What makes the nuclei of our atoms stable? The atomic nucleus consists of a collection of protons and neutrons (collectively called Nucleons); for example, the typical oxygen nucleus has 8 protons, and 8 neutrons packed densely into a ball approximately of radius 2x10^-15 m (One billionth of a dust particle!). Since protons are (positively) charged particles, they repel each other. Neutrons act as fillers, and thus weaken this eletromagnetic force of repulsion, and allow the strong nuclear force (the force that binds the nucleons in a ball) to dominate, which makes the nucleus stable:).

A typical magical shell (Courtesy: SUNY Stony Brook)However, then the question becomes: how many neutrons is enough? Too less, and the nucleus will fall apart due to repulsive forces; too many, and the nucleus will be unstable as it tends to beta decay (process by which a neutron converts into a proton, and emits a electron). Therefore there is a optimal region, when the nucleus is most stable.
According to the nucleus shell model proposed in 1949, the nucleons inside the nucleus are arranged in shells. The nucleus is most stable when there are enough nucleons to fill a shell. This number is known as the magic number, are are represented by the sequence 2, 8, 20, 28, 50, 82, 126 and so on. Any nucleus containing these many nucleons are the most stable:):).
Now, nuclear physicists have created an isotope of silicon that contains twice as many neutrons as protons. Measurements made with silicon-42 - which contains 14 protons and 28 neutrons - will shed new light on the concept of "magic numbers" in nuclei.
The fact that silicon-42 is stable, was a surprising find. Paul Cottle and colleagues at Florida State University, Michigan State University, the Lawrence Berkeley National Laboratory and Surrey University in the UK produced the silicon-42 nuclei by crashing sulphur-44 nuclei into a beryllium target at the National Superconducting Cyclotron Lab (NSCL) at Michigan State University. The results show that the silicon-42 nucleus remains stable despite containing a large excess of neutrons. The data also suggest that the proton number 14 is semi-magic because it corresponds to a closed subshell, which means that the nucleus is also spherical :):).

Each of our brains are unique. In addition to genetic factors, conditions inside the womb as well as random factors contribute a lot to the way our brains are, and the way we are. No two brains are alike; even the brains of identical twins are considerably different. An interesting find now suggests that there is a connection between the variety in the brain’s neurons and certain genes that can change their position in the genetic code. These so-called jumping genes (or Transposons) may gently scramble the blueprints for the brain. According to Fred Gage from the Salk Institute, this mobility adds an element of variety and flexibility to neurons in a real Darwinian sense of randomness and selection.

Jumping Genes (Courtesy: Saint Anselm College)Transposons have been known for a long time. These are genes that can move around to different positions within the genome of a single cell. This can cause mutations and change the amount of DNA in the genome. This can disrupt the functions of neighboring genes, and thus can directly change some trait in the species, which if beneficial, might aid in its evolution. Jumping genes are found in all living things. Approximately 20 percent of the genetic code in mammals is of the jumping variety! But only a small fraction of these are active – which means they are able to successfully reinsert themselves into a new spot in the code.
The fact that these certain jumping genes can directly affect the brain is what is interesting in Dr. Gage's research, to be published in the journal Nature. He found that a gene called long interspersed nuclear element-1, or L1 for short, jumped positions in cultured brain cells of rats. This is the first time such a jump has been seen in cells other than the sperm or the egg:).
Evolutionarily, this has significant implications. It might be that we owe our intelligence to some so-called jumping gene, and not to a gradual adaptation and improvement as the human species evolved:).

My favorite website is 10 years old today. Happy Birthday, APOD :). APOD, which stands for Astronomy Picture of the Day has brought me countless pictures from outer space, and has both dazzled and saddened me from time to time. I still remember the first time when I visited the APOD site (quite by accident, I think), in 1996. I was using a HP-Unix 90MHz computer then:)). How things change! The computing power has taken a 30 fold jump, and APOD still continues to dazzle and sadden me.

APOD Editors (Courtesy: APOD)Editors Robert Nemiroff and Jerry Bonnell are two professional astronomers who spend most of their time researching the universe. Robert Nemiroff is an associate professor at Michigan Technological University in Houghton, Michigan, USA, while Jerry Bonnell is a scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Hope springs eternal. Hope I can continue writing this blog for as long as I can :).

The neutrino is a chargeless, near massless particle which interacts very weakly with ordinary matter. It is created during nuclear fission/fusion reactions; in fact, during every second, billions of (solar) neutrinos pass through our body:). It would take about one light-year (~10¹³km) of lead to block half of them! Obviously, it is very hard to detect these elusive particles.

