This came through my door today and really made me laugh. “Jesus meets a corpse – hot dogs afterwards”

Link

A new geological study has set a more accurate age for planet Earth, according to scientists.

Researchers say their investigation shows the Earth is 70 million years younger than the 4.537 billion-year-old planet “we had previously imagined”.

Link

Star formation is hidden from view by dust surrounding the sites where it occurs. Optical light is blocked by dust, but we are able to see the dust itself thanks to submillimetre and far-infrared radiation that still escapes. Until recently we did not have the technology to map such active, hidden regions at these wavelengths. Planck and its sister telescope, Herschel, are changing that using ultra-cold detectors in the vacuum of space, positioned far from the Earth.

These images of star formation in Orion and Perseus show us two very different regions of our galaxy. The Orion molecular cloud complex is huge – if you could see it it would take extend all the way along the well-known constellation – and the above 15×15 degree snap of part of it, shows us prestellar cores and structure in the cold dust that makes up the region. (You can see the full image here). You can see the same part of the sky in other wavelengths using this Chromoscope link.

The image below shows how this Planck image compares with the stars of Orion’s belt, and shows the location of the Orion Nebula and the Horsehead Nebula (the two lower bright spots). The Planck image is bigger than you might think. The left-hand, monochrome image is the visible DSS map (i.e. the naked-eye shot) and the right is the Planck map. The central image shows the two overlaid. You can see a great river of material that seems to almost flow out of the Orion Nebula in the bottom, centre part of the image.

If you look at just the 850 micron image, in green below, you are essentially seeing cold dust in the Orion cloud complex. You can make out some amazing detail. Fine clumps and points in this wavelength are showing us objects known as prestellar cores. These dense points in the cold dust map are likely to be about to collapse and form stellar systems. These maps will be used to determine the mass and dimensions of such objects to help us understand the origins of such systems, including our own Solar System.

The map of Perseus (below) shows an even larger region. This map is 30×30 degrees and you can see even more cores and structures in the dust. This region is not as active in terms of star formation, and this gives it a more ‘even’ feel with less very bright sections and less dominant physical features. You can also see the plane of our galaxy as the broad, busy section in the top half of the image.

Perseus is less distinctive than Orion in the night sky but here is a similar optical (DSS) image shown blending into the Planck map of the region. The Pleiades are visible in the bottom-left. It is interesting to see how this striking, young clutch of stars is much less pronounced to Planck’s eyes. Only the small portion of dust surrounding it remains visible and it just forms one knot in a vast structure spanning either side of the cluster itself. A bright reflection nebula is seen near the centre of the image as being bright red in the Planck map. This is nothing to do with dust but is seen in red as synchrotron emission, a result of hotter interactions from the same radiation that lights up just that part of the nebula is the visible image.

These images reveal the amazing sights and science that Planck will deliver. Curiously these images are a kind of side-effect of Planck’s primary goal, which is to map the Cosmic Microwave Background. It just happens to make these detailed maps as it sweeps around the sky – and as a star formation astronomer, I’m very pleased about that indeed.

[Read more in ESA's news article for these images. ]

Take the numbers 1 2 3 4 5 6 7 8 9 and make them equal 100 by placing any mathematical symbols you like between them. Any symbols are fine – I have yet to attempt using any of the numbers as indices, but that’s fine too. You must keep the numbers in the same order but you can combine them into larger numbers (e.g. 12, 56, 789) or chop them up using decimal points (e.g. 2.3, 7.8). As examples here are three possible solutions to show you how it works:

123 – 45 – 67 + 89 = 100
1 x 23 x 4 – (56/7) / 8 + 9 = 100
1 + 2.3 – 4 + 5 + 6.7 + 89 = 100

There are well over 100 solutions to this which means it is a game filled with multiple victories. Enjoy!

The original Galaxy Zoo and Galaxy Zoo 2 both used data from the Sloan Digital Sky Survey and recently, after reaching 60,000,000 classifications those projects began to wind down. The timing was excellent though as it allows Galaxy Zoo: Hubble to launch today, for the 20th anniversary of the space telescope. Images of galaxies taken using the legendary space telescope are there for everyone to classify and I recommend that you go and do just that.

A lot of the fainter galaxies look like those seen in the Sloan catalogue from Galaxy Zoo 2 (this is a good sign, since we don’t want galaxies to change wildly depending on what telescopes we use!) however in amongst these there are some real gems to be discovered in the Galaxy zoo: Hubble data. I just found a couple in my first tentative classifications, I’ve shown them here to whet your appetites.

