Cosmology Planetarium Shows with ICG

Script for the A-level Cosmology show made in collaboration with Karen Masters at ICG.

Start outside dome

After safety briefing introduce yourself and your research. Introduce WAA and the Stellarium software/ apps. Introduce Cosmology ‘ trying understand the nature of the Universe as a whole’ Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order. I actually studied an individual supermassive black hole in a galaxy as part of my research, a cosmologist might also study supermassive black holes but they would think about them in terms of ‘the part they have played in Galaxy evolution in the universe as a whole’5 mins

In dome

Play WAA  25 mins Play ‘Zoom through telescope’ Movie 1 min 17sec

Go into Stellarium

Finding North

Starting with Big dipper, which is an asterism, part of the constellation ursa major, which means the Great Bear.  And Ursa Minor, which means small bear. The lowest too stars in the saucepan point to North Star.

It looks like a saucepan, with a handle and a place to put your beans, counting from the 2 stars at the end of the pan, count in a straight line about 5/6 steps (at a step distance of the gap between those 2 stars). There you will find Polaris aka the North star.  Many people think North Star is the brightest in the sky! It isn’t! it is only important because it is directly above the North Pole, and stays above the north pole as the earth spins on its axis causing all the other stars to spin around! Think about spinning top (from Christmas cracker) the top part, which you spin around with your fingers, doesn’t appear to move while the sides of the top are whizzing around. The middle of the top represents the North Pole with the North Star is right above it. Make sure they realise none of the stars actually move, and it’s us that are moving?

(speed up time L in Stellarium so they can see stars going around in arcs)
Mentioned Axis of Earth ( if time mention Southern Hemisphere doesn’t have a star above south pole :( They use Southern Cross and point to an area which is above/below the South Pole)

Constellations      Make sure can see both Cass and big dipper

Ask ‘what is a constellation? ‘     Explain these are 48 constellations in total.

Turn on constellation art press ‘r’ key

Patterns of stars in sky, imagine the ancient Greeks without TVs very bored so used to join the stars together like a dot to dot, Mention that the Saucepan/Big Dipper is an Asterism not constellation, as it is part of the great bear. Turn off constellation art  r

Circumpolar stars 

Explain that the constellations of Cassiopeia and Andromeda and Ursa Major etc are Circumpolar constellations and never set.

Cassiopeia

Cass looks like a W or an M for McDonalds, find her from the Big Dipper by drawing a line through North Star. Cass is a queen married to King Cepheus (he is in sky near by looks like a house drawn by a child). Andromeda is Cass’s daughter. Mention film ‘Clash of Titans’ and Greek Mythology but don’t talk about it any further.

Zoom to Andromeda

Locate Andromeda.. go along same line from Polaris, to Cass, and thru to Andromeda.. (Search Fn-F3 for M31, and zoom in using / in stellarium)

When in Andromeda constellation, say it is our nearest spiral galaxy Andromeda (in local group.) It is 2.6 million light-years (2.5×1019 km) away. And it is the most distant object you can see with the ‘naked eye’.

 Andromeda looks a lot like our own galaxy and you can imagine if you were flying in space outside our Milky Way it would like very similar to Andromeda.

Andromeda is actually has double the amount of stars that the MW has.

Dark matter in Andromeda 

 So I just mentioned that Andromeda has more stars than the Milky Way. But astronomers think that the Milky way is actually more massive, as it has more Dark Matter. Can anyone tell me what dark matter is?

Vera Rubin is a scientist from the USA who studied the variation of the velocities of the gas in between stars (interstellar medium) with distance from the center of the galaxy. She found that …

Black hole in Andromeda. 

Now it might shock you to know that our Solar System is orbiting in our galaxy around a Supermassive black hole

And there is also a supermassive black hole at the centre of Andromeda galaxy.

These supermassive BH were predicted by Einstein’s theory of general relativity. They exist at the centre of all galaxies, a million times that of sun. The BH in our MW is actually 4 million times mass of sun! Ask ‘how do you think astronomers know the mass? Cos they can’t just weigh it with a scales?’ Using Keplers Third Law which hopefully you have heard of this equation which relates the speed of stars which are orbiting the Mass, to the mass of the thing they are orbiting. This is exactly how we measure the mass of the Sun.

Astronomer measured high speeds of stars orbiting around an object known as Sagittarius A* which is at the centre of our galaxy the MW.

Can zoom / into Sagittarius A*/ search for Sagittarius using Fn-F3. Can’t see much there, turn off the constellations , c and search fnF3 for M25 this is a near by cluster of stars

Explain that at the centre of our galaxy astronomers measure the speeds and orbits of stars just like that’s how they know there is a supermassive black hole there!

Ending thought about black holes.

Most people think of black holes as monsters but Astronomers now think they play a large part in the early formation of galaxies. As we learn more about how galaxies were formed in early universe it seems that the BH at the centre plays a large part in forming galaxies, remember that the jet from the centre of the galaxy can reach into other galaxies, these jets of particles might start star formation to occur in galaxies where it might otherwise not have occurred. This means that without our blackholes the universe might of not formed galaxies. And without galaxies there wouldn’t be stars, without the stars, no solar systems of planets and with out planets, no humans, so black holes may not something to be afraid of.

