Sunday, 24 July 2011

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...

Saturday, 18 June 2011

The alternative history of Radio Astronomy

I wrote this history for my thesis but apparently it's 'too colloquial' and 'not relevant' - so this is the edited version, which I've made more colloquial and crazy times...(Papers you may want to read, if you are that way inclined are in  curly {} brackets, just go on arXiv astro-ph and you should find them).

Below is a piccy of me standing on one of the radio antenna at the Very Large Array, just cos that's the kind of rock and roll thing I do generally.

Standing on a Very Large Array Antennae

I start this story of radio astronomy with James Clerk Maxwell in 1873. Maxwell had prooven that visible light was not the only type of electromagnetic radiation, and that actually there was a wide spread of wavelengths either side of the optical spectrum. Inspired by these findings Heinrich Hertz set out to both create and detect electromagnetic radiation, in particular the longer wavelength radio waves {Smith74}. Hertz' work on electromagnetic radiation was held in high regard, resulting in the unit of frequency (Hertz, abbreviated to Hz; equal to one wavelength per second) being named after him. In 1887 Hertz succesfully discovered radio waves; but he was a modest man was Mr Hertz, oh yes,  he did not predict any use for this long wavelengths of radiation that our eyes could not detect. Luckily Guiglielmo Marconi was not as short-sighted and set about to use the radio waves to transmit signals across large distances.

 While Marconi was trying to sending signals across the Earth the likes of Thomas Edison and Sir Oliver Lodge started an attempt to detect radio waves from the Sun. As you do! However, no solar radiation was detected since the detectors available at the time were not sensitive enough and the experiments were actually set up to detect the wavelengths of radio emission which are intercepted by our ionosphere. Bit silly, but hindsight is a wonderful thing...

The birth of radio astronomy finally came in 1932 when Karl Jansky detected radio waves from space while carrying out intereference experiments for Bell laboratories. Jansky was able to determine three possible sources of intereference for communication systems: local thunderstorms, distant thunderstorms and a mysterious signal that occured 4 minutes later every day. The fact that the mysterious signal was coming from a certain direction in space which was fixed relative to the stars, but not fixed with respect to the Earth or Sun allowed him to identify its position as the centre of our galaxy, the Milky Way {Jansky33}.  So what is this mysterious-ness at the centre of our galaxy huh?? This achievement led to the unit of flux density (Jansky, abbreviated to Jy) being named after him.

Further developments in radio astronomy were hindered by the Second World War. However, amateur radio astronomer Grote Reber had been inspired by Jansky's work and took on the challenge of building his own steerable parabolic reflector dish, 30 feet in diameter. As you do!

With his device he was able to map the radio sky and show the startling differences between the optical and radio sky for the first time {Smith74}. Reber published his work in 1940 and 1942 and at the end of the war astronomers collected these findings together with the radar research of scientists such as James Hey. Hey and many other scientists had been employed by the military to improve radar and communications. Hey and his colleagues reported on the efficieny of army radar equipment and investigated reports of jamming by enemy transmitters. These reports led to findings that active sun spots emit radio waves in the metre wavelength region and were later followed up by radio observatories in Sydney and Cambridge. Hey also discovered that meteors leave trails of ionisation in the upper atmosphere which reflect radio waves and that a fluctuating signal coming from Cygnus was a result of the terrestrial atmosphere and that the source itself trasmits steady radiation. Later in 1944, van de Hulst calculated the wavelength of the hyper fine hydrogen spin-flip transition and found that it lay at 21cm, which lies in the radio regime. Astronomers were then able to use radio techniques to trace the motion of this hydrogen gas and map the spiral arms of the Milky Way. Our Earth, orbits the sun in the Orion arm of the Milky Way, and our sun is just one of over 400 billion stars in our galaxy......
The Milky Way

The earlier discoveries acted to catalyse the science of radio astronomy and as radio detectors improved there came the discovery of the cosmic microwave background and pulsars.

