The startling reaction between Diet Coke and Mentos sweets, made famous in thousands of YouTube videos, finally has a scientific explanation.

If you drop a pack of Mentos into a bottle of Diet Coke, you get this huge fountain of spray and Diet Coke foam coming out,” says Tonya Coffey, a physicist at Appalachian State University in Boone, North Carolina. “This was a good project for my students to study because there was still some mystery to it.”

Experiments in a 2006 edition of the Discovery Channel programme Mythbusters suggested the chemicals responsible for the reaction are gum arabic and gelatine in the sweets, and caffeine, potassium benzoate and aspartame in the Coke. But there have been no rigorous scientific studies of the reaction until now…

ABC News: Mentos-Diet Coke Explosions Explained

I rather like this one!

xkcd - A webcomic of romance, sarcasm, math, and language - By Randall Munroe

I can hardly type this without thinking of the Muppets’ ‘Pigs in Space’. Whilst writing about space debris recently, and preparing to do a talk on the subject of stuff that we’ve put into space, I got to once again thinking about those frogs that NASA put into space in 1970 (for which this very blog is named).

How many other animals have been put into space and why? Looking into the subject, it’s quite entertaining. so here’s my top ten list of animals sent into space:

10. Flies

In 1942 the first animals were put into space. they were ironically flies. Fruit flies and corn seeds took a one way trip on a US V2 rocket, (you know the ones they built using Nazi technology and slaves).

9. Dogs

On November 3rd, 1957 the first animal in orbit was Laika, the Russian space dog. She flew aboard Sputnik 2 and died during the flight. The Soviets flew 10 more dogs on that programme until April 12, 1961 when Yuri Gagarin became the first man in orbit.

Belka and Strelka (seriously, who named these dogs?) were the first mammals to be successfully returned to the Earth after orbital flight in 1960. you can them in the picture. The other canine record holders are Veterok and Ugolyok, two dogs that spent 22 days in space before returning unharmed in 1966.

Strelka’s puppy, Pushinka was given as a present to the Kennedys and many of her descendants are known still today.

8. Fish

Several fish have visited space. specifically the species Mummichog, Japanese Killfish and Zebra Danio. The Killfish were in fact the only survivors of the Columbia distaster.

More than anything I was simply pleased to find out there is an animal called a Mummichog.

7. Spiders

Experimenting with low gravity environments is obviously a big reason behind putting animals in space. So can a spider build a web in orbit? The answer is yes. Anita and Arabella were two garden spiders that flew on SkyLab in 1973.

The webs were seen to be finer that on Earth and to have variations in thickness throughout each web, unlike the highly uniform webs spun on Earth. Anit’s remains are still kept in a jar at the Smithsonian for all to see. You can see her web above.

6. Cats

Two cats have graced the skies, both put there by the French. The first was Felix in 1963, who survived his trip despite having electrodes implanted into his brain. The second cat’s name does not seem to be obvious, but he did not survive. I can has spacesuit?

5. Newts

In 1985, the Russians sent 10 newts into space after amputating their forearms. They were trying to study the regeneration of cells in low-gravity.

4. Mice and Rats

Many mice have been into space. The US reportedly put loads of them up there in the 1950s, but only the first one survived. In the 1960s, China, the USA and Russia all put many mice into space and into orbit. Nothing much seems to have come of this so far as popular culture is concerned. Douglas Adams, may have had other things to say about that though.

Russia flew rats and mice, as well as hordes of other animals, during its Bion programs in the 60s and 70s. Bion spacecraft (shown above) were designed to test organisms in space. As you can see they look very comfortable. If only NASA had made them, they would have at least had cupholders.

3. Frogs

My favourite space dwellers are the Orbiting Frogs that were sent up in 1970. Why? Well of course it was to sudy motion sickness in space. Don’t you know that frogs get carsick?