The massive Jets from galaxies like M87 and 3c273 are so far reaching that they can actually reach into nearby galaxies.  Astronomers think that these jets can affect the surrounding galaxy giving the surrounding galaxies more energy. This might mean that idea that black holes are monsters is wrong; they actually might be responsible for the formation of galaxies like our own. And of course without the galaxy there is no solar system and without the solar system no place for us to live!

For example if our Sun turned into a black hole we wouldn’t all get sucked in, the Earth would actually orbit around quite happily. Obviously, without the energy from fusion humans would not exist though.

Gravity works for black holes just like it does for everything else. Black holes don’t suck – they just have very strong gravity, so it’s dangerous to get very close. But far from a black hole things orbit them normally.

Blueshift and redshift 

Ask if they have heard of red shift or doppler shift? Remind them that that it is to do with the wavelength of electromagnetic radiation. When an object is moving away from you (like most galaxies are moving away from us) the radiation or light we detect is shifted to longer wavelengths because of the motion of the object away from us means the light waves get stretched out, i.e. the energy of light measured by an astronomer is nearer the lower energy red end of the spectrum , hence the name ‘red shift’ – compare with the pitch of the ambulance siren as it goes past you with the wavelets bunching up in front of the ambulance when it is moving towards you, and spreading out behind. Sound wave compressed as it came toward you, and stretched as it went away. Same is seen in stars, and used to observed the motion of galaxies.

 Say that the light from Andromeda is actually blue shifted! Ask them what this means? So MW and Andromeda are actually moving toward each other in space at about 100km per sec which seems very fast and might scare you but this is actually equivalent to  400 lightyears every million years (and remember Andromeda is 2.6 million light years away) attracted to each other by gravitational forces due to their large masses, in 4.5 billion years they will collide making a much larger galaxy.

Out of Stellarium

Play ‘Redshift blueshift’ movie 12.27-12:37 10 secs

You can see the light is redder or stretched because the galaxy is moving away from us.

Galaxies come in different types. We’ve seen the Milky Way and Andromeda which are both spiral galaxies, but we think after they merge together they might form an elliptical galaxy which are the other kind.

Play ‘highresgalaxycollision’ movie 53secs

Lots of astronomers work to try to understand how the different kinds of galaxies formed and how they got the shapes they have.

Now hopefully some of you have heard of the Galaxy Zoo project. This is an site where members of the public, like yourselves can help the astronomers by classifying galaxies. You do this by going on the website and just looking at the shape of the galaxy to decide which type you think it is.

Our view of the universe has changed. 

It is only since the 1500’s that we have really started to understand the solar system and our universe.

Play ‘Solar system models.mov’ 1 min 05:15-06.09

Before telescopes were invented everyone believed the earth was the centre, we thought the sun, moon and planets orbited around it.

Then in 1543 Nicholas Copernicus proposed a different model with the Sun at the centre, it was a radical idea and he didn’t have any evidence to prove it. Nearly 65 years later, Hans Lippershey fixed 2 small pieces of glass into a tube and made an Eyeglass. Galileo saw these designs and made his own telescope and observed Jupiter, and noticed some points of light either side of Jupiter which appeared to move around it. He soon discovered these were moons orbiting around Jupiter, and this made people realize that the Earth wasn’t actually so important, since objects could clearly orbit around other planets like Jupiter. The telescope was then used to prove Copernicus’ new theory that the earth was not the center of the Universe. It was also used to learn more about our Galaxy

Play ‘Galaxies.mov’ 1 min 48  12.37-14.33

Our Galaxy and Other Galaxies

We have only known that we have lived in a galaxy for the last 100 years. Before the 20^th century thought the universe consisted of a flat disk of stars with the earth and the solar system at the centre.

Caroline Herschel made a map of this disk, but because telescopes did not have the resolving power of todays telescopes. They thought the other galaxies were part of this disk. An astronomer named Edwin Hubble observed Cephid Variables and was able to determine that these galaxies were extremely far away.

There was a massive public debate in 1920 between two astronomers about if “spiral nebula” were external, or in our own Galaxy. Harlow Shapley thought they were in our Galaxy because it was really huge. Heber Curtis thought our Galaxy was smaller and the others were all external. Turned out they were both right as the universe is much bigger than they could imagine. Our Galaxy is as big as Shapley thought it was and the others are all outside it!

An astronomer named Edwin Hubble observed Cephid Variables in the mid 1920s and was able to determine that these galaxies were extremely far away. He also used these measurements to show that the further galaxies get from us the faster they are moving away from us (using measurements of their redshift). This demonstrated that our Universe is not only vast, but also expanding!

Play ‘Fly through HST galaxies’ 1 min 20.48-21:33 

We now have such good telescopes (like the HST) that we can see galaxies that are so far away that the light from them has taken almost half of the age of the universe to reach us.

Light travels very fast – about 1 metre in 3ns, but it still takes 8 minutes to reach us from the Sun, 3 years from the nearest star, and millions or billions of years from the external galaxies.

These galaxies show an incredible variety of different types of galaxies even very early on in the Universe.

Sloan Digital Sky Survey Play Journey_3D_HD (on desktop) 1min 23sec

This visualization presents a 3-D view of the largest structures in the Universe via data from the Sloan Digital Sky Survey. The SDSS is the most ambitious astronomical survey ever undertaken. It provides a 3-dimensional map of about a million galaxies and quasars. As the survey progresses, the data are released to the scientific community and the general public in annual increments.

