Showing posts with label physics. Show all posts
Showing posts with label physics. Show all posts

Sunday, December 5, 2010

Dark matter goes the way of the Luminiferous Aether

There is now an estimated 3x1022 stars in the known universe. For those of you who are keeping track that’s an increase of 200 sextillion star systems. This has hit all the major news outlets with just about everyone emphasizing that the increased estimate implies more potential life sustaining planets may exist. Not a single article mentioned the most important aspect of this discovery.
More important than the possibility of other potential Earths is the idea that the mystery of the theoretical Dark Matter may also have been solved. So what is this hypothetical Dark Matter and why does it make a difference?
Astronomers have had trouble accounting for observed gravitational effects in many galaxies. These galaxies behave gravitationally as if there is more matter present than we can see. The movements of stars and galaxies, as well as the light from stars around galaxies are all effected by the gravitational pull of matter. Scientists use a collection of formulas based on Newton's Laws and Einstein’s theories of gravity to determine how the stars should be behaving and have found that in every observed system of galaxies and stars (outside of our own) the stars are moving as if there is extra gravity. This means the stars are moving as if there is unseen matter pulling them as only matter warps space-time enough to cause gravitational effects.   
Based on these calculations astronomers have concluded there should be more matter in every galaxy observed. Astronomers and physicists then go on to propose hypothetical “dark matter”, called ‘dark’ because it must be there and we just can’t see because it does not produce or reflect light (like black holes but they are certainly not black holes). [For a collection of possible explanations and candidates for dark matter visit this website: http://map.gsfc.nasa.gov/universe/uni_matter.html and for a map of the dark matter around 3 of nearest galactic neighbors: https://academic.oup.com/mnras/article-abstract/468/2/1962/2970349/Mapping-substructure-in-the-HST-Frontier-Fields?redirectedFrom=fulltext).]
This new estimate tells us that there is about 60% more matter in the form of red dwarf stars than previously thought. Dark matter estimates are on the order of 85% of the universe. If the known matter of the universe is increased then the unknown amount that is attributed to dark matter must decrease significantly. By how much this unknown amount will decrease is a huge question. Making this new recalculation more difficult is the doubt that will be placed on the estimates of the total number of other stars and massive objects in the universe.
When making an estimate on order of 1020+ any small discrepancy is multiplied tremendously. To be fair it doesn’t eliminate the existence of dark matter but it will make theoretical physicists rethink the possibilities of dark matter and its prevalence. This isn’t the first time physicists have made this kind of mistake.
Before Einstein’s theory of special relativity it was assumed that space was filled with the ‘luminiferous aether’, a hypothetical medium through which light could propagate. What dark matter shares with the ether is a phenomenon in science where theorists invent whatever is necessary to provide a solution for missing knowledge. The question still remains how scientists can still make these errors.
The reason this kind of mistake can happen is that astronomers aren’t necessarily counting every star in a galaxy when they are calculating gravitational forces for example. Instead, an estimate is made based on closer galaxies. Red dwarf stars are dim long lasting stars whose presence is generally estimated in galaxies far away. Based on these estimates gravitation observations are made and matter seems to be missing. Missing matter, or gravitation anomalies can’t exists, so a space-filling matter must be posited to solve the mystery.
There will always be gaps in our knowledge of the universe, mainly because we are so isolated and our attempts to understand the rest of the universe relies heavily on estimates based on what is close to us and what is close to us is no closer that the distance it takes light to travel in a year (5.9 trillion miles). The more we can do to dispel these dark theories the more we can say we have actually knowledge of the universe. Next lets try to get rid of all this ‘dark energy’ nonsense.

Sunday, July 18, 2010

Scientific Revolution in the Age of Information

We can safely say that the greatest technological innovation of the past 30 years is the proliferation of the internet. I will qualify ‘greatest’ as influencial, far reaching, across genres, changing more other industries than any other innovation since the personal computer (Mac’s included). The most shocking part of this innovation is that its influence is disproportional to the leap in technology necessary for it to happen. To be blunt, no leap was necessary.

The innovations that led to the widespread internet use we see today were not leaps and bounds ahead of the technology of yesterday (i.e. early 80’s and 70’s). In fact the internet has been around almost as long as digital computing. The internet originated as a tool to share information quickly. The technology necessary to make it possible has been around; however the main innovations have been software improvements. This isn’t to say that hardware innovations trump software innovations in the hierarchy of technological development, but they certainly get overlooked in comparison.

Yes, cheap high-speed internet and the infrastructure necessary have improved significantly, however those technologies are modest improvement over cable TV technology. The receiver is now your cable modem instead of your cable box and the signal is not a digital moving picture, it’s a wide variety of digital data coming into your home, which probably includes your digital moving pictures in a package deal offered by your provider to further entice you into the realm of speedy internet access.

The true innovation in the internet is the manufacturing not of physical products like cable modems, computers, browser software, online shopping and gaming. The manufacture of a market for internet/high-speed internet and the transition from that initial luxury or business market to a household necessity is the real innovation of the internet. How that happened is an inquiry for another time. How the internet has effected what we have come to expect of science is of interest in this inquiry.

Let’s get up to speed first. The history of scientific revolutions has been elucidated in every popular physicist’s best seller. From Brian Greene and Stephen Hawkins to even Albert Einstein we can get a view of which discoveries and theories have really re-written the physics and history books. In short there were a few major developments that changed everything. Thomas Kuhn in The Structures of Scientific Revolutions focuses on what he calls the major paradigm shifts in science. For my purposes we will focus on the discipline of Physics often considered the hardest of the ‘Hard Sciences’.