The image at the top of this post was taken during Servicing Mission 4, just after the Space Shuttle Atlantis captured Hubble with its robotic arm in May 2009, beginning the mission to upgrade and repair the telescope. Thanks to that upgrade, Hubble will continue to provide amazing images and science for many years.

You can follow Galaxy Zoo on Twitter, read the Galaxy Zoo blog or  - more importantly – go and classify some galaxies!

During my talk I used an online tool called Chromoscope to show the night sky in multiple wavelengths. An excellent example of an object in Chromoscope might be the Orion nebula seen in Hydrogen. I have had a part in the development of Chromoscope and it was originally developed to showcase multiwavelength data to the public at exhibitions. Chromoscope is lead by Stuart Lowe at the Jodrell Bank centre for Astrophysics in Manchester and you can find his excellent Astronomy Blog here.

You can find photos of the event’s first session and second session on Flickr and you can visit the TEDx Cardiff website for more information. you can follow me on Twitter @orbitingfrog and there is a TEDx Cardiff list of attendees, organisers and speakers as well. If have any questions regarding my talk, either ask them here, in the comments, on on Twitter.

If you’re interested in my life beyond TEDx, I work in Oxford University on citizen science projects. See the Zooniverse website for lots of information about what I do or visit Galaxy Zoo or Solar Stormwatch to have a go at being a citizen scientists and helping astrophysics research in the UK and around the world.

Tonight, after a heads-up tweet from astronomy writer Will Gater, I headed outside and took some snaps of Venus and Mercury which were setting quickly. The best result is shown below.

I also took the opportunity to photograph Orion, hanging over Birmingham. Perhaps not the most glamorous setting for the hunter, but a nice picture none-the-less.

I highly recommend you go and take a look at the two inner planets as they set together in the next couple of days – if weather permits. With Mars riding high in the South, you can really get a feel for your location in the Solar System. With the two inner planets setting in the East and our nearest outer neighbour over your shoulder, you can almost feel yourself flying around the invisible Sun, turning gradually into the night side of planet Earth. Pretty cool.

[7 TeV] is still only the energy in the motion of a flying mosquito – BBC News

Well there you have it. Wait… hang on. What on Earth does that mean? I can see why journalists are scraping the bottom of the analogous barrel on this one – energies are notoriously hard to understand. Energy of motion refers to kinetic energy, which is 0.5 * mass * velocity-squared.

Taking the mass of a mosquito as about 2 milligrams (Wikipedia) and the velocity as about 1 – 1.5 miles per hour (Amazing Mosquito Facts, about 0.5 metres per second) we get a kinetic energy of 0.00000025 Joules, or 1.56 TeV. So they must have fat mosquitos at the Beeb. Or maybe their mosquitos are on speed – seems more likely. They are right though, to an order of magnitude, the LHC collisions between proton beams will occur with all the power of a mosquito.

This has got me thinking about energy units so I’ve done some conversions for you. The 7 Tev collision at the LHC is the equivalent to:

• 3.1 x 10^-13 kilowatt hours
• 2.6 x 10^-16 tons of TNT
• 7 x 10^-15 gallons of jet fuel
• 2.7 x 10^-10 kcal

You switch this final one around to say that there are 1.2 x 10⁺¹² LHC collisions in a Snickers bar. Or perhaps more poetically, there are as many electronvolts in a flying mosquito as there are LHC collisions in a Snickers bar. Oh dear, I think I’ll leave it there…

• Red: 750 – 620 nm
• Orange: 620 – 590 nm
• Yellow: 590 – 570 nm
• Green: 570  -495 nm
• Blue: 495 – 450 nm
• Violet: 450  -380 nm

Here I’ve used the figures given by Wikipedia (sourced from catchily titled the CRC Handbook of Fundamental Spectroscopic Correlation Charts). The same ranges are shown on the image below.

You might notice how narrow the Yellow and Orange bands appear and, if you’re a keen colour cadet, that Indigo isn’t on the list at all. The rhyme I learned at school was Richard Of York Gave Battle In Vain – seven colours in the order of they appear in the spectrum. In fact Indigo used to lie between 450 and 440 nm. That is a really tiny waveband. Why? Because most people cannot tell you the difference between indigo and either blue or violet. Essentially the colour is more akin to one of those Dulux paint charts from the DIY store that it is to any of the ‘real’ basic colours. You may as well include biscuit, lavendar and lime in the spectrum.