We also have massive surveys of galaxies in the Universe. This movies shows 1 million galaxies which have been mapped by the Sloan Digital Sky survey.

We can’t see galaxies everywhere. These black areas are the modern equivalent of “here be dragons” anything there is hidden from our view by our own galaxy.

But the web like structure is real. This is showing how galaxies formed where there were clumps of dark matter in a filamentary web. We can understand things about cosmology from carefully mapping the shapes seen in this structure.

When we look at the most distance galaxies, we are looking further back into time. This is because the light from the most distant galaxies has taken such a long time to get to us. Therefore, the furthest point we want to look back to is the creation of the Universe, the time of the ‘Big Bang’.

Each marker here is actually real data , which is why there is a big gap in this data. It doesn’t mean there aren’t galaxies there; we just haven’t looked there yet.

Quasars are thought to be the first massive structures which formed in the beginning of the universe, half a billion years after big bang. In this data you can see a clustering of the galaxies in certain areas. Astronomers think the reasons why quasars seem to be surrounded by dense clusters of galaxies is because the jets from these early quasars actually played a part in fuelling the formation of galaxies.

The CMB represents the edge of observable universe. When I say observable universe what I mean is there are galaxies and quasars out beyond this boundary it is just that we cannot see them, remember this is real data taken by telescopes and they can only observed the light from galaxies out to a certain distance. Just like when you are in power cut with a candle and can only see things right in front of you.

CMB

End with CMB on sky from movie

Beyond the quasars we have the light from the Cosmic Microwave Background or CMB , this light marks the edge of observable universe. This is not really the edge of the Universe but it is the light from the very beginning of the universe 380,000 years after the Big Bang when electron and protons started to form into hydrogen atoms...and we can’t see the light from back any further than this

The CMB fills the universe almost uniformly. It may not look like it from this image of the CMB but Astronomers say that the CMB shows us that the Universe is Isotropic and Homogeneous Isotropric means the same in all directions, and Homogeneous means the universe will look the same from whatever position you stand in.

The CMB is at a temperature of 3 degrees above absolute zero(or 3K)

And has a wavelength between the mm-cm regime, which is comparable to radio and TV Wavelengths.

This means you can use your TV to detect radiation from the big bang, if you tune a TV between channels about 1% of the static is from the CMB.

These spots of different colour represent very small fluctuations in the density of the CMB and it is in these most dense regions where galaxies would have formed.

END

Take questions outside of dome for 5 mins….

First Planetarium show at INTECH

My first planetarium show at INTECHs massive planetarium in Winchester was a lot of fun, and also a little scary. I am used to doing shows for 30 students in a small blow up, travelling, planetarium but a show for over a 100 people wearing a microphone is another thing.

The planetarium show was written in collaboration with the planetarium manager Jenny Shipway to compliment Dr Phil Uttley's talk on Black Holes. During 18-22nd July 2011 many astronomers descended on Winchester for the Black Holes Astrophysics:Tales of power and destruction conference.

The script I wrote for the Black Hole planetarium show is below:

1. Hello my name is Sadie Jones and I am just finishing my postgraduate studies at the University of Southampton at the moment, my research is on a specific super massive black hole at the centre of a spiral galaxy much like our own milky way, but this galaxy has an active centre, which features jets. Jenny and I are going to give you a 30minute planetarium show, which should introduce you to the locations of some of the black holes within our universe.

      2. I will start by teaching you how to find the North Star. Here is the plough or the big dipper, I think it looks more like a saucepan, which is a small grouping of stars within a larger grouping of stars called a constellation. The constellation which the saucepan is in is called Ursa Major which means Great Bear, using the 2 stars at the end of the saucepan and taking the space between them as a ruler, count about 5 steps in the direction of the ruler and here you will find Polaris, the north star. This star is interesting because it just happens to be above the north pole so as the earth is spinning us around it appears as all the other stars circle around the North star yet it stays in the same position. Have you ever noticed that the stars rises in the east and sets in the west as the night goes on ? Of course the sun does this too.

      3. However, there are some stars that do not set and can be seen any time of the year above England provided there are clear skies. The great bear group of stars is an example of a group of stars which never set and this is where my favourite black hole is. It is called we called NGC4051 and lives at the centre of a galaxy Phil and I have done a lot of research on this galaxy, this is in the rump of the Great Bear, and we will talk more about this active galaxy later.

4.     Before I point out any other black holes in the night sky I am going to ask Jenny to move us around from our current position facing North, to another group of stars in the South. These grouping of stars are called the summer triangle, this is because they unlike the great bear constellation they do set, which means they can only be seen in the autumn and summer.

5.     Summer triangle, this asterism joins three of the brightest stars which can be seen in the summer, with one in constellation of Cygnus, and the others in Lyra and Aquila. One of the black holes I will talk to you about shortly , actually exists within our own galaxy the Milky Way and its location as seen from our place on earth is here, in the centre of the body of the swan group of stars , called Cygnus.

6.     Next we are going to Virgo. There are two black holes in this constellation which I will tell you about, and one is in the bowl of Virgo . Here there is a massive cluster of galaxies.

