The Rosetta Mission – This generation’s Moon landings?

The thing everyone seems to talk about with the moon landings is the idea of the whole world stopping to watch. It was a mission that overcame nationalism, it wasn't "America" putting a man on the moon, it was "Us", humankind. With Rosetta, the whole world not only watched but they were part of a real time conversation with mission control. Over the next few months as the scientists analyse the Rosetta data it might tell us many new things about our early solar system. The extremely detailed pictures of the comet are our first look at this strange world. The science data and pictures definitely have a place in inspiring people to become more interested in space/science subjects, but there will always be something incredible (even unbelievable) about humans beings, or robots that humans have engineered, going out into space and actually touching down on worlds beyond our Earth!

Now, I am too young to have personally witnessed the Moon landings, but despite that there has always been something about the subject of space that has totally entranced me. Back in the nineties I personally felt the afterglow of excitement left by moon landings and I am sure they have inspired many of the public young and old to take an interest in science. In fact, I was so inspired during my primary education that when my teacher informed the class that for the last week of term we could do our own project, which could be on any subject, it was our own choice! I chose, what I assumed to be, the most exciting and obvious choice: a project on ‘space’. I remember researching as much as I could find in all the books my school library had to offer on the subject and then writing out my discoveries about the planets, the moon and astronauts onto multi-coloured A4 pages with a pencil, in my neatest handwriting and sticking them together to make a book. I even remember doing an elaborate drawing of an astronaut, which included a cutaway into his astronaut suit so you could see all the tubes inside the suit that helped him breathe and go to the toilet. In fact, I had researched so much information on space that my project workbook was one of the thickest in the class! I really think the buzz surrounding the Rosetta mission will regenerate this excitement and I think it has actually provided us with a greater awareness of possible space/science careers, and now after watching interviews with many of the scientists, engineers and control room operatives it’s not just the astronauts or the landers that are the stars of the show!

All these years later, I work for the University of Southampton doing public outreach for the astronomy department, so space has dominated my career choices. And before I started my current job in communicating science I did a PhD on the subject of black holes. Now, after dedicating four years of my life to one single object, I’m pretty excited to talk about it, and as soon as the students hear that you know about black holes they too get pretty excited and ask many questions! The most common questions I get asked about my black hole research is ‘Has anyone ever been to a black hole?’ or ‘What would happen to me if I fell into one?’ I can tell them about my research on the radiation from the edge of the black hole ‘til I’m blue in the face, but, what I have learned in these past 3 years of trying to communicate astronomy research is that what the students want to know most is not the complex science of these objects but what it would actually be like to go to a black hole and touch it!

The Rosetta mission gave the public an insight into something that was happening right now! They could feel the emotions of every minute and track the spacecraft in real time from wherever they were. They could put themselves in the place of the scientists in the control room, who were nervously waiting for news from Philae, they even had up to date information on what little Philae was ‘feeling’ as he descended to the comet surface. They could see that the scientists and engineers all just looked like normal people, they weren’t superhero-genius types with crazy hair; they even made mistakes! The public became part of this enormous community and through social media they could talk with people all over the world about the next stage in the mission and the science that would come out of it.

The Rosetta mission is no longer breaking news and certainly some people will now focus on the parts of the comet landing that went wrong. Some will argue that we have missed out on much science data from Philae. But, there is something about this mission that overrides all that and that is the fact that, for the first time, humans landed a probe on a comet! And to quote my mother ‘they landed on the moon, and that’s big! But a comet, well, that’s mind blowing! That’s just a bit of rock flying through space!’

____________________

I wrote this piece because I was asked by the University media team to write a short article for The Conversation website on the #CometLanding. What you have just read is the original unedited version which I sent to them :) - to see the shorted edited version which ended up on the website click here.

Letter to a local Primary school in response to their astronomy questions...

I will try to answer all your questions in one letter, please email me if you have any future questions or tweet me @SotonAstrodome

What are black holes? How are black holes formed? Are they really black?

