Goodbye Ulysses

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This will be very brief as (a) I’m not a solar astronomer so (b) I don’t really know very much about this spacecraft, but as one of the longest running space missions I think we should mark its passing. The Ulysses satellite was launched on 6th October 1990 and has been observing the solar environment at all latitudes ever since – a remarkable 18 years, 9 months (and this is without any servicing or repair visits, unlike the equally long-lasting Hubble Space Telescope). Today at around 2100 GMT the final command – to turn off its transmitter – will be sent and the mission will be officially over.


Ulysses was the first solar satellite to have a polar orbit (i.e. unlike the Earth, which stays in the region of the Sun’s equator, it passed over its poles), meaning that it could map previously unexplored regions of the heliosphere. There’s a good movie of its orbit here. In total it orbited the Sun three times, meaning it managed a total of six polar passes.

The mission has already lasted four times as long as originally predicted but the weakening power supply, combining with diminishing scientific returns means that sadly its time is now up.

Volcanoes from space (not space volcanoes)


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This amazing image of an erupting volcano was a lucky shot taken by the astronauts in the International Space Station, whose orbit just happened to pass over it at the right moment. Now I know that technically this blog is supposed to be about things outside the Earth, which should rule out this picture, but I’m making an exception as it comes from NASA! The volcano itself is called Sarychev Peak and it’s located in the Kuril Islands, northeast of Japan and the picture was taken with a normal digital camera, fitted with a 400 mm lens.

I didn’t realise until I investigated this photo further that the astronauts on the Space Station are trained, assisted and encouraged to take photos like this by NASA’s Image Science & Analysis Laboratory. All the resulting images are also available on the internet at The Gateway to Astronaut Photography of Earth. There are over 600,000 photos on the site, including images from the earliest space missions so they form an important scientific resource for people studying how the Earth has changed over the past decades. It can also provide the answers to some less serious questions…

If you’re interested in volcanoes, more information on the photo (reference: ISS020-E-9048) can be found here.

Shoot an X-shooter

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Many things and people have cocktails named in their honour. Bombers, comic book characters and even a dodgy U.S. president. But none as far as I know have been named after an astronomical instrument, until now….

Recently on Paranal a new spectrograph was commissioned for one of the elements of the Very Large Telescope. Spectrographs (as the name suggests) split the light from astronomical objects into spectra. These can be used examine what elements are present in the object, what physical processes are going on in or on it and also to measure things like the gravity, temperature or magnetic field strength of the objects. Most spectrographs can only take spectra in one small colour range at a time. This means that if you want information about an object across a range of wavelengths (say from visible light to the infrared) then you need to make several observations often using several different instruments separated by days, months or even years. If the object you are studying varies with time this could be a bit of a problem. This is where the new X-shooter
instrument built in the Netherlands, Italy, France and Denmark comes in. It is actually three spectrographs combined, an ultraviolet-blue arm, an arm covering visible light and a near-infrared arm. This means astronomers studying a fast fading Gamma-Ray burst or a rapidly varying interacting binary star system can now get information about them over a wide spectral range at the same time.

Now to the important bit. As part of the X-shooter instrument was built in Nijmegen, a small drinks reception was planned to celebrate the instrument’s commissioning. It was suggested that as the instrument had shooter in its name, it deserved a shooter named in its honour. Obviously the three component spectrographs indicated that a cocktail of liquids of three different colours would be required. Unfortunately everyone was too busy with trivial things like data reduction and writing papers to design the cocktail, so the drinks came and went with no cocktail and much raw herring (this is the Netherlands). However my colleague Andreas (who I shall now christen mix-master) went away, plotted, experimented and at a recent party he set about making his X-shooters. Luckily the astronomers here like cocktails (apparently this is quite common) and they were willing to put Andreas’ creation to the test.

The result was described as being “sweet” and “refreshing”.

If you want to make your own X-shooter (the drink, not the spectrograph, orbiting frog has that covered) you will need,

1 part blue Curacao
1 part white rum
1 part orange syrup
1 part blackcurrant syrup

Mix the rum and orange syrup in the shot glass to make the visual component, then pour in the blackcurrant syrup (the near IR component). The denser blackcurrant should sink to the bottom of the glass. All that is left is to pour the blue Curacao in over a spoon to add the UV-blue component.

