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.

Australia Witnesses a Bright And Slow ‘Meteor'; It’s Just Space Junk

A bright object lit up the Australian night sky earlier today evening. It’s widely believed to be nothing more than space junk, and not an actual meteor.

Cropped frame grab from a YouTube video.
Cropped frame grab from a YouTube video.

At about 10 PM local time, on the 10th of July, there were widespread reports of a bright object streaking across the sky over southeastern Australia. It was initially thought to be a naturally occurring rock which had invaded the Earth’s atmosphere. However, it moved very slowly. Experts later confirmed that the flaming object was a piece of the Soyuz 2-1B rocket which was launched a couple of days back, in order to put a meteorological satellite called, ironically, Meteor M2 in orbit. The witnessed object is just the upper stage of the Soyuz rocket.

It is highly unlikely that anyone would be hit by such space debris, but the sight did cause a massive sensation. There were even occasional fragmentation as one would expect from such an object making reentry into the Earth’s atmosphere. However, the aspect which caught most Australians off-guard was the very slow speed. Here is a video which is being circulated. It was shot using a mobile phone camera:

So, it’s just space debris making a lively reentry.

No Ambulance Needed: Unexpected Diboson Excess at LHC Keeps Super-Symmetry Alive

The grapevines are buzzing again – and there is again a sliver of hope. Many believe that Super-Symmetry (SUSY), the purported next step in high-energy physics is almost dead, with the LHC, the big boy on the block, finding no signatures of it as yet. Just this week, however, a paper and a presentation at the prestigious global International Conference on High Energy Physics (ICHEP), happening in Valencia, Spain, aims to correct that situation a bit. They shout ‘Stop the Ambulance‘, employing a nice play on words.

An event consistent with the Higgs decay. It can decay into two Z-bosons, which can give the four muons (red lines in the pic).
An event consistent with the Higgs decay. It can decay into two Z-bosons, which can give the four muons (red lines in the pic).

What’s left to know?

Their claim is simple – we have seen an excess number of events, unexpected if the known Standard Model of Particle Physics is all there is. The Standard Model (SM) forms the backbone of known particle physics, and it has been rigorously verified over decades. With the discovery of the Higgs, almost exactly 2 years ago, it is believed to the ‘complete’. Physicists are now looking into the chinks in the armour of the SM, hoping to find a crack here or a broken seam there through which they can glimpse some new physics. So far, the armour has been imposing and flawless, but there are still checks to be done.

One of the most important particles in the SM is the W-boson. It can either be positive or negative. All processes producing these bosons are well-known and calculated. Basically we know how they are produced quite accurately. So far, all measurements confirm our theoretical calculations. However, this group reports on an excess of diboson production seen by the LHC, which basically means that there are more pairs of W-bosons being created than expected from the SM.

There’s more

What is more intriguing is that the single W-boson production rates, the single Z-boson (a companion to the W, but neutral in charge), WZ production and a pair of Z-boson productions rates have matches with the predicted SM rates. The pair of W-bosons just don’t seem to comply – and the discrepancy isn’t too small. What more, the discrepancies are in the same direction for both the CMS and ATLAS collaborations of the LHC.

The authors of the paper have taken up a simplified model, consisting of the SM and a few SUSY particles and have showed that their model fits the data way better than the SM. Their model has a light stop, winos and binos.

That said, the data is still quite inadequate to claim anything solid. Everyone is eyeing the 2015 restart of the LHC runs. Let’s hope that SUSY survives till then.

Biological Nanodots Enable Smartphone Battery To Recharge in 30 Seconds

The Microsoft ThinkNext symposium at Tel Aviv might be the launching pad for a future in which we spend more time using our smart devices rather than charging them. StoreDot, an Israeli startup, has demonstrated their brand new model of electrodes which can help charge a smartphone battery in flat out 30 seconds. Take a look at their video here:

Batteries take a long time to charge because you need to reverse the chemical reactions that fuel it. If you rush this reversal process, you run the risk of damaging the electrodes and also depleting the chemical fluid, called the electrolyte. For the sake of longevity of the battery, you need to spend hours every day charging everything from your laptop battery to your cell-phones. And that can be a painful wait, especially without coffee.

Enter Nanodots

What StoreDot has going for it are tiny biological particles called nanodots. These are tiny synthetic bio-molecules – chemically synthesized peptides – which radically improve electrode capacitance and electrolyte efficiency. They make this process of reversal much faster than earlier.

