All posts by Debjyoti Bardhan

Is a science geek, currently pursuing some sort of a degree (called a PhD) in Physics at TIFR, Mumbai. An enthusiastic but useless amateur photographer, his most favourite activity is simply lazing around. He is interested in all things interesting and scientific.

Huge Solar Flare Headed Directly For Earth; To Strike In A Few Hours

A huge Solar Flare is heading towards Earth and is expected to collide in a few hours. On the 4th of March, night time in the Eastern Hemisphere, the Sun released a huge amount of charged particles travelling at large speeds in what was a X1.1 class Solar Flare. These particles are going to collide with the Earth’s atmosphere and generate spectacular auroral shows near the poles, and may even cause problems in communication in certain places.

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Direct Aim

The bad news is that this solar flare, or Coronal Mass Ejection (CME’s), ejected from the active sunspot AR1429, is aimed directly at Earth. This falls in a series of very big solar flares from the Sun over the last year or so, leading up to the maximum of the 11-year Solar Cycle in 2013. The only difference between this present one and the previous ones is that the earlier ones were not directly straight at us.

You may expect significant disturbances in satellite communications, may be even partial blackouts for a few hours. Power grids are also expected to be hit. NASA is also tracking the exact trajectory of the CME, fearing for the astronauts on the International Space Station.

The expected arrival time is about 2300 EST on 6th March, but it could be early morning on 7th March.

What To Expect

The bottomline is this: Watch out for Auroras if you are in the higher latitudes, whether in the Northern or Southern Hemisphere. In addition to that, do not be surprised if you are rendered without mobile network or even power for a few hours, especially if you reside in the higher latitudes. Do make light preparations for that.

Fireball Spotted Across Britain, Reactions Range From Excitement To Paranoia

A fireball has been spotted across the length of the British Isles, starting as north as Scotland and ending as south as Devon. At about 21:40 GMT yesterday, eyewitnesses reported seeing a “bright light” with and “orange glow” and there were fears of an aircraft crashing through the atmosphere. However, these fears were calmed by what the Met Office tweeted, slightly incorrectly:

Hi All, for anyone seeing something in the night sky, we believe it was a meteorite.

A meteor that was spotted in Australia in 2009. This is NOT what was spotted in Britain yesterday

Meteorites are large pieces of rock, which are usually the end-products of some planet forming event that didn’t quite succeed. They are the leftovers. When such a leftover piece enters the Earth’s atmosphere, it is burnt up due to friction with the atmospheric molecules. If it is big enough, it survives until impact on the Earth’s surface, earning the label ‘meteorite’ in the process. This is where the Met Office tweet goofed up; there is no evidence to show that the fireball actually landed somewhere on Earth.

The police forces were inundated with calls from frantic eyewitnesses and were busy assuring them that nothing was wrong. Here is a grainy video taken of the fireball:

From Excitement to the End of Life

Laura Yusuf of Surrey saw the fireball while driving on M6 and reported:

It was an amazing sight. Bright orange flames trailing behind it as it slowly burnt itself out,

However, many were less than rational about it. Gary Fildes, a director of a local Observatory, who also spotted the meteorite first hand, was at the receiving end of a lot of frantic calls. He recalls a particular one, which he apparently had fun answering:

They went absolutely mental. I was getting questions about what it is and is it going to end life on Earth? It was massively exciting.

The meteor was spotted as far south as Devon, meaning that it had to be a big rock that was streaking across the skies.

NASA’s Cassini Spacecraft Detects Oxygen Gas On Saturn’s Moon

It’s not quite breathable, but Saturn’s moon Dione still has a bit of molecular oxygen within its very thin atmosphere. The oxygen atoms are very sparse, only about one molecule of oxygen per 11cubic centimeters (cc) of space. The fact was reported by NASA’s Cassini Spacecraft.

An artist's impression of the Cassini spacecraft flying past Saturn.

But how did it get there?

The interesting bit about the oxygen is how it comes to be! The oxygen is not made by biological organisms, unlike here on Earth, but by physical processes like dissociation of molecules in the atmosphere due to the bombardment by highly energetic photons. They can also come from geological activity. How the tiny Dione holds on to this thin layer of gases is, however, not understood. Saturn’s biggest moon Titan, possibly the biggest in the Solar System, has a thick atmosphere, but then it’s much bigger than Dione. Dione’s atmospheric problem compounds the problem astronomers have of explaining the atmosphere around Rhea, another small satellite of Saturn.