So anyone willing to try an X-shooter or to suggest their own astronomy themed cocktails? Suggestions please….

First Herschel PACS images out

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The first images from one of Herschel’s cameras are out! While not from the spire instrument which was worked on at Edinburgh this is still pretty exciting!

In a Bose–Einstein condensate no one can hear you scream!

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ok perhaps not as catchy as “in space no one can hear you scream!” but its a pretty apt description of the work of a number of condensed matter physisits who have recent created the worlds first acoustic black hole. Now I know what you are thinking … it was the same thought I had as soon as I heard about this work : acoustic black hole + coldplay = a better world for us all. In my head its like those flying flat prison things from superman … but we let out the brutal superhuman dictator and replace him with the far greater evil of coldplay

Seriously though this is some really cool stuff. As we all know in our current theory of gravity, matter and energy bend space and time around it and in turn light and matter will move along the contours of this curvature. In a black hole the density of the matter/energy doing the warping of space time is so great that light (and everything else) is unable to escape from that region. Now what you might not have known (I certainly didn’t!) is that it turns out that in a certain state of matter, known as a Bose-Einstein condensate, the equations which govern the paths of sound through the matter are the same as those which govern how light travels along the curvature of space. This throws up an pretty intriguing idea: could we create within a Bose-Einstein condensate a region from which no sound can escape? A form of  coldplay prison acoustic black hole?

Well it turns out that not only is the answer a resounding “hell yeah!” but some scientists form the Israel Institute of Technology, in Haifa have done just that. They created a region within the Bose-Einstein condensate which had a  supersonic flow, that is the material which makes up the condensate is moving faster than sound. Within this region little packets of sound called phonons (an analogous version of photons but for sound instead of light) can never escape this region. Its sort of like running on one of those flat escalators that you get at airports, if its moving faster than you can run you can never get off it. The border between the supersonic region and the rest of the condensate then acts like an event horizon in regular black holes.

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Superhero science

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One of the things I love about science is how in some rare cases it can make the seemingly impossible happen. Its something that’s encapsulated in Arthur C Clark’s third law:

“Any sufficiently advanced technology is indistinguishable from magic”

Or as I think should the moto of all engineers and product designers:

“Any technology distinguishable from magic is insufficiently advanced.”

Occasionally working in science and actually more often science communication you come across situations where despite knowing exactly how something works it still feels like there is a little bit of real magic in the world. I think this is why a lot of the same people who get in to science also love movies and books about fantasy and the fantastic, regardless of the world or setting they are always looking for things that simple make them think : hell yeah that’s cool!

A while ago we had a visit form Ben Craven, a master of creating magic from science. At a workshop for science communication Ben brought along a bag of his tricks to wow us all. After messing with our sense of colour and got us scrattching our heads with his gravity defying machine (well perhaps intuition defying would be a better description) he allowed us for a brief few minutes to pretend like we where fire wielding superheroes. While I look a little nonchalant about my new super power I think that the expression on Rita’s face conveys how unbelievably cool this felt. Of course the real magic is that it isnt really magic at all. Ben simply bubbled some gas through a soapy water solution to make bubbles full of flammable gas,  a little water on our hands to stop them burning and a healthy deposit of the magic bubbles later and you have your very own flaming hand! AWESOME.

Some people will say that knowing the ticks destroys the magic. The same people will usually also tell you that knowing what causes the aurora or why the sunset is the colour it is takes away from their beauty. I know it’s a sentiment that has been expressed before by many people but whenever I get to do things like set my hand on fire it just reminds me of how wrong these people are. The wonder is in the explanation, the magic is in the ability to make something cool happen within the rules of nature not by breaking them … and I always want to know the secret to the magic trick.

Incidentally we are still waiting for our invitation to join the xmen

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I recently came across this comic, which nicely encapsulates part of my difficulty in blogging about Astronomy, especially to a completely unspecified audience. I’m easily excitable, and will get a kick out of most of what this physical world can throw at me. Also chocolate. However, I fear that sometimes the usual perception that the rest of world might not share this enthusiasm of well… everything.. can hold me back. Well, not here. It might not be wireless, chocolate-empowered robots which will ultimately destroy the world, but if I think it’s cool, there’s a chance you might too. Watch this space!