Indigo was originally included in the spectrum by Isaac Newton, the man who formally discovered that light is split into different colours. Using a prism he showed that white light was a mixture of what he saw as seven basic hues, including indigo. He chose seven because he was attempting to make the colours of the Universe fit in with what he was as a numerological pattern appearing elsewhere.

Isaac Newton was not what you would recognise today as a scientist. He believed in alchemy (the idea that you can convert one element into another, e.g. lead into gold) and was extremely mystical. He was quite eccentric and didn’t even publish his most famous works until long after he had finished working on them.

At the time when he split light into a spectrum there were seven known planets in the Solar System. there were seven musical notes (do ra me fa so la and te) and of course there are seven days in a week –  a Biblical determination. So seeing his spectrum as being made of seven colours was quite a natural idea and he made it fit. The image at the top of this post shows his original colour circle – musical notes are shown around the edge, matching certain colours.

It got me wondering how many colours I would have divided the spectrum into if I had been the first to properly measure it. Ten colours, to match my decimal upbringing – maybe 5? Perhaps I would have added octamarine? It would be interesting to get children to divide up the spectrum themselves and then compare it with Newton’s result. How many colours can you see?

The story of Newton ‘inventing’ indigo is one I heard a while back but dismissed. It came back to my mind last night after it was mentioned on BBC Radio 4′s The Unbelievable Truth. They also mentioned another Newton tale which I shall finish up this post with. Newton spent a short part of his life (1689-1690 and 1701-1702) as a Member of Parliament for Cambridge University. During his two-year tenure he is only recorded to have made one speech: he asked for the window to be closed because he was cold. I think that tells you a lot about him.

This new body will have an annual budget of about £230 million behind it (a drop compared to the BNSC) and it is being created now because of predicted dramatic increases in the space sector in the coming years. Britain’s space industry is expected to grow, creating lots of jobs in the coming years. This is all very good stuff for the government to be talking about just weeks before a general election – ahem.

Sadly, politics are very much behind today’s launch. There was a time when the idea of a UK space agency would have really excited me. Now that I am a real-life scientist though, and given the circumstances, I feel a bit worried about it. There will no doubt be many scientists involved and employed by the UKSA (or will it just be ‘UKSA’) but there seems to be very little mention of research in all the hype surrounding today’s events.

Most of the UK’s involvement in the space industry has been centred around scientific research (astrophysics, climatology, etc) and it worries me that this new agency is going to take money away from that in order to put out the image of the UK as a space-faring nation.

On a less cynical note, the creation of the UKSA is something that people nationwide should be talking about. This could be a good chance to get classrooms, living rooms and pubs buzzing with talk of astronauts and trips to the Moon and Mars. After all, the schoolchildren are the ones that might actually go to such places!

I’m going to let my younger self lead the way on this one. When I was little I was so jealous of NASA and the way American’s got to own the galaxy by default. My 8-year-old self is really excited that the UKSA – even if it does have a terrible name – is here with it’s union flag logo to lead us all into the unknown. I realise that this agency represents spending cuts not increases and that this launch has been a bit of rubbish start – but there’s hope in the idea of a united space agency for the nation.

So I’m giving the UKSA a tentative thumbs up after my initial moaning. It may sound naive, but I hope that when this economic collapse levels off, the UK Space Agency will ultimately allow more astrophysics research to be undertaken. The UKSA could be a fresh beginning for the way we think about space in the UK. It might help us to reframe exploration, research and astronomy in general.

Here’s to strange new worlds, new life, and new ways of taking your tea – as the UK heads for infinity, and beyond!

[Photo above from ESA showing Major Tim Peake, Britain's first official astronaut]

The ISS orbits overhead at around 350km (about 220 miles) and completes an orbit roughly every 90 minutes. So you can imagine that Soichi gets to see quite a range of places all at different times of day. I’ve posted some of my favourite photos from his Twitpic feed here, but I encourage you to go take a look yourself and if you’re on Twitter, follow him.

Houston, Texas by night

Mahajamba river delta in Madagascar

Patagonia glacier

Paris by night

Astronaut Stevie "Ray" Robinson

Space Shuttle Endeavour making re-entry

Moonrise over Australia

Lake Pukaki, New Zealand

Whilst I have been trapped in the thesiverse, I have been diligently attempting to ignore all my other projects – but they keep moving along. Whilst Avalon sits behind me in a playpen saying “ba ba” to several bears – and offering the dog a squeeky toy – I thought I would try and write a quick update on some of the projects I intend to resume with whatever free time I find myself with after submission.

