Finally my paper studying the Ophiuchus star-forming region is done and dusted and has been accepted for publication. Thanks to one of my intrepid co-authors, that paper appeared today on astro-ph, the preprint paper listing for astronomy and astrophysical theses.

We re-analyse all of the archive observations of the Ophiuchus dark cloud L1688 that were carried out with the submillimetre common-user bolometer array (SCUBA) at the James Clerk Maxwell Telescope (JCMT). For the first time we put together all of the data that were taken of this cloud at different times to make a deeper map at 850 microns than has ever previously been published. Using this new, deeper map we extract the pre-stellar cores from the data. We use updated values for the distance to the cloud complex, and also for the internal temperatures of the pre-stellar cores to generate an updated core mass function (CMF). This updated CMF is consistent with previous results in so far as they went, but our deeper map gives an improved completeness limit of 0.1 Mo (0.16 Jy), which enables us to show that a turnover exists in the low-mass regime of the CMF. The L1688 CMF shows the same form as the stellar IMF and can be mapped onto the stellar IMF, showing that the IMF is determined at the prestellar core stage. We compare L1688 with the Orion star-forming region and find that the turnover in the L1688 CMF occurs at a mass roughly a factor of two lower than the CMF turnover in Orion. This suggests that the position of the CMF turnover may be a function of environment.

It is a study of star formation and prestellar cores, the objects that precede protostars. You can access the online abstract and get more information at arXiv.org or simply download the PDF from Orbiting Frog.

Well it finally happened: SCUBA’s successor, SCUBA-2 has been installed on the JCMT in Hawaii. SCUBA stands for Submillimetre Common-User Bolometer Array and the original was a ground breaking instrument that finally allowed astronomers to probe the depths of star-forming regions and distant galaxies. SCUBA-2 will more of the same and then some.

SCUBA-2 can scan the sky much faster than SCUBA and will allow researchers to measure the properties of protoplanetary disks around young stars, amongst other things. Exciting stuff. It is however very big.

Whereas SCUBA was comparable to a hefty water-heater, SCUBA-2 is more like a minivan. Mostly this is because of the cryostat that is required to keep the technology inside SCUBA-2 at a very low temperature. This technology has been developed principally in Edinburgh but also in Cardiff as well a few other places.

I saw SCUBA-2 in Edinburgh in 2006 and noted its large size at the time. When I observed at the JCMT last November (2007) I asked how on Earth they intended to get the the very expensive SCUBA-2 inside the very expensive JCMT without damaging either. The answer gave was that it would be tricky, and now thanks to a series of photos from April 2nd and 3rd I know what they meant.

The full gallery of 600 photos can be found on the Joint Astronomy Centre’s JCMT pages. There is also a fairly large animated GIF file (22MB) if you would like to see the installation in action.

This is my second conference poster and it is going up at the UK National Astronomy meeting in a couple of weeks. It will found in the Star Formation section of the conference proceedings. I have taken data from the HARP instrument on the JCMT and processed it as 3D models in order to gain a different perspective. You’ll need red/cyan 3D glasses to view this poster fully.

Soon I will be off on an observing run in Hawaii. I will be using the 15m JCMT telescope on Mauna Kea to take spectral line data using an instrument called HARP.

Since this will be my first professional expedition I will be taking lots of pictures and notes as I try to get to grips with using a real telescope to doing real science.

As much as possible I will blog here, though at this stage I really don’t know what will be possible.
So in case you suddenly notice an absence of blog posts in the next while, fear not - it is just me being all busy and such.

If you have any questions about my trip drop me a line via the comments thread here and I will get back to you.

If you’ve ever wondered what it is that I do (this one’s for all you family and friend types), then worry no more. Today I’m giving a talk to the incoming PhD students as part of our Postgraduate Conference. All the 2nd years give talks to all the 1st years and simultaneously bore all the 3rd years.

Fun! So my talk, as a flash animation, is shown over at this link if you’re interested.