In 1965 Penzias and Wilson were studying radio emission from the Milky Way and found a source of noise they could not explain. At first they thought it had something to do with birds poohing on their reciever, so they cleaned it but the noise was still there. Then they realised the noise source wasn't even coming from our galaxy.... This background noise eminated from outside our galaxy with a temperature of 2.7K. Then amazingly, this temperature fitted with an earlier theory that radiation from the Big Bang would have a temperature about 3K. Oh My golly gosh!huh?

Also in the late 60's, Anthony Hewish and Jocelyn Bell working at Cambridge were using a dipole array of 128 elements and found a signal of regular radio pulses due to beamed radiation from strongly magnetised neutron stars {Hewish68}, they had discovered pulsars. At first they thought they had discovered Little Green Men (LGM) aka Aliens, but well they hadn't, nope , just some rapidly rotating neutrons stars...Now you may not think this is that awesome, but it is I can assure you, and when I saw Jocelyn Bell walking down a corridor when I was working in Oxford Uni last Easter, I was very star struck, because here in front of me was the discoverer of pulsars, I mean forget Lady GaGa, this is the real deal as far as inspiring women go, I think!! (Controversely she didn't get the Nobel prize for discovering pulsars, her supervisor did..but hmmm i shan't comment on that). By the 1970's several radio interferometers had been built in an effort to improve the resolution of radio imagery, this now means we can see deep into the centre of active galaxies and resolve jets of material which emerge from the supermassive black hole at the centre.

My thesis is basically based on Very Large Array (VLA) data of an active spiral galaxy (looks a bit like our Milky Way but with a bright 'active' centre, maybe some jets from centre) , which is why there is a picture of me standing on it (the VLA that is, not the active galaxy). But also you should be aware that the VLA is an example of one of these early interferometers which has been around since the 60's. It might also interest you to know that "AIPS" which is the program used to reduce radio images (usually by foolish PhD students who probably niaevely chose radio astronomy ) is based in FORTRAN, which is a rather old programming language (from the 60's)...however, please don't let me mislead you because if you love FORTRAN and can code FORTRAN , that by no means suggests you can use AIPS with ease....Banana Banana. 

Although I may sound pessimistic about my own radio astronomy research I would like to make you aware that at the moment radio astronomy is thriving. What I mean is alot of new and exciting interferometers are being built, and with the building of new devices comes the need for researchers to look at all the masses of data they create, i.e. this means alot of jobs have been recently created in radio astronomy, which is good. LOFAR which is currently the worlds largest telescope (never mind radio telescope) is currently expanding, with antenna based all over the world. And in 2012 they might decide where the SKA will be built, this will be an awesomely sensitive radio interferometer, with very good resolution also.. basically the future is radio bright, the future is astronomy.

Meeting Sir Patrick Moore

Sir Patrick Moore & Me, at his garden party.
I was lucky enough to attend a garden party at Sir Patrick Moores house, a few weekends ago :). The party was a fundraising event to send students from an afterschool science STEMclub at Cantell Maths and Computing College in Southampton  to NASA in the US of A. It was a great success the weather was lovely and Sir Patrick seemed rather cheerful. He wished me luck with my PhD which I thought was amazingly cool, and alot of money was raised, so hopefully the kids will have no problem getting to NASA. I have been lucky enough to go to the Kennedy Space centre myself a few years ago, it really was awesome. Discovery was on the launchpad when I was there :) Didnt see the launch though, I did however see alot of crocodiles at the centre, which was un-expected, and I have told the STEM kids this and hopefully they will be weary of them crocs. (If Steve Irwin has taught me nothing else, it is that crocs are to be taken seriously, and very probably feared, anyway I digress...).