When a massive star, about 8 times bigger than our sun dies the star explodes, this is called a Supernova. The core that was at the centre of the star gets left behind, this core is so massive that it can’t hold itself up anymore, the massive gravity forces on it squash it down so much that it gets squashed into a very small invisible point known as a black hole. Black holes are actually more ‘invisible’ than black, but because space is black then this makes sense. They are invisible because they don’t give out light (like the Sun) or reflect it (like the Moon).

Are there any black holes in space? If so, how many are there? Is there a black hole in the Milky Way?

Yes! There are loads of black holes in our Universe; in fact there may be as much as 100 million black holes (which are each about the size of 8 suns, squashed into a very small volume) inside our own Milky way galaxy.

There is also a supermassive black hole in the center of our Milky way galaxy, which has a mass as big as 400 million suns. We know how big it is by looking at the speeds of stars moving around this invisible object at the center of our galaxy.

We don’t know the exact value for the number of black holes in our galaxy (or the Universe) because black holes are black, they don’t give out light like stars, or reflect it like planets, so we only know they are there when we can see stars orbiting the black hole, or being eaten by a nearby black hole.

Did any spaceships go into any blackholes?

No, we have not sent any spaceships to any black holes. Firstly they are all extremely far away and it would take many hundreds of years to get to the nearest black holes with the current technology. Also from using Mathematics and Physics formulas we can predict that any spaceship would get ripped apart by the strong gravity forces before it go to the black hole. Even if the spaceship was able to enter the black hole the signals it would send back to Earth, to tell us what was going on as it fell into the black hole, would also get sucked into the black hole. No information (not even light which is the fastest thing ever) can leave a black hole when it goes in. So basically, we will never known what goes on inside black holes exactly. They are very bizarre environments where our science theories fall apart, but we will keep trying to understand them.

Is there life on Mars? Is there life in the Andromeda galaxy and the rest of the Universe?

We have found water on Mars (mainly as ice or vapour) but at the moment we have not found any life, on Mars or anywhere else in the Universe. I personally believe that there IS such a thing as ‘Life on other planets’ or Aliens because from using the Kepler telescope to look at stars inside the Milky way we have found over 2,000 planets orbiting these stars.

You can actually help us find planets from this Kepler data by going on the website http://www.planethunters.org/

Current scientific research tells us that at least 1 in 5 stars that exist, have at least one planet. And there are 100,000,000,000 stars in the Milky way and 100,000,000,000 galaxies in the Universe, so there are a lot of places for Aliens to live. The Universe is SO big I think there has to be life out there somewhere.

What planets are we most likely to find life on?

If we assume that ‘Aliens’ are like us humans then we are more likely to find them on planets like our own Earth. This means the planets should have liquid water on them, and their distance from their star (which is probably like our Sun) is in what we call the ‘Habitable Zone’ or ‘Goldilocks Zone’ where the temperature is such that water is liquid on that planet.  Although, if these ‘Aliens’ don’t need liquid water then it is quite possible they could live on any kind of planet, hot or cold and their planet could orbit a star which is nothing like our Sun.

Did any things fall on the Earth? What are the things?

Rocks from space land on Earth all the time. When the rocks fall through our atmosphere they burn up and we see them as shooting stars, these are called Meteors. When these rocks actually land on the Earth they are called Meteorites. Meteorites are usually made of stones or iron and we think most of them come from the asteroid belt between Mars and Jupiter.

A famous meteorite called ‘Alan Hills 84001’ fell to Earth in 1984 and landed in Antarctica, it came from the planet Mars. It was thought to show evidence of fossilised life from Mars inside the rock. After further investigation from the scientists it was decided that the fossils were not proof of life on Mars and possibly a result of contamination from Earth life.

What is negative energy and is it real?

I think you mean ‘Dark Energy’. This energy is very real, and is responsible for giving the Universe the energy to expand outwards at a higher rate than expected.

Is it true that in space your spine grows in length?

Yes, astronauts on the International Space Station who spend time living in microgravity have been known to grow taller in space, for example, someone 6 feet tall can grow by as much as 2 inches.