Any questions? Send them my way.

A very timely new paper to aide me in my research which states that Rho Oph is 135pc away. give or take a few parsecs.

read paper

I recently saw a Digg article which linked to a space.com page about the 10 Strangest Things in Space. All but 2 of the items were not pictures at all but computer simulations, or artists impressions. So here to correct this injustice to phenomena everywhere I present the REAL 10 Strangest Things in Space - or at least in my opinion. Feel free to suggest any others in the comments.

V838 Monoceroti Expansion (Hubble)

It wasn’t anything interesting until it happened but the star V838 Monoceroti, which had simply sat in obscurity, flared up in 2002 to become 600,000 more luminous than our own Sun. It didn’t take long for the star to fade back into the darkness but the Hubble Space Telescope managed to get quite a few pictures of it during its active phase. (Click for animated version)

In this series of images you can see how the star’s outer layers were first expelled and then cut away by the powerful radiation from the star. The event was made even more interesting by the fact that a ‘light echo‘ was seen. During the expansion the object appeared to expand faster than the speed of light - the effect was however merely an astronomical optical illusion.

The Egg Nebula (Hubble)

Also known as CRL2688, the Egg Nebula shows a pair of mysterious ’searchlights’ bursting out from a dense cocoon of dust surrounding a hidden, Sun-like star. We see the light escaping in the directions where the cocoon is thinner. Objects like CRL2688 are rare because they are in a phase of their evolution that is short-lived. Images like this one are very important to understanding how stars like our Sun will ultimately die.

The Sun in UV (SOHO)

The surface of the Sun is far more active than most people would think. This ultraviolet video taken by NASA’s SOHO spacecraft gives brilliant detail. It allows us to see one full revolution of the Sun on its axis, which normally takes about 25 days. In this video you can make out large flares erupting from the surface and the striking magnetic loops that seem to whirl about them as they go. (Full 512×512 MPEG Here)
Red Square Nebula Nebula (Hale/Keck)

Discovered in 2007, this ruby-like nebula may be the result of two interacting stars. If one star is dying then the material from it may be dragged into a disc around the orbits of both objects. Material can then only escape from the system along the poles of the disc, resulting in two cones leading out of the stars. When viewed from the edge these cones seem like two triangles. Here the system is seen in the infrared. Structures like this are rarely seen in nebula but there is in fact a Red Rectangle Nebula which is less symmetric but still quite interesting to look at.

Abell 39 (NOAO)

Here we see an almost perfect planetary nebula that sits about 7,000 light years away in the constellation Hercules. The dot at the centre is the original star, which - as it died - released the expanding gas shell also seen clearly here. The ghostly appearance of the shell is due to the blue-green filter used to take the image, which picks out the oxygen emitted light at 500.7nm.

Saturn’s Rings (Cassini)

This marvelous panoramic view was created by combining a total of 165 images taken by the Cassini wide-angle camera over nearly three hours on Sept. 15, 2006. Cassini was sheltered from the Sun’s glare by positioning itself behind Saturn. Ring structures are revealed here in detail as they brighten substantially at viewing angles where the Sun is almost directly behind the objects. These observations allowed Cassini to detected two new faint rings.

The Horsehead Nebula Swallowed Something (SCUBA)

Observers used the JCMT submillimetre telescope on Mauna Kea in Hawaii to take this image of the familiar Horsehead Nebula, who’s outline can be seen here. When observed at 850 microns, we are seeing the cold dust at temperatures close to absolute zero. This dust is deep inside the optical nebula normally seen, which is transparent at this wavelength. It seems from the image that the Horse has swallowed a ‘lozenge’ which is in fact a region of dense dust that may be collapsing under gravity. In fact this could be a star system in the making.