.Astronomy

Earlier this week, we had a meeting of the .Astronomy team to discuss the third .Astronomy workshop. It was very exciting with lots of possibilities for locations and dates discussed. We also caught up on some of the projects created and advanced at the Leiden meeting.

A big question that came up – and one I am still mulling over – is that of the nature of .Astronomy. What exactly is it, and how do I know it when i see it? I tend to use it as a descriptive term now (e.g. “ah yes, that is very .astronomy”) but I think it is time to figure out why. This question being raised, and serious discussions of sponsors and venues for a 2010/2011 event leave me feeling very proud. .Astronomy has clearly demonstrated that it is worthy of continuation and expansion.

I can’t wait to get back into a more fully-engaged mode with the whole project. I am extremely glad to have the whole team working with me, and letting me focus on my thesis in recent months. Thanks guys and gals!

365 Days of Astronomy

365 (as people seem to call it) is expanding into 2010 and the days are filling up fast. More sponsorships are needed and I fully intend to dive headlong into comment moderation and posting when I finish the thesis. Another thing that I want to do – and any of you could also do this – is create some backup podcast episodes for 365. When scheduled contributors don’t appear or cancel it is useful to have a bank of backup episodes ready to go.

Chromoscope

Exploring the universe in multiple wavelengths is a lot of fun but I’ve had so litle time to offer this project recently, I’m starting to feel very guilty. We’ve recently added Gamma Ray to the site, from Fermi, and I am slowly compiling a massive UV map, using GALEX. Stuart has been chipping away at new Chromoscope features (such as language support, and making Chromoscope embeddable) and there is talk of an iPhone app in the near future.

Everything Else

There are also my Tweprints and OverTwitter projects which both have potential, large-scale alterations to be made. I shan’t go into details here but maybe these are things I could work on at the next .Astronomy meeting. There is also a cool new project that came out of .Astronomy (I’m currently calling it Zombie) which I really want to get my hands dirty with. Like all the others though, it will have to wait.

The Thesiverse is a large and expanding, multi-dimensional reality. Time is quite variable there too. Next week I am relieved of childcare duties to make a final push at finishing the beast, so wish me luck. Hopefully I shall find my way to a singularity and pop out into your realm once more. Oh dear, Avalon is now trying to get the dog into the playpen so I must go. See you on the other side!

Pluto is so small and distant that the task of resolving the surface is as challenging as trying to see the markings on a soccer ball 40 miles away.

Plans are now being made to use Hubble’s new Wide Field Camera 3 to make further Pluto observations prior to the arrival of New Horizons in 2015. Advanced Hubble images will help the New Horizons team to take better shots of the dwarf planet when the probe arrives, and to make the most efficient use of time as it explores the Pluto-Charon system.

The new images have also been combined into a great video showing the current surface of Pluto rotating. You can find a small (iPhone-friendly) version right here or you can grab the HD one from the NASA site by clicking here. Read the full NASA press release here.

Thanks to Mike Brown (@plutokiller) for pointing this out via Twitter.

What is Your Favourite Planet?

Shaheer, Esme and Thea all want to know what my favourite planet is. It’s an important question. At first I want to say that the Earth is my favourite planet but that’s cheating, isn’t it? In which case, I think it has to be Jupiter.

Jupiter was one of the first planets I looked at through a telescope (I was 12) and when you do that you can see that it has four very bright moons. These moons are called the Galilean Moons because they were observed by Galileo, the first man to look at the sky with a telescope – and that was 400 years ago! You can also sometimes see that Jupiter is stripy and that it has a big, red spot. Saturn is also good to look at  - with its bright rings – but Jupiter changes every night, which is very cool and interesting. The moons move and the stripes and spot rotate around the planet.

Why are There Craters on the Moon?

Sean asks why there are craters on the Moon. The answer is that that space is not empty. The Solar System is a very busy place. As well as planets and moons and the Sun, there are also other objects in the Solar System. yoiu might remember I talked about comets and asteroids. These are rocky bodies, smaller than planets, that also go around the Sun. There are also even smaller rocks out there, flying around. Quite often these rocks hit the larger planets and moons. The craters on the Moon are the left over pock-marks from rocks hitting the surface of the Moon.

We see craters all over the Solar System. Mercury and Mars are covered in them, and so is any other object that is rocky and not covered in clouds. Even the Earth is hit by rocks sometimes. We can see some craters here on Earth! They are harder to find because of all the grass and volcanoes and glaciers and rivers covering them up – but sometimes they are found. They can be very big!