The Orbiting Frog Otolith housed the bullfrogs for a week as they circled the Earth. Scientists measured their vital signs and once the experiment was over the simply left the frogs to work it out for themselves. Needless to say it pleases and disturbs me greatly that there are possibly still two frogs up there somewhere.

Also, Toyohiro Akiyama, a Japanese journalist, carried a tree frog with him on a visit to Mir in 1990.

2. Tortoises

The tortoise is held in my esteem on this blog entry because it is the unlikely holder of not one, but two space records! In 1968 a Russian Tortoise became the first animal to go into deep space when it orbited the Moon and returned safely to the Earth.

There must be something about Tortoises that Russian space scientists like (or dislike) because a Tortoise also hold the record for longest flight time in orbit. In 1976 two tortoise and a fish spent 90.5 days in orbit on Salyut 5. They were never recovered and the craft burned up during re-entry in 1977.

1. Monkeys

Of course I had to end with monkeys. On June 11th, 1948 a monkey named Albert was the first to be put into space by NASA. He was under anesthetic during the launch and never returned. Many other monkeys have famously been put into space.

In 1959, Able and Baker, a rhesus and squirrel monkey respectively, were the first to survive spaceflight. It sounds like the premise of a Warner Brothers’ cartoon. They were placed in the nosecone of a missile and shot nearly 400 hundred miles above the surface of the Earth and over a distance of 1,700 miles. They travelled at 100,000 mph for 16 minutes. Needless to say they experience G-forces above and beyond anything normal (Wikipedia says 16g).

Able died a few days later from complications related to one of his implanted electrodes, but Baker lived until 1984 in the NASA Spaceflight centre in Huntsville, Alabama, possibly running the place.

In 1961, Ham the Chimp was launched into orbit. He was been trained to operate his craft (seriously, Warner Bros again?). He survived and lived a life of luxury afterwards. He appeared many times on television and even starred in a film with Evel Knievel!

17 more monkeys and chimps were flown in the years that followed, by the US, Russia and France, including two that went up on one of the first space shuttle missions.

I would like to end on the tragic is the story of Gordo. A young squirrel monkey from South America, Gordo also flew in the nosecone of a missile. In fact he paved the way for Able and Baker to do so more successfully a year later. He rocketed upward and survived the 10g launch, to the delight of NASA supervisors. However, during the 100,000 mph re-entry, whilst experiencing a whopping 40g, Gordo’s parachute failed to deploy. The squirrel monkey, sealed in the nosecone, sonicly-boomed into the ocean, more than a 1000 miles from Florida. He has never been recovered.

Originally posted in August 2007.

There was a New Scientist feature last week on Boltzmann Brains. Now I hadn’t heard of these before, and so I thought it may be worth a blog post. A Blotzmann Brain is an intelligent, self-aware entity which arises as the result of a random fluctuation in the entropy of the universe.

I have put this post back on the front page for a while as it has generated some comments since the New York Times ran an article on the same topic (Link)

Lugwig Boltzmann suggested, by invoking the anthropic principle, that we are all here thanks to an extremely unlikely low-entropy fluctuation. If you consider the notion of a virtually infinite inflationary universe then such an organised blip is not only possible but eventually inevitable.

This leads to an interesting conclusion. Our planet sits here with myriad trillions of extremely organised organic beings, not to mention billions of intelligent human brains (mostly). If we can exist here, representing a very high order system indeed, then any lower order systems must also exist in greater numbers. An example of a lower order system would be a Boltzmann Brain, simply a conscious being floating in the universe, able to know what it is.

So are we in fact outnumbered in this universe of ours by Boltzmann Brains? If so then Cosmology is heading for trouble. Much of cosmology is based on the idea that we are typical observers in a typical part of the universe. If the Boltzmann Brains are sitting out there in their trillions, all over the dark void of empty space then we are not typical, they are. Does this change the nature of cosmology, or of the nature of the universe as we understand it.

Let me add one final odd point to this peculiar topic. It is far more likely that rather than a solar system and a planet on which sit six billion individual, intelligent brains, the universe would actually create a singular brain pre-programmed with false memories and experiences, unaware of its true nature as giant floating head. So maybe our individual experience is not so different to that of a Boltzmann Brain after all.