At the ThinkNext symposium, StoreDot demonstrated their new technology on a Samsung Galaxy S3, but said that they would definitely widen their reach to other big names, like the iPhone.

Samsung Galaxy S3 charged in under 30 seconds. Photo Courtesy: StoreDot
Samsung Galaxy S3 charged in under 30 seconds.
Photo Courtesy: StoreDot

In an interview to Gizmag, StoreDot CEO Doron Myersdorf said:

In essence, we have developed a new generation of electrodes with new materials – we call it MFE – Multi Function Electrode. On one side it acts like a supercapacitor (with very fast charging), and on the other is like a lithium electrode (with slow discharge). The electrolyte is modified with our nanodots in order to make the multifunction electrode more effective.

On their own website, StoreDot touches upon the fact that their new technology is not only revolutionary, but also eco-friendly. They plan to replace all cadmium and lead based technologies with their biomolecules, making them easier to dispose off as well. It won’t be too costly either – StoreDot claims that the chargers will cost only about twice that of regular chargers we have today.

Of course, the spillover into other areas like laptop batteries and, even, electric cars is inevitable. StoreDot seeks two more years to perfect its technology – 2016 is the year to watch out for.

Discovered: Liquid Water Beneath Surface of Saturn’s Moon Enceladus

Saturn’s moon Enceladus may have liquid water hidden away at its South Pole. Or so say NASA’s Cassini, the spacecraft dedicated to map out different aspects of the beautiful planet Saturn.

Enceladus, as mapped by Cassini. Look at the craters and the ravine-like structures.  Photo Courtesy: NASA/Cassini
Enceladus, as mapped by Cassini. Look at the craters and the ravine-like structures.
Photo Courtesy: NASA/Cassini

Enceladus is a tiny moon of Saturn, barely measuring 500km across. It’s been a curious object for many years, since it shone brightly in reflected sunlight, the surface being covered by a white layer of water-ice (meaning, frozen water). The surface is fractured into various patterns, indicating erosion in the past. Much of the surface is cratered; objects, mostly small rocky bodies, pulled in by Saturn’s gravity slam into Enceladus. A spectacular display is seen at the South Pole of the moon, where giant plumes of liquid and gaseous water rise, after penetrating the fractured surface. These shine in the Sun’s rays and also provide material to Saturn’s E-ring.

Cassini picks up the plumes of water vapour and liquid water towards the south pole of the moon.  Photo Courtesy: NASA/Cassini
Cassini picks up the plumes of water vapour and liquid water towards the south pole of the moon.
Photo Courtesy: NASA/Cassini

How Cassini Discovered Water

Cassini has made several flybys past Enceladus, in 2010 and in 2012, mapping its surface in great detail as it flew less than 100 km from the surface. It has also mapped the gravitational field of the object and this is what led to the discovery of a possible liquid water reservoir right beneath the surface. During these flybys, the trajectory of Cassini changes slightly due to the gravitational field of the moon. Being a light object, Cassini is quite sensitive to local gravitational fields, and corrects its path accordingly. This means that one can use this information to map out the gravitational field of the moon. If there is a major concentration of mass, like a large mountain, we can feel a positive addition to the field, while a hollow will show up in a negative way.

Artists' impression of what Enceladus might look like on the inside.  Image Courtesy: NASA/Cassini,
Artists’ impression of what Enceladus might look like on the inside.
Image Courtesy: NASA/Cassini,

Cassini, mapping the gravitational field in the South Pole of Enceladus, found that there was a mass deficit on the surface, but a large mass excess abut 30-40 km below the surface. This ‘subsurface anomaly’, meaning a deviation from the standard mass distribution found below the surface, is, ‘compatible with the presence of a regional subsurface sea’, says the paper on the subject.


The next obvious question is this: does this sea of liquid water harbour life? The answer is that we don’t know. For a long time, Jupiter’s Europa was a happy hunting ground for alien-hunters; this status might be usurped by Saturn’s tiny Enceladus. A good, though quite a bit technical, answer can be found in a paper co-authored by Carolyn Porco, head of the Cassini mission here. This, however, predates the recent Cassini discovery and hinges its arguments on the plumes of liquid water seen emerging from the South Pole.