I have worked for over 3 years with this Year 9 STEM club. The first 2 projects were on Aliens and life in our universe, this project was great and the end of the project I presented the kids with a gift that allowed them to send their own message into space. The message they decided on was  'Welcome to earth we make nice tea', which I thought was a nice message, and very English, i do hope it was Yorkshire Gold tea we will be giving those aliens mind, as only the best will do..even for none humans.... The most recent project I devised was a galaxy project which involves the students using GalaxyZoo and various worksheets to understand the different types of galaxies which exist. At the end of the project the team present their work to  their classmates, teachers and other academics. The students talk was very good and at the end of the project the students (girls) revealed how their work has made them realise the 'vastness of space', they were shocked at how big the universe is and all the things it is comprised of and , and I assume that now, like me, they consequently feel very insignificant in comparison to the universe.

When offered various science projects,  based on Galaxies, Chemistry of the ISS, exercise bikes that power mobile discos and sound vibration projects do only girls pick the one on Galaxies?

Sunday, 6 March 2011

Launching a creme egg into space

This talk is aimed at GCSE/A-Level students... I wish to expand their knowledge of Weight, Mass and Gravity. Particuarly Newtowns Universal Law of Gravitation.


So..why do I want to launch a creme egg into space firstly?
Well I love creme eggs and recently had to have a rather large tooth out as result of the decay caused by the sweet lovely creme eggs. As I was sat last week watching Discovery, in alot of Discovery made it's final flight to the International Space Station, I came to the revelation, the only way I will stop eating creme eggs is if they are not everywhere, i.e. in bookshops, at tills in Boots, etc, they needed to be removed from Earth so as not to tempt me. The only way that made sense as I watched Discovery shoot into space was to launch the creme eggs into space aswell....

The first thing I need to think about is the Forces that are acting on the creme egg.....and how I can create a force big enough to overpower the force of gravity acting on the egg which is 'forcing' it toward the surface of Earth.

What is gravity?

Gravity is an attractive force between all objects that have mass. This means that two students in a class sat next to each other have an attractive force between them, this doesn't mean they 'fancy' each other it means their mass is causing a gravitational force to act between them. However, this force between two classmates is very small..but for big masses like that of the Earth. We do feel a gravitational force, and this force causes all objects on earth to accelerate toward the surface at 9.8 metres per second.

When you ask your friend their weight, if they don't take you to be very rude, they will most likely answer with a value in Kgs or stone. What they actually give you is their Mass, not their Weight.

Weight is a Force, which like all forces is equivalent to the product of Mass and acceleration.
In the case of a body of mass being acted on by the force of gravity, the gravitational acceleration (g) is equal to 9.8 metres per second...

Why is g=9.8m/s ?

Well the value of g (acceleration of gravity) we all know and love represents an speed increase of about 10 metres per second per second. But why is it 9.8/10 ? where does this value actually come from???

It actually depends on the planet! 
Why? Because the planet is the large mass causing other smaller masses to accelerate toward it....It's the big mass causing the attraction.

So the value of g actually comes from equating Weight (which equals mg) to Newtown's gravitational force. This force depends on G, which is a gravitational constant , the mass of earth which is largest, the mass of the object we are trying to launch into space (or the object falling toward the earth)....divided by the distance between the centre of masses of the two masses...

In the case of the creme egg which we are trying to launch into space the distance (R), in the gravitational force equation is approximately the distance from the centre of the earth to the centre of the creme egg, which we can assume is basically the radius of the earth...

When we substitute all these values into the Newtowns force equation, firstly we notice that the mass of the creme egg cancels out, so the acceleration, g, is the same for all objects accelerating toward earth...10 metres per second squared!!!!

g only.. depends on the mass and radius of the larger mass object

What do we know about the Creme egg ?

How will we launch it?
I am assuming my arm is so strong that I can give the egg enough kinetic energy upwards to over come the force of gravity acting downwards.

Want ke bigger than potential energy, potential energy is energy creme egg would gain from being dropped from a certain height or extended radius from earth.

Think about when your at the top of the hill on your bike, takes alot less energy from your legs to get to the bottom this is cos of the potential energy you gain from working in direction of gravity. When you work against gravity going up hill have to overcome this gravitational force, which requires more kinetic energy from your legs, and will burn more calories... (calories are just a unit of energy).