There is a very big crater in Arizona in the USA called Barringer Crater – I have put a picture of it here for you. It is 1,200 metres across (nearly a mile) and it was formed 40,000 years ago when a 50-metre wide rock crashed into the Earth from space.

You can play with a fun Earth-smashing, asteroid simulator called Down2Earth. It lets you try and smash all sorts of different sizes of rock into the Earth and see what damage they would do.

Living on Other Planets

Thea asks whether people live on other planets. Currently no, they don’t. People do live in space now. There is always a crew onboard the International Space Station. New astronauts arrive to change-over roughly once every six months.

A lot of people think we should go back to the Moon one day and set up a Moon base so that we can learn how to live on other planets and maybe mine the Moon for minerals – like we mine the Earth. Living on the Moon might mean that we can figure out how to go and live on Mars one day too.

I’ll leave it there for now. I have more questions to answer but I’ll leave that for part 2. A lot of you said how much you liked the images of the nebulae that I showed you. At the top of this post you’ll see a lovely picture of the Orion Nebula from the Seeing in the Dark website.

The image below shows how it looks in the far-infrared using IRAS data from Chromoscope. I have drawn on the stars of Ursa Minor as a guide and also placed a green box around the footprint of the Herschel data. You can see the ‘flare’ as the arch of material streaming up and way from the central ‘blob’ where Polaris lies. Being an astronomer requires so much technical jargon!

The Polaris Flare was discovered in 1990 by Heithausen and Thaddeus who mapped the region in CO. It is a molecular cloud complex at a distance of 110 parsec. The flare appears to surround the star Polaris – the North Star – but in reality the two may not be related. Herschel mapped it as part of the science demonstration phase of operations and the images were shown at the Herschel meeting held in Madrid before Christmas. This was the same meeting that showed off the amazing Herschel data of the Rosette region.

The black-and-white image at the top (RSS readers click here), available as part of Alain Abergel’s talk, shows a chunk of the Polaris flare and reveals its delicate, cirrus structure. This image is from the SPIRE instrument and shows data at 250 microns. What you’re seeing is fairly cold dust in the interstellar medium (the material that lies between stars and is involved in their evolution).

A portion of the flare was mapped as a taster for one of the Herschel key projects: Evolution of Interstellar Dust (the footprint of the Herschel data is shown above as a green box). This is a group researching the structure and properties of the interstellar medium in different environments. One interesting thing to note is that this image – which is actually generated from a very high resolution set of data – contains a whole lot of something very different to cirrus nebulosity.

If you were to zoom in to a small portion of the image and change the contrast so that the background was revealed, as is done in the image below, then you would see a lot of small speckly dots. There are hundreds of thousands of them speckling the background of the whole molecular complex. These objects are galaxies. Lying far beyond the nebula itself, but ever-present in this far-infrared data, such a backdrop is rather confusing when you are trying to measure the properties of the nebula itself. This is a problem that star-formers will have to overcome in order to make detailed analyses of images like this.

Conversely of course, astronomers studying galaxies will wish the nebula was the thing that was removed. Astronomy is a very murky business indeed.

I don’t intend to do too many blog posts about the shop, but once in a while I’ll put one up – one has to pay the bills. To start things off here are some of my favourites: the constellations. T-shirts, bags, baby-grows and other items with different star constellation on it. I’m adding more constellations as and when I get the chance, but to start we have all the zodiac signs, as well as a smattering of my favourites such as Orion, Perseus and Cygnus.

Click here to visit the Orbiting Frog Shop on Spreadshirt.

The swirl of cloud heading in from the southeast is bringing more snow tonight and tomorrow for much of the country as the big freeze continues. You can keep track of the snow via the user-generated #uksnow map from Ben Marsh.

2010 is going to be a big year for me and my family. I will be submitting my PhD thesis in February and am currently applying for jobs – something made far more daunting by all the recent STFC funding news. However, my CV is in the works right now all the same!. Between all that and the baby I am thoroughly occupied.

Luckily blogging is the perfect thesis procrastination activity, so I leave you with wishes for a very happy new year and a productive 2010.

Tonight is also a blue moon. This merely means it is the second full moon of the month. This happens just about once in three years and simply caused by the lunar cycle being slightly off from the monthly calendar cycle.

Maximum eclipse is at 19:22 UT and the Moon is in the East, in Gemini. The eclipse is visible from Asia (all the way down to Malaysia), Europe, Africa and most of the North Pole (if that is useful to you). North America and most of South America will be missing out. The map above outlines this better than my explanation.