7.     Hopefully from listening to Phil’s talk you will remember that there is actually a black hole at the centre of our galaxy the Milky Way and the location of the centre of our galaxy is in the grouping of stars called Sagittarius. We know there is a super massive black hole there because as you might remember from Phil’s talk, astronomers have tracked the paths of stars moving around a very heavy object. From estimating the speeds of these stars around the object they can estimate how heavy it is. The faster the star is moving stronger the force needed to keep it in place, which means the weight of the object being orbited will be heavier. From measuring the speeds of 6 stars around this invisible heavy object astronomers estimate the weight of the black hole to be about 4 million times as heavy as our sun. And our sun is equivalent to a trillion trillion 2000kg elephants.

The orbits of 6 stars around the black hole at the centre of the milky way

8. Now the Milky Way, the galaxy we are in can be seen earth as plane of dust across the night sky. Because Sagittarius A* is at the centre of our Milky way it makes sense that its location is within the dust and gas of the milky way as we see it as a strip across the sky.

The distance from the centre of the super massive black hole at the centre of the milky way out to its edge is about the same size as the distance from the sun to the orbit of Uranus, now this might not seem very small. But the only object we know which can be so massive, 4 million times as heavy as our sun, in such a small area is a black hole.

9.     Sun So now I’ve told you the locations of the black holes we are going to visit I am going to ask Jenny to fly us out wards from a place on Earth into our solar system. First we see our nearest star which of course is the sun, and we can see the orbits of all the planets out to Neptune.

So what do you think would happen if I was to replace the sun with a BH the same size as the sun??(Phil discussed this in his talk by imagining the Earth becoming a BH?? Yes! you are right! As long as the planets don’t get within a certain distance of the sun ( which is called the event horizon and for the sun is 3km ) They will still orbit just the same as they do when the sun is there,  they will not get sucked into the black hole. Because this bh has the same mass as the sun it means the planets orbiting it will behave exactly the same. Beyond the 3km event horizon all the laws of physics breaks down.  From phils talk you have learned small black holes do exist. When I say small black holes, they are only small in comparison with the super massive black holes at the centre of galaxies! These small black holes are usually about 10 times as heavy as our sun, these actually exist within our galaxy and survive by sucking material off nearby stars, we say they are in binary systems because there are two objects, the star and the black hole. Now we are going to fly to one of the most famous binary black holes which is called Cygnus X-1 and like I mentioned earlier this is in the grouping of stars which looks like a swan as seen from earth.

10. Cygnus-X1   was the first source discovered using X-ray telescopes which was widely accepted to be a black hole and it remains one of the most studied objects by astronomers . It is now estimated to have a mass about 9 times the mass of the Sun and has been shown to be too be to dense to be any known object other than  a black hole. The radius of its event horizon is probably about 26 km. It’s known as a High Mass X-ray Binary system by astronomers. It was once two stars but the one star which was probably more than 10 times heavier than the other star could no longer carry out the process of fusion in its core so it would have swollen up into a red supergiant and then died in a supernova explosion, these explosion occur at the end of the life of star and if the star is big enough will leave a dense core which will either become a neutron star or a black hole!  As you can see the one star which is called a blue supergiant is orbiting this black hole. When material falls onto the black hole it releases large amounts of energy as jets which we can detect with our X-rays observatories in space.  There are many of these binary black hole systems in our Milky way and It is interesting that the combined mass in these black hole binary systems may actually add up to more than the super massive BH at the centre of our Milky Way galaxy, however, it is difficult to be sure of this since we can only see the black holes which are actively eating stuff.

11. Fly out to Milky Way, as we Fly out of our galaxy, you can see that the red lines which link the groupings of stars are not all at the same distances, they are just in the same region of sky as viewed from earth. The Sun is just one of 100 billion stars in our galaxy and this galaxy is just one of 100 billion galaxies in our universe, and our sun is orbiting around the centre of the Milky Way. It takes us 230 million years to orbit the centre of the galaxy once, and you can see the orbit of our sun around the centre of the MW is very circular. As I explained earlier the milky way has a super massive black hole at the centre of it , but we are not getting sucked down it as you might imagine, you can see from the orbit of the sun around the BH that we are just merrily orbiting around the centre, just as the earth merrily orbits around the sun.

M87 in the X-ray, radio and optical

12. M87 Now we are going to fly out into the universe from our galaxy to look at another galaxy, this is called M87- and is one of the galaxies in a large cluster of galaxies in the constellation of Virgo which I pointed out earlier, this cluster of galaxies is called the Virgo Cluster and you can see the galaxy is within this large bubble which marks the high density clustering of galaxies in this area. This is also a galaxy with a SMBH at centre but it is not a quiet BH like the BH in the Milky Way, it is very active and it has massive jets which are very powerful. You may think it looks more like a star than a galaxy, but it is a galaxy, it just has a  different shape to our milky way which is spiral galaxy, this galaxy is called an elliptical galaxy since it is a lot more rounded the stars are not in a disk like MW, but a sphere . It has jets like Cygnus X-1 but these are a lot more powerful and result from the black hole eating a lot more fuel. You can actually see this jet using optical telescopes, our eyes detect optical light so this means if you were flying about in the universe your eyes which also detect optical could see this massive jet. This means that the Particles released by the jets from black holes are actually going into your eye, so your eye in a way is interacting with a black hole. The jet from the black hole in this elliptical galaxy actually extends out 5,000 light years which is about the same as the typical distance between galaxies.