If the tail was smarter, the tail would wag the dog.

Two things have just come back to me at the same time and collided wonderfully, thanks to an article over at Universe Today. The article is one about the liquid mirror telescope that a NASA researcher proposes could be built on the Moon in the near(ish) future. The eagle-eyed among you may recalled I blogged the same story back in May, thanks to a link from Wired.

This isn’t me trying to say ‘I got the scoop’, because clearly I didn’t, but it got me thinking about the effect the internet can have on science. I think about the internet quite a bit, and its possible long-term influence on our culture. In fact my friend writes a blog about the internet and its effect on literature and fiction. Also, I found myself an almost-expert on blogs in recent years. So I would say I was a knowledgeable person on the matter.

The Wired article, so far as I can tell, was an original piece (compared to my own which was a link to it). They had interviewed this guy, Roger Angel, and created a journalistic piece on his research for NASA. Digg found the story, as did a host of other astronomy and science blogs (I can’t be bothered to link to all of them) and it did the rounds in the blogosphere. That was all back at the end of May. now, one month later an official NASA news release describes how the technical article for a giant liquid mirror telescope has been made public etc etc. The article is to appear in Nature.

So what happened? Clearly the internet knew about this before Nature could publish it. So this concept had reached the public domain before the journals had processed it. I rather like this fact and it was the first thing that occurred to me when I realised the echoed story had occurred.

The other thing that came back to me today was a book called ‘The Long Tail’, by Chris Anderson the editor of Wired magazine (a coincidence!). I found out it is out in paperback, but I listened to in on audiobook a while ago. The book outlines how massive niche markets have been shaping the economy in recent years thanks to the internet and sites such as eBay, iTunes and Amazon. It turns out that millions of highly selective minor purchases (such as niche music on iTunes) actually make up most of the sales compared with the more popular, mass marketed items (i.e. hit songs). Once the restriction of shelf space is removed, retailers no longer have to only stock certain items and the internet provides a forum for distributing digital media on an unlimited scale. No shelves required. Well its a great book - read it.

Anyway, my point is that science could easily go the way of entertainment because it is now digital. Papers no longer need to be published by journals to be read, they are instead deposited on vast pre-print archives online. Good ideas that capture minds can be distributed via the niche interest blogs, email, and within university department - all instantaneously and without the restriction of paper, time and money.

I am finishing my first year of an astronomy PhD and have never, not once so far, picked up and read any edition of any journal. Weird, huh? Not really, I get an automatic daily email from the astro-ph pre-print server and I browse a daily list of new articles and papers related to my subject. I can also just as easily read a Canadian or Japanese paper as a UK one.

So what about the liquid telescope? Well it seems that in this case, Wired beat Nature to the scoop. In fact there is very little about astronomy which Nature picks up, that I do not hear about first from some other source. Now maybe at this point we still need Nature to tell us, retrospectively, what was important and notable. Perhaps they have the skill as mavens of interestingness.
Imagine if the ocean of scientific ideas was truly democratic, in the internet sense of the word. I don’t know what it would mean for science long-term but I have a feeling that if it could be kept free of the corrupting influence of marketing, then an open source science community could be the future of many discplines.

Digg.com’s science categories are - on the whole - reflective of current interests and may act as an experiment of sorts. The question is whether the old boy’s club of astronomy will be open to the idea of the internet in their lives. I shall be watching very closely.

Following last week’s open letter to the AQA, Wellington Grey has posted on his blog to thank everyone for their support. It seems he had quite a response, being linked from digg, reddit and boingboing. He has followed it up with two things.

The first is an online petition, which Wellington himself says is most probably futile, but there it is none the less. At this time, the link to the petition from Wellington’s site was not working and I couldn’t find any trace of it via the government site’s search.