A nice video on the subject by JPL and NASA can be found here:

NASA’s Telescope Detects Strongest Hint Yet of Dark Matter Particles from Galactic Center

NASA’s Fermi Gamma Ray Telescope has spotted something which should interest every physicist. Looking at the heart of our Milky Way galaxy, Fermi has unequivocally showed a bright gamma-ray glow. Scientists have then removed all known gamma-ray sources and, while it removes quite a bit of the contributing source, it still leaves a bit unaccounted for. We don’t know what’s causing this excess gamma ray glow. Given that gamma rays are some of the most energetic radiations known, it is unlikely that they are caused by some thermal event. The best explanation at the moment is that something unknown – some unknown particles – are annihilating each other and giving off these radiations. The question is then, what are these particles.

The signal that Fermi saw. On the right, we have the same signal with all the known sources removed. A strong glow still remains - we don't know what that is!
The signal that Fermi saw. On the right, we have the same signal with all the known sources removed. A strong glow still remains – we don’t know what that is!

These particles ought to be quite heavy; the gamma ray emission hints at their mass. One very likely explanation for these particles is that they are Dark Matter particles. Humorously called WIMPs, short for Weakly Interacting Massive Particles, these heavy particles are likely candidates for Dark Matter (DM). In other words, the gamma ray lines seen by NASA’s Fermi telescope are because of DM annihilation.

Dark Matter 101

But what is DM you ask? DM is conjectured to be a type of matter beyond which we already know about, responsible for about 27% of the total mass-energy of the Universe. It was first hypothesized by Fritz Zwicky to explain why some galaxies can actually rotate as fast as they do without breaking apart. He surmised that there must be some invisible form of matter, which does not have any electromagnetic interaction, and thus doesn’t give off light, but are massive and, thus, can interact via the gravitational force. Today that conjecture stands on firmer grounds, with observations of known deviation from expected rotation speeds spanning thousands of galaxies. DM has been indirectly hinted at by many experiments such as the CoBE, WMAP and the recent Planck experiment, which all map out the distribution of Cosmic Microwave Background Radiation in our Universe. A host of other experiments also detect strong anomalies which can be easily explained away by the DM hypothesis.

In other words, we are quite sure that DM exists.

The mass-energy estimate of the Universe as given by the Planck experiment.  Courtesy: Planck/ESA
The mass-energy estimate of the Universe as given by the Planck experiment.
Courtesy: Planck/ESA

The clinching evidence would be to a actually detect it and one way is to let it annihilate each other into two known particles. These two particles then annihilate and produce some radiation which we can detect. The heavier the DM particles, the more energetic the final radiation; thus by knowing the final states, we can figure out the masses of the initial particles.

It is to be noted that no-one is jumping up and saying that DM has been found. While the evidence is highly suggestive, it’s not yet clinching, because, as most scientists like to say, not enough data has been collected. They would conservatively err on the side of mundane humility rather than make a mistake making an extraordinary claim.

Keep watching this space for more.

The official paper:

The following video was released by NASA:

Human Genes Cannot Be Patented, Says A Landmark US Supreme Court Ruling

A Supreme Court ruling may change the landscape of genetic research forever. The US Supreme Court ruled that human genes cannot be patented, in a landmark hearing giving a huge victory to the American Civil Liberties Union (ACLU) while disheartening Myriad Genetics. The issue was the BRCA genes, the mutations on which are believed to be responsible for increasing the susceptibility to breast cancer.

The Contention

Myriad Genetics had claimed patent over this gene, claiming to have ‘invented’ this gene, which meant that all treatments and even detection of the BRCA gene would entail a royalty to Myriad. This would’ve raised the costs of detection, costs and treatment of breast cancer significantly. In a beautiful moment when calm commonsense prevailed, the Supreme Court struck down the ‘invention’ claim by saying:

Myriad did not create anything. To be sure, it found an important and useful gene, but separating that gene from its surrounding genetic material is not an act of invention… Myriad found the location of the BRCA1 and BRCA2 genes, but that discovery, by itself, does not render the BRCA genes … patent eligible.


The Consequences

This, of course, means huge losses for the pharmaceutical industries, but it’s the cancer patients who stand to benefit in the long run. The costs of detection tests and their subsequent treatment would come down, as no one company would have the monopoly on the technology and research. As it should be!

Myriad’s defence even involved a ludicrous ‘baseball’ argument, in which they argued that the “baseball bat doesn’t exist until it is isolated from a tree. But that’s still the product of human invention to decide where to begin the bat and where to end the bat”. This analogy fails on many levels and the court noted that merely deciding the start and end points of a gene sequence doesn’t deserve a patent. Official ruling said:

The baseball bat is quite different. You don’t look at a tree and say, well, I’ve cut a branch here and cut it here and all of a sudden I’ve got a baseball bat. You have to invent it.