The beautiful and lovely bain of my life, NGC 4051

13. NGC 4051 –So now we are going to fly from the M87 in the virgo cluster to mine and phil’s favourite black hole. As we fly out ever dot in the planetarium is no longer a star but a  galaxy . This black hole called NGC 4051 is also at the centre of a galaxy,  its actually within a spiral galaxy much like our own. It looks like our milky way and is about the same size as the milky way, but this one is important, because even though it looks alot like our own MW, it is actually eating alot more fuel which means the centre of the galaxy is very bright. Astronomers call these galaxies active galaxies and some active galaxies have jets which are launched from the black hole at the centre. Phil and I have done a lot of research on this galaxy looking at both the material falling into the BH and the particles emitted by the jets of the radiation which astronomers believe are launched from close to the BH. My research has been into understanding why this galaxy has jets and the relationship between the jets and the material falling into the black hole. The jets in NGC4051 are not nearly as powerful or as far reaching as the jet from M87 I showed you earlier. Astronomers still don’t really understand why some black holes have jets of particles coming out of them, and a lot of work at the Uni of Soton is on trying to understand these jets…Just to remind you if you are looking from earth this active galaxy called NGC 4051  was in the grouping of stars called the great bear.

14. So far I have talked about spiral galaxies and elliptical galaxies both which have super massive black holes at the centre of them, and I have also shown you an example of  the smaller binary black holes exist within our own galaxy.

15. 3c273 – Now I will ask Jenny to Fly out to Quasars. Quasars are the most powerful type of black hole and they are the first large structures which formed at the beginning of the universe. Each marker here is actually real data , which is why there is a big gap in this data. It doesn’t mean there aren’t galaxies there; we just haven’t looked there yet. Now 3c273 is actually the first discovered quasar, the reason it was discovered first is because one of the two powerful jets launched from the black hole is beamed directly toward Earth !! This makes the quasar very bright and easily detectable by X-ray observatories in space.  3c273 is 187 million times the mass of the sun and is one of the most distant objects which can be seen with your telescope.

16. These Quasars are thought to be the first massive structures which formed in the beginning of the universe, half a billion years after big bang. In this data you can see a clustering of the galaxies in certain areas. Astronomers think the reasons why quasars seem to be surrounded by dense clusters of galaxies is because the jets from these early quasars actually played a part in fuelling the formation of galaxies. The massive Jets from galaxies like M87 and 3c273 are so far reaching that they can actually reach into nearby galaxies.  Astronomers think that these jets can affect the surrounding galaxy giving the surrounding galaxies more energy. This might mean that idea that black holes are monsters is wrong; they actually might be responsible for the formation of galaxies like our own. And of course without the galaxy there is no solar system and without the solar system no place for us to live!

17. (When out at 1.3Gpc distance) the light left these galaxies about 5 billion years ago when the earth was formed. Now we are going to fly out even further to the quasars at the edge of observable universe. When I say observable universe what I mean is there are galaxies  and quasars out beyond this boundary it is just that we cannot see them, remember this is real data taken by telescopes and they can only observed the light from galaxies out to a certain distance. Just like when you are in power cut with a candle and can only see things right in front of you.

The CMB !

18. Beyond the quasars we have the light from the Cosmic Microwave Background, this light marks the edge of observable universe. This is not really the edge of the Universe but it is the light from the very beginning of the universe 380,000 years after the Big Bang when electron and protons started to form into hydrogen atoms...and we can’t see the light from back any further than this.

19. Ok now we are going to Fly back home to our Earth. Back through the quasars, and the galaxies, into the milky way and our own solar system and now here . Home sweet Home.

20. Hope you enjoyed this introduction to the black holes in our Universe. Thank you very much for listening...

Life Cycle of Stars - Planetarium GCSE script

This blog is an extended version of the script made for the first ever use of the inflatable planetarium  ...oooh exciting :)

This first show is based loosely on the Life Cycle of Stars...aimed at students studying GCSE  Physics and GCSE Astronomy. If the kids are younger than GCSE or below, nicer to start with Planets and Ecliptic and star signs stuff, detailed in Optional Start, leaving out more complex stuff on Neutron Stars and Black Holes.

Stellarium commands are in blue

Red notes are optional facts to add, and depend on age of audience and time.

The talk should take 20-30 mins depending on how much science/mythology you elaborate on. Suggest that it is nice to do this show condensed into 20 mins at the end of We are Astronomers… to give a 40-45minute show.

Me with the dome :)

From blue young stars to black hole death

Optional easing-in start

Do this if audience have no real knowledge of the stars and planets - best starting point for younger kids, if GCSE probably not needed can jump straight in at Finding North, but check!

In stellarium start with sky as it is with sun (a for atmosphere) and ground, g. and at current time  8 .

Ask ‘Can we see any stars in the night sky?’

 Expect responses such as ‘Only the Sun, no because it’s too bright’-

Ask  ‘so why can’t we see the other stars in the day?’ -

Get response cos our star the sun, too bright, light bounces off atmosphere, stops us seeing the other stars. Mention the light pollution in cities bouncing off the inner atmosphere stopping us seeing stars even at Night!

Speed up time and see sun moving across the sky, ask why the sun is moving?

Explain that sun is not actually moving it’s us that is moving about on our axis and this makes the sun appear to rise in the East and set in the West. Normal time rate Get to some time tonight , about 9pm by speeding up, then switch to Normal time.

Turn the sun off (a) and the planets and ecliptic on < , >.

Explain what the ecliptic is (all the planets in our solar system are in the same plane so as we look out at them they all seem to follow the same path on the sky, (red curved line in stellarium) Point out the planets they should be able to see tonight.