Secondly though, and back to form perhaps, Wellington Grey presents a new cartoon, this one outlining ‘The New Physics Exam‘. Note that question 3 is a real one from an AQA textbook.

Wellington Grey is a guy I just read about on BoingBoing. He is a physics teacher in the UK who is currently very irked by the teaching of his subject (I agree) and on the side he makes fun diagrams, including the recent WiFi will kill yours babies one.

Not incidentally, his open letter to the AQA about the teaching of physics is excellent and everyone in the UK should take heed of what is happening all over the sciences in particular. Here are some extracts which anyone should think hard about.

…this past academic year things changed. The Department for Education and the AQA board brought in a new syllabus for the sciences… While my colleagues expressed scepticism, I was hopeful. After all, most pupils will not follow science at a higher level, so we should at least impart them with a sense of what it can tell us about our universe. That did not happen

Wellington Grey then goes on to explain that he thinks the problems fall into four categories: the vague, the stupid, the political, and the non-science. In order these are then dissected and explained in turn. My favourite is from the stupid category:

One questions asks `why would radio stations broadcast digital signals rather than analogue signals?’ An acceptable answer is ‘can be processed by computer / ipod [sic]‘ Aside from the stupidity of the answer, (iPods, at the time of this writing, don’t have radio turners and computers can process analogue signals) writing the mark scheme in this way is thoughtless, as teachers can only give marks that exactly match its language. So does the pupil get the mark if they mention any other mp3 player? Technically, no.

In conclusion, Wellington implies that he is not only dissatisfied but tempted to leave He asks that the AQA let him do his job. He also offers advice to people like me who may be tempted by teaching in the near future.

There is a teacher shortage in this country, but if a physicist asked my advice on becoming a teacher, I would have to say: don’t. Don’t unless you want to watch a subject you love dismantled.

I hope that the AQA pays attention.

The Darwin Lecture for the National Astronomy Meeting 2007 was given by Dr. Reinhard Genzel. He spoke about the black hole which sits at the centre of the Milky Way, our own galaxy.

Early infrared astronomy showed very fast motions in the central mass of the galaxy. 20 years later we still agree with these early results but now have other data which confirms the existence of Sagittarius A*, the black hole in the middle of the Milky Way.

VLBA measurements have shown that Sgr A* does not move with respect the centre of the galaxy. Observations of nearby stars orbiting Sgr A* have velocities which suggest it is a supermassive black hole. There is relatively low amounts of gas spiraling onto Sagittarius A*, perhaps because in such active regions, supernovae have blown away much of it away.

Although this is by far the closest supermassive black hole, it is still hard to study because there are many thick clouds of interstellar dust, which absorb visible light, between us and Sgr A*. Astronomers rely on X-rays, radio waves, and other wavelengths of energy to study the Milky Way’s core.

The object is 8,000 parsec away (~27,000 light years) and is thought to have a mass of around 3 million times that of the Sun. That’s big! It is believed tha this beast of a black hole holds in its gravity more than 100 of the galaxies most massive and energetic OB Stars within just a few light years and these stars may be the evidence that gives it away, as seen in this animation.

Sgr A* also has the peculiar property that it experiences a periodic burst of brightness every few hours, for an hour or so. This may be the result of it swallowing up material and releasing energy or even of objects careeering into each other as they in turn infall into this monstrous gravity guzzler.

Reinhard Genzel has been working on this object for some time, amongst other things, and so his talk on thse subject was excellent. It was a pleasure to hear someone speak on a topic that doesn’t end up being an utter mystery or controversy for a change. That’s not to say that Sgr A* is all wrapped up, because it certainly isn’t. This is an object that will remain a topic of intense study for some time and no doubt Genzel will be at the front of it.

I know this is literally yesterday’s news but here is my take on the story anyway. Researchers using the ESO 3.6m telescope in Chile have analysed the wobble of a star known as Gliese 581 (centre of starfield below). This star is about 20 light years away. Previously, a Neptune-like planet was found around this star by people using the HARPS data.