However, Myriad did get part of the pie, when the court ruled that the Myriad can have its patent on the invention of the cDNA – complementary DNA – which is actually a synthetic form of DNA.

“The lab technician unquestionably creates something new when cDNA is made,” said the court.

The ruling here:

Is The Kepler Space Telescope Entering Its Last Days?

A darling of NASA and of the general public, the Kepler Space Telescopes, dedicated to looking at extra-solar planets, may be soon ending its run. A recent hardware failure on the Kepler has led experts to give Kepler just one more year.

Artist's rendition of Kepler Space Telescope
Artist’s rendition of Kepler Space Telescope

Kepler had four reaction wheels, which keep Kepler steady and able to focus unerringly at distant stars and planets. Kepler really needs three wheels to achieve this job, but has four just in case. Earlier, in July, 2012, one of these wheels had broken down, putting engineers slightly on the edge. Kepler, however, continued to function as well as it always did.

On 9th May, engineers found Kepler in automatic safe mode, since something was wrong. To their dismay, they found that one of the three remaining wheels had malfunctioned. Kepler’s days seemed numbered.

Kepler stares at faraway world, shielding its own cameras from the glare of the Sun. However, light from the Sun hits the craft (and, in fact, fuels it) and exerts pressure on it, called radiation pressure. No matter how small this is, this is enough to throw Kepler a bit off its line of sight. And this is where the wheels come in, ensuring that the photons are not the nuisance that they really are.

Engineers are scrambling for ideas to save Kepler. They are trying to use the boosters to compensate for the reaction wheels, but this won’t give the stability that Kepler enjoyed. Its planet watching days may be over.

NASA Detects A Burst Stronger Than Any Seen Before

A recent blast from a dying star has left astronomers, gaping in awe at the sheer magnitude. A distant eruption, classified now as a Gamma Ray Burst (GRB) and named GRB 130427A, has now set the record for the brightest GRB ever. NASA’s Swift satellite and Fermi-LAT, both specialized for the gamma ray part of the spectrum, have recorded this mind-boggling event. Julie McEnery, project scientist for NASA’s Fermi-LAT, said that this was a “shockingly, eye-wateringly bright” burst.

An artist's impression of a GRB. Note the strong jets on either side of the collapsing star. (Courtesy: wikimedia commons)
An artist’s impression of a GRB. Note the strong jets on either side of the collapsing star. (Courtesy: wikimedia commons)

What are GRBs?

Gamma Ray Bursts are the most powerful explosions known to mankind that occur in the Universe, ranked second right after the Big Bang itself. GRBs occur when an extremely massive star collapses into a massive black hole, and the material falling into the black hole heats up so much that it radiates in the gamma ray region of the spectrum. These jets of gamma rays puncture the material envelope of the dying star and can be detected from a long distance. Unlike smaller supernova (which happen for moderately large stars), GRBs are responsible for throwing out a large amount of energy in the surrounding space, often energizing the gas around and making it glow. The duration for such a burst might last from a few milliseconds to minutes or even hours and the burning embers can often be seen for days and months. We generally count the time for which the radiation energy exceeds the GeV (giga-electron volt) threshold, which is about a billion times more energetic than visible light.


For our present GRB, the GeV radiation lasted for hours and it was observed by Fermi-LAT, a space based gamma ray telescope, for a long time. Even ground based telescopes caught more than a glimpse of the GRB. The Swift satellite caught the first glimpse, as it is designated to do, during one of its rounds. Energetic emissions were recorded by Fermi-LAT, with one of the gamma ray lines having an energy of 94 GeV.

This animation is made by stacking a large number of images taken by the Fermi-LAT satellite from 3 minutes before the burst to 14 hours later. You can clearly see the burst and then the radiation flux drops and plateaus off. The burst then rose in flux again and stayed bright (more then GeV energy lines were abundant) over several hours. (Courtesy: NASA/DOE/Fermi-LAT collaboration))
This animation is made by stacking a large number of images taken by the Fermi-LAT satellite from 3 minutes before the burst to 14 hours later. You can clearly see the burst and then the radiation flux drops and plateaus off. The burst then rose in flux again and stayed bright (GeV energy lines were abundant) over several hours. (Courtesy: NASA/DOE/Fermi-LAT collaboration)

Apart from the strong gamma emission lines in the spectrum, there are also lines present in the infrared, visible and radio wavelengths. These were detected by ground-based telescopes. The distance of the burst was estimated to be 3.6 billion light years away, which is actually quite small when it comes to GRBs. This falls within the 5% of the closest GRBs ever recorded.