Turn on the constellation pictures of all the stars signs (c – constellations v – names  r - art ). Explain that a constellation is a grouping of stars made by the ancient greeks they used them to navigate and made up stories about different constellations.   You will notice that all the zodiac constellations, ie. Star signs lie along this line called the ecliptic. These star signs divide the ecliptic up into 12 equal zones, which is why they are 12 of them.  (Leave constellations on but pictures off! r)

From here can either start explaining how to find North and follow show from there , or (Cut out north and Cass and Andromeda )

Go straight into Orion and start talking about life cycle of stars just within Orion.

Finding North

Big Dipper to Cassiopeia

Starting with Big dipper, which is an asterism, part of the constellation ursa major, which means the Great Bear.  And Ursa Minor, which means small bear. The lowest too stars in the saucepan point to North Star.

It looks like a saucepan, with a handle and a place to put your beans, counting from the 2 stars at the end of the pan, count in a straight line about 5/6 steps (at a step distance of the gap between those 2 stars). There you will find Polaris aka the North star.  Many people think North Star is the brightest in the sky! It isn’t! it is only important because it is directly above the North Pole, and stays above the north pole as the earth spins on its axis causing all the other stars to spin around! Think about spinning top (from Christmas cracker) the top part, which you spin around with your fingers, doesn’t appear to move while the sides of the top are whizzing around. The middle of the top represents the North Pole with the North Star is right above it. Make sure they realise none of the stars actually move, and it’s us that are moving?

(speed up time L in Stellarium so they can see stars going around in arcs)
Mentioned Axis of Earth ( if time mention Southern Hemisphere doesn’t have a star above south pole :( They use Southern Cross and point to an area which is above/below the South Pole)

Circumpolar stars -Cassopeia to Andromeda

Make sure can see both Cass and big dipper

Ask ‘what is a constellation? ‘     Explain these are 48 constellations in total.

Turn on constellation art press ‘r’ key

Patterns of stars in sky, imagine the ancient Greeks without TVs very bored so used to join the stars together like a dot to dot, Mention that the Saucepan/Big Dipper is an Asterism not constellation, as it is part of the great bear. Turn off constellation art  r

Circumpolar stars

Explain that the constellations of Cassiopeia and Andromeda and Ursa Major etc are Circumpolar constellations and never set.

Cassiopeia

Cass looks like a W or an M for McDonalds, find her from the Big Dipper by drawing a line through North Star. Cass is a queen married to King Cepheus (he is in sky near by looks like a house drawn by a child). Andromeda is Cass’s daughter.

Andromeda

Locate Andromeda.. go along same line from Polaris, to Cass, and thru to Andromeda.. (Search Fn-F3 for M31, and zoom in using / in stellarium)

When in Andromeda constellation, say it is our nearest spiral galaxy Andromeda (in local group.) Andromeda looks a lot like our own galaxy and you can imagine if you were flying in space outside our Milky Way it would like very similar to Andromeda.

Mention that Andromeda is actually alot bigger than the Milky Way, has many more stars!, make sure they know the Milky Way is our galaxy! Say that the light from Andromeda is actually blue shifted! Ask if they know what this mean? So MW and Andromeda are actually moving toward each other in space, attracted to each other by gravitational forces due to their large masses, in 4.5 billion years they will collide making a much larger galaxy.

Milky Way (MW)

Make sure they know MW is our galaxy, talk about the reason for the name, i.e. the ancient Greeks thought it looked like someone had spilt milk across the sky. Spiral arms are dust and gas that is orbiting a supermassive black hole which exists at the centre of all galaxies. We are in Orion arm of our galaxy. (Leads into talking about Orion, then can miss out Andromeda and Cass story if not much time)

Can mention other satellite galaxies, LMC and SMC.

Andromeda-Cassiopeia story

Cassiopeia

(only do this story if have time!, best for Year 8 and below.)

If you have seen the recent film Clash of the Titans you will know this story already, but you might not know how it relates to the stars…

Put on constellation art r , Make sure all people in story are in sky and point to them with laser

Cass Queen and Mother and daughter Andromeda were both very beautiful but Cassiopeia committed a 'sin' in the eyes of the Greek gods, by saying that herself and her daughter were even more beautiful than the sea nymphs. This made Poseidon, god of the sea really mad so he struck the water with his Trident and flooded the lands, calling up the sea monster, Cetus, to destroy the kingdom. Cepheus her husband the King, was scared for his kingdom so he asked an oracle how he could save the kingdom and she said "you will you have to sacrifice your daughter to the sea monster to save it"...