So why not go out tonight and take a look if it is clear where you are? You can toast the new year under a red, blue moon.

[Post image of partial lunar eclipse from Flickr user JP.G]

The image was taken as part of the oddly-named HOBYS (Herschel imaging survey of OB Young Stellar objects) program studying young, massive stars. Giant OB stars are an important part of the dynamics of galaxies. They die in massive explosions, live extremely energetic lives and shape the evolution of nearby regions with their powerful radiation. Understanding where they come from and how they form is a big deal in star-formation research. It also appears to be a process quite different to that which seems to form the kind of low-mass object I look at in my own resesarch.

Herschel allows us to look deeper and farther, such that we can can see lots of the precursors of these giant stars – enough to begin to make statistical samples and maps. HOBYS will use all five Herschel imaging bands for 126 hours to make images of up to 13 different massive-star-forming regions.

The Rosette Nebula is situated just over 5,000 light years away and is 100 light years across. It is shown here in an optical image by Robert Gendler. You can see it through a small telescope in the constellation of Monoceros. Inside the nebula lies NGC 2244, a cluster of bright, young O stars. You can see them sweeping out a hole in the centre of the nebula. Ultraviolet radiation from these stars makes the surrounding nebula to glow.

At the bottom of this post is a image showing how the optical and Herschel far-infrared images correlate. You can see how Herschel is seeing the much cooler material, farther out from the centre than you see in the optical image. The Herschel image is made up of three of the five Herschel wavebands (70, 160, 250 microns) making up the blue, green and red colour-channels.  It has the look of a gathering storm, or perhaps crashing waves. It is a spectacular image and I’m surprise that more has not been made of it.

You can download Sylvain Bontemp’s HOBYS talk as a PDF, which features many more images. Including a great set of RCW120, a sampling is shown here. If you’re into the science stuff, I’d suggest taking a look at lots of the talks, which can all be found here.

If you’re new to the idea of the celestial sphere then you have to imagine the sky depicted as a really big sphere, with us sitting inside it. The sky stays stationary as the Earth rotates inside it. So the North pole of the sky, Polaris, lines up with the Earth’s North Pole and so on. If you are sitting at the North Pole then Polaris appears directly overhead all the time. If you’re sat at the equator then Polaris is at the horizon and the celestial equator rolls more or less overhead.

Over the course of a year, the Sun will appear to oscillate just above and below the celestial equator (by about 23 degrees), because of the tilt of the Earth’s axis (see above). However, on any given day it will seem to stay in same place, circling the sky following an approximate line of latitude. This is what is depicted below. The path of the Sun at each solstice is drawn and the celestial sphere. In each case the longest path is the Summer solstice and the shortest is the Winter solstice. As you move from the equator to the pole, the difference between the paths drawn by the Sun gets larger until near the pole (at about 70 degrees latitude) there is no Winter track because the Sun is below the horizon all the time. You are now inside the arctic/antarctic circle.

There are a couple of interesting points raised by these images. Note that at the equator, the Sun does not always go directly overhead. In fact this only happens at the equinoxes (the time in the middle of the two plotted tracks). In the 50 degree latitude diagram, there are little faint circles depicting the Sun below the horizon – these indicate that it is still contributing to some sort of twilight – which above 50 degrees lasts all night during the Summer solstice! This is why astronomy can be so difficult in midsummer here in the UK, for example, but not in Southern France.

The diagram showing the solstice at the pole lets you imagine the Sun spiralling closer and closer to the horizon as the year goes by. Six months from perpetual midday comes perpetual midnight, each day the Sun creeping lower and lower before skirting the horizon and then disappearing at the equinox.

Something I had never though of, but which is pointed out in the Wikipedia article, is that until 20 degrees latitude, the Sun is either in the North or the South depending on the time of the year. This is counterintuitive to most of us who are used to the Sun always being in the South (for the Northern Hemisphere) or the North (for the Southern Hemisphere). For example, in the UK, south-facing views are sunny ones. However below 20 degrees latitude in the Northern Hemisphere, the Sun can arc through the sky in the North, not the South, because of its oscillating position around the celestial equator. This becomes obvious in these diagrams but I had never thought about it before.

All of this is as much geometry as it is astronomy but I think it is interesting. These excellent diagrams do a great job of giving you feel for the why the seasons are so different and why the solstice happens (they also have added detail in the types of tree shown).

The 2009 Winter Solstice occurs at 17:47 on December 21st (the exact publication time of his blog post), the 2010 Summer solstice will be June 21st at 11:28.