Gomez’s Hamburger (Hubble)

Arturo Gomez found this odd object in 1985 and it became known as Gomez’s Hamburger for obvious reasons. It is actually a proto-planetary nebula, an earlier version of Abell 39 perhaps. The curves of light (the bun) are reflecting light from the star which is being obscured by a thick band of dust (the burger). The whole thing is only only a fraction of a light year across and located 10,000 light years away in Sagittarius.

The Solar Spectrum (NOAO)

If you could catch a rainbow and put it under a microscope you would see that it was not a continuous blend of colours. Along the width of it would be seen, scattered irregularly, dark patches. Atoms and molecules in the Sun’s atmosphere pick out specific frequencies of light and absorb them, diminishing their intensity by comparison. This images shows the spectrum of light from the Sun stretched out to make these absorption lines visible. We use the reverse of the idea (emission lines) when we make coloured lights. For instance, we excite sodium atoms to emit a signature orange light in street lamps. In this image you can see two prominent dark bands in the yellow-orange section which are the absorption due to sodium.

Update to This Entry

The Sombrero Galaxy in Infrared (Spitzer)

By looking at things in different wavelengths we can see much more than meets the eye. This image is a perfect example. Just as with the Horsehead image above we are seeing cooler material. This time it is dust in the Sombrero galaxy. The red ring is a thick band of dust encircling the whole galaxy. In the optical, this dust ring is what gives the Sombrero its distinctive black, obscuring line.

Oddities in the Orion Nebula (Hubble)

Deep within high resolution images of the Orion Nebula taken by Hubble we can see dark blobs. When you take a closer look you can see that these are like little flattened blobs. Some show a dim, red glow at their centres, others are just dark. These are proto solar-systems.

The red glowing is a protostars attempting to burst through and the dark disks are thick dust regions where one day planets may form. 6 billion years ago, this is what our Solar System may have looked from very far away.

So my name is now on a (soon-to-be) published paper. How and why this happened is a little over my head, but I shall try to explain. One thing you should know however, is that I haven’t really done anything so far to help get this paper out. I haven’t written anything for it. I have never attended a meeting about it or even met most of the people I have co-authored it with. So how am I now a published scientist?

You’ll find ‘my’ first paper here on the astro-ph preprint server (Link), and you can download a PDF version here (Link). It is 60 pages, but about 20 are references and figures. It is titled ‘The James Clerk Maxwell Telescope Legacy Survey of Nearby Star-Formiung Regions in the Gould Belt’.

Science is often done in groups these days. It takes a lot of combined effort and time to get the kudos and the know-how that gets money and recognition. This isn’t always the case but it is more true now than it was a decade ago.

The other day, on the blog, I was talking about how science could be more open. This is one area where, as Stuart pointed out in the comments, astronomy is very much open already. Of the 62 authors on the paper, I would imagine only a few have had a strong, guiding hand in the paper’s creation. A good bulk of them, lets say 80%, will have been involved at least in some significant way. The remaining handful - like myself - will have none nothing or a least very little. Those numbers are guesses since I’m new at this.

In this way, trams of scientists benefit from distributed expertise - each individual contributing their own unique talents and knowledge.
I am however signed up to help execute this survey. I am scheduled to man the telescope if needed for observations of the following areas Serpens, Cepheus, Pipe Nebula, CrA. I signed for it much like you would register for a website or something. A most unusual experience I felt.

The purpose of the survey as the title suggests is to look at the Gould Belt, which is an area in the sky that forms a ring around our position, roughly. It is shown in the image above along with some of the survey’s target areas. This ring, or belt, is home to many of the most active star forming regions in our neighbourhood and some of the brightest O-type stars in the sky as well. It is about 350pc in radius.

It was first seen by John Herschel, observing from the Southern Hemisphere in 1847 and later completed into a ring by a guy named Gould in 1879, hence the name.

By mapping the whole region we will achieve an impressive and broad catalogue of protostars and prestellar sources which will enable us to determine some key information about these young objects as they become stars.