So he decided he would sacrifice his daughter, so Andromeda was chained to a rock with the sea monster sent on her. Luckily Perseus who was very strong and handsome decided he would save Andromeda so he flew to her on Pegasus and said, "Hey I'll kill the monster if become my wife" so of course she did, since he was handsome, and there was the fact she was just about to face certain death. However, the story doesn’t end here though, because the people of the kingdom were not happy that Perseus and Andromeda were together, one person with a problem with this was a former lover of Andromeda, he set 200 hundred warriors to attack the couple (and her mother was involved in organising this, also, you can see from this story that Andromeda parents weren’t really very nice, her mother especially evil). Luckily Perseus had the head of the Medusa which he used to wear on his belt (handy!) and anytime you look into the eyes of Medusa she will turn you all to stone, so he was able to turn them all to stone by angling her head at the 200 warriors. The Gods flung Cassopeia into heavens as punishment for causing all this to happen for being so vain. She sits on her throne the W in the sky and as we learned earlier she is circumpolar goes from M to W she is being banged on her head (with her skirts flying up over her with each revolution)...And Perseus and Andromeda lived happily ever after! Turn off constellation art r 

Milky Way to Orion

Orion the hunter

From Cass through Perseus to Auriga then Orion, or Search for Orion Fn-F3 M43, 

Orion

The constellations we see depend on the time of year. Because the aswell as the earth is spinning around on its axis , which gives us day and night, the earth is moving along its orbit around the Sun, this gives us seasons and also means we are looking into different parts of the sky during the course of the year. The constellation Orion is a Winter Constellation, and is very famous because of the 3 stars which make up orions belt.

Point out 3 stars and then turn on constellation art, explain about him being a hunter, shape of his body then turn off.

Orions belt 
3 stars these are young blue stars, baby stars if you will. Introduce Betelgeuse on the shoulder. Ask which stars are hottest type of stars or coldest?

Zoom in / Search Fn-F3 M43 Orion Nebula, Talk about stars being born out of dust and gas. In Orions sword. Star forming region nursery. Like Orion is pregnant. Tell them about the different colours recap, blue, young star, yellow, teenage star, red giant star dieing... then finally death brings...large explosion...BOOM! Our Sun, is considered to be a low mass gently throw outerlayers out in a planetary nebula, burned out core that remains is a White Dwarf.

High mass stars like Betelgeuse which I will talk about in a moment, end their lives by , powerful supernovae explosions which can be as lumionous as an entire galaxy of stars! These Supernovae throw out particles called neutrinos, and leave behind a Neutron Star or a Black Hole. (If kids old enough mention that if Star was bigger than 1.4 times the Mass of sun NS if bigger than 3 times the size of sun BH.)

Heavy elements formed inside star are now enriching space, recycling,

new stars are born from this. We are all made from the elements formed in stars :)*****

This Image shows the full cycle of the stars life.

For example the process of Fusion combines H to He then to Oxygen then to Carbon, and us Humans are known as Carbon based life forms.

Betelgeuse –arabic for armpit of the central one.

This super giant star has been in news recently because astronomers think it might blow up or go supernovae very soon (in fact it may have already blown up). This is red star, which is cooling down because it is coming to the end of its life. Our star the Sun is in the stable phase of its life. If we think of the new born stars (protostars) as mainly made of H where the process of Fusion hasn’t started. The sun has been Fusing it H into He steadily for 4.5Billion years, this steady phase is called the main sequence, and it will be another 4.5 billion years before it runs out of all its H and swells up into Red giant star. When the sun ends its life it is not big enough to cause a supernova explosion it will just leave a small star called a white dwarf.

Betelgeuse is a supergiant red star about 500 light years away - that means it would take the light from Betelgeuse 500 years to reach us on earth. So when astronomers are looking at B they are actually seeing the star in the past, as it was 500 years ago. This is why it is difficult to tell if has blown up.  Now nothing can travel as fast as light, for example the Sun is 8 light minutes away from us. This means light from the sun takes 8 mins to reach us. So even if for some reason the sun suddenly stopped emitting light to us, it would be 8 minutes before we would know about it.

B is so big if you placed it into our solar system in the place of the sun it would extend out past Mars and the asteroid belt and into the orbit of Jupiter. The reason why it is so big that it has run out of H and can’t fuse atoms together. This means the forces on the star are no longer balanced which is why the outer layers start to swell outwards and eventually it will go boom! When it does go ‘boom’ even though it is over 500 light years away it will be very bright, we may even be able to see it for several weeks in the daytime. However, do not fear if it does go supernovae within our lifetime (could go bang tomorrow could be the next million years) it won’t affect us, apart from the firework show.

For kids older than Year 9 can say astronomers call the young blue stars, O stars these are 33,000 K, hottest, and the coldest, M stars, red 3,700K (say degrees), compare this with the temperature of the sun 6,000K.  Can also explain light year, 6trillion miles! (6 with12 zeros which is a distance equivalent to 240 million times the circumference of Earth.

Sun

When our sun becomes a red giant star in about 8 billion years from now it will actually swell up so big it will knock us out of orbit.

Crab 

The Crab, and the Neutron Star at the centre

Try not to repeat stuff, which is talked about for Betelgeuse with the Crab Go to Taurus, NW of Orion, Search for Fn F3 M1 / zoom in then back out\, on one of horns of the Bull, Taurus.

Link with B if talked about it, explain that this is the Crab nebula, star that went supernovae in 1054 and the Chinese saw it first. Now even though it is 6,500 lyrs away (about a 100 times further than B), it was brightest thing in the sky except for moon, so this just shows you how bright these explosions are when massive stars die! It got its name, the Crab, because it has these extended filaments make it look like a crab? see if you agree in photo later...if doing photos.

The Crab Nebula, has exploded and left a very dense type of star at its centre, called a Neutron star. These stars are extremely dense, Ask if they know what dense means?

Give example that a NS the mass of our sun would be the size of a city like Southampton.

