Prof. Brian Cox Accidentally REVEALS the TRUTH About the LHC!!!!

(Note the clever use of CAPS and excessive exclamation marks in the title. It speaks volumes.)

I guess this confirms I was wrong. Consider this an apology to all the crackpots, doomsayers, cranks and Walter Wagner. I’m sorry I got it all… so… wrong.

While out on the town in London, Bad Astronomer Phil Plait pulled Prof. Brian Cox out of a pub and subjected him to some intense interrogation. Obviously caught with his guard down, Cox folded under the pressure and briefly told the world what we can expect when the Large Hadron Collider (LHC) recommences experiments in November. Wow, just… wow.

This made me giggle. Looks like TAM London was a tonne of fun, hopefully next time I can go.

But for now, sorry Walter, you’re still wrong.

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Whatever Happened to Hyper-Velocity Star HD 271791?

One scenario: Exploding star flings binary parter away at high velocity (Max Planck Institute for Astrophysics)

One scenario: Exploding star flings binary parter away at high velocity (Max Planck Institute for Astrophysics)

HC 271791 is a star with a problem, it’s moving so fast through our galaxy that it will eventually escape from the Milky Way all together. However, there is a growing question mark hanging over the reasons as to why HD 271791 is travelling faster than the galactic escape velocity.

So-called hyper-velocity stars were first predicted to exist back in 1988 when astrophysicist Jack Hills at Los Alamos National Laboratories pondered what would happen if a binary star system should stray too close to the supermassive black hole lurking in the galactic nucleus. Hills calculated that should one of the stars get swallowed by the black hole, the binary partner would be instantly released from the gravitational bind, flinging it away from the black hole.

This would be analogous to a hammer thrower spinning around, accelerating the ball of the hammer rapidly in a circle around his body. When the thrower releases the hammer at just the right moment, the weight is launched into the air, travelling tens of meters across the stadium. The faster the hammer thrower spins the ball, the greater the rotational velocity; when he releases the hammer, rotational velocity is converted to translational velocity, launching the ball away from him. Gold medals all ’round.

So, considering Hills’ model, when one of the stars are lost through black hole death, the other star is launched, hammer-style, at high velocity away from the galactic core. The fast rotational velocity is converted into a hyper-velocity star blasting through interstellar (and eventually intergalactic) space.

Hills actually took his theory and instructed the astronomical community to keep an eye open for speeding stellar objects, and sure enough they were out there. HD 271791 is one of these stars, travelling at a whopping 2.2 million kilometres per hour, a speed far in excess of the galactic escape velocity.

However, the 11 solar mass star didn’t originate from the Milky Way’s supermassive black hole (inside the radio source Sgr. A*), it was propelled from the outermost edge of the galactic disk. There is absolutely no evidence of a supermassive black hole out there, so what could have accelerated HD 271791 to such a high velocity? After all, stars aren’t exactly easy objects to throw around.

If HD 271791 used to be part of a binary pair, its partner would have had to suddenly disappear, releasing its gravitational grip rapidly. One idea is that HD 271791’s sibling exploded as a supernova. This should have provided the sudden loss in a gravitational field — the rapidly expanding supernova plasma will have dispersed the gravitational influence of the star.

However, according to Vasilii Gvaramadze at Moscow State University, the supernova theory may not be sound either; by his calculations a binary pair simply cannot produce such a large velocity. Gvaramadze thinks that a far more complex interaction between two binary pairs (four stars total) or one binary pair and another single star some 300 solar masses. Somehow, this “strong dynamical encounter” caused HD 271791 to be catapulted out of the system, propelling it at a galactic escape velocity.

Although this complex slingshot theory sounds pretty interesting, the supernova theory still sounds like the most plausible answer. But how could a sufficient rotational velocity be attained? As Gvaramadze points out, even an extreme rapidly orbiting binary pair cannot produce a star speeding at 530-920km/s.

This is in contrast to research carried out by scientists at the Max Planck Institute for Astrophysics and the University of Erlangen-Nuremberg. In a January 2009 press release, Maria Fernanda Nieva points out that this hyper-velocity star possesses the chemical fingerprint of having been in the locality of a supernova explosion. This leads Nieva to conclude that HD 271791 was ejected after its binary partner exploded. What’s more, a Wolf-Rayet may have been the culprit.