After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem and asked, “Where is the one who has been born king of the Jews? We saw his star in the east and have come to worship him.”

Can you spot the peculiar error? The Magi came from the east, yet they saw the star in the east. Yes that’s right – either the text is confused or the Magi travelled all the way around the globe, the wrong way, until they reached Bethlehem some two oceans and many thousands of miles later.

In other versions of the Bible (why oh why does it even have versions?!) they don’t specify the star being in the east. They sometimes say it rose and then settled in the right location, over Bethlehem. I grant you, if you want to quibble about specifics in the Bible then there are much better places to start but come on, God! Sort it out! Matthew is the only gospel to mention the Magi – where Mark doesn’t mention the nativity at all.

So assuming that there even was one, what might the biblical ‘Star of Bethlehem’ actually have been?

Possible options include

• novae and supernovae (stars being explosive somehow)
• a planetary conjunction (bright alignments of planets from the perspective of the observer on Earth)
• a comet.

No known supernovae match with the date (assuming it to have been between 10 B.C. to 10 A.D.). Planetary conjunctions pose a problem: namely there are lots of conjunctions between Jupiter, the Moon, various stars, other planets etc etc. Picking the one that would have meant that a king was being born is difficult. Halley’s Comet passed by in 12 B.C. but this is surely too early. Halley’s comet would also have moved over a fairly short period of time – which doesn’t match the notion of ‘following’ a star. Not without wandering in circles anyway.

The best bet for a Star of Bethlehem candidate is a “comet or nova” observed by both Chinese and Korean astronomers in 5/4 B.C. Either or both years is possible. This was an object that appeared in March and remained visible for some seventy days – without moving relative to the stars. This object would have made a nice conjunction with the Moon around that time, which might add significance to the mystical Magi.

However if I told you that some significant star was seen in 112 A.D. then I imagine you could find one to within a few years. Or for 560 B.C. or 1999 A.D. – the point is that there are lots of significant astronomical events all the time – that is one reason astronomy is such a popular hobby! Finding a match for a Christmas star is therefore quite likely if you make your criteria loose enough, i.e. it has to be bright, and can happened up to ten years either side of 0 A.D.

I’m afraid that the Star of Bethlehem is widely regarded as fiction. Like the visit of the Magi themselves, the Star of Bethlehem simply didn’t happen. It is also incredibly unlikely that much of the nativity happened, but there you go. Let’s also throw into the mix the fact that Christianity prohibits astrology. Astrology is seen as sorcery and being of the occult. Intertwining it with the birth of Jesus seems bizarre and slightly problematic for the Church.

In researching this blog post I found a nice website, with a related book, all about the Star of Bethlehem. If you’re interested in reading more I’d suggest taking a look. Other than that I’d say ‘stop worrying, and live you’re life’! Enjoy Christmas, be with the ones you love.

Today is the Winter Solstice, the Sun is at its lowest point in the sky and the night is as long as it gets in the year. The days get longer now, but Winter sets in for a while. It is time to get gorge yourselves and cuddle up with someone special to keep warm. That is the true origin of Christmas, and of myriad other winter festivals of light. So embrace it – eat drink and be merry – and may I wish you all a very merry Christmas and a happy new year!

[Star if Bethlehem image from Flickr user Ashish T]

The rusty red material you see is dust and it contains within its filaments and structure, some 700 protostars ready to burst into life. The thick dust in this region had, until now, totally obscured all the amazing content. The blue areas are places where stars have already formed and are now illuminating nearby hydrogen gas.

This image has been keeping an officemate of mine busy for quite some time already. Identifying the 700+ protostars and myriad other objects in this image – which is only one of hundreds of images yet to come – is a big challenge for astronomers working with Herschel data. I can’t help but wonder if the answer to this data-rich problem may lie somewhere in the Zooniverse.

You can find more on Herschel on the ESA website, and you can read more about this particular image via this ESA link. This image was released alongside a new website called OSHI (Online Showcase of Herschel Images) which although a bit sparse right now, is worth bookmarking for the future.

I’m not one to engage in STFC politics – I’m far too vulnerable and ignorant as a PhD student. There are much better blogs to read about that sort of thing. However in light of the prospect that I might shortly head into this funding minefield to try and get a job, I figure I may as well make a few observations. It is also worth spreading the word around the blogosphere. Most of my readers are from outside the UK and are likely unaware of the disaster unfolding in UK astronomy.