Not that big a surprise

The detection of molecular oxygen was done using ion and neutral mass spectrometers. Earlier, Hubble had picked up the signature of ozone, so molecular oxygen was always on the cards, since ozone is just the oxygen molecule with one more oxygen atom.

It is not clear whether there are rarer gases in Dione’s atmosphere and, if present, what their composition is.

The conclusion comes from analysis of the data taken on the Cassini flyby on Dec 12, 2011.

Novel New Material Graphyne Can Be A Serious Competitor To Graphene

The carbon nanostructure revolution refuses to cease. First, it was carbon nanotubes, followed by graphene. After these two “hot” materials, it may now be the dawning of another wonder material called ‘Graphyne’. Graphyne may surpass even graphene in its electrical properties. While graphyne has been researched for the last 30 years, it has suddenly become a hot material for condensed matter physics.

An artist's impression of graphene

Graphene is known for its extremely high conductivity owing to a peculiar property of graphene electrons. In graphene, the so-called valence and conduction bands touch. Near the points where the two bands touch, called the Dirac point, the energy-momentum relation of the electrons is linear (graph, right), instead of quadratic as seen for other particles. This leads to the mass of the charge carriers (electrons or holes) inside the material being effectively zero. This allows them to travel at extremely high speeds, giving rise to very high mobilities and superior conduction properties. It was precisely this that led to the 2010 Nobel Prize being awarded to Andre Geim and his student Konstantin Novoselov.

Graphene and Graphyne

Graphyne doesn’t really exist; it has to be synthesized using special techniques. However, computer simulations show that its conduction properties can be better than graphene. Graphyne is a 2D lattice, just like graphene, but with double and triple bonds, rather than just single bonds as it is with graphene. The graphene lattice is strictly hexagonal, while graphyne lattice can take up an arbitrary shape due to the presence of the double and triple bonds. In particular, it can take up a rectangular lattice shape.

The key to good conduction is not only high mobility of the electrons, but also directionality. The electrons should be free to travel in a straight line. For graphene, the lattice has no preferred direction, but for graphyne, the lattice being rectangular, prefers conduction in one direction over the other. This means that it has gating properties depending on the direction of passage of current.

6,6,12- Graphyne

Simulations and predictions

A recent paper in Physical Review Letters, by Andreas Gorling and colleagues (link) presents simulations of electronic properties of graphyne. They discuss the so-called 6,6,12-graphyne (pic above) and simulate its properties. Density functional simulations predict the presence of Dirac cones in graphyne, which were thought to be unique to graphene. Moreover, the conduction turns out to be superior to graphene.

We should stress the fact that graphyne has not been made in the laboratory in significant quantities as yet; only trace amounts have been fabricated. Only proper experiments on real samples can verify the simulation results, but Mikhail Katsnelson, a big name in the field of graphene physics, expresses confidence in the density functional methods. The next step would be to prepare proper graphyne samples for study. Only then can all the fancy experimental tests be applied.

New material on the block and a lot of new physics to be known – it’s a mouth-watering prospect for physicists.

More about the mechanical properties of graphyne: http://web.mit.edu/mbuehler/www/papers/Carbon_2011.pdf

Shut Up! The Japanese Have Built A Speech-Jamming Gun

This may be the most innovative (and useful) non-lethal weapon invented till date: the speech jamming gun. It’s a great way to shut people up, literally and it works just like any other gun; you point, you aim, you shoot and you silence! Two Japanese researchers, Kazutaka Kurihara and Koji Tsukada from the National Institute of Advanced Industrial Science and Technology and Ochanomizu University respectively have come up with this marvelous invention.

A figure taken from the paper

The Silent Treatment

The principle is simple. A person’s speech is fed back to him with a slight delay of a few hundred milliseconds, using a mechanism called ‘Delayed Auditory Feedback’ (DAF). This can force the person to stop speaking. It exploits a well-known functionality of the brain called ‘auditory feedback’. The brain not only instructs speech, but also guides it, analyzing the every piece of vocal output. The trick is to stop the brain from hearing what actually comes out of our mouths. When the person’s own words are played back to him/her, the auditory cognition of the brain can be scrambled and, because it affects the logical cognitive processes in the brain, it becomes impossible to continue speaking!

