Series of Dreams

Series of Dreams
by Bob Dylan

I was thinkin’ of a series of dreams
Where nothing comes up to the top
Everything stays down where its wounded
And comes to a permanent stop

Wasn’t thinking of anything specific
Like in a dream, when someone wakes up and screams
Nothing too very scientific
Just thinkin’ of a series of dreams

Thinkin’ of a series of dreams
Where the time and the tempo drag
And there’s no exit in any direction
’Cept the one that you can’t see with your eyes
Wasn’t making any great connection
Wasn’t falling for any intricate scheme
Nothing that would pass inspection
Just thinkin’ of a series of dreams

Dreams where the umbrella is folded
Into the path you are hurled
And the cards are no good that you’re holding
Unless they’re from another world

In one, the surface was frozen
In another, I witnessed a crime
In one, I was running, and in another
All I seemed to be doing was climb

Wasn’t looking for any special assistance
Nor going to any great extremes
I’d already gone the distance
Just thinkin’ of a series of dreams

Olivine Crystals in an Extrasolar Proto-Kuiper Belt

Right, let's kick off with a study reported recently in the journal Nature by B.L. de Vries et al. In this study, olivine crystals were detected in the Beta Pictoris system. 

Background

Beta Pic is a relatively young system (~12 million years old),  just over 60 light years away and is a solar system in the making. The star at the centre of the system has just entered the stable main sequence phase but beyond lies swathes of gas, dust, cometary debris and planetesimal belts. Astronomers detect debris disks by measuring strong infra-red (IR) radiation emission. As the light from the host star travels through the gas and dust it's scattered to longer wavelengths. Mapping this radiation flux can then tell you about the geometry of the system. Are we viewing the debris desk edge on? Or is the debris disk inclined to our line of sight? The asymmetry of the disk was found in the 1990s with IR observations and later the Hubble Space Telescope revealed disk bulges close to the host star:

Early imaging in the 1990s with telescopes in Hawaii revealed the asymmetry of the disk in Beta Pictoris. Above is Hubble Space Telescope (HST) imaging of Beta Pic. The high resolution of HST and lack of atmosphere in orbit around the Earth allowed vertical bulging of the disk to be observed close to the star at 50AU (1AU is the distance from the Earth to the Sun). The above image is false colour to accentuate the features of the disk.

Disk asymmetry and bulging was thought to be down to a planet in the system. Remarkably this planet was eventually imaged by the Very Large Telescope (VLT) in 2003 and 2009. In order to replicate the physical properties of the system the planet was found to be about 9 Jupiter masses, orbiting at a distance of 8-15AU. This is a very interesting result as before no disk had been observed hosting a planet! We know that disk lifetimes are around 10 million years, as radiation pressure from the star disperses gas and dust required for planet formation. So actually seeing a planet form with a disk that was still intact was good news for planet formation modellers. Planets can and are forming, in our own backyard.

VLT imaging of the gas giant in orbit around Beta Pic, seen as the bright white spot.  The image on the left was taken in 2003 and the one on the right was taken in 2009. Using the projected separation and how the planet orbits in time the orbital period was found to be 17-35 years.

The planet observed in Beta Pic was observed to lie in the plane of the disk. However, we have and are finding planets that aren't orbiting in an orderly fashion. Unlike the solar system, planet hunters are finding planets that orbit in directions opposite to the rotation of their star (as if Earth orbited the opposite way) and in highly oblique orbits. Is this evidence that planets gravitationally interact? Or is the star simply tilted due to its interaction with the disk? I mention this because I'm working on it at the moment. I might talk about it at a later date and possibly bore you with it. Hopefully not.

The Study

Just as was mentioned near the start of this blog post, we can use scattered radiation to reveal a great deal of information. As the Beta Pic debris disk is very much intact planetesimals such as comets and asteroids collide. When these collisions occur dusty material and debris is ejected then bathed in host star radiation. As the radiation scatters from the material we can begin to say something about its chemical composition using spectroscopy. The authors report a detection of the 69 micron band of olivine in the spectrum of Beta Pic. The crystals are then associated with a proto-Kuiper belt (the belt that planet Pluto is a part), the magnesium composition is determined and the fraction of the total dust mass is reported.

Why olivine anyway?  

To understand terrestrial planets we need to understand olivine. Olivine makes up around 50% of the Earth's upper-mantle and is one of the Earth's most common minerals. The other terrestrial planets are thought to have high quantities of olivine (the Mars Curiosity rover detected olivine in its first soil sample) but is this true of other solar systems? Do all terrestrial planets form in the same way?