This is exciting and a lot of backup measurements will follow this initial detection.

More info:

When Size Matters: Story of the Incredible Shrinking Proton!

The size of the proton matters in the field of the ultra-small and it seems that no one can agree on the correct value. The answer was long believed to be well-known, but the puzzle seems to be back to haunt the physics community. The proton seems to have suddenly shrunk in size.


How do we look?

The radius of the proton is found out by shooting high energy electrons at it and then finding how it forms a bound state. It’s very much like forming an atom, except that this atom is much smaller than the normal atoms which make up matter. Energetic electrons fired at protons often get bound to the proton, and form a hydrogen-like object. However, since the electron has a lot more energy than the ordinary hydrogen atom electron, it is attached much closer to the proton than the normal hydrogen electron. As a result, the proton can no longer be treated as a point particle, but its spatial extent become important.

So we can form a bound state and then measure the minute transition between energy levels and these now have an imprint of the proton magnetic moment and the proton radius. And thus, the proton radius can be determined.
For a long time, physicists were safe in their determination of the proton radius and their value was 0.8768 femtometers (a femtometer is a millionth of a billionth of a meter, or a meter divided by 10^15). Case closed, right? Wrong…

New experiment

A new experimental result threatens to blow this question of the radius wide open again. The muon is a close cousin of the electron. It has a negative charge and behave very much like the electron in a magnetic field, except that it is 200 times heavier than an electron. Recent experiments shoot these heavy electrons – or muons – at protons and these now form a bound state. The higher mass of the muon (by a factor of 200) means that at same energies, the muon is much closer to the proton (by a factor of 800 million). It can ‘see’ the proton much better and measure the radius to greater accuracy.

However, this has produced a shocking reduction in the accepted value – 0.84087 femtometers – a reduction of 4%. That is huge, well above the experimental uncertainties.

So, what’s going on?

Physicists are not very sure what’s going on. Why should the muon behave any differently from the electron? Is the muon, being closer to the proton experiencing some short range force, other than the usual long ranged electromagnetic and the short ranged weak force, that we just don’t know about? Is a new force of nature at work here? Is there new physics, something beyond the Standard Model of particle physics?

The muon measurements were made by a group of scientists at the Max Planck Institute of Quantum Optics, led by Randolf Pohl. Of course, the crudest explanation to all of this is that the experimentalists simply bungled and got the value wrong. No one’s ruling that explanation out right now, but other avenues are also being explored.

Muon scattering experiments like MuSE will only be ready in a few years, so this debate will continue for some time. When size does matter, we just don’t want it to change.

Hint of Discovery of a Dark Matter Particle – Is It Finally Reality?

“Tantalising hints” is a phrase high energy physicists have a love-hate relation with, and for good measure. Often all major discoveries remain tantalizing hints for a long time, creating a lot of confusion, generating a lot of debates and then either fade away into oblivion or become something so big that history just cannot ignore it. A recent demonstration of this phenomenon was given at the LHC during the hunt for the Higgs, where what remained as a ‘tantalising signal’ for months, grew steadily and offered the LHC physicists their first opportunity to say ‘Hurrah!’ A similar event may be afoot at the giant Super Cryogenic Dark Matter Search (SuperCDMS ) experiment, located deep inside a tunnel in the Soudan Mine in northern Minnesota. There is a ‘tantalizing hint’ of the detection of a particle which might be the elusive Dark Matter particle.

The CDMS detector
The CDMS detector

The recent tidings have excited physicists, as they have detected three events in the detector of a possibly weakly interacting massive particle (WIMP). However, they need more events. The surety of the discovery of these WIMPs is only 99.8 %, which amounts to a wee bit more than what physicists call 3-sigma confidence level. This is at the ‘tantalising hint’ level. At 4-sigma, it gets interesting and only at 5-sigma (which is a massive 99.9997% surety), do physicists say that they have a discovery.

The star is the central value.
The star is the central value.

The mass of the particle is somewhere about 8-10 GeV, which is about 8 to 10 times the mass of the proton. That’s low mass in the context and this particle, if present, should turn up in some of the other colliders and detectors, especially the LHC, in the near future.

Theorists are already busy at work figuring out how all of this fits into their theory. Can a supersymmetric theory, a theorist’s dream for a long time, accommodate the particle of mass 10 GeV? If so, which version and how has that version fared at the LHC?

For now, let this hint promote itself to the level of a discovery – we have seen too many tantalizing signals come and then disappear to be hasty.