Now the new research shows that there three planets, currently designated Gliese 581b, c and d (a is the star). The c planet is the Earth-like object. With a mass five time that of Earth and a diameter about 1.5 times. Using the fun AstroGrav software, which models masses such as solar systems as they interact via gravity, I made a mock up of the Gliese 581 system to help better visualise it using th data given in the paper.

So naturally the similarity in size and orbit, with the temperatures needed for liquid water (and thus life as we know it) has lead to much speculation on the news (bloody BBC Breakfast!) that this is our best best for life so far. Whilst this is true, it involves two large assumptions that are so far unfounded. There is no reason to think there is water on this planet. Not a single molecule of it necessarily exists and we will need to work very hard to detect it given its distance and that it sits in an (as far we know) three planet system.Secondly, we really don’t know anything about this little planet.

Yes, it is exciting that as our method improve we can find smaller and more Earth-like planets. However there is nothing to indicate that this planet looks anything like the Earth.Now don’t get me wrong, I am excited by this discovery. The indication, as I just said, that we might be able to pick out such tiny planets in the galaxy and relatively nearby is very exciting. This world has very strong gravity and a neighbour planet that flies through its sky every few days, possibly causing subtle eclipses and displaying rapidly changing phases like our Moon. Such an exotic world inspires the imagination and i hope that as we discover ever-more Earthy worlds we can see how our way of existing is just one of millions of possibilities in our galaxy alone.

So to conclude I shall change my tone. Yesterday we had news of the most Earth-like planet yet discovered. The cool thing though, is that we haven’t even begun our search for these terrestrial worlds really. The telescopes and techniques that are coming into use in the nest few years will completely bow away this amazing find. In about twenty or so year we might be lucky enough to even see a picture of one of these worlds. Maybe it will have continents and oceans like our own, maybe it will be more exotic than we had ever dreamed.

Maybe someone will be looking back.

These days we’ve all seen pictures of other worlds in stunning detail. We are familiar with pictures of the Moon and of the Earth and well know that the circles we see online and on paper are really globes, floating around in outer space. Now NASA’s STEREO mission to observe the Sun as it interacts with the Earth is giving us our first 3D images of real events. Anyone can knock up a computer generated model of the Sun or anything else but these are real images taken of the star we see in our skies everyday (well that’s an exaggeration, I suppose).

You’ll need to dig out a pair of standard 3D glasses to see the current slew of pictures and videos but they are well worth it. You can watch solar flares in 3D and see the Sun rotate. At present the videos are sadly not very high resolution, but the images are and look quite stunning, click on the ones below for larger versions. I hope that someone can reprocess these in different ways to enhance the 3D component as i’m sure there are clever things to be done.

The STEREO mission is made up of two identical spacecraft called STEREO-A and -B. The A (for After) craft trails behind the Earth in its orbit around the Sun, whilst the B(efore) craft goes ahead of us. The twin craft are loaded with scientific instruments for measuring the material ejected from the Sun and how it interacts with the Earth. This is the same material that causes the aurora here on Earth and which can damaged power grids and satellites or even kill astronauts.

As time goes by the two craft will move about, changing their angle of viewing of the Sun and Earth. This will enable better creation of 3D images amongst other things, but more importantly will give researchers a fuller view of the relationship between the Sun and Earth, which is now a very large field in astrophysics, as was demonstrated by the huge number and variety if talks on the subject at NAM.

STEREO has only just begun to take real observations in the past couple of weeks and new and exciting data and images are sure to start pouring onto the internet and into journals.

The image above shows the Bullet Cluster. Also known as 1E 0657-56, this is a pair of clusters of galaxies some 3.4 billion light years away. As Jon Davies told us in yesterday’s Astrolunch meeting however: you should be careful about believing everything you see. This image is not a regular photograph by any means. You can see the galaxies scattered about with an orange glow. This much is familiar. Layered onto this optical data is the pink, X-Ray picture from the Chandra telescope. This pink light is actually the high energy X-Ray radiation from a hot gas that permeates the cluster. Again though it is not unusual to see two different wavelength regimes seen in the same photograph.