Results

Olivine, chemical formula (Mg,Fe)₂SiO₄ comes in two types: iron rich and magnesium rich. Asteroids that form close in to the Sun in our solar system are Fe rich and Mg rich further out from the Sun. This is because Fe is refractory and Mg remains gaseous at very high temperatures so only can begin to condense at cooler temperatures and larger distances, where stellar irradiation isn't as intense. 

The authors report a detection of the 69 micron emission feature of olivine using the Herschel PACS (Photodetecting Array Camera and Spectrometer) instrument. Measuring the emission feature at 69 micron is especially interesting as the width and position of the emission feature determines the temperature and chemical composition of the olivine crystals:

Modelling the 69 micron feature, determining the width and wavelength position determines the temperature and composition of olivine.

The exact wavelength position of the 69 micron feature indicates Fe/Mg=0.01-magnesium rich olivine. Also the measured temperature from modelling resulted in a temperature of 85 +/- 6K placing the olivine at a distance of between 15 and 45 AU from the central star. This position, beyond the so-called snow line, is the realm of icy cometary bodies i.e. the Kuiper belt in our own Solar System. The Mg rich content is also of a similar composition to that of Solar System cometary bodies suggesting a familiarity in the way olivine was transported through the debris disk.

Final Words

• Study suggests that olivine processing may not be Solar System specific
• Implications for astrobiology suggesting terrestrial planets perhaps form in a similar way

In case you're not super excited about olivine crystals by now check out the Fukang pallasite, found in the Gobi desert, China:

Fukang Pallasite: a staggering ~1000kg was recovered in 2000 in Fukang, Xinjiang Province, China. A Pallasite is a class of meteorite with an iron-nickel matrix encasing beautifully transparent green olivine crystals. Pallasites are thought to have formed in the early Solar System when planetesimals differentiated to form an iron-nickel core and liquid mantle. Pallasites were formed at the core-mantle boundary and were liberated from impacts. 

Just take a look at the scale for a moment. Yes, you are reading that correctly-91cm!  If you think that's impressive just look at...

THIS! 

'World renowned as the most spectacular example of natural cosmic splendor, the Fukang pallasite will undoubtedly become one of the greatest meteorite discoveries of the 21st century. This awe-inspiring main mass weighs over 925 pounds (over 420 kilograms). The Fukang pallasite displays celestial yellow-green olivine crystals in an illustrious nickel-iron matrix. Backlit slices from the Fukang mass are reminiscent of stained glass windows crafted in the ancient solar system'-Southwest Meteorite Lab

Blog the First

I've now got the urge to start blogging again. This will now be a new place where I'll write about whatever is interesting me at the time. More than likely it will contain a healthy dose of Astronomy, a sprinkle of writing about film and literature and amateur photography exploits. Warning: this scientist may get political when provoked. It is about time our 'private' political opinions made it out into the open whatever our discipline. After all, only through debate and discussion can we have any hope of moving forward.

What you can hope to find here in future:

• Interesting pieces on the latest astronomy research and where possible connecting it with a wider political, cultural and historical context.
• The life and times of an astronomy PhD student through the joys and I'm sure, the many, many horrors.
• Literature and film reviews and maybe short essays on the directors and novelists that mean something to me.
• Short essays on ideas.
• Posts of my photography and thoughts/tips/hints on using Photoshop. 
• Adulations of the lyrics of Nick Cave.

I'm sure you'll see much more as this blog gets rolling. So stay tuned readers!

"The surface of the Earth is the shore of the cosmic ocean. Recently, we've waded a little way out, maybe ankle-deep, and the water seems inviting. Some part of our being knows this is where we came from.We long to return, and we can, because the cosmos is also within us. We're made of star stuff. We are a way for the cosmos to know itself."

Carl Sagan

The End of the Space Age?

A sobering and provocative article was released in The Economist on June 30th: The End of the Space Age. In this piece it was argued quite pessimistically that 'it is likely the Space Age is over' where the furthest humans will reach into space will be the technosphere- the swarm of satellites that envelop the Earth. With the final shuttle launch approaching it appears this will be the case. Of course there will be robotic forays to planets within the solar system but

'Every planet has now been visited, and every planet with a solid surface bar Mercury has been landed on. Asteroids, moons and comets have all been added to the stamp album. Unless life turns up on Mars, or somewhere even more unexpected, public interest in the whole thing is likely to wane. And it is the public that pays for it all.'

Is it true that only human space exploration gains public support? And what is the point in human space travel anyway?

Unlike others if I was asked to justify human space travel I wouldn't quickly turn to scientific spin-offs (something Prof. Dawkins claims is the 'non-stick frying pan approach') or praise engineering ingenuity. I think human spaceflight represents something more implacable, intangible and wondrous. Nobody could have predicted the impact of Apollo 8's lunar orbit. The iconic 'Earth Rise' image, photographed on Christmas Eve, has been seen by some to have spawned the environmental movement. Viewing the Earth as a blue jewel in the void of space the planet seemed vulnerable, its silent poetry presenting human follies as pointless, its beauty worth saving.