Up to now such a scenario has been dismissed for hyper-velocity stars, because the supernova precursor usually is a super-giant star and any companion has to be at large distance in order to orbit the star. Hence the orbital velocities are fairly modest. The most massive stars in the Galaxy, however, end their lives as quite compact so-called Wolf-Rayet stars rather than as super-giants. The compactness of the primary leaves room for a companion to move rapidly on a close orbit of about 1 day-period. When the Wolf-Rayet-star exploded its companion HD 271791 was released at very high speed. In addition, HD 271791 made use of the Milky Way rotation to finally achieve escape velocity. –Maria Fernanda Nieva

Even though Gvaramadze’s stellar pinball theory sounds pretty compelling, the fact that HD 271791 contains a hint of supernova remnant in its atmosphere, the supernova-triggered event sounds more likely. But there is the fact that just because this 11 solar mass star was near a supernova some time in its past, it certainly doesn’t indicate that a supernova was the cause of it’s high speed.

For now I suppose, the jury is still out…

Publication: On the origin of the hypervelocity runaway star HD271791, V.V.Gvaramadze, 2009. arXiv:0909.4928v1 [astro-ph.SR]

Original source: arXiv blog

The UK’s Brain Drain (been there, done that)

Professor-Stephen-Hawking-001

Back in 2006, I remember sitting in my local UK Job Centre finding out how I could claim for unemployment benefits.

I can see it now, the moment I explained to my liaison officer that I had been looking for work but received little interest. She looked at me and said, candidly, “Have you thought about not mentioning you have a PhD? It might help.” She smiled.

What? I now need to hide my qualifications if I want to get a job? Isn’t that a little counter-intuitive? Actually, as it turned out, she was right. Many of the jobs I had applied for didn’t require a postdoc to do them; why would a company hire me when they can hire a younger postgrad with lower salary expectations?

Up until that moment, I was still hopeful that I might be able to land an academic position; possibly back in my coronal physics roots, but funding was tight, and I hadn’t done enough networking during my PhD to find a position (I had been too busy scoping out the parties and free booze at the conference dinners).

So there I was, with all the qualifications in the world with no career prospects and a liaison officer who deemed it necessary to advise me to forget the last four years of my academic career. It was a low point in my life, especially as only a few months earlier I had been enjoying one of the highest points in my life: graduating as a doctor in Solar Physics.

Fortunately for me, I had another option. My girlfriend (now lovely wife) was living in the US, and although searching for a job in the UK was a priority for us (we were planning on living in the UK at the time), I knew I could try my luck in the US as well. So after a few months of searching, I cancelled my Job Centre subscription and moved to the other side of the Atlantic.

I had just become a part of the UK’s “brain drain” statistic. I had qualifications, but I was in a weird grey area where companies thought I was over-qualified and funds were in short supply for me to return to academic research.

A lot has happened since those uncertain postdoc times, and although I tried (and failed) to pick up my academic career in solar physics in the US (it turns out that even the sunny state of California suffers from a lack of solar physics funding), the job climate was different. Suddenly, having a PhD was a good thing and the world was my oyster again.

To cut a long story short, I’m happily married, we own five rabbits (don’t ask), we live just north or Los Angeles and I have a dream job with Discovery Channel, as a space producer for Discovery News.

Although I’d like to think that if I was currently living in the UK, I might have landed an equivalent career, I somehow doubt I would be as happy as I am right now with how my academic qualifications helped me get to where I am today.

Why am I bringing this up now? Having just read about Stephen Hawking stepping down as Lucasian professor of Mathematics at Cambridge University and the Guardian’s report about the risk of losing British thinkers overseas, I wonder if employment opportunities have improved since 2006. What’s most worrying is that there appears to be this emphasis on making money as quickly as possible, rather than pursuing academic subjects. However, in my experience, having a PhD doesn’t mean you can even land a job in industry, you might be over-qualified.