Black Hole Event Horizons & Quantum Entanglement

Question from Peter (A-level student) -

An aspect of physics which has always interested as well as confused me is

quantum entanglement. I believe that this is a part of the new theory,

perhaps incorrectly dubbed "burn up", for one of the theories of what

happens past the event horizon of a black hole. I would be greatly

appreciate it if you could pass this on to someone with the expertise

to explain what quantum entanglement is and how it affects this "burn

up" theory of black holes.

Quantum Entanglement - credit http://www.tumblr.com/tagged/quantum%20entanglement

Answer from Dr Marika Taylor - see her personal website below.

http://www.knaw.nl/Pages/DJA/23/085.bGFuZz1ubA.html

Your questions about burning up at the surface of a black hole and quantum entanglement were passed along to me to answer, since I work on black holes.

I think your questions must be in the context of some recent works on black holes, involving so-called firewall problem, see this popular article

https://simonsfoundation.org/features/science-news/mathematics-and-physical-science/alice-and-bob-meet-the-wall-of-fire/

which discusses these ideas.

The question of what happens at the horizon of a black hole has been hotly debated for close to forty years now, since Stephen Hawking discovered that black holes aren't really black, because quantum effects cause them to emit radiation. There's a nice heuristic picture of how this radiation gets created, which relates to the firewall and entanglement discussion - in quantum theory particles are continually created in pairs, live for a short time and then annihilate. When such pair creation happens near a black hole horizon, however, one member of the particle pair can fall behind the horizon where it gets trapped, and so can no longer annihilate with the other member of the pair. The particle outside the black hole horizon can escape off t infinity, far from the black hole horizon, where we could measure it with a detector. In this picture the particle behind the horizon and the particle which escape to infinity are said to be entangled, which really just means that they have complete information and knowledge of each other.

Soon after Hawking discovered black hole radiation, he realized an important consequence of his calculations - regardless of how the black hole was formed astrophysically the particles measured coming out of the black hole seemed to be the same! That means that what we measure doesn't seem to depend on what happened earlier, in the formation process of the black hole. However, physical measurements at a given time not depending on what happened at earlier times (technically, non-unitary evolution in time) is not what we expect for a physical theory. For about 25 years people debated whether black hole evolution was indeed non-unitary or not until various breakthroughs in building  a quantum theory of gravity (string theory) convinced people that actually black hole evolution indeed had to be unitary - Somehow we must actually be able to do measurements which tell us how the black hole was formed.

Right now the growing consensus is that the only way we will be able to recover enough information from the black hole to deduce how it was formed is if the description in terms of Enstein's theory of gravity isn't quite right, it must miss some important physics near the horizon. There is not however consensus about what physics is missing near the horizon. The authors mentioned in the article above think that the basic problem is in the entanglement of particles produced near the horizon. In other words they don't think it is true that the particle which fell behind the horizon and the particle which escapes to infinity actually have complete information about each other, they think that the one which falls behind the horizon gets strongly entangled with a gas of particles living there. They also think that this gas of particles is so hot that anything falling behind the horizon would be burnt up by it, hence the name firewall.

As I said the consensus is indeed that something happens behind the horizon, there is some gas of particles which record the history of the black hole's formation. But there is very little evidence for the firewall - the authors mentioned in the article above were the only people in a recent black hole conference to think that the firewall exists! A more popular viewpoint, which I have worked on, is the fuzzball picture. In this picture there would be a gas of particles behind the horizon telling us about how the black hole was formed but something passing behind the horizon wouldn't get burnt up, it would just interact weakly with this gas and then eventually escape back across the horizon, out of the black hole.

I hope this explanation helps in understanding what entanglement means in this context. Please feel free to ask if there is something I can explain further.

Abi's Work Experience

My name is Abi and I am an As level student. I spent three days with Sadie, in the Physics and Astronomy department at Southampton University. I experienced both outreach and the general physics department.