So why am I on the paper? Well the whole team gets credit for each paper in the survey. If and when I go observing and reduce data on the Gould Belt, I will have the help and expertise, as well as the background papers published, by a team of incredible experts. We collaborate to achieve good science by sharing both the workload and the results.

So I’m chuffed with this incredibly low-effort publication and hope to actually have some involvement and maybe a paper ‘of my own’ in the next couple of years.

What follows is my submitted entry for the Wellcome Trust’s New Scientist Essay Competition 2007. There are prizes involved and the top one is publication of the essay in New Scientist. I am very inexperienced with such things, but thought I’d enter anyway, so just in case I don’t win, I’ll publish this myself on the lowly but kindly Orbiting Frog. The images has been added for the blog entry only.

There is something special about the Sun. At least that’s how we all think here on Earth. Truthfully though, the Sun represents just one type of star – a common one in fact – in a catalogue of stars that is seen to be fairly consistent all over the universe. Understanding where that consistency comes from, and where the trillions of stars and their planets come from, are two of the goals of an area of astrophysics called star formation.

How the Sun came to be in this neck of the galactic woods with its family of planets, dwarf-planets and other miscellany – including us – is certainly worth knowing. It is fortunate then that star formation is about to boom.

ESA’s Herschel space observatory (launching 2008) and the upcoming SCUBA-2 camera (that will be fitted to the James Clerk Maxwell Telescope in Hawaii, in 2008) are two examples of a handful of eagerly anticipated instruments set to produce more data than star-formation researchers have ever had. They will enable astronomers to see deeper than ever before into the murky depths of the dustiest regions of the galaxy, where stars are born. Many of these sites are the beautiful nebulae now so familiar thanks to images like those from Hubble. Others are huge, dark clouds that are too cold and dense to see, but give away their location by obscuring background light.

It is hoped that these new facilities with help answer several of the big questions facing astronomy. For example, why do stars form in clusters of hundreds or thousands? Why do they have the same catalogue of masses that is seen everywhere we look? What are the initial conditions of planet formation?

The physics involved crosses huge orders of scale. A good demonstration is this: imagine the Sun were a metre across. At this scale the nebula from which it formed would be the size of France! Incidentally that makes the Earth a mere pea. To compress all that material down by a factor of a million in size involves complex physics. In order to understand where we came from, you need to understand that physics.

As a discipline, star formation slots into almost all areas of astrophysics. For instance, in order to study galaxies you need to know what they’re made of. Even cosmology, often seen by its champions as being less ‘astro’ and more ‘physics’ has recently encountered a star-formation problem. In order to account for observations of stars that appear to be as old the universe itself, they need to explain how a population of stars could have formed so rapidly and so soon after the Big Bang. Whichever angle you look at it from, star formation is vital to modern astronomy.

Star formation is also important to you, personally. This isn’t just because the various stages of stars give you pretty objects like the Orion Nebula and the Pleiades (above) to look at with your telescope. Star formation tells us something very fundamental: we are all made of stardust. The Sun, planets and everything else around us were formed from the same giant cloud of material – most likely a cloud left over from an even older star when it died. Yet that same process creates a whole array of stellar classes and different planetary characteristics. Only star formation can tell us how all of this works.

NASA’s planned Darwin mission and ESA’s Terrestrial Planet Finder will both be able to resolve Earth-like planets around other stars. These, along with Herschel and SCUBA-2 will enable us to look at whole stellar systems from the outside, a perspective we have never had before. Observers will look at systems like our own at various stages of existence, from barely formed blobs about to start collapsing under gravity through to ancient star systems; we will even see planets in formation.

As a subject, star formation is set to explode. It will allow us to see ourselves better than ever before and to understand the origins of our existence. This is inspirational science, and definitely worth keeping an eye out for in the years to come.