The invention finds a place in the Cornell University Archives. The arXiv paper, titled ‘SpeechJammer: A System Utilizing Artificial Speech Disturbance with Delayed Auditory Feedback’, can be found here.

The paper says:

In general, human speech is jammed by giving back to the speakers their own utterances at a delay of a few hundred milliseconds. This effect can disturb people without any physical discomfort, and disappears immediately by stop speaking.

One is merely limited by one’s own imagination as to how important and useful this instrument can turn out to be, especially in the hands of students in a classroom or in the hands of husbands in front of their wives. Enough said, time to stop talking.

CP Violation: Tevatron Detector Data Reconfirms What The LHC Had Already Said

The Tevatron at Fermilab may not be active any longer, but the data it has collected over its lifetime is still capable of inspiring great thoughts. The data, now fully analysed, has revealed what the LHCb had already found earlier, thus giving more credence to hypothetical ideas. The data yields answers to questions as basic as “Why is there matter in the Universe?”.

The CDF detector

CP Violation

In November 2011, we had reported about a reported CP violation in the charm quark sector. We inferred that by looking at the so-called D0-D0 bar mixing. The news can be found here. A more detailed discussion and explanation of the various things is given here.

So, let me just quote the basic figure. The LHCb quotes a figure of 0.82% deviation from the expected value of zero, from the Standard Model. A non-zero value of CP violation goes towards answering the question of why matter won over anti-matter, when equal amounts of the two were produced right after the Big Bang. Now, the CDF gives the same hints.

The CDF quotes a deviation of 0.67 % from zero. The result says -0.67% +/- 0.16%. Alongwith the LHCb results, the CP Violation stands at 3.8 sigma confidence level.

The Standard Model predicts that if CP violation is detected, it might signal the existence of new particles. So far, we have no data to indicate that so far!

With Upgrades, LHC Will Be More Energetic And Be Able To Handle More Collisions

The LHC is taking a vacation right now, but it promise to return with a bang! The LHC is due to run very soon, but instead of the usual 7 TeV (1TeV = 1 Trillion electron volts) total energy, it will try and go a bit higher and reach 8 TeV. Also the luminosity (basically number of collisions per second) will increase, but the increase won’t be substantial and there are reasons for that. Physicists promise enough data to pinpoint the Higgs and to verify the tantalizing 125 GeV peak that was reported earlier(here). Furthermore, after a packed 2012 schedule, the LHC will hibernate for a longer time and will wake up in 2014. During this time, the LHC will be fitted with newer instruments.

More work: ATLAS detector

Upgrade

The hardware upgrade will have to wait till end of 2012, when the LHC will shut down for an extended period of 14 months, waking up again in 2014. The hardware upgrade will allow the LHC to run at a huge energy of 14 TeV and much higher luminosity. This is crucial, since it is not only the energy, but the number of collisions that makes a lot of difference in the experimental data. More luminosity means lower uncertainty in the measured values. The current electronics won’t be able to handle the rate of data acquisition that the LHC is planning to achieve.

Higher luminosity

The LHC currently runs at 3.5 TeV per beam, giving 7 TeV on a two-beam collision. They plan to upgrade it to 4 TeV per beam, giving a total energy of 8 TeV. Each beam of protons is made up of bunches of protons, with each bunch being separated by a certain amount of time. Each bunch has a certain number of protons. The team will also look to increase the number of protons per bunch, but keep the number of bunches constant, thereby increasing the luminosity. The current bunch spacing is 50 nanoseconds. The LHC electronics is built so as to handle bunches separated by 25 ns. The LHC team might look at this small deadtime when it resumes in 2014.

All in all, the full blown search for Higgs might end soon, but the LHC is poised for more daring adventures!

Faster-Than-Light Results Debunked by Computer Glitch? Hold On, Not So Fast!