On my first day I was given a tour of the physics building, all five floors! I also went onto the roof to see the observatory but unfortunately it was very wet so they couldn't be opened. I met some PhD students and some of the resident astronomers, to find out what they research. Sadie gave me a presentation of her PhD work, and I learnt a lot about supermassive black holes and what the department is researching as a whole. It was very interesting and enjoyable. I also did a worksheet based on the Hubble constant, which was a first year undergraduate experiment, measuring recessional velocity and distance of galaxies to calculate redshift and size of the galaxies. I also attended a seminar by a visiting astronomer, Karina Caputi, who is an assistant professor from the Kapteyn Astronomical Institute at the University of Groningen. The seminar was called "Massive Galaxies in the first 2 billion years," it was very interesting, but a little tough as it was aimed at the PhD students.

On my second day, I was given a tour of the university campus, including the library, the union and the sports facilities, by Ridwan. It was very interesting, if a little soggy, as I would really like to study at Southampton University. I was also given a tour of the physics undergraduate laboratories, by Mark, a demonstrator. He showed me the 1st, 2nd and 3rd year experiments and the labs that they use, including diffraction, radioactive materials, circuits and superconductors. I was shown the lasers, class 3 and 4 (the most dangerous type of laser). I was also taken to the mechanical workshops, where they design and build equipment for institutes all over the country. I was shown the milling machines and the computer 3D modelling software.

Anechoic room.

On my last day I worked with Dr. John Nesbitt to try and explain his research, but in a way a 14 year old would understand. It was called time resolved incoherant anti-Stokes Raman spectroscopy, so it was quite difficult. For example, we changed phonons to vibrations. I spent the afternoon with Dr. Steve Dorney, he gave me a tour of the vibrations and acoustics department, it was amazing! He showed me the Anechoic room, which is a room completely free of echos.

Echo room.

I then went in the Echo room, which is the complete opposite of the Anechoic room. All of the walls are asymmetrical, and are designed to mimic a cave.

I was shown some of the experiments that are used in the roadshow that Dr. Steve travels around the country with, including a dragon bowl and a thunder drum.
I was also given a vibration rod, a metal rod thats rings different notes when you rub it.
 http://www.youtube.com/watch?v=qQgP9zG681g 

Vibrating rod.

Dragon bowl.

I have learnt a lot from my time at the university, I have developed my communication skills after talking to PhD students and lots of new people. All of my co-workers were friendly and very welcoming, and it was an amazing opportunity to experience life at the university. It has definately exceeded my expectations, I have had an amazing time and met some amazing people.
I would like to thank everyone that I have met and everyone that worked with me, and I would recommend the work experience to anyone that is interested in physics and astronomy.

World Wide Telescope workshops for GCSE students

World Wide Telescope Script

Edited by Sadie on 30^th March, for Uni Genius event. Introducing A-level students to WWT. Total session length 30 mins including – 10 min Intro of programme and 20 min .wwt tutorial.

Main jist of talk

1.    Introduce WWT, yourself and helpers

2.   Give quick tutorial of WWT, make sure all users are in programme.

…..Look in more detail and stuff discussed in the dome show.

3.   Orion & Orions Nebula & Star birth

4.    Star Death, Crab Nebula & Neutron stars and Pulsars

5.   M101 a recent supernovae

6.    X-ray Binary black holes & Cygnus X-1 (Look in X-ray)

7.    Sagittarius A* our supermassive black hole, diff Wavelength (Look in Infrared) Galactic Centre

8.   NGC 4051 looking in optical and X-ray bands explain my PhD research

9.     M87, elliptical galaxies, mergers, part black holes play in galaxy formation?

10.                 Hubble Deep field get an idea for how massive the universe is…

11. The End, Any questions

Script

1.    World Wide Telescope this is a Microsoft program which you can download for you own computers for free, you do need a good internet connection, because all the images are downloaded as you zoom into them. Explain top and bottom menu bars and the search bar.