Giving up on that tradition of deep intellectual discovery in favour of immediate economic benefit is a huge mistake. You lose the gem of creative, insightful, long-term thinking. That is what Britain has done so spectacularly in the past, and to give that up is a tragedy.” –Neil Turok

A special thanks to Brian Cox, who tweeted the inspiration to this post.

Life is Grim on the Galactic Rim

The White Star approaches the Shadow's homeworld of Z'ha'dum on the Galactic Rim.

The White Star approaches the Shadow’s homeworld of Z’ha’dum on the Galactic Rim.

It would appear that scientists have confirmed that the outer edge of the Milky Way is a bad location for life to even think about existing.

This research reminded me of the “Galactic Rim” in the 90’s sci-fi TV series Babylon 5. The Rim is the mysterious region of space right at the edge of our galaxy where only the hardiest of explorers dared to venture. As explained in the season 2 episode of B5, “In the Shadow of Z’ha’dum,” Captain Sheridan (Bruce Boxleitner) discovers that his wife (when exploring The Rim) went missing on a planet called Z’ha’dum. It turns out that an angry ancient alien race — called the Shadows — lived on this mysterious world and their discovery led to them being used in all kinds of plots during the latter four seasons of this awesome sci-fi show.

However, the existence of any kind of life (let alone life as complex as the evil Shadows) in the badlands of the Milky Way is looking very unlikely.

Located some 62,000 light years from the core of our galaxy (over twice the distance of the Earth from the galactic centre), two very young star clusters in the constellation of Cassiopeia have been studied. Chikako Yasui, Naoto Kobayashi and colleagues at the University of Tokyo, Japan, found these clusters in a vast cloud of gas and dust called Digel Cloud 2. The stars inside these clusters are only half a million years old, and the majority of them should possess proto-planetary disks (which is characteristic of local star-forming regions). However, it would appear that these stars contain very little oxygen, silicon or iron (i.e. they have very low metallicity) and only 1 in 5 of the 111 baby stars analysed in both clusters have disks.

If proto-planetary disks are rare, this means there will be a rarity of planets. This is an obvious bummer for life to form. After all, Life As We Know It™ is quite attached to evolving on Earth-like planets.

So why are these young stars lacking proto-planetary disks, when local star forming regions don’t seem to have this affliction? The authors of the paper, soon to be published in the Astrophysical Journal, suggest that these stars did have disks, but some mechanism is rapidly eroding them.

The most likely scenario is that low metalicity proto-planetary disks are more susceptible to photoevaporation. Simply put, these disks evaporate when exposed to EUV and X-ray radiation from their parent stars far more rapidly than disks that are metal-rich.

Therefore, if an alien race was able to form, they’d be very rare or they’d be very different from what we’d expect “life” to be like (i.e. they thrive in low metalicity star systems). Sounds like the mysterious Shadow homeworld of Z’ha’dum would be a very rare sight on The Rim of our Milky Way after all.

Publication: The Lifetime of Protoplanetary Disks in a Low-Metallicity Environment, Chikako Yasui et al., 2009. arXiv:0908.4026v3 [astro-ph.SR]
via New Scientist

There’s a Fractal in My Brazilian Rainforest

Lago Erepecu and Rio Trombetas, Brazil (NASA)

Lago Erepecu and Rio Trombetas, Brazil (NASA)

The shapes of fractals appear in nature all the time, but when I saw this Earth Observatory image from the International Space Station, I thought I was looking at a zoomed-in portion of the famous Mandelbrot set graphic. This picture wasn’t formed by the calculations of a computer, however. This is what nature does when chaos comes out to play.

Imaged from orbit on August 25, 2009, an astronaut was able to get the timing just right with his/her Nikon D2Xs digital camera (plus 180 mm lens) so that sunlight was reflecting off Brazil’s Lago (Lake) Erepecu and Rio (River) Trombetas. Usually, water masses in the Brazilian Rainforest are too dark to be picked out in any detail, so this sunglint was very useful to pick out the fine detail of the waterways.

Source: Earth Observatory Program

Say Hello To My Little Friend: The Atom, Imaged

atom_photo

I am fascinated with outer space, this is true. But if you stop to think about it, the inner space between the atoms is just as awe-inspiring as the vast distances separating the planets, stars and galaxies. In actuality the volume inside an hydrogen atom is essentially empty; the single electron “orbits” (if we consider the simple Bohr model of the atom) the central proton at a huge distance. It’s analogous to a quantum star system, where a planet orbits its parent star, hundreds of millions of miles away.

