Sun's Destiny in Dust Shells

Dust Rings around CW Leonia, Image credit ESA/PACS/MESS & ESO/VLT 

A team of astrophysicists, led by Professor Leen Dacin at K U Leuven, have made an amazing discovery. The research, published in Astronomy & Astrophysics, shows dozens of cold dust arcs around a giant star known as CW Leo. Leo, a late-stage red giant star, gives us an insight into how our own Sun may look in 4.5 billion years time.

            Stunning new images showing dust shells emitted at intervals of 500 to 1,700 years have been obtained from the Herschel Space Observatory, launched by ESA in 2009. Professor Decin explained: “Herschel is made to observe cool material, like that found far away from the central star. So, it was not really an accidental discovery.” The researchers deliberately employed PACS, one of two cameras onboard the Herschel Space Observatory, as it was specifically designed to look at the far-infrared light associated with extremely cold objects. This was crucial to the identification of the shells, as their temperatures can reach as low as -248^oC, leaving them beyond the scope of many observatories.

            The laborious process of refining the PACS images proved fruitfull when the team identified the long suspected, non-concentric shells of dust as far as 1arcmin from the stars centre. “Until recently it seemed the surroundings of giant stars were homogenous, but more and more we see that this isn't the case”, Professor Decin enthused: “The new Herschel images confirm that in a stunning way."

            It is assumed that further dust rings existed but may have already collided with and dispersed into the interstellar medium; a mixture of ions, cosmic rays and other matter surrounding the star. Dr Tanya Lim, a collaborator on the paper from the Rutherford Lab in Oxford, revealed: “It is the interactions between the dust and interstellar medium which are interesting because these interactions change the chemistry of the ISM.”

            However, where these shells occur also says something about the history of mass loss for these carbon rich stars. CW Leo is a direct analogy for our own Sun, and research like this could be invaluable for determining how it will react in it’s later stages.

We saw it first!

Tomorrow, CERN are set to make an announcement. A big announcement. Speculation began when the researchers set the topic for their press conference: the status of their search for the Higgs Boson. Supposedly, they have now looked at a much wider range of data than they had by the summer conference, leaving the physics world a-buzz with rumour. If the Higgs has been identified it will be a great triumph for the standard theory of physics, as it is the only missing puzzle piece left in our current understanding of particle physics.

Cogitating over what the announcement might be, my practical group for Imperial's MSc Science Communication decided to produce a short animation, demonstrating exactly what CERN do. If the so-called 'god particle' has been found, this is proof we saw it first!

(Credit: Georgia Bladon, Sam Cavenagh, Heather Cruickshank, Harriet Jarlett, Peter Larkin, Kelly Oakes, Antonio Torrisi and Dharshani Weersekera)

Geologists, the Coolest and Sexiest People Alive.

To many people a 'Geologist' is a bearded figure, dressed in an anorak and talking to a rock. Geologists themselves would love to dispel this myth but since we lick rocks, know Lagerstatten is more than a beer, and think anything under a few million years is 'recent' its not too far from the truth! Below I give you my top five references to Geologists in popular culture. Number 5 is my favourite, although I wish number 1 was true. Vote on your favourite below. (Come on Geologists- don't let the Bad ones win!)

The Good:

1) American Dad- Geologists, the smartest sexiest men alive. (Women too!)

2) Brad Pitt- GEOLOGIST. Not funny but it's Brad Pitt. As a geologist.

The Bad:

3) The Big Bang Theory- Erm...actually it is.

4) Friends- Geologists are the lowest of the dating barrel, shame some other Geologists don't realise this...

The Sadly Truthful:

5) Fresh Meat- actual geology bar games

Earth was frosted with gold

Like the glaze on a pastry, the Earth, after its inner structure was established, received a final icing of gold to it's crust. The abundance of gold ore make it an easily accessible economic resource. However, this incredibly heavy element, and other iron-loving elements like it, should have sunk 3 000 km deeper, into the Earth's core.

New research, published this month in Nature, lends support to the theory that without a late bombardment of meteorites being stirred in, there would be hardly any siderophile (iron-loving) elements in Earth’s mantle.

Willbold et al, from the Bristol Isotope Group, measured the variations of tungsten in rocks from the Isua Greenstone belt against an average found in modern day mantle. The Isua rocks are unique as they were unaffected by the late bombardment 500 million years ago, but were still formed after the Earth possessed it’s core. In theory, they should have slightly more tungsten compared to rocks that formed whilst the Earth was still accumulating material.

Other theories suggest that, when the Earth collided with large objects, such as the Mars-sized planet now widely accepted to have resulted in our Moon, it caused huge areas of melting. During this melting, iron and other metals seperated out and sank to the core. At the pressure and temperatures found beneath the huge magma ocean, it was thought that siderophiles might lose their affinity to iron and rise up through the mantle. Although, this would not have worked for all of the elements.

Experiments predicted that, to have the current proportion of gold in the crust, we would need 0.5-1% of primitive meteoritic material to have mixed into the mantle. Willbold et al measured tungsten more precisely than ever before, to show that the samples from the Isua Greenstone belt are slightly enriched, compared to average mantle. The magnitude of this small enrichment, 13 parts per million, is exactly that predicted if there had been 0.5-1% of primitive meteoritic material.

Dr Willbold commented that his "work shows that most of the precious metals on which our economies and many key industrial processes are based have been added to our planet by lucky coincidence when the Earth was hit by about 20 billion billion tonnes of asteroidal material.”

It is possible that the late mixing of material by convection occurred only in large patches of crust. Some areas of the Earth's mantle may not have mixed with late accreted material and so would have remained, and in fact still remain, isolated. The late bombardment might have given us more than just ore deposits, it may have given us the mantle dynamics we still see today.