The neutrino story is still not an open and shut case. You’ve probably read about the supposed computer glitch by now. If you haven’t, we have it right here. However, as more details pour in, more surprises tumble out! It turns out that there wasn’t just one computer error, there were, in fact, two!! And this complicates matters

Twin Glitches

Error #1

New York Times reports that one source of error is the GPS measurement system, or more precisely, the optical cable connecting the GPS receiver to the detector. This is a five mile long cable and the faulty wiring could’ve easily put the measurements back by 60 nanoseconds, which was the exact amount of time by which the neutrinos beat the speed of light. This is the story we reported earlier.

Error #2

However, it seems that there was yet another unaccounted systematic error! There is a piece of equipment that marks the exact time for the GPS measurements, taking into account all sorts of relativistic corrections.

However, this would speed up the neutrinos even more, making the case for the violation of relativity even stronger.

The first error has been corrected, but the second error is yet to be taken care of.

Add and subtract the errors? No? What’s wrong?

As any student of physics would know, errors like these cannot simply be added or subtracted. For extreme precision experiments, like the OPERA  experiment, one cannot tweak the experimental data in order to do take into account all technical glitches. The only way to resolve this would be to fix the systematics and run the experiment again!

The experiment would definitely need an independent test to be refuted, now more than ever, since these unexpected question marks have been put up against it.

Discovered: Solid Buckyballs In Space!

They were popularized by being compared to nanoscale footballs, made up of a large number of carbon atoms. However, no one thought that they were as ubiquitous as the latest Spitzer results suggest them to be. They are called Buckminsterfullerene, or more commonly, buckyballs, after the architect, Buckminster Fuller, whose geodesic designs resemble these natural structures.

A C-60 buckminsterfullerene

Spitzer discovers buckyballs

Enter Spitzer, the premier infrared satellite in the world right now. It roams around in space in an orbit around the Earth, since the atmosphere would block most of the infrared radiation. It has recently caught buckyballs around the double star system XX Ophiuchi. What’s more, the buckyballs are in solid form, and this can be easily figured out since the diffuse gaseous form gives a different absorptions spectrum compared to the solid one.

This is the first detection of solid buckyballs in space. Incidentally, the relatively wide presence of buckyballs in space was established by Spitzer itself in 2010.

Buckyballs are quite useful here on earth. They are extremely resistant to heat, pressure and chemical action. They have been thought to be shrink wraps, with the buckyballs acting as ‘cages’. Furthermore, their high tensile strength can be utilized in things like armour.

Buckyballs in space. An artist's impression (Courtesy: JPL/NASA)

More carbon, better it is!

Buckyballs being found in outer space means that there is much more carbon in space than previously thought. Scientist think that this allotrope of carbon might indicate that more common allotropes like graphite might be present.

Mike Werner, NASA’s Spitzer telescope project scientist currently at JPL, Pasadena, California, says:

This exciting result suggests that buckyballs are even more widespread in space than the earlier Spitzer results showed. They may be an important form of carbon, an essential building block for life, throughout the cosmos.

The story appears in the Monthly Notices of the Royal Astronomical Society. Just before you leave us to do more mundane terrestrial stuff here’s a nice video, courtesy Space.com.

BREAKING NEWS: Simple Computer Glitch To Blame For Faster-Than-Light Neutrino Results

The supposedly greatest anomaly ever detected in physics, capable of undoing a hundred years of physics, may turn out to be a mere computer glitch. There are rumours that the anomaly may be due to a faulty connection between a GPS unit and a computer receiving signals from it.

We had reported the faster-than-light neutrino results in great detail in several posts earlier. The physics group at Gran Sasso laboratory, near CERN, had detected that neutrinos arrives 60 nanoseconds before they are expected to, if they travelled at light speed. This means that they travelled faster than light, violating the cosmic speed limit imposed by Einstein’s Special Theory of Relativity, by a factor of full one-ten thousandth, which is a huge number when it comes to Lorentz violations.

The rumour is that sources inside Gran Sasso say that when a connection between a GPS receiver and the optic fibre was adjusted, the time of flight comes out exactly 60 seconds longer than measured, exactly cancelling the seen anomaly.

New data from independent experiments is still needed to confirm the non-violation of the cosmic speed limit. If this rumour is true, it is face-saving time for the Gran Sasso scientists.