Herschel can see!

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The Herschel Space Observatory, launched last month, achieved an important milestone this morning when the command to fire the bolts holding down the cryocover appears to have been executed successfully. The cover has been protecting the three science instruments from being contaminated during (and shortly after) launch. If this had failed the telescope would be blind (known in the trade as a ‘single point failure’), making it a tense moment for everyone involved in the project! There’s still a lot of work to be done in commissioning and testing though until the telescope can start its routine operations, but this is a very important step on the way.

There’s a neat video on youtube which shows what would have happened in slow motion.

What would a pulsar look like close up?

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I was in a long discussion at work about pulsars when a slightly odd question hit me. What would a pulsar look like close up? In sci-fi films and TV series often a spaceship or spacestation is orbiting a planet covered in continents and oceans like the Earth or swirling clouds a la Jupiter. Sometimes they may even be in orbit close to a star with spectacular coronal loops reaching up to lick at the craft’s hull. But what would the view from such a craft be if it were circling a pulsar? Let’s leave aside the fact that you may get fried by the radiation coming from the pulsar and consider what the surface of one of these objects is actually like.

A pulsar is a rapidly spinning neutron star, the dense remains of a star more than eight times the mass of the Sun that has spectacularly exploded in a supernova. What is left is 10-20km across, 1.4 to 2 solar masses and rapidly rotating.
The Crab Pulsar, Credit: NASA/CXC/SAOThese fire out massive amounts of radio emission from their magnetic poles and when one of these points towards the Earth a radio pulse is detected. As these objects spin so fast many pulses a second can be detected, hence the name pulsar. In the centre of the swirling X-ray emission in the picture on the left is the Crab Pulsar (Credit:NASA/CXC/SAO). This remnant of a supernova explosion seen in 1054 spins 30 times per second. As well as radio emission, the pulsar emits bright visible light from the area near each pole in addition visible light from its hot surface.

As you can probably guess neutron stars are quite dense. Imagine if it started snowing flakes with the density of the material in a neutron star. Two inches of this neutron star snow covering Amsterdam (or just one inch covering Andorra) would have the same mass as the Earth. It is thought that these objects have a solid outer crust a few kilometres thick with some kind of fluid interior. Like on the Earth this crust can sometimes fracture and this causes a
starquake. These can be used to tell a bit about the internal structure of the star. What would these quakes look like? Well there is this
rather cool animation which seems to show fractures in the surface. One study predicts that neutron star crusts may be strong enough to support mountains despite the extremely high gravity of these objects. But these would only be a few centimetres high so clearly this is the Danish definition of a mountain.

So neutron stars have quakes causing fractures in their surface, brighter optical emission from each magnetic pole and maybe (very, very, very small) mountains. However you have to remember these things are going round tens or (in the case of millisecond pulsars) hundreds of times a second. Hence any surface features would probably be blurred out when viewed from our hypothetical spacecraft. So what would a pulsar look like close up? Well my best guess is like this.

Shrinking stars

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Betelgeuse is one of the brightest stars in the constellation of Orion. Its name apparently translates as the “Warrior’s Armpit” which pretty accurately describes its location! It is a red supergiant star which basically means that it is very large (about 20 times bigger than the sun), short lived and nearing the end of its life. Stars of this type die in a spectacular explosion known as a supernova, following a massive internal collapse.

New results presented this week at a conference in America suggest that since 1993 Betelgeuse has shrunk in size by around 15%, which could be a sign that this explosion is imminent. Of course, this is not the only possible explanation for the difference – it could be an illusion caused by the star’s bumpy surface (which can make it look smaller from certain angles) or it could just be a long term wobble, and it will eventually grow again. I know this is all very vague but the thought that it might explode within my lifetime is really exciting – it’s likely to be so bright that it’ll even be visible in the daytime sky for several months.

Conferences always throw up interesting stories like this that get picked up by the press. Unfortunately, this result is being overshadowed in the UK by this story (though I think this may be because of the accompanying animation and ‘end of the world’ overtones). Personally, I think the possibility that we might get to see a supernova in action close up is definitely more interesting. I’ll certainly be looking out for it!