Or another way of thinking of it, one tablespoon of material from a NS would have the same weight as Everest. Neutron star held up by neutrons only, everything else has been squashed out by the strong gravitational forces acting on the star, which act due to its great mass. In order to escape from the surface of a NS you would have to travel at 1/2 the speed of light, which is equivalent to about 300Million miles an hour! Pulsars are an example of a spinning neutron star, which is spinning due to the conservation of the angular momentum of the original star.

Make sure zoomed out \ and can see all of Taurus….

Pleiades are the most famous star cluster in the night of sky and the Greeks said this cluster was like the ‘fleas on the back of Taurus’

These are bright white/blue stars called then seven sisters; you may have seen these on the badge of the Car, Subaru. The native Indians used these as an ancient eye test. If you could see maybe 6-9 by the naked eye you could become a hunter, but if you can only se about 3 or 4 you had to be a farmer. This doesn’t apply if you are looking from Soton because of light pollution from the city you will be lucky to see Taurus, never mind the Pleiades. This cluster actually has hundreds of stars, which are gravitationally bound to each other. Zoom in to see Pleiades / by searching for it. FnF3

Can zoom back out and speed up time L, to see Orion chasing Taurus across sky he is a hunter after all.

Sirius

Orion's belt - follow to Sirius

Line drawn from Orion’s belt to Sirius

, point out with laser , Talking about different stars, leads on to asking if ‘Anyone know what the brightest star in the sky is?’

Sirius, which is Greek for ‘glowing or scorching’ is an example of a massive young white star and also that this is the brightest star in the sky and is on the eye

Zoom in to /collar of Orion’s dog.

Ask ‘why is it so bright?’-

Hopefully they will say because it’s close by, yes it is only 8.7 light years away which when you compare it with Betelgeuse its very close, another reason why it is so bright is because it is actually 2 stars in what astronomers call a binary system, the one star is size of sun, and other is twice size of sun.

Black hole M87

Navigate from Crab in Taurus to Virgo or, Search Fn-F3 M87 (back to ursa major/big dipper, thru Bootes, and then Virgo is there) Zoom / see elliptical galaxy

M87 is an example of a black hole. Black holes are either formed at the end of the life of a star and these small black holes can exist within our galaxy, the MW and have masses about 10 times that of the sun, other supermassive black holes like M87 are 1000, million times that of the sun!! These are thought to be formed in the beginning of the Universe when large galaxies were merging together (M87 is at the centre of an elliptical galaxy Jet goes out 5,000 light years, which is astounding when you think that about as far as we are from the Crab Nebula.). For a collapsed or dead star with a mass of about 8 suns where there is such extreme gravity between the remaining mass, that even the neutrons can hold up the star, and these neutrons get squashed out, making a hole in space time. Ask ‘What speed do you need to travel to escape from a black hole?’- Hopefully answer is speed of light, which is equivalent to a speed of 600 million miles an hour! Go onto explain this is why we can’t see black holes. Astronomers (as shown in We are astronomers) use the EM Spectrum to look at the light from stars, be it the gamma rays, X-rays or visible light that we can detect with our eyes. Black holes suck in all those different types of light, so the only way astronomers know they are these is by measuring the speed of objects which are orbiting them, or looking for high energy X-rays being given off by material falling into the black hole.

Compare with our Sun as a BH.

If you replaced our own Sun with a black hole of the same mass, the planets etc would all still orbit around in the same way, we wouldn’t get sucked in, the only time you get sucked in is when you get too close.

Now it might shock you to know that our Solar System is orbiting in our galaxy around a

Supermassive black hole

These supermassive BH were predicted by Einstein’s theory of general relativity. They exist at the centre of all galaxies, a million times that of sun. The BH in our MW is actually 4 million times mass of sun! Ask ‘how do you think astronomers know the mass? Cos they can’t just weigh it with a scales?’ Using Keplers Third Law, equation which relates the speed of orbits stars to the mass of the thing they are orbiting, exactly how we measure the mass of the Sun.

Astronomer measured high speeds of stars orbiting around an object known as Sagittarius A* which is at the centre of our galaxy the MW. Can zoom / into Sagittarius A*/ search for Sagittarius using Fn-F3. Can’t see much there, turn off the constellations , c and search fnF3 for M25 this is a near by cluster of stars explain that at the centre of our galaxy astronomers measure the speeds and orbits of stars just like that’s how they know there is a supermassive black hole there!

Ending thought about black holes.

Most people think of black holes as monsters but Astronomers now think they play a large part in the early formation of galaxies. As we learn more about how galaxies were formed in early universe it seems that the BH at the centre plays a large part in forming galaxies, remember that the jet from the centre of the galaxy can reach into other galaxies, these jets of particles might start star formation to occur in galaxies where it might otherwise not have occurred. This means that without our blackholes the universe might of not formed galaxies. And without galaxies there wouldn’t be stars, without the stars, no solar systems of planets and with out planets, no humans, so black holes may not something to be afraid of.

Pictures to show at end of show

First explain Messier looking for his fuzzy blobs.....why alot of items we talked about have M numbers, i.e. M1 and M87.

Andromeda & Milky Way- spiral galaxy, milky way from earth see LMC and SMC

Planetary Nebula - what will happen to Earth.

Supernovae! Crab with NS at centre, nice chandra Xray image

video by nasa at http://en.wikipedia.org/wiki/Crab_Nebula

can we warp this and show them at the end?

Red giant (Betelgeuse ?)

M87, cool pics http://en.wikipedia.org/wiki/Messier_87

Pleides

White dwarf

Orion - different coloured stars.