George Stephenson (inventor of the steam locomotive) talks robots

Me and George Stephenson (credit: Elfy Chiang)

In starting my MSc Science Communication at Imperial College I didn't know quite what to expect. And when confronted by essays and critical analysis of articles, I was completely out of my depth. Thankfully, amongst the philosophy of science essays and semiotics there is a large amount of fun!
Our core practical involves making a TV interview and radio clip about a certain aspect of science. Our group got the surprisingly difficult task of explaining Artificial Intelligence.

 This week my core practical group and I (thanks guys!) went out with portable radio equipment to interview the public in the Science Museum. We asked them what they would like robots to be able to do for them ('housework' was the most popular answer) and in the process encountered a strange figure.

Dressed in a top-hat, tails and with mutton-chops to rival Wolverine, he looked like he'd stepped straight out of the 1800's. Turn's out, he had! It was George Stephenson speaking to us from 1840, desperate to share his knowledge of  the first steam locomotive, The Rocket. Listen to what he had to say here:

Much love to the rest of my core practical group who I did this with.

New dinosaur liked a fight

Talos Sampsoni - the new species discovered in Utah

Any kid who watched Jurassic Park through their fingers is aware of how terrifying the raptors were, and their claw-like 'toes' didn't help their menacing demeanour. Yet, up until now their function was a mystery. After the discovery of a new species in Utah, Scientists may have found their purpose, it seems they weren't all for show, or scaring children.

 

The claw is distinctive of dromeosaurs, the group which includes Velociraptor. The new species was discovered 3 years ago in the 1.9-million-acre Grand Staircase Escalante National Monument in southern Utah, one of the last undamaged dinosaur graveyards in the US. The dinosaur was named Talos sampsoni after the winged god from Greek mythology which succumed to a wounded ankle. Weighing under 40kg (about the size of a 4yr old child), it hardly inflicts the terrorising image of the 7ft tall moviestar Raptors. But Lindsay Zanno, lead author of the study, believes they were still fearsome creatures and described little Talos as "a scrapper".

There have been many things learnt from imperfect fossils over the years, about the lifestyle and habits of the animal, (there is a pretty cool Pleiseosaur at the Natural History Museum which is either pregnant, or ate lots of miniature versions of itself), and this new fossil is no different. It's second toe, with the big claw, is deformed where Talos either took a fall and fractured it, or got in in a fight and had it bitten. Originally, the team put this deformation down to the differences in species, but the excitement grew as they realised it had a different story to tell.

Detailed CT scanning, like that used in hospitals, was used to see the full extent of the injury. It was deemed to have been made during a fight with another dinosaur for food, a theory which holds up against the fossils found in the 1980's of two raptors caught in combat. The team discovered that the dinosaur had lived for months with the injury, meaning it must have been capable of catching prey/defending itself/ shaking hands with just the right foot and both talons weren't necessary to survival.

Trackways found at other sites suggest the toe was raised when Talos walked and so the damage, which didn't reach the rest of the foot, wouldn't have affected it's movement. "Our data support the idea that the talon of raptor dinosaurs was not used for purposes as mundane as walking," Zanno commented. "It was an instrument meant for inflicting damage."

A Gem of a Discovery

Image of Pulsar and Planet in orbit (Image credit – Swinburne Astronomy Productions)

Like an oyster in the ocean, opening to reveal a pearl, new research has discovered stars can be stripped apart to reveal diamonds.

Nicknamed "The Dish", the Australian CSIRO Parkes telescope stumbled on the discovery whilst searching for pulsars, as part of the "High Time Resolution Universe" survey. Pulsar J1719-1438 had a peculiar signal and upon closer inspection they discovered it was being orbited by a dense planet, five times the size of Earth and made entirely of diamond.

Pulsars are stars with a diameter of around 12 miles, about half the size of the Isle of Wight. Astronomers at CSIRO use these pulsars to study some of the fundamental laws of the universe. About 2-3 of them are discovered every month, so it's hardly breaking news when they find one. However, only certain pulsars such as, J1719-1438, are classed as rarer milisecond pulsars. This means they spin much faster than others and are likely to have unique properties. In this case of this star, it's uniqueness was found in it’s companion, dubbed The Diamond Planet.

Even more unusual, CSIRO's Dr Michael Keith explained, is that "Although the composition of this "diamond planet" is not really similar to any planets in our solar system, it orbits the pulsar more like a planet than a star. Typically pulsars and their companions both move in similar sized orbits, however in this case the large difference in weights means the pulsar does a rather small wobble whilst the companion swings around in a wide, circular, orbit."

All stars, when they become white dwarves, find the carbon they are made from is put under such great pressures that it crystallises into diamond. Even our Sun, when it finally burns out, will find a diamond at its centre. This is how the universe's largest, trillion carat diamond 'Lucy' formed. However, the Diamond Planet, appears to have befallen a sadder fate and was stripped down by the pulsar to reveal the diamond core within. Now only the diamond core remains, orbiting the pulsar and providing it with the energy to spin faster.

When asked if it can really be called a planet, since it used to be a star Keith answered, "certainly the object began its life as something that is unquestionably a star, however it now is clearly "of planetary mass". It's not too hard to imagine a situation where a gassy planet similar to Jupiter accreted enough mass to start nuclear burning and become a star, so why not go the other way round and have a star lose enough mass to become a planet."

It seems that this discovery really is a diamond in the rough for astronomy.

Hear a quote from Dr Michael Keith here:

How it feels to discover a planet