To launch the creme egg into orbit we want to give it a k.e. energy larger than the potential energy it would have at the height of 'space'.

When you equate the p.e. and the k.e. you notice the m, mass of the creme egg cancels out. You can then re-arrange the equation to make v, the velocity the creme egg needs to escape the gravitational down force of earth and get into 'space'.

Subbing in the values for G, M (mass of earth) and R( radius of earth)... we first notice that the escape velocity is the same for any object, and is independent of the mass of the object, in this case the creme eggs mass....

Therefore if you can get any object to a speed of 11.2km per second.... it should get into space.

Of course, it will be alot harder to get an elephant to that speed than it will to get a creme egg to that speed :).

The speed to escape from Earth's gravity, is called the escape velocity and is 34 times the speed of sound...planes, such as a Boeing 747 travel at 560mph, therefore we need the creme egg to travel 45 times faster than a plane...
....basically, this is going to be a massive challenge.

You will realise that NASA shuttles/rockets like Discovery do not actually travel this fast...
....the escape velocity assume you give the object/creme egg this speed and it continues at this speed through atmosphere, with no loss of speed due to friction....
...... the shuttle has fuel which allows it to accelerate and increase its speed at various points, it also looses mass as it uses up this fuel, which means it does not need to travel at 11.2kms per second. They actually travel about 6,250mph.

So.....if you can give the creme egg enough energy to set it off from the surface of earth at 11.2 km per second (and it doesn't get slowed down by friction) it WILL get into space!!!

But, we are forgetting something. The shuttle is heavily shielded because it heats up going in and out of the layers of the atmosphere....the speed it goes is proportional to the heat encountured.

 Shielding designers actually use the relation that the temperature is approximately 1000 times the velocity... therefore our creme egg will have to withstand a temperature of 11,200 degrees C..... 

It's not looking good for our creme egg getting into orbit is it?

When I gave this talk I offered the creme egg which I was using as a prop to the best question. But no one actually wanted to eat the creme egg, (which I thought was quite rude). So of course I had to eat it........

There's probably a moral to this story some where, so if anyone has any questions or knows what the moral is please do comment below...

the moral of the story?

Anyway! I had some tough questions like , 'what is gravity?'
'what is a force?' 
I am just going to let you ponder on those, as I am not convinced my answers actually helped the people asking them......
.... :S

Suggestions for the future
It has been suggested that I remove alot of the equations from this talk because they are likely to scare GCSE students...I can't remember that far back into my past, but I love equations so I am biased? Thoughts?

Saturday, 12 February 2011

How I ended up as an Astronomer ?

Never underestimate the importance of enthusiastic teachers who love their subject. It was this lack of enthusiasm that lead me away from my dream job at 16. I was very creative and after making my own web page had decided that Art and Computing was where my future would be......

However my art and computing teachers were no where near as excited or enthused as my Physics and Maths teachers were during my GCSE and College studies. Actually I sensed that my computing teacher hated computing and that my art teachers were just jealous that some artists in my class were alot better them. Meanwhile my physics teacher was telling us all these inspiring stories about crazy physicists with gold noses, who fly kites in thunderstorms and get hit on the head with apples etc. So, even though I had aspirations and dreams of becoming an interior designer/artist/fashion designer/graphic designer/web-page designer, I actually ended up liking Physics and Maths more. 

I enjoyed that you could work through your formulas do your calculations and you could be very confident of getting all the marks. This was just the opposite in art where I felt exceptional artists could do amazing pieces of work and the art teachers interpretation of it would be a grade E, where as in my own opnion these great artists deserved a B in the was all a bit "hand wavy"..This is why I feel maths with mechanics/physics thrown in is so awesome. You get a nice sense of achievement when you get your answer out, especially when you know the answer is a real value with physical meaning. for eg. the speed you would have to throw a creme egg to get it to escape the earths atmosphere...... its not just maths, for the sake of maths! 

