way to get used to this program is to download it and experiment with it yourself.
3. To start we will look at Orion, which I may? have shown you in the planetarium show you were shown orions belt, 3 stars in a row, WWT allows us to zoom into the star forming region just below the belt. Stars just like humans live and die, our sun has about 5 billion years left in it, and these stars in the nebula have just been born. The length a star lives for depends on how large it is. The biggest stars have the shortest lives, and stars survive by fusing elements, which releases energy.. Stars can fuse everything up to Iron and then all the other elements, things like silver and gold are made in the death of the star, in the supernovae explosion.
4. Now you also saw the Crab nebula in the planetarium and you will remember I said it was a composite image made from X-ray to look at the neutron star and optical to see the explosion of the different elements. Now I want you to search for the crab and use the bottom toolbar to look at all the different ways you can see it with the different parts of the EM spectrum.
5. M101 – The recent (August 2011) supernovae in the ‘pin wheel’ galaxy. They come in various types, and the one we’re interested in is probably due to a white dwarf (the core of a dead star) which is literally sucking matter from a companion star. If the white dwarf accumulates enough matter, it starts to fuse hydrogen atoms into helium, causing the whole star to explode. Such an explosion releases so much energy that it can outshine its parent galaxy! Type IA supernovae are a bit special, as we think they all explode in a similar way, which allows to use them to determine distances of far away galaxies. It is actually thanks to these stars that scientists discovered the expansion of the Universe was accelerating.
M101 is a spiral galaxy, located about 25 million light-years away. It is also huge, as it contains about a trillion stars, 10 times more than our Milky Way Galaxy! Because it’s very close, the study of this supernova should be rather easy, and it was spotted pretty early. Most supernovae occur very far away, and they are detected only after a few days, when they reach their maximum brightness. The earlier they are observed, the better: scientists gather more data, and it is essential to better understand these phenomena.
6. Now if the star which made the crab had been a bit bigger say 8 times bigger than the sun the left over core would become a black hole not a neutron star. So next we are going to look for one of the most famous black holes called Cygnus X-1 it is one of the first sources which was widely accepted to be a black hole. It’s in the head of the Swan, Cygnus constellation and was discovered using X-ray observatories. Make sure they are looking in visible, i.e. what your eyes would see, so when we look at the sky in this visible survey image you can’t see any source here in the neck of the swan. Now we know that when material falls onto a black hole and moves at very high speeds, particles gain energy, and achieve the high energies required to produce X-ray radiation. Now when they turn on the X-ray survey of the whole sky taken by the ROSAT X-ray telescope you suddenly see a source appear, this is X-ray radiation released as a result of material spiralling in a disc around the black hole, We call this an accretion disk. The mass of the black hole in the system is 9times that of the sun. Over three decades ago, Stephen Hawking placed -- and eventually lost - a bet against the existence of a black hole in Cygnus X-1. Today, astronomers are confident the Cygnus X-1 system contains a black hole. In fact, a team of scientists has combined data from radio, optical, and X-ray telescopes including Chandra to determine the black hole's spin, mass, and distance more precisely than ever before. With these key pieces of information, the history of the black hole has been reconstructed. This new information gives astronomers strong clues about how the black hole was born, how much it weighed, and how fast it was spinning. This is important because scientists still would like to know much more about the birth of black holes. Talk about your x-ray research and intermediate mass bhs. Now the black hole in Cygnus is one of the many small black holes within our galaxy, but there is a really massive one at the centre.
7. Now we are flying around to look at our view of the galaxy we are in, the Milky Way. Our solar system is on one of the spiral arms of the Milky way and here you can the plane of the galaxy…Astronomers have looked at the centre of the galaxy and the stars which orbit that centre. Now the centre of the our galaxy is in the region of Sagittarius A*. From measuring the speed of 6 stars at the centre scientists have estimated the mass of the bh at the centre of our galaxy is 4 million times the mass of our sun. No other object can be so massive and in such a small volume of space. Now if we look at infra red survey of the sky we can see that the galaxy plane shows up a lot better. This is because infrared radiation is associated with heat (this is how police cameras work, picking up the heat of the criminals at night in order to locate them) Astronomers use the same principle here, now the material at the centre of the galaxy has more energy and therefore releases more heat energy. Infrared also allows us to see areas of star formation.
8. NGC 4051 – talk about my thesis
9. Now finally we are going to fly out to M87, which is galaxy, but it is called an elliptical galaxy as it is more rounded. The supermassive black holes size is estimated to be billion times the mass of the Sun, astronomers think elliptical galaxies might be formed by the mergers of 2 spiral galaxies. When we view this galaxy in optical light we just see a circular galaxy, however when we look in X-ray and infrared we see other features and jets coming from the centre. In fact the jets from this black hole actually extends out 5,000 light years
10. Hubble deep field – near ursa major (as is NGC 4051) One peek into a small part of the sky, one giant leap back in time...
Mankind's deepest, most detailed optical view of the universe — provided courtesy of NASA's Hubble Space Telescope — was unveiled today to eager scientists at the 187th meeting of the American Astronomical Society in San Antonio, Texas.The image, called the Hubble Deep Field (HDF), was assembled from 342 separate exposures taken with the Wide Field and Planetary Camera 2 (WFPC2) for ten consecutive days between December 18 and 28, 1995.
Representing a narrow "keyhole" view stretching to the visible horizon of the universe, the HDF image covers a speck of the sky only about the width of a dime located 75 feet away. Though the field is a very small sample of the heavens, it is considered representative of the typical distribution of galaxies in space because the universe, statistically, looks largely the same in all directions. Gazing into this small field, Hubble uncovered a bewildering assortment of at least 1,500 galaxies at various stages of evolution.
Most of the galaxies are so faint (nearly 30th magnitude or about four-billion times fainter than can be seen by the human eye) they have never before been seen by even the largest telescopes. Some fraction of the galaxies in this menagerie probably date back to nearly the beginning of the universe.
11. The End, any questions?