Archive for August, 2012

The Higgs Boson was named after an Edinburgh physicist, Peter Higgs. It is often thought that the Higgs boson forms an overwhelming majority of the composition of the answer to the question of how matter has gained mass. To those of us in agreement with the popular theory of the Big Bang as the origin to the universe, it is thought that shortly after the beginning of the cosmos, mass was inexistent. Indeed, nor were atoms and elements, but that is a different story. A field known as the Higgs field is thought to be the reason for the existence of mass – particles interacting with this field gain mass. This came about due to the decrease in the temperature of the universe (below a certain threshold value), and the amount of mass is directly proportional to the strength of the interaction between the particles.

In the 1970s, it had come to the attention of the global physics community that two of the fundamental forces were actually very closely related. The thing is, the proposed explanation for a unified force, namely the electroweak force, required that a field exist, whose constituent particles carry no mass. Unfortunately, it is known now that this is untrue, and so Higgs and his colleagues set about finding a solution.

Ian Sample has conveniently created an analogy using, rather imaginatively, ping pong balls, food trays, and brown sugar. Basically, as the universe was formed, a field known as the Higgs field came into existence. Many particles interacted with this field, and the more they interacted, the heavier they became, and no longer moved at the speed of light. The Higgs boson is analogous to a grain of sugar, i.e. the constituent of the Higgs field. As you may know, just like light itself, which has dual properties of wave and particle, so may the boson. The question scientists endeavour to answer is how a particle whose properties are yet to be ascertained, could be the reason behind the existence of mass. Sample conjectures that amongst other products from a collision between protons travelling at 0.999999c, Higgs was one of them. The problem is, unlike most other particles, such as photons, quarks, electrons etc., the Higgs boson decays very quickly, and as such is very difficult to observe. The standard model of the universe, developed in the 1970s, which is used today, has met unprecedented success over the past decades in having aspects of it being proven to exist, aside from links to gravity. However, the fundamental tool that is needed was the proof of the existence of the Higgs boson.

The 4 fundamental forces of nature

Why is it called the boson? Well, earlier I mentioned the electroweak force, a force unifying electromagnetism and the weak nuclear force from the standard model, which in itself contains the four fundamental forces – gravity, electromagnetism, and the strong and weak nuclear forces. Scientists propose that each of these forces has a carrier particle, collectively named the boson, which interacts with matter. For example, the electromagnetic force has the photon as its boson, which carries the electromagnetic force with it, and transfers it to matter. Bosons are believed to be able to snap back in and out of existence in an instant and also be ‘entangled’ with other bosons around them. You see, this boson is not only a ‘fundamental force carrier’, it is also a term used for force carriers of various natures and designations. As a conveniently relevant example, I can explain the significance of the photon and bosons called the W and Z particles.

Going back to one of the constituents of the electroweak force, the weak force, its force carrying particles, as the photon is for the electromagnetic force, are two bosons named W and Z, discovered in the 1980s. Unlike the photon, these do have mass. A possible analogy for this next part is to think of these force carrying bosons as balls that are exchanged as particles exchange these force carriers to observe the weak force. Heavier balls have a lower throwing range, and similarly, so do heavier force carriers – this was known. But what gives these force carriers mass, which affects their behaviour? The Higgs theory. This is what scientists think could account for this fundamental difference between photons and the  W and Z bosons, and, by extrapolation, for all other force carriers with nonzero masses. It has been estimated that 96% of the universe is invisible, made up of dark matter and physics that have not yet travelled within our grasp. The Standard Model only accounts for the 4% of the universe which we know so well, hence why we know it can never be a complete, unifying theory. For this, we need to be able to build on the concept, much like Einstein built on his theory of Special Relativity in order to account for gravity – which, incidentally, we are able to conclusively explain very little of. So in reality, the quest for the single Higgs particle (in this specific context) includes determining whether it is a Standard or Non-Standard Higgs particle.

