Showing posts with label inflation theory. Show all posts
Showing posts with label inflation theory. Show all posts

Sunday, October 9, 2011

The God Particle


Jack Dikian
October 2011

The Higgs boson is sometimes referred to as "the God particle" after the title of Leon Lederman's book, The God Particle: If the Universe Is the Answer, What Is the Question?

The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of the known subatomic particles. The Standard Model gives us a framework for our understanding of the fundamental particles and forces of nature.

A theory to answer why particles have the masses they do or why they have any mass at all, however, isn’t so straightforward. Back in the early 60’s Peter Higgs proposed, the idea that space is permeated by a field, similar in some ways to the electromagnetic field. As particles move through space they travel through this field, and if they interact with it they acquire what appears to be mass. The Higgs boson is thought to give all matter mass.

This is similar to the action of viscous forces felt by particles moving through any thick liquid. The larger the interaction of the particles with the field, the more mass they appear to have. Thus the existence of this field is essential in Higg's hypothesis for the production of the mass of particles. As well as possibly explaining how particles receive their mass, some think it could also explain how the universe got its shape.

A theory put forward by researchers at Switzerland's École polytechnique fédérale de Lausanne argue that the Higgs boson might allow us to account for inflation, the otherwise unexplained process in which the early universe grew by a factor of at least 10^26 in an instant.

The Higgs boson is, however, the only elementary particle in the Standard Model that has not yet been observed in particle physics experiments.

Tuesday, September 27, 2011

Many universe theory explains a lot of things

Jack Dikian
September 2011

Inflation theory is the theorized extremely rapid expansion of the early universe by a factor of at least 10^78 in volume. The inflationary epoch lasted from 10^36 seconds after the Big Bang to approximately 10^33 seconds. This is a mind-boggling small period of time. It’s 0.000000000000000000000000000000000000 of a second after the big bang.

There are a number of variants to inflation theory or inflation models. An interesting model is the eternal inflation, which says (roughly speaking) that shortly after the Big Bang space-time expanded at different rates in different regions of the early universe, giving rise to bubble universes (that may function with their own separate laws of physics.

Our universe might just be one of many. While the concept is bizarre, it's a possibility, according to scientists who have devised the first test to investigate the idea at Imperial College London. The basic premise of the study is to look for collisions between universes by examining tell tale signs left behind in the cosmic microwave background radiation. This is the diffuse (thermal radiation) light left over from the Big Bang and pervades our universe.

Researchers used data from the Wilkinson Microwave Anisotropy Probe (WMAP) identifying four regions in the universe as promising candidates. However, statistical analyses suggested these patterns were likely to be random, resembling the circular shapes of collisions simply by coincidence. The European Space Agency's Planck satellite data set to be released in 2013, and the researchers plan to look again, surveying in particular the four areas of interest from this study.

A researcher from the University of British Columbia in Canada, agrees that the present data from WMAP is not likely to be precise enough to make a definitive statement, also excited by what the more detailed data from the Planck satellite might revel.

The obvious benefit that a multi-verse theory provides is an explanation for the strange coincidences in our own universe. Many of the fundamental constants such as the strength of gravity and the speed of light, seem perfectly calibrated to produce a universe in which galaxies, stars, planets and even life can form.

The scientists detailed their study in two research papers published recently in the journals Physical Review Letters and Physical Review D.

Sunday, September 11, 2011

We are living but on a spec of dust looking out into the darkness

Jack Dikian
September 2011

The more I think about just how much we have been able to infer about the universe we live in the more amazing it all seems. I mean, here we are living on an unassuming rock orbiting a star near the outskirts of a galaxy. Our galaxy is estimated to contain 200 to 400 billion stars. Current estimates guess that there are 100 to 200 billion galaxies in the Universe. The universe is vast and we are living but on a spec of dust looking out into the darkness, looking back in time, and trying to make sense of it all.

The WMAP Explorer mission that launched June 2001 to make fundamental measurements of cosmology is analogies to a trapdoor spider coming out of its silk-lined burrow to examine the perimeter surrounding its burrow before it goes back inside to think about how might other terrains be like, what kind of soils, how small puddles of water be compared to vast oceans, and so on and so forth.

But, that’s exactly what the WMAP has been able to achieve. It has been able to study the properties of our universe as a whole. WMAP has been stunningly successful too, producing our new Standard Model of Cosmology. The 7-year data provide compelling evidence that the large-scale fluctuations are slightly more intense than the small-scale ones, a subtle prediction of many inflation models.

One of the problems the Big Bang theory was not able to explain is the horizon problem. Distant regions of space in opposite directions of the sky are so far apart that, assuming standard Big Bang expansion, they could never have been in causal contact with each other. This light travel time between them exceeds the age of the universe. Yet the uniformity of the cosmic microwave background temperature tells us that these regions must have been in contact with each other in the past.

The Inflation Theory, developed by Alan Guth, Andrei Linde, Paul Steinhardt, and Andy Albrecht, offer a solution to this and several other open questions in cosmology. Inflation supposes a burst of exponential expansion in the early universe, assuming distant regions of the universe were actually much closer together prior to Inflation than they would have been with only standard Big Bang expansion. Thus, such regions could have been in causal contact prior to Inflation and could have attained a uniform temperature.

Other reading

Alan H. Guth & Paul J.Steinhardt, "The Inflationary Universe", Scientific American, May 1984.

Andrei Linde, "The Self-Reproducing Inflationary Universe", Scientific American, November 1994.

Scott Watson, "An Exposition on Inflationary Cosmology", WWWarticle, 2000.

Alan H. Guth, "The Inflationary Universe : The Quest for a New Theory of Cosmic Origins", 1998.