Neutrino Ripples: fluctuations of order of ±30μK (Courtesy: RAS)But detecting these particles is very important, as copious amounts of it is theorized to have been created at the Big Bang, according to which neutrinos permeate the Universe at a density of about 150 per cubic centimetre. Now scientists have for the first time found evidence of ripples in the Universe’s primordial sea of neutrinos, confirming the predictions of both Big Bang theory and the Standard Model of Particle Physics.
To be published in Physical Review Letters, Dr. Roberto Trotta, Lockyer Fellow of the Royal Astronomical Society at Oxford’s Department of Physics, and Dr. Alessandro Melchiorri of La Sapienza University in Rome combined data produced by the NASA Wilkinson Microwave Anisotropy Probe (WMAP) satellite and the Sloan Digital Sky Survey, to get the above neutrino fluctuation distribution.
As the results matched perfectly with the current understanding of both Big Bang and Particle Physics, the research shows that theories of the infinitely large (cosmology) and the infinitely small (particle physics) are in agreement!!
This, even by itself, is such a beautiful thing :):).

Of the nine planets circling our Sun, Pluto is the most mysterious. Travelling on the outskirts of the Solar System in an highly eccentric orbit (At times it is closer than Neptune, e.g. from January 1979 thru February 11 1999:))), it takes about 248 years to travel around the Sun! It is the only planet not yet visited by a spacecraft. But hopefully, that is about to change, as the first spacecraft designed to study Pluto, took the first steps on a long journey today when it was shipped from the Johns Hopkins University Applied Physics Laboratory - where it was designed and built - to NASA's Goddard Space Flight Center, for its next round of pre-launch tests.

Artist's Concept of the New Horizons (Courtesy: PhysOrg)Tentatively named New Horizons, the spacecraft is scheduled for a launch in 2006, and it should reach Pluto and its moon Charon by 2015. s part of an extended mission, the spacecraft could also head farther into the Kuiper Belt to examine one or two of the ancient, icy mini-worlds in the vast region at least a billion miles beyond Neptune’s orbit:D:D.
Over the next three months at Goddard the mission team will check New Horizons’ balance and alignment in a series of spin tests; put it before wall-sized speakers that simulate the noise-induced vibrations of launch; and seal it in a four-story thermal-vacuum chamber that duplicates the extreme hot, cold and airless conditions of space. This fall, New Horizons will be transported to Kennedy Space Center for final launch preparations.
Hey Pluto! Here we come:D:D:D.

In this digital age, security of online documents and web connections is paramount. Digital signatures are used to authenticate website connections, emails and legal documents in some countries. They work because they are unique to the file or software that is signed, as they are created from the contents of the signed file. Therefore, if someone tries to cut a digital signature from one document and stick it to another, the signature fails because it no longer matches the document. However, recently exposed cracks in the digital signature algorithm make it possible for someone to extract a signature from one file, and use it with another! This means that attackers could potentially forge legal documents, load certified software with bogus code, or turn a digitally-signed letter of recommendation into one that authorises access to private information.

How Digital Signature Works (Courtesy: Microsoft)The signature is generated using a public algorithm, called the Hash function. These algorithms convert a digital file into a fixed-length string of bits (made up of “0”s and “1”s) called a hash, which is considered unique. The hash is then bound up with the digital signatory’s key to generate their signature. The signature is verified by a trusted third party that removes the key and compares the remaining number with a hash of the document.
Cracks first appeared last year, when Xiaoyun Wang and colleagues at the Shandong University of Technology in China generated two documents that had the same MD5 signature. In February 2005 Wang demonstrated the same thing - called a collision - but with the US Government’s gold-standard algorithm SHA-1, which was considered more secure than MD-5!!
Stefan Lucks of the University of Mannheim and Magnus Daum of the Ruhr-University, Bochum, both in Germany, combined Wang’s work with a clever trick in order to produce two meaningful documents with the same hash function. They used a capability in a file-type known as postscript, which is similar to the PDF format. Postscript allowed them to bind up two documents in the same file, but to reveal only one document and hide the other, and vice versa, without changing the hash of the whole file:)).
According to Dan Kaminsky, an independent security consultant based in Seattle, Washington, It’s not the end of the world yet, but we need to stop using MD-5 and SHA-1 before it is!

Granted, the first human spaceflight to Mars is still far, far away. But when we are there, we got to eat! And obviously, we cannot carry all the food that we would need, so why not derive (at least some of) the ingredients from Mars :D:D?
French chefs are helping the European Space Agency develop recipes that could be used to make food grown in space tasty as well as nutritious. The menus were based on nine main ingredients that could be grown in future space-based greenhouses. The dishes could be made with 40% of these ingredients, and the remaining 60% could come from Earth-based ingredients.

Spirulina Gnocchis :)) (Courtesy: ESA)The recipes created were 'Martian bread and green tomato jam', 'Spirulina gnocchis' and 'Potato and tomato mille-feuilles'. The challenge for the chefs was to offer astronauts well-flavoured food, made with only a few ingredients that could be grown on Mars. According to Christophe Lasseur, ESA's biological life-support coordinator, the nine basic ingredients might be grown on other planets are: rice, onions, tomatoes, soya, potatoes, lettuce, spinach, wheat and spirulina – all common ingredients except the last. Spirulina is a blue-green algae, a very rich source of nutrition with lots of protein (65% by weight), calcium, carbohydrates, lipids and various vitamins that cover essential nutritional needs for energy in extreme environments.
Now if only I had a jug of Romulan Ale to go with it :D:D:D.