However, atoms aren’t as simple as Niels Bohr’s famous model (although Bohr’s model is none-the-less important as it always has been). The electrons occupy a cloud, rather than specific orbits, and the electron’s position cannot be defined as a point, more a statistically defined volume. As dictated by quantum theory these clouds vibrate at certain frequencies, depending on the electron energy. These electron energies are analogous to the simple electron “shells” physicists refer to in the textbooks; each progressively higher shell occupying a higher energy state. In reality, in the slightly fuzzy quantum world, the frequency of electron oscillation increases with energy.

Examples of electron atomic and molecular orbitals. The "lobes" are representative of the electron clouds surrounding the nuclei

Examples of electron atomic and molecular orbitals. The lobes are representative of the electron clouds surrounding the nuclei (source)

When I was in university, I loved seeing the different modes of electron energy in 3D visualizations of the atom (pictured right). Lobes of electron clouds vibrating at different energies seemed to make sense. But now, for the first time, the clearest photographs of a single atom have been taken, with lobes of electron clouds — as predicted by quantum theory — intact.

This research soon to be published in the journal Physical Review B, demonstrates detailed images of a single carbon atom’s electron cloud (pictured top). Taken by Ukrainian researchers at the Kharkov Institute for Physics and Technology in Kharkov, Ukraine, these images clearly show the electron cloud in two energy states.

This amazing feat was accomplished using a field-emission electron microscope. Although this microscope has aided physicists since the 1930’s to image the vanishingly small, the Ukrainian researchers have developed a new way of making the tool so sensitive, single atoms can be imaged. After arranging a ridged chain of carbon atoms (only tens of atoms long) inside a vacuum chamber, the researchers passed 425 volts through the atoms. At the tip of the chain, the end carbon atom emitted its electrons and a surrounding phosphor screen captured an image. This image was of the electron cloud surrounding the single carbon atom.

Up until this point, field emitting microscopes have only been able to resolve the arrangement of atoms in a sample. This is the first time physicists have been able to see the structure of an electron cloud around an atom.

It’s always nice to validate a bedrock physics theory with photographic evidence, it’s exciting to think what the Kharkov Institute scientists will do next…

Source: Insidescience.org

Unexpectedly Large Black Holes and Dark Matter

The M87 black hole blasts relativistic plumes of gas 5000 ly from the centre of the galaxy (NASA)

The M87 black hole blasts relativistic plumes of gas 5000 ly from the centre of the galaxy (NASA)

I just spent 5 minutes trying to think up a title to this post. I knew what I wanted to say, but the subject is so “out there” I’m not sure if any title would be adequate. As it turns out, the title doesn’t really matter, so I opted for something more descriptive…

So what’s this about? Astronomers think they will be able to “see” a supermassive black hole in a galaxy 55 million light years away? Surely that isn’t possible. Actually, it might be.

When Very Long Baseline Interferometry is King

Back in June, I reported that radio astronomers may be able to use a future network of radio antennae as part of a very long baseline interferometry (VLBI) campaign. With enough observatories, we may be able to resolve the event horizon of the supermassive black hole lurking at the centre of the Milky Way, some 26,000 light years away from the Solar System.

The most exciting thing is that existing sub-millimeter observations of Sgr. A* (the radio source at the centre of our galaxy where the 4 million solar mass black hole lives) suggest there is some kind of active structure surrounding the black hole’s event horizon. If this is the case, a modest 7-antennae VLBI could observe dynamic flares as matter falls into the event horizon.

It would be a phenomenal scientific achievement to see a flare-up after a star is eaten by Sgr. A*, or to see the rotation of a possibly spinning black hole event horizon.

All of this may be a possibility, and through a combination of Sgr. A*’s mass and relatively close proximity to Earth, our galaxy’s supermassive black hole is predicted to have the largest apparent event horizon in the sky.

Or does it?