So....I ended up in Astronomy specifically, as opposed to just Physics..manily because of all the pretty Hubble images of space that were about at the time. This imagery appealled to my creative side, and showed me that Physics and Astronomy was not only beautiful from equations, theory and formula point of view, but also you could see it's beauty. 

The Butterfly Nebula credit: Hubble
Looking at these images allowed my imagination to run a bit wild. The history of astronomy was also rather interesting to me; it taught me that to learn about our environment, some times the answer is far away in space.......Lots of physical laws e.g. gravity were discovered by scientists looking beyond earth, to the planets and out into the galaxy.

Wednesday, 9 February 2011

Black Hole Talk to St Annes

St Annes is a local girls school which is lucky enough to offer GCSE Astronomy to its pupils.

I have given a talk about black holes to a class of approximately 10 students and a teacher on 2 occasions. I gave the talk originally to fit in with the fact they had got to black holes on the syllabus, and I was asked back by the teacher to give the same talk the year after. The second time I gave the talk there were double the number of students (more due to a school show, as opposed to more students taking the GCSE).

As part of the GCSE the students study the electromagnetic spectrum and black holes.

Contents of Talk

I start with how I ended up doing a PhD in Astronomy  (see blog on this subject) . This introduction manily shows the importance of teachers, and also how at the age of about 15/16 you are changing your mind about what you want to do with your life, and what you most like learning about.

My Research is based on black holes using radio and X-ray astronomy. I therefore start most talks especially GCSE with the electromagnetic spectrum (which is on the syllabus I believe). I explain how the radio waves are the longest wavelength radiation, with low energy, and low frequency, and compare to the high frequency X-ray radiation. I then usually talk about radio waves on earth, man made from radio and TV and X-rays for looking at bones etc.

After discussing all about how black holes form, and the types of black hole and the supermassive black hole at the centre of the milkyway. I then go onto my research on a specific supermassive black hole at the centre of a galaxy called NGC 4051.

Optical Image of NGC 4051 (Caltech)

I link my research on the supermassive black holes to those smaller, binary black holes within our own galaxy by showing the students the 'fundamental plane of black holes'. This basically is a plot showing the relationship between the X-ray radiation from the disk around the black hole, and the radio radiation from the jets. The fact that a straight line can be drawn through all black holes big and small in this plot suggests there is a link between the smaller and the supermassive. This is good for astronomers as it means we can look at the near by black holes and scale up what we 'see' and make predictions about the supermassive black holes at the centre of galaxies.

I finish the talk by summarising all about black holes and my research, and why i think it is exciting. I then go on to tell them the kind of jobs available to me/astronomers, specifically in radio astronomy, LOFAR and SKA. Finally I tell them about other jobs Physics students go into, such as finance, teaching, computing etc.

Interesting questions from the students and teacher

Why do we want to know about the X-rays from black holes?

Why should we spend money on astronomy ? is it not better to spend it on things that help people on our earth? rather than worry about things millions of miles away in space?

Ways to improve the talk in the future

At end of the second talk the teacher introduced me to some Carl Sagan music. This might be nice to introduce in the future, and the girls seemed to find it quite funny.

Worm holes, and Relativity

These students also came to a SEPNET event on black holes, worm holes and time travel, which the students asked alot of crazy out there questions, such as various paradox's of general relativity, which I was definetly not aware of at GSCE level- This just shows you should not, not talk about einstein etc just because you did not understand it, and probably still don' is a very though provoking subject for the student.

Wednesday, 26 January 2011

Radio Astronomy & LOFAR Talk at Brookfield School

I gave the talk to an after-school astronomy club, consisting manily of year 9's on an accelerated GCSE program. There were 7 students present and their teacher. The talk was ~45-50minutes long with questions at the end which lasted a further 15 mins. The students also asked many questions during the talk.

Talk Overview 

The talk was mainly about Radio Astronomy in general and why LOFAR is such a new exciting telescope. I begin with why I myself got into astronomy, from my GCSE's, then into the electromagnetic spectrum, explaining that radio has the longest wavelength. 