The Standard Model Higgs particle would, if confirmed to be true, only one of numerous different types of Higgs particles. In order to gain an insight into the sheer complexity of the process and the need for excruciatingly thorough and systematic procedural protocols, consider the following. One of the possible ways a Higgs particle can decay, as it will within an instant of being detected, is by emitting two photons, which can be detected. However, there are so many other two-photon events that occur, which by themselves have had countless statistical analyses carried out on them in order to determine various values, some simple ones being the percentage of decay events leading to two photons being produced. Not only this, any discovery can only be (tentatively) validated if the confidence levels from data have a discrepancy of less than one in a million.

I hope that my chaotic and quick run through the world of Higgs has, if not invoked interest, at least informed you in an understandable manner. For those who are interested, the analysis of the Higgs boson’s (possible) discovery is scheduled to be completed by the end of 2012, for which time we should not only be hoping to know whether the Higgs particle that had been discovered is Standard or Non-Standard, but also whether it exists at all. Despite the disappointment that will no doubt be experienced by the disproval of the Higgs boson’s existence, each of the three possible outcomes will lead to progress, either building on current proven theories, adding flesh to the bones of hypothetical theories, or starting afresh in order to encourage the development of entirely new concepts altogether, which may or may not be more effective than building on our current ones.




Made for my Nuffield Bursary work placement.

Sorry for not posting for the last couple of weeks but things got rather hectic at work. Good news is, we’ve got some really interesting results, and my supervisor will be presenting them at a conference in Germany in October! If anything gets found then I might be a co-author on the paper. It’d be nice to be published before I got into university! If you guys want a special blog post all about the work I’ve done then let me know and I’ll put something together.

– Harry Saban – The Octave Doctor (Phd pending)

The fantastic accomplishment of the Curiosity probe landing on mars has once again turned the world’s eyes towards the heavens (if we forget about the Olympics for a moment of course). Using this recent feat of human ingenuity and resourcefulness and a recent trip to the Kennedy space centre for inspiration I’ve decided to write a short piece on the history of human exploration in space, with a post soon to follow about the Curiosity probe, I hope!

Exactly 70 years ago, Wernher von Braun watched on as his brainchild, the V-2 sub-orbital ballistic missile, became the first man-made object in human history to leave the atmosphere and enter, by today’s standards, outer space. In the words of Walter Dornberger, the head of the V-2 rocket programme

“This third day of October, 1942, is the first of a new era in transportation that of space travel…”

Three years later, 1945, at the onset of operation Paperclip and operation Backfire, the American and British scramble for Nazi weaponry and technology, hundreds of V-2 rockets were secretly shipped back to the US, along with some of the Third Reich’s most able minds. For nearly a decade after this, nothing happened, there was little advancement on the German designs and schemes as both western and eastern scientists struggled to come to grips with the sheer complexity and intricacy of the Nazi engineering, but that was soon to change

While the Americans and British were messing with rockets little more advanced than large fireworks, with the fantastic German scientists side-lined for matters of national pride, something interesting had been happening on the far side of the iron curtain…

Using some of this stolen Nazi tech, the Russian space programme, after languishing behind the rest of the world for several years, suddenly kicked into high gear. For years the Soviet cosmodromes had been churning out successful rockets in the forms of the R-1, R-2, R-5 and R-7 families, but here the Russians hit a stumbling block, where do they go from here? The Americans provided them the perfect answer. On 29th July 1955 the U.S. President Dwight D. Eisenhower announced that the United States would launch an artificial satellite during the International Geophysical Year of 1957. Terrified that the Americans would use this satellite as a spy satellite, or worse, the Russians rushed into action, planning, designing and building a fully functioning satellite in just over two years, and on the 4th October 1957 they launched the world’s first satellite into low earth orbit, Sputnik 1. The space race had begun.