The funding gap is an astonishing £70 million which itself begs some explanation. How on Earth did it come to this? As I understand it, the STFC is going from around £100 million of annual spending power to just £30 million. That is a massive drop and although I understand where some of it came from (exchange rates and loans, for example), it always seems to hark back to a more general problem of bad management. The merger of PPARC and the CCLRC was clearly a disaster – you cannot merge two financial entities, remove a huge chunk of money and expect everything to be hunky-dory.

The management of the fallout from that merger was also appalling and confusing. The best example was in a town hall meeting at the 2008 National Astronomy Meeting. A student who asked why he should ‘take the risk’ of studying solar physics when there were now going to be no UK jobs in the field was told by the head-honchos of UK astronomy that he could either wait ten years or go and work abroad. Brilliant.

The STFC – like many other organisations and individuals – isn’t standing up and fighting for science enough. With the current economic climate you can see how education and hospitals might get defacto precedent over radio telescopes and PhD grants – but the truth is that there IS money around still – just not as much. If astronomy doesn’t fight for it then someone else will obviously get it – we shouldn’t just willingly roll over and perish. If the STFC won’t argue the case for the benefits to society from astrophysics research then who will?

Finally there is the issue of people vs. facilities. Job security in UK astronomy is rock-bottom right now and not just because of these looming budget cuts. The rolling grants that sustain many researchers in the UK  - including many of my friends at Cardiff University – are reducing dramatically and coming up for review more often. In short many people no longer know if they’ll have a job from one year to the next. This is terrible for recruitment and terrible for morale. I have joked before about the deathly way in which we are sometimes told of colleagues ‘leaving astronomy’ – something that is almost always a one-way shift – but for many UK astronomers at the moment this is likely the sound option if you have a family or a mortgage. It usually pays better too.

The tragedy is that as 2009, the International Year of Astronomy, comes to a close, astronomy in the UK sits under an ironic cloud. Having spent the year trying to inspire the country to become excited by astronomy, many professional astronomers may go into 2010 as financial analysts, software developers or web designers. This country has an incredible astronomical history and, although I’m sure that will continue in the long term, it will be a very sad thing if tomorrow we learn that 70% of UK astronomy is no more. There is surely some other approach to the problem than slashing budgets, culling jobs and pretending that this is the direction we were aiming for all along.

If anyone on the STFC Council is reading – and I doubt they are – how about holding steadfast to the people instead of the facilities? You can always buy back into some telescope down the road but you’ll not get back the postdoc who is forced to leave to go work for a bank. How about making the case for UK astronomy and fighting for more money from the government?

Just a few observations. Like I say, I don’t know enough about all this. I’ve probably oversimplified it and brushed over the details. But it affects me and my family, it affects my country and my future and since I have a voice in this blog, I might as well use it. I hope I’ve got it all wrong and I await the news tomorrow afternoon. But I have a feeling this Christmas will be a crappy one for far too many astronomers.

UPDATE: In view of Amanda’s comments below I’d thought I’d add that if you want to try to help save astronomy you should visit http://www.saveastronomy.org.uk/ and take a look around. You can write to your MP, as I have done, and just tell people about it. They have examples of letters, links to online petitions and general information. You can also read Paul Crowther’s website which explains every part of this disaster in stunning detail.

This means that each year I have spent probably too much time thinking about nice, simple physics demonstrations that vaguely relate the the holiday season. One of my favourites is the one I concocted to try to demonstrate the principles of teleportation using LEGO.

The only way I can think that Santa might be able to deliver so many presents in just 31 hours (think about it) is that he must be able to teleport – unless he can time travel. If he delivered all the presents by parking the sleigh, descending into the house and laying them out then it would take him thousands of years to get the job done.

To demonstrate teleportation in a lecture theatre turns out to be quite easy – and fun. You need some LEGO and a bench with a dividing screen on it. After a brief preamble explaining the basics of teleportation you ask for two volunteers to act as ‘supercomputers’. You give one a small LEGO model of Santa and ask them to disassemble the model and put the pieces in a pot. Then the pieces are passed to the second ‘supercomputer’ who has to reassemble the model with only the pieces and instructions from the first volunteer. This is done under a time limit for a bit of extra excitement. They will almost undoubtedly not reassemble Santa correctly and this can be very funny by itself.

It illustrates rather nicely how much information storage/transmission would be required to teleport something as they do in Star Trek. There is also the issue of the nature of the LEGO blocks themselves. If you pass the same pieces over then you have to explain how that would be done. Alternatively you can use other identical pieces but then is that really the same Santa that you started with?