2.   (Get them to do this within software as you explain it!). Now by Clicking on your favourite image in bottom ‘Look at’ menu, I’ve chosen the Pleiades which is a group of stars in Taurus. By right clicking on the images you can see the ‘Finder Scope’ this shows you the RA and DEC of the object which is basically the co-ordinate system astronomers use to assign positions to objects like stars and galaxies. You will notice the Alt and Az , which is another co-ordinate system is moving. This is because the stars move across our sky. The Magnitude is the measure of brightness and the distance to the stars is given in Ly, where a light year is equivalent to about 6 trillion miles, that’s a 6 with 12 zeros! If you want to know more about a specific object select ‘Research’ and there are loads of other options which allow you to explore information about the object. Including the Simbad database which is used by astronomers like myself. Choose ‘lookup on Simbad’, as you can see these is a lot of information here and lots of ways you can look at it. So the best way to get used to this program is to download it and experiment with it yourself.

3.   To start we will look at Orion, which I may? have shown you in the planetarium show you were shown orions belt, 3 stars in a row, WWT allows us to zoom into the star forming region just below the belt. Stars just like humans live and die, our sun has about 5 billion years left in it, and these stars in the nebula have just been born. The length a star lives for depends on how large it is. The biggest stars have the shortest lives, and stars survive by fusing elements, which releases energy.. Stars can fuse everything up to Iron and then all the other elements, things like silver and gold are made in the death of the star, in the supernovae explosion.

4.    Now you also saw the Crab nebula in the planetarium and you will remember I said it was a composite image made from X-ray to look at the neutron star and optical to see the explosion of the different elements. Now I want you to search for the crab and use the bottom toolbar to look at all the different ways you can see it with the different parts of the EM spectrum.

5.   M101 – The recent (August 2011) supernovae in the ‘pin wheel’ galaxy. They come in various types, and the one we’re interested in is probably due to a white dwarf (the core of a dead star) which is literally sucking matter from a companion star. If the white dwarf  accumulates enough matter, it starts to fuse hydrogen atoms into helium, causing the whole star to explode. Such an explosion releases so much energy that it can outshine its parent galaxy! Type IA supernovae are a bit special, as we think they all explode in a similar way, which allows to use them to determine distances of far away galaxies. It is actually thanks to these stars that scientists discovered the expansion of the Universe was accelerating.

M101 is a spiral galaxy, located about 25 million light-years away. It is also huge, as it contains about a trillion stars, 10 times more than our Milky Way Galaxy! Because it’s very close, the study of this supernova should be rather easy, and it was spotted pretty early. Most supernovae occur very far away, and they are detected only after a few days, when they reach their maximum brightness. The earlier they are observed, the better: scientists gather more data, and it is essential to better understand these phenomena.

6.    Now if the star which made the crab had been a bit bigger say 8 times bigger than the sun the left over core would become a black hole not a neutron star. So next we are going to look for one of the most famous black holes called Cygnus X-1 it is one of the first sources which was widely accepted to be a black hole. It’s in the head of the Swan, Cygnus constellation and was discovered using X-ray observatories. Make sure they are looking in visible, i.e. what your eyes would see, so when we look at the sky in this visible survey image you can’t see any source here in the neck of the swan. Now we know that when material falls onto a black hole and moves at very high speeds, particles gain energy, and achieve the high energies required to produce X-ray radiation. Now when they turn on the X-ray survey of the whole sky taken by the ROSAT X-ray telescope you suddenly see a source appear, this is X-ray radiation released as a result of material spiralling in a disc around the black hole, We call this an accretion disk. The mass of the black hole in the system is 9times that of the sun.  Over three decades ago, Stephen Hawking placed -- and eventually lost - a bet against the existence of a black hole in Cygnus X-1. Today, astronomers are confident the Cygnus X-1 system contains a black hole. In fact, a team of scientists has combined data from radio, optical, and X-ray telescopes including Chandra to determine the black hole's spin, mass, and distance more precisely than ever before. With these key pieces of information, the history of the black hole has been reconstructed. This new information gives astronomers strong clues about how the black hole was born, how much it weighed, and how fast it was spinning. This is important because scientists still would like to know much more about the birth of black holes. Talk about your x-ray research and intermediate mass bhs. Now the black hole in Cygnus is one of the many small black holes within our galaxy, but there is a really massive one at the centre.