Apollo 11 launches from pad 39 A

Skip forward 10 years, to 1967, and Von Braun’s greatest achievement sits atop a launch pad, aimed for the sky, the Saturn V rocket. Even to this day the Saturn V holds several records, for being the tallest, most powerful and the heaviest rocket ever produced. For several years the Americans had trailed behind the Russians in the great space race, relying on reverse engineered technology for their flawed and unreliable Vanguard class rockets, but after the Soviet success of Sputnik the Americans panicked and at the orders of the government, placed Von Braun and his team in direct command of rocket design for the Americans. Almost instantly the American space programme began to pick up speed, and with the declaration in 1961 by John F. Kennedy of the national goal of “landing a man on the Moon and returning him safely to the Earth” there seemed like there could be no stopping the Apollo space programme, the Americans method of placing a man on the moon. Even with its fantastic and, at the time, outlandish goals Apollo succeeded despite the major setback of a 1967 Apollo 1 cabin fire that killed the entire crew during a pre-launch test. Six manned landings on the Moon were achieved. A seventh landing mission, the 1970 Apollo 13 flight, failed in transit to the Moon when an oxygen tank explosion disabled the command spacecraft’s propulsion and life support, forcing the crew to use the Lunar Module as a “lifeboat” for these functions to return to Earth safely. But despite all of this, at Apollo’s discontinuation, NASA declared the programme as “a success”.

This success of landing a man on the moon signalled the end of the space race between the US and Soviet Russia, but it was by no means the end.

The next major breakthrough was Salyut 1, the world’s first space station. Beaten to the moon by the Americans, Russia began to concentrate its resources on sustaining a manned low earth orbit. Although this goal wasn’t achieved truly successfully until Salyut 3 (Salyut 1 was left to fall out of orbit after one crew couldn’t dock successfully and another died on re-entry, Salyut 2’s flight control system failed and an unexplained incident where four solar panels were torn off the craft meant the station was left without power or a way of controlling it, this was again left to re-enter and disintegrate). Salyut 3’s main purpose was as a spy satellite and as a result It tested a wide variety of reconnaissance sensors, returning a canister of film for analysis. On January 24, 1975, after the station had been ordered to deorbit, trials of the on-board 23 mm anti-satellite cannon were conducted with positive results at ranges from 3000 m to 500 m, the departing crew reported that a target satellite had been successfully destroyed.

The latest hurdle crossed in space station building has been with the ISS (international space station), an international collaboration of five space agency’s: the American NASA, the Russian Federal Space Agency, the Japanese JAXA, the European ESA, and the Canadian CSA.

While all of this continues in low earth orbit, countless satellites and probes have been sent deep into the solar system. Some of the most famous ones being the Viking probes of mars, the first man-made objects to successfully land on the red planet and the Voyager probes, currently the furthest man-made objects ever (voyager 1 has recently entered the heliosheath and is predicted to enter interstellar space sometime around 2015). And recently there’s a new one to add to this very exclusive list, the Curiosity Mars probe, the largest and most advanced probe to ever land on another planet. The size of a small car and powered by a nuclear reactor, the Curiosity probe hopes to give us new insights into the history of mars, and whether there has ever been life on the red planet. It plans to do this by incinerating rocks with an on-board laser and analysing the gas given off to detect organic particles and elements and molecules that could support life.

Now we’ve had the most recent, and now we move onto the future. The future of space exploration is a tricky beast to wrestle with, as no one’s quite sure what’s coming. No-one could have predicted the sheer speed at which we progressed from Wernher von Braun’s V-2 rocket, only seventy years ago; after all, we’re now planning manned missions to mars! But there is one group of people who’ve had a go. Project Daedalus was a study conducted between 1973 and 1978 by the British Interplanetary Society, the oldest society of its type, to design a plausible unmanned interstellar spacecraft. Intended mainly as a scientific probe, the design criteria specified that the spacecraft had to use current or near-future technology and had to be able to reach its destination within a human lifetime. The proposed design revolved around a hydrogen-3 pellet driven nuclear-pulse fusion rocket to accelerate to 12 per cent of the speed of light. Aimed at Barnard’s star the probe would carry 18 smaller micro-probes, with an aim to study the atmospheric configuration, the magnetic field strength, and to send back pictures of the star system and its planets, sending this data back to earth via the main probe, which would use its massive 40 metre engine bell as a communications antenna. However, due to its incredible speed, the probe would be unable to stop, hurtling on through space for the rest of its life.

And that’s that, a quick flyby tour of the human exploration of space and where we might be going with it. And to add I would love to have included everything in this article, from Yuri Gagarin and Laika the dog to the British Black Arrow project and America’s plans for a habitable mars base, but, alas, I have a word count to keep to, but if you really want, you could always look them up yourself?

Alex Davis