So I’m still musing about the reasons for studying star formation and so I have begun trying to think in a more positive way. This is what I came up with earlier today…

Star formation is a science at a turning point. It will not be long now before astronomers have the choice of several world-leading instruments capable of observing at millimetre and sub-millimetre wavelengths. NASA’s Spitzer telescope is already orbiting above our heads taking new and exciting images with an array of instruments. Herschel, an eagerly anticipated multiple-instrument space observatory akin to Hubble will be launched by ESA within a year or so. SCUBA-2 is a high-technology camera that will be fitted to the James Clerk Maxwell Telescope (JCMT) atop Hawaii’s Mauna Kea and allow rapid surveys of star forming regions to be made at speeds many tens of times faster than has been done previously.

Within the next decade it is hoped that several of the big questions of star formation may be answered. Why do stars form in clusters of hundreds or thousands of stars? Why do stars have the signature spread of masses that is observed? What are the initial conditions of planet formation? There are many more but these give a good example of the kind of thing that star formation theorists and observers are out to explain.

Whilst returning to the Moon and Mars will hold the public eye for decades to come, the nitty gritty of the origins of our creation are mostly hidden in understanding star and planet formation. To understand how the Sun and it’s ever-growing family of planets, dwarf-planets and other miscellany – including us – came to be here in this neck of the galactic woods is a vital part of the much larger puzzle that is star formation itself.

As a discipline, star formation slots neatly in almost all areas of astronomy and astrophysics. If you want to understand galaxies you’ll need to know what they’re made of and if you want to get to grips with nebulae then you’d better know where they’re headed. Even cosmology, so often seen by my own colleagues as putting the physics in astrophysics, has recently been bitten by the star formation question. Namely, they need to explain how stars formed so early in the universe after the big bang. If they can’t, then there is some explaining to do since we have observed stars at ages very close to that of the universe itself.

Those three examples are very overarching but they get the point across: star formation is vital to modern astronomy. Part of the mystery of the subject is that it often crosses huge orders of scale in the same physical process. A good example told to me recently is that if the Sun were a metre across then the nebula from which it formed would be the size of France. The Earth on this scale is only the size of a marble! To compress all that material down through a million orders of magnitude in size obviously involves complex physics, yet if you want to understand where we all ultimately came from, then you need to know. So to save you the trouble of having to figure it all out, the astronomers are willing to do it for you.

So as well as fitting nicely into most areas of astronomy, star formation actually fits into your life – it’ll change the way you think of things. This isn’t just because the various stages of stars give you pretty objects like the Orion Nebula (Above) and the Pleiades (Top) to look at with your telescope. Star formation tells us something very fundamental: we are all made of stardust. The Sun, the planets and everything else you know were formed from the same giant cloud of material – most likely a cloud left over from an even older star when it died. Anything that wasn’t there to begin with was made inside the Sun and it is the Sun that protects from anything outside our Solar System with its enormous gravitational and magnetic fields. Only star formation can tell us how all of this works and how the cogs in the great celestial machine got turning in the first place.

Soon we will be in the position to look at other solar systems from the outside, a perspective we have never had before. If the current theories are correct then star formation is about to turn a corner. Astronomers will look at whole systems like our own at various stages of existence, from barely formed blobs about to start collapsing through multiple stars with their many shapes and sizes to single suns with rocky bodies in orbit and who knows what else. This will in turn allow us to see ourselves even more clearly then we ever have before and to figure out how we got here and why it happened.

This is inspirational science, and worth keeping an eye out for in the years to come. I welcome views on what I have written here from astronomers and non-astronomers alike - what do you think?

Why is my subject of research worthy of study?

This is a question I am going to try and answer in the next week. The science of star formation is something which involves money, time and great effort. Is that expenditure by the taxpayer, the telescope operators and even the scientists and themselves worthwhile?

I want to ask myself this for two very good reasons. The first is that if I cannot justify to myself why star formation is a worthy pursuit then why am I doing my PhD? Secondly, there is a competition and I can win £1000. So lets get cracking.