7.    Now we are flying around to look at our view of the galaxy we are in, the Milky Way. Our solar system is on one of the spiral arms of the Milky way and here you can the plane of the galaxy…Astronomers have looked at the centre of the galaxy and the stars which orbit that centre. Now the centre of the our galaxy is in the region of Sagittarius A*. From measuring the speed of 6 stars at the centre scientists have estimated the mass of the bh at the centre of our galaxy is 4 million times the mass of our sun. No other object can be so massive and in such a small volume of space. Now if we look at infra red survey of the sky we can see that the galaxy plane shows up a lot better. This is because infrared radiation is associated with heat (this is how police cameras work, picking up the heat of the criminals at night in order to locate them) Astronomers use the same principle here, now the material at the centre of the galaxy has more energy and therefore releases more heat energy. Infrared also allows us to see areas of star formation.

8.   NGC 4051 – talk about my thesis

9.   Now finally we are going to fly out to M87, which is galaxy, but it is called an elliptical galaxy as it is more rounded. The supermassive black holes size is estimated to be billion times the mass of the Sun, astronomers think elliptical galaxies might be formed by the mergers of 2 spiral galaxies. When we view this galaxy in optical light we just see a circular galaxy, however when we look in X-ray and infrared we see other features and jets coming from the centre. In fact the jets from this black hole actually extends out 5,000 light years

10.                 Hubble deep field – near ursa major (as is NGC 4051) One peek into a small part of the sky, one giant leap back in time...

Mankind's deepest, most detailed optical view of the universe — provided courtesy of NASA's Hubble Space Telescope — was unveiled today to eager scientists at the 187th meeting of the American Astronomical Society in San Antonio, Texas.The image, called the Hubble Deep Field (HDF), was assembled from 342 separate exposures taken with the Wide Field and Planetary Camera 2 (WFPC2) for ten consecutive days between December 18 and 28, 1995.

Representing a narrow "keyhole" view stretching to the visible horizon of the universe, the HDF image covers a speck of the sky only about the width of a dime located 75 feet away. Though the field is a very small sample of the heavens, it is considered representative of the typical distribution of galaxies in space because the universe, statistically, looks largely the same in all directions. Gazing into this small field, Hubble uncovered a bewildering assortment of at least 1,500 galaxies at various stages of evolution.

Most of the galaxies are so faint (nearly 30th magnitude or about four-billion times fainter than can be seen by the human eye) they have never before been seen by even the largest telescopes. Some fraction of the galaxies in this menagerie probably date back to nearly the beginning of the universe.

11. The End, any questions?

What is exciting about correlated X-ray and Radio radiation from Black Holes?

As part of my PhD studies we are asked to produce posters on a yearly basis to showcase our research to members of the physics department. Below is a poster aimed at students with at least an Undergraduate level of Physics studies behind them. I made this poster in 2010, and the question which is the title of poster was based on a question from a GCSE Astronomy student. The student asked me at the end of a talk on my research 'But why do you study the radio and X-ray from black holes, what is interesting about it?'...This question threw me at the time, but it did help me make this poster more accesible I think. It's those fundamental questions that people in research should ask themselves daily, as this can help you get through the day and remind you why you are doing all this research/banging your head against the wall in the first place!

JPG of my poster for .pdf version that you can zoom in on click link below

For the PDF version of the 'exciting' poster,aimed at Physics Undergraduate level please click here.

Below is a poster I prepared for the European Very Long Baseline Interferometry (VLBI) Meeting  also in 2010...This poster is on the same material as the poster above but at a slightly more advanced level and focuses mainly on the radio radiation from the supermassive black hole, and the VLBI imagery of the galaxy.

JPG of Poster for the EVN Conference in 2010, for the .pdf version that you can zoom into and read click below

For the PDF version of the EVN poster, aimed at Physics Undergraduate level and above please click here.

Below is one of Dan Plant's posters about Black holes. This poster was done for an MPhys project at Lancaster University. Dan is now studying for his PhD, also in black holes, here at the University of Southampton.

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...