Talking about radio waves follows into my radio research using the Very Large Array (VLA) telescope in New Mexico, USA . I try to explain how interferometry works. High angular resolution is particularly important for looking at the active galaxies (galaxies with an active centre i.e. jets spurting out from galaxy) because astronomers still don't know how jets work. Seeing deep into the core of the galaxy where the jet is will help astronomers to understand what is happening. I also explain the 2 different types of black holes; supermassive and binary, with a major focus on active supermassive black holes which I study.
M87- Jet in active galaxy- resolution increasing.
From my research where I investigate the relations between X-ray radiation from the disk of active galaxies to Radio from the jets of active galaxies, I go into talking about LOFAR.


LOFAR is a real-time multiple sensor array, specifically designed to detect radio emission below 240MHz. It's a revolutionary device in that utilises electronic beam steering rather than mechanical pointing and uses low-cost dipole antenna instead of as the dish type antennas of the VLA. The base of array is in the Netherlands, and when complete will consist of 36 apeture array stations distributed over an area with a diameter over 100km. Several international stations have been built in UK, Germany, France and Sweden, achieving resolutions of 0.2 arcseconds, with the largest baselines across Europe of the order of 1500 kms.  I was lucky enough to help build many of the Low Band Antenna (LBA) at the LOFAR UK station during June 2010, (see Image below). One of the Key Science goals of LOFAR is the Epoch of Reinoisation which is the time at the beginning of the universe, when it was a few hundred million years old (about a twentieth of its current age) and objects started to form out of the plasma of the Big Bang!

Square Kilometer Array (SKA)

The location of the SKA has been shortlisted to Australia or South Africa with a decision being made in 2012. This array which will create a telescope with a collecting area equivalent to a dish with an area of about one square kilometre and combines three different type of antenna. It will combine high frequency dishes (like the VLA) with low frquency apeture arrays (like LOFAR) to provide continuous frequency coverage from 70 MHz to 10 GHz and will become the world's best imaging and surveying telescope.

Having fun after final LOFAR LBA antenna was finished.

I started the talk at Brookfield by explaining why LOFAR is so different to radio antenna most people are aware of (VLA antenna, dishes). I explained how we built the 96 LBA antenna at the new UK site in Chilbolton, and showed them a video of us making the telescope from YouTube where Professor Bob explains how LOFAR works and about the Epoch of Reionisation. After explaining all about this time in the universe, when the first stars and quasars (black holes) were being created I then tried went on to explain about the Neutral Hydrogen 21cm. It is is this wavelength of Hydrogen which we associate with this time in the universe, but the frequency has been redshifted to low frequencies, below 240MHz and can therefore be detected by LOFAR. 

This led me into explaining Doppler shift and showing spectrum where various atomic lines had suffered red or blue shift, I think this part of the talk went over alot of their heads but some of them seemed to understand quite well.

I finished the talk by explaining spin off in Technology from Radio Astronomy. I think it is important to put these in since we need to show how important it is that science and astronomy are not allowed to stop due to government etc cutting the money...I start with the  invention of wi-fi which earned Australian astronomers 200 million AU Dollars (all of which they are ploughing back into the new square kilometer array, SKA telescope) . I also talked about Satallite Navigation systems, a spin off from Cambridge radio astronomers trying to find accurate postions of their movable antenna with respect to their fixed antenna to carry out radio interfermetry.

Questions and Thoughts
The majority of questions from the students were about black holes and jets. There were some very good questions about how black holes form in the early universe, as opposed to the normal, end of a star life, and a good question about why a galaxy should rotate in a certain way.
There was only one or two questions about the LOFAR antenna which manily related to the lack of moving parts and why there needed to be so many of them. All questions after talk went off onto a tangent about worm holes, time-travel and E=mc2 and what happens when a black hole comes to the end of it's life....very good questions, shows they were thinking alot during the talk...but maybe not thinking so much about radio astronomy :P... I had a good go at answering all these and explained to them that with regards to jets and exploding black holes, astronomers are still preety clueless, so this is why we need intelligent people like them to become astronomers and help us work it all out . Finally just as I was leaving one boy asked me for advice on buying an optical telescope (which I was unable to help with :P).