M87 Might be a Long Way Away, But…

As it turns out, there could be another challenger to Sgr. A*’s “largest apparent event horizon” crown. Sitting in the centre of the active galaxy called M87, 55 million light years away (that’s over 2,000 times further away than Sgr. A*), is a black hole behemoth.

M87’s supermassive black hole consumes vast amounts of matter, spewing jets of gas 5,000 light years from the core of the giant elliptical galaxy. And until now, astronomers have underestimated the size of this monster.

Karl Gebhardt (Univ. of Texas at Austin) and Thomas Jens (Max Planck Institute for Extraterrestrial Physics in Garching, Germany) took another look at M87 and weighed the galaxy by sifting through observational data with a supercomputer model. This new model accounted for the theorized halo of invisible dark matter surrounding M87. This analysis yielded a shocking result; the central supermassive black hole should have a mass of 6.4 billion Suns, double the mass of previous estimates.

Therefore, the M87 black hole is around 1,600 times more massive than our galaxy’s supermassive black hole.

A Measure for Dark Matter?

Now that the M87 black hole is much bigger than previously thought, there’s the tantalizing possibility of using the proposed VLBI to image M87’s black hole as well as Sgr. A*, as they should both have comparable event horizon dimensions when viewed from Earth.

Another possibility also comes to mind. Once an international VLBI is tested and proven to be an “event horizon telescope,” if we are able to measure the size of the M87 black hole, and its mass is confirmed to be in agreement with the Gebhardt-Jens model, perhaps we’ll have one of the first indirect methods to measure the mass of dark matter surrounding a galaxy…

Oh yes, this should be good.

UPDATE! How amiss of me, I forgot to include the best black hole tune ever:

Publication: The Black Hole Mass, Stellar Mass-to-Light Ratio, and Dark Matter Halo in M87, Karl Gebhardt et al 2009 ApJ 700 1690-1701, doi: 10.1088/0004-637X/700/2/1690.
Via: New Scientist

Deconstructing Doomsday

Alex Young in front of the cameras in the post-Apocalyptic setting of a Brooklyn building site.

Alex Young in front of the cameras in the post-Apocalyptic setting of a Brooklyn building site.

The funny thing about being involved in a doomsday documentary is trying to find a suitable balance between entertainment and science. This is the conclusion I reached after the interview I did for KPI productions in New York for the upcoming 2012 documentary on the Discovery Channel last week (just in case you were wondering why Astroengine.com was being a little quiet these last few days).

Apparently, the Apocalypse will be very dusty.

Apparently, the Apocalypse will be very dusty.

Naturally, the production team was angling for what it might be like to be hit by a “killer” solar flare, what kinds of terror and destruction a brown dwarf could do to Earth and what would happen if our planet’s magnetic poles decided to do a 180°. It’s always fun to speculate after all. However, I wasn’t there to promote half-baked theories of 2012 doom, I was there to bring some reality to the nonsensical doomsday claims. But with real science comes some unexpected concerns for the safety of our planet — not in 2012, but sometime in the future.

An added bonus to my NYC trip was meeting the awesome Alex Young, a solar physicist from NASA’s Goddard Space Flight Center. Alex was asked to New York for the same reasons I was, but he has a current and comprehensive understanding of solar dynamics (whereas my solar physics research is so 2006). He actually works with SOHO data, a mission I have massive respect for.

Alex Young and myself... very excited about doomsday.

Alex Young and myself... very excited about doomsday.

My interview was carried out on Wednesday morning, and Alex’s was in the afternoon. The KPI guys were great, a joy to be involved in such a professional project. The documentary producer, Jonathan, asked me the questions in a great location, a huge Brooklyn building that was undergoing renovation. Very dusty with a post-apocalyptic twist. If I was going to shoot a movie about the end of the world, this building would be it.

The KPI documentary will certainly be very different from the Penn & Teller: Bullshit! episode I was involved with, but it was just as much fun, if not more so (it was like a day-long science fest).

Of particular note was Alex’s sobering words about the woeful lack of funds in solar physics (i.e. Earth-damaging solar flares and CMEs). I hope his closing statement about NOAA space weather prediction funding makes the final cut; it was nothing less than chilling.

Jon and Sarah from KPI on the set.

Jon and Sarah from KPI on the set.