To begin with I need to clear about what I mean by star formation. Wikipedia’s description is found below and is what i would generally agree with. I assume by its presence on Wikipedia that this statement is generally accepted as it has remained unedited for some time.

As a branch of astrophysics, star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of early type stars and planet formation as its immediate products. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.

Initially I thought about tackling this by comparing my area of research to other disciplines, such as a few questionable fields in sociology or the study of mating habits of unknown beetles. Alas this approach won’t hold water ultimately since the act of placing star formation on some fictional scale of importance still doesn’t answer the direct challenge of proving its value to the world.

The next logical place to argue from is the statement that star formation theory benefits the word at large. This seems more promising. If we understand where stars (and thereby planets) come from then we understand where our own Sun and the Earth have come from. Everybody (mostly) accepts that the planet didn’t just pop into existence for our benefit. The process by which the solar system, including the building blocks of life, came about 5 billion years ago is knowledge that would be fundamental to our understanding of our place in the world.

Even I have to say that what I have just said sounds a bit dreamy. The astronomers I have met are not in general on a soulful quest to understand their place in the cosmos. not the ones I have so far encountered. But when I think about it, I guess I am. My interest in astronomy started with back garden stargazing, which I enjoyed because it let me think about my place in world I didn’t understand. Understanding the distances to Mizar and Alcor and the radius of the Sun and the sheer number of galaxies in the sky let me in on a really good secret: we are very very small. Its a secret i still think most people haven’t been let in on.

I have always been a bit of a thinker. By that I don’t mean that I have always been academic, but rather that I like to think about life, the universe and things like that. I ponder God and more recently the lack of it over cups of tea and this doesn’t seem to be regular. So if I am unusual in this respect then surely this cannot be the reason that star formation is worthy of any of society’s time and energy. To simply please someone’s personal quest to understand his place in reality is no reason to spend millions of pounds.
Could it be that my own interest in star formation and the motives for it are not unusual? I have encountered a great deal of bravado in the astronomical community, which I did not expect. Perhaps many of the people I meet are socially unwilling to proffer any personal reasons for their interest in astronomy. It does seem uncharacteristic of those i have met so far to get emotional about their research. In fact scientific dispassion is almost encouraged. If it were the case that there were thousands of people who wanted to know for their own reasons, would that constitute worthiness? Maybe.

As I write, I come to the conclusion that ‘worth’ is based in my view on some kind of odd equation. Could it be that personal reward multiplied by persons rewarded is the value of something to society? If a thousand people want to know and will be pleased by knowing something that makes it worthwhile. If one person will live if we know something and die if we don’t then that too is worthy, hopefully more so. However this argument is so subjective it cannot possibly be the reason for studying star formation.

An argument from the basis of unknown benefits could be invoked for space studies in general. You could say that understanding star formation may not seem beneficial right now, but who knows what it may reap in the future! again this seems a very weak argument in the face of things such as cancer research or education and health institutions.

Anyway, i am no master of words so i will stop there for a while and come back with Part 2 at a later date. However I would very much like to hear from anyone with an opinion on this subject. If you study astronomy or another field which doesn’t seem obviously or directly like it helps humanity then how do you justify your work? This doesn’t just apply to the sciences. If you reviewed films for a living then are you really bettering the world? If you were the editor of Heat magazine, could you justify that as worthwhile?

Please feel free to comment. Why do any of us do anything? More specifically though why is astronomy beneficial to the world, and star formation in particular? Questions, questions, questions…

So Hubble is now 17 years old and so NASA/ESA have released some incredible pictures take with Hubble’s Advanced Camera for Surveys (ACS) of the Carina Nebula. This nebula contains one of the largest known stars Eta Carinae, which is a highly unpredictable variable with a brightness greater than 4 million suns! It can be see in the far left of this image.

The Carina Nebula is situated an estimated 7 500 light-years away in the southern constellation Carina, that lies at the keel of the ship Argo Navis. This fifty light-year-wide view gives us a peek into star formation as it commonly occurs along the dense spiral arms of a galaxy.