Suggestions for Future Talks

Happy overall with science content.
Need more science relating to LOFAR (specifically with the UK antenna that has been added)
Obvious interest in black holes, so tie in black holes to LOFAR.
Better explanation of Doppler and Red Shift.
More stuff on black holes relating to sci-fi stuff, time travel etc.

Monday, 17 January 2011

Intech Astronomy Day

I was at Intech on the exhibition floor from 9am till 5pm. Luckily I had my parents there to help set up the display board and to drive me there, both are practical things that I struggle with.... :P

I had 3 LOFAR stands from QMU and a display board from Southampton University, with one of my own research posters (Research using VLA radio antenna in USA), pictures of the build at Chilbolton, pictures of Dame Jocelyn with a LOFAR low band antenna, the "how mobile phones work" poster made by the University of Southampton , a solar poster in 3D (but did not have 3D glasses unfortuntely). 

On the table we had LOFAR, and Uni of Southampton bookmarks, SEPNET postcards and the laser music kit, an ASTRON news brochure, with the current lofar science in and a BBC stargazing brochure. 

One of the LOFAR posters I placed (by my mother) at the entrance with a notice on it to 'see exhibition floor', this was because the amateurs had alot of activities to do on the astronomy day and might not have seen me on the exhibition floor otherwise. I had an actual LOFAR antenna attached to the table.

At Intech there were many members of the general public  manly families and then many amateur astronomers including some amateur radio astronomers.

I talked to approximately 8 members of the general public, and about 15 of the amateur astronomers.

Most of the amateurs only came to talk to me in the 15min breaks in between the various workshops and planetarium shows that were being put on from 10-4.30pm. Alot of them had heard of LOFAR, i.e. seen it on the news when we built it :)

Members of the public were interested since they were suprised, firstly that there was a radio telescope up the road and how simple the radio dipole antenna was, and i talked to them about black holes and my research with radio astronomy and X-rays, and how LOFAR is important for looking at epoch of reionisation. I talked to the younger children about fibre optics and the internet with the laser-music device and mobile phone poster, and linked that in with lofar since they have to send data in real time at 15gb per sec etc. I also told one boy who was interested in astromony ,specifially black holes, how radio astronomy is a good place for jobs at the moment etc, what with LOFAR and SKA.

Alot of the radio astronomy amateurs wanted to know how easily they could make their own antenna and connect them with other amateurs, I told them that the antennas are the cheap part it is the problem of correlating the signals with each other which is the problem , especially if you want to do it in real time etc. Several of them wanted to actually visit the Chilbolton site, etc, so I gave them Rob Fenders at Uni of Sotons name as a contact.

The gentleman who gave a talk on amateur radio astronomy mentioned how easy it was to make your own and gave a link to an amateur website where you can borrow one of their radio antenna and connect directly to a computer and do your own radio astronomy which was very interesting and seemed quite simple to do, the graphs you get out are quite basic but it shows how much of a challenge radio astronomy is..because  you can see radio signals from the trees, the sun (basically everything) due to electrons being accelerated in everything!!!

But ,he stated that since radio astronomy can be done in daylight , or at night when it's cloudy,  he and the other radio amateurs say this is why they chose radio astronomy since the optical astronomers rarely see anything in the UK, because of our fabulous, very cloudy weather.

Me talking to some amateur astronomers

The Stand, with Antenna on the right.

Suggestions for the Future
Get links with the radio amateurs and make own radio telescope, use their ones (Find out where on this site you can access the radio antenna that anyone can use.)

More pictures/posters of actual LOFAR research, and why it is different to other radio telescopes, i.e. Epoch of Reionisation stuff and explaining dipoles themselves; how they work, the multi-user and the whole sky view aspect of LOFAR.

More info about the super computer and the pipelines etc used to get images.

Higher resolution images since the UK station has been added etc.