Although we both hammered home the point that the fabled Earth-killing solar flare wont happen in 2012 (let’s face it, our Sun is still going through an epic depression, why should solar maximum be anything spectacular?), it is probably the one theory that holds the most scientific merit. In fact, as both Alex and I agreed, for a civilization that depends on sensitive technology in space and on the ground, we really need to prepare for and understand solar storms far better than we do at present.

I won’t go into any more details, but the documentary will be on the Discovery Channel in November, so I’ll give plenty of warning to fire up those DVRs.

Thank you Sarah, Jonathan and the rest of the crew from KPI for making the New York visit so memorable…

The Naked Singularity Recipe: Spin a Black Hole, Add Mass

naked_singularity

The event horizon of a black hole is the point of no return. If anything, even light, strays within the bounds of this gravitational trap, it will never escape. The event horizon is what makes a black hole black.

But say if there was a way to remove the event horizon, leaving just the black hole’s singularity to be “seen” by the rest of the universe? What if there is a special condition that would allow this infinitely small, yet massive point to become naked?

Generally physicists agree that this is a physical impossibility, but the mathematics says otherwise; a naked singularity could be possible.

Previously on Astroengine, one “special condition” was investigated when an extreme black hole collision was simulated by a Caltech researcher. In this case, the black hole pair was smashed together, head-on, at a velocity close to the speed of light. The gravitational waves travelling away from the collision were then modelled and characterized. It turns out that after this insanely energetic impact, 14% of the total mass was converted into gravitational wave energy and both black holes merged as one.

While this might not be very realistic, it proved to be a very useful diagnostic tool to understand the conditions after the collision of two black holes. As an interesting observation, the Caltech researchers found that although the collision was extreme, and there was a huge amount of mass-energy conversion going on (plus, I’d imagine, a rather big explosion), neither black hole lost their event horizons.

Case closed, wouldn’t you think?

Actually, another theory as to how a black hole could be stripped naked has been knocking around for some time; what if you added mass to a black hole spinning at its maximum possible rate? Could the black hole be disrupted enough to shed its event horizon?

It turns out there’s a natural braking system that prevents this from happening. As soon as mass is dropped into the black hole, it is flung out of the event horizon by the black hole’s huge centrifugal force, preventing it from coming close to the singularity.

However, Ted Jacobson and Thomas Sotiriou at the University of Maryland at College Park have now improved upon this idea, sending mass in the same direction as the spinning black hole. Only this time, the black hole isn’t spinning at its fastest possible rate, the simulation lets the orbiting matter fall into the event horizon, speeding up its spin. The result? It appears to disrupt the black hole enough to strip away the event horizon, exposing the singularity.

The most interesting thing to come of this research is that swirling matter is falling into black holes all over the universe, speeding up their spin. Jacobson and Sotiriou may have stumbled on a viable mechanism that actually allows naked singularities in the cosmos. Unless nature has found another way to prevent the cosmic censorship hypothesis from being violated that is…

Source: New Scientist

Would You Like a Slice of Moon with that Solar Observation?

The Hinode view of the eclipse (JPL/NASA).

The Hinode view of the eclipse (JPL/NASA).

On July 22nd, Asia witnessed the longest solar eclipse of the century. I saw the pictures, it looked like fun. I’ve only seen a partial solar eclipse in the past, so when I heard about last week’s eclipse lasting nearly 7 minutes, I was more than a little envious.

So another eclipse, another momentous event if you could witness it, but if you couldn’t, at least you had some nice pictures to look at. However, there seems to be one forgotten spectator who had the best seat in the house to watch the moon pass in front of our Sun: the Hinode solar observatory.

Hinode (meaning “Sunrise”) is a space-based observatory launched by the Japanese space agency JAXA in 2006, and since then it has changed our perception of the inner dynamics of the solar corona. It can image the fine-scale magnetic structure of coronal loops and track plasma features with astounding precision.

On Wednesday however, Hinode caught an entirely different feature in its lens.

Actually, I’m a little surprised there’s not much of a fuss about the eclipse from space. Admittedly, the lunar transit across the solar disk didn’t attain totality, but it sure looks amazing!

For more of the Hinode eclipse, have a look at the Flickr gallery