Also released was another close up image of a part of the same region showing intricate details of star forming regions, including a massive bipolar jet of heated material. These are just the kind of incredible images that Hubble has always given us, and if SM4 goes ahead as intended Hubble will continue to amaze us as it moves into its third decade.

You can find more pictures and information over on the ESA press release page.

NASA researchers using the Spitzer space telescope have laid out what they have called ‘planetary danger zones’ around stars. In these zones, extending from bright O-stars, protoplanetary disks will be swept away by the strong stellar winds given out by the star. Smaller,cooler stars will continue forming planets from accretion disks so long as they remain at least 1.6 light years (10 trillion miles) from any nearby O stars.

Planets form in dusty accretion disks around stars but the powerful O and B type stars bellow out ultra viloet radiation too powerful to allow these disks to remain in tact. They are swept up by the radiation and the protoplanets inside never form. So long as they remain outside any such danger zones, it seems these planets will survive.

The team at NASA surveryed the Rosette Nebula over 5,200 lights years away in the contellation Monoceros. This is a star forming region and a well studied object in the sky. They used Spitzer to observe over 1,000 stars in the vicinty of an O type star and found that only 27 percent of those sytems within 1.6 light years had any kind of disk compared to 45 percent outisde of this danger zone. The image at the top shows the nebula and five of the O stars with their danger zones highlighted.

Stars are not static and do move around, especially within the timescales of planet formation. This study helps scientists to start to pin down the possible speed of planet formation. It could be thet Jupiter-like planets form quickly and would be able to withstand the motion of its parents star toward one these danger zones. Earth-type planets are thought to take longer to form however and would not survive even a brief foray inside sich a barrier.

It is thought that our Sun, like most stars, formed in a group which would have included such powerful O stars. If so then this means the Sun must have migrated out of the group before the planets we are familar with formed. For more on this story check out NASA’s press release.

At NAM I heard a great talk by Gary Fuller on Methanol Masers (a sort of laser created by gas in space). Whilst I find the topic quite interesting its a bit beyond this blog for now. However the telescope used as part of his research is the Parkes 64m telescope in Australia, shown above.

This is the telescope that helped relay the images of the Moon landings in 1969. NASA was quite unsure about the Australian approach to the mission and the events surrounding the days and week preceeding the historic mission are detailed in the 2000 movie ‘The Dish‘.

The giant 64m radio dish sits on top of the control room and moves about to view different parts of the sky both day and night (since it is a radio dish and sunlight is unimportant). I went to the Parkes Observatory website and found lots of useful material including this cool movie of a day in the life of the telescope.

There are many categories, or classes, into which a star can form, based its temperature and luminosity. The size of the star is related to these factors. Supergiant stars are typically 10,000 times brighter than the Sun and 100 to 1000 time larger (that is that they have a radius 100 to 1000 times larger).

But how big is the biggest star? Well firstly lets explain that biggest is not necessarily brightest nor most massive. You might for example have a very dense, small star which is technically more massive than a low density giant star.

If we take biggest to mean physical dimension we can say that we looking for the star with the largest radius. The southern hemisphere star, Eta Carinae is almost 11 AUs in radius. AU stands for Astronomical Unit and is the distance between the Sun and Earth. 11 AU means that if you swapped Eta Carinae for the Sun, it would extend outward to engulf Jupiter’s orbit.

However it seems that the generally accepted winner in the largest star category is the Pistol Star, with an radius 340 times larger than the Sun’s. It is also 150 times more massive than our Sun and a million times more luminous.

Like Eta Carinae, it is part of the category of stars known as Luminous Blue Variables. It can found in the constellation of Sagittarius and only ranks in at a measly magnitude +4 when viewed from Earth compared to Sirius at -1.47 and Venus which sometimes reaches -4 or more (I should point out that the lower the magnitude, the brighter the star).