What is unusual is that the blue ‘light’ seen here is not photographic in nature at all. It is the location of the mass in this region deduced by weak gravitational lensing - it is not a real effect but rather a mathematical interpretation of where the mass should be. As you can see it does not line up with the visual traces of the mass that we see as light and X-Ray material.

This is because it is believed that the Bullet Cluster shows us quite nicely where the dark matter can be found in this cluster. The interpretation of this image by the researchers who have studied it is that the hot, pink gas is the energy released by ordinary matter in this pair of clusters as they have collided with one another. The energy of the collision has excited the gas to emit in the X-Ray.

However not all the mass in the region is ordinary (something believed to be true about most of the universe). Dark matter is material that has mas but doesn’t interact with other, ordinary matter by the usual routes. It does not feel magnetism, or electrical forces or emit light. But is stays tethered to the ordinary matter by gravity alone.

As these two clusters collided the dark matter passed through like an ordinary pair of gaseous objects would, where as the regular, every day material became heated and disturbed and distorted in shape.

There is a wonderful video of a simulation of this hypothetical collision which you can find here.

This lovely picture adds to the already heated debate among the astrophysical community as to the existence of dark matter.

Day two of the UK’s National Astronomy Meeting was very good. It started with two excellent talks given by two excellent speakers. It ended with drinks and dancing at Preston’s National football Museum (odd venue choice, in my opinion).

The day began with a talk titled ‘50 Years of Nucleosynthesis’ and it was given by Dr. Amanda Karakas of the Mount Stromlo Observatory in Australia. She is interested, essentially, in the chemicals that stars make and the nuclear reactions that go on inside them at various times in their lives. Her talk was a tribute to an article called ‘Synthesis of the Elements in Stars’ by Burbidge, Burbidge, Fowler & Hoyle which first appeared in 1957. The paper changed the way people thought about what happened inside stars. It was an excellent overview of the various nuclear processes that are taken almost for granted now but which were a brilliant insight back in ‘57.

The second talk was called ‘The Angry Sun’ and was given by Jim Klimchuck who is a researcher as the US Naval Laboratory. He gave a very entertaining talk which finally helped me understand a few mysteries about the Sun and particularly its fierce coronal mass ejections. You’ll find one such video here. I’ll be putting up more soon.

The day ended with the Conference Dinner and Ceilidh at the National Football Museum at which I took some cool photos including the one at the top of this blog post. A good day - much better than day one - hoping day three matches up.

Dydd G?yl Dewi yn y Labordy Ffiseg

Originally uploaded by huwwaters.

I don’t speak Welsh but assume this says something like ‘daffodil that was frozen in nitrogen and then crushed during first year physics lab’. I know that because I crushed and froze it myself and this photo was taken by one of the lab students, Huw Waters.

The daffodil only took a few seconds to freeze after I dipped it into the liquid nitrogen. We then crushed it as it had the texture of tissue paper and I held it for a moment until the cold started to seep through the glove. I placed the yellow shards onto the black plastic mat and then later we put another, unscathed, daff next to it as a nice comparison.

This was of course all in aid of St. David’s Day which is on March 1st and in Wales at least, a big deal. I hereby chair Huw as the bard for this lovely photo and curse myself for next bringing my camera along. Next week: we freeze bananas!

So I got my PhD in Cardiff and formally accepted it today. good news, yay etc. I am very excited and have made myself a little something to get me more excited still about one day being an astronomer man.

In the end I received offers from both Cardiff and Exeter and deciding between them was tricky but in the end it had to be Cardiff for so many reasons that i shan’t bore this blog with. It was win win though in reality since both departments seem to be fantastic and filled with very nice people.

So I may end up gazing to the stars for a living one day, maybe even a proper astronomer. In the meantime though I’m looking forward to doing a good PhD and learning lots about the world above me.