It's true that space has gradually lost support since the last Apollo flight of 1972. Even during the Apollo missions interest waned. Ask anyone who the first men to walk on the moon were and you would, more than likely, get the right answer. But who would know that Eugene Cernan was the last to walk on the moon? Bizarrely, after the giant leap of 1969 continuing to walk on the moon seemed old news. The inbuilt, impatient explorer in everyone wanted to see what was over the next hill.

With the first Shuttle flight of 1981 came a reusable taxi into Earth orbit. In truth amongst its major achievements in assisting the assemblage of the ISS, taking satellites into orbit, taking the Hubble Space Telescope (HST) into orbit and carrying out a Hubble reservicing mission, none had the grandeur or drama of walking on a new world. But even though a lot of the shuttle missions went largely unnoticed by the general populus it kept the wonder alive from the Apollo era, whether directly or indirectly: humans floating above the great blue Earth in ambitious space walks and the myriad images captured by the HST, opening up the cosmos like never before. Yes, public interest dimmed with the Space Shuttle but at least the candle of exploration was still burning.

So it is with sadness that I will watch the final Shuttle flight on 8th July. Difficult economic times may have led to the Obama administration cancelling the shuttle program and yes the batton has passed to ESA and Russia's space transportation. Then private companies will eventually take over in the intervening time NASA decides what to do with itself. But for me the candle of wonder and exploration will burn with a dimmer light. All we can hope for is that the flame will burn bright in the future.

Desperation

Desperation is a mammoth novel written by Stephen King in 1997. Set in and around the Highway 50 in the middle of the desert, near Ely in the USA, the novel centres around the Carver family, Johnny Marinville (National Award Winning author) and Peter and Mary Jackson. All find themselves bizarrely confronted by a towering cop, Collie Entragian, and taken back to the arid, delapidated mining town, Desperation. It rapidly becomes clear that it is not simply a case of a quick warning from the police; Entragian has his own dark agenda. Or is it his own? The star of the novel is David Carver, a sagacious, clear-thinking, recently converted Christian, who is seemingly directed by God. Will Entragian's victims follow David, in this epic battle of Good Vs. Evil? It seems the Evil once burried beneath Desperation has been unlocked. Faith is the only hope, in David and God.

King's characterisation in Desperation is sublime as in many of his other novels. We really get deep into the minds of the characters, undestanding their motives, quirks and histories. This is especially the case for David Carver where his past experience and conversion to Christianity is an overarching theme of the novel. What is clear thoughout is the sense of claustrophobia, possibly enhanced by the reader entering the character's minds. King seems to have a grasp of human thought under strain as he doesn't focus on the solemn but shows the banal or perverse side to human thought even when pushed to such terrifying extremities. What makes this novel such a page-turner is King's use of perspective and dramatic irony; King shifts perspective at tense moments and witholds his return to the altered perpsective. This works as to deepen our sense of dread and impending doom.

But what stood out most for me was King's detailed study of faith. Indeed, Desperation is inherently about God. However, King isn't in the Dawkins camp: faith is painted in a positive light. Perhaps King's introduction of charcters such as the hedonistic Merinville, transforming within the confines of the novel teaches us that when the human condition is pushed to the farthest reaches of extremity only faith will provide the guiding hand. Otherwise failure is inevitable. Desperation is gripping, terrifying, intelligent. It's a shame King isn't writing such good material nowadays...

The Wrestler

Well I've just watched The Wrestler directed by Darren Aronofsky and thought I would give it an impulsive review.

Randy 'The Ram' Robinson was a well-loved wrestler of the 1980s and 20 years on is still wrestling in gyms and theatres around the US. Having lost contact with his daughter and holding no real relationships, he thrives from the thrill and drama of the live show. However, Randy is forced to face the reality of what lies outside the ring when he has a heart attack and his identity begins to slip away. Trying to reestabilish what he once had, Randy tries to reconnect with his daughter and begins a romance with an aging stripper. But the live crowd beckons and what lies outside the ring does not compare with what lies within.

Micky Rourke is spellbinding as Randy and the film is executed extremely well. Aronofsky is known to push his actors to extreme limits and here it definitely pays off. Also there was no fixed storyboard so actors were allowed to ad lib giving the film a raw, edgy, documentary feel. The wrestling was actually filmed at weekends interspersed in real live performances with a live crowd, providing an unpolished immersive aesthetic. Retrospectively, the $5 million dollar budget is perhaps a necessary requisite to create such passionate realism. Overall a brilliant film and Aronofsky's message is one of dedication; stick to your guns and don't let anything stand in your way.