We begin with Aristotle and what is left of his writings on Physics, from which we retain the name of the discipline to this day. Aristotle was the first to apply logical formulations to the natural world. The key assumption of Aristotle and scientists for centuries after his writing, was the idea that logical analysis, thinking about the problems and nature of the universe we could solve the mysteries of nature. The idea that all we need is our minds, a great deal of concentration and the tools of logic and rationality we will be able to provide all the answers. To say that this ‘worked’ or was ‘useful’ for almost 2050 years would be generous. To say it was influential would be an understatement.

Physics didn’t really begin to move forward until Isaac Newton published the most influential book in physics since Aristotle; The Principia: Mathematical Principles of Natural Philosophy (1722). Yes the Principia uses mathematics, logic, reasoning to figure out the laws of Nature. The key and most important distinction is that Newton relied heavily on observation to make those laws. The observation that heavy objects didn’t fall faster than lighter ones was just the start. Interestingly enough this was also based on the logical paradox that heavier objects must fall faster. If a heavy object were tied to a lighter object by a small string, the lighter object, wanting to fall slower, would tug on the string holding back the heavy object, which wants to return to its original state at a faster speed, thus slowing down the heavier object. This paradox prompted experimentation which then led to the invention of calculus to accurately describe the falling bodies and the birth of all physics as we know it today.

Why did take 2 millennia for someone to finally place primacy on experimentation? One can only guess the various instabilities in the cultures of the western world didn’t allow academic pursuit of knowledge to flourish. Before we go blaming religion, namely Christianity, keep in mind that the ancient texts of western civilization were saved, copied and translated by monks dedicated to keeping the knowledge of antiquity alive, while conquering forces from around the globe were busy sacking cities and burning those cities cultural centers. In fact, in that regard the science of politics also has a major world altering revolution in the birth of modern democracy and the de-legitimatization of monarchic rule shortly after Newton publishes this groundbreaking book. Here we should note that this is over 200 years after the printing press was invented and at the end of the Renaissance of Europe when society was relatively stable (compared with the Middle Ages and late antiquity after the fall of Rome) and had rediscovered the wealth of knowledge of the Ancient people of the Mediterranean. In short it took another 2000 years for a large population of people to be able to devote time, effort and money to the pursuit of knowledge for its own sake.

Many circumstances had to align for this pivotal scientific revolution. This revolution is about as big as it gets and I have ignored many smaller revolutions. The implications of Newton’s Principia are farther reaching than any other development in any other area of science since. The precision and universality of the laws that result have been the standard for ‘hard science’ ever since. This standard is so hard to achieve that it may be the main reason for a lack of overarching scientific revolution today. The next revolution was Albert Einstein’s Special and General Theories of Relativity.

Following the Industrial Revolution scientific knowledge exploded into the 20th century. Advances in all areas of science were made at an incredible speed. With the beginning of the Nobel Prizes in 1895 fame was introduced into Academia. An argument can be made that the honor did more to legitimize the pursuit of scientific knowledge than anything else in modern times; Albert Einstein being the other contender for most important figure in valuing and popularizing scientific pursuit in the minds of the public.

The most unique aspect of Einstein’s revolutionary theories was that they didn’t destroy the previous very effective and accurate Newtonian Laws. Special and General Relativity added to the knowledge in a revolutionary way. Applying Einstein’s theories to Newtonian Laws made for mind boggling accurate predictions. Newton’s laws still explained the universe and described the movement of the natural processes very well however Einstein now provided what every scientist and philosopher is looking for; the answer to the question why? Why is Newton’s Universal Law of Gravity true? General Relativity provides such an answer: It’s the nature and structure of space/time that makes all objects ‘fall’ towards each other.

What makes this revolutions stick out during this time period is its simplicity and elegance. The exponential expansion of knowledge at this time still has its effects in today’s world. This period of scientific revolution, marked most notably by Special and General Relativity, has not even been approached in the past 100 years. Our base of knowledge has not been expanded upon much in the realm of physics. Yes there have been amazing developments in quantum mechanics 50 years ago and string theory for the past 20-30 years, however nothing as far reaching to constitute a revolution in the sciences has happened since Einstein. What of the role of the greatest technological innovation in 30 years on scientific revolution?

Andrew W. Lo and Mark T. Mueller of MIT have published a very interesting paper: WARNING: Physics Envy May Be Hazardous To Your Wealth!, which deals with financial analysis aspiring to the standards of accuracy available in physics. Perhaps having standards of revolution based on the changes of physics over history leads us to a similar mistake of expectation. It is possible that a truth has been reached that there is no further improvement upon. Here is where the proliferation of the internet can either hinder or help the cause of scientific revolution.

With the easy access to information and the vetting of such information left up to the reader, understanding of all levels, laymen, expert and everywhere in between has been expanded beyond belief. Misinformation and information are everywhere and with simplification comes oversimplification in many cases, so the quality of the information is a bit suspect to be generous. What is really missing and may be a hindrance to future scientific revolutions is the ability to be uninfluenced by the plethora of knowledge. Einstein was operating outside of academia when he wrote his special theory of relativity and operating on the fringes of physics, able to think in imaginative, novel ways he was able to change physics and shape the modern world. Is such novel thought possible in the age of the internet or, even worse, is such thought even recognizable in the sea of ideas that the internet has produced? Has the internet in providing such an accessible medium for the productions and dissemination of knowledge eliminated the possibility of scientific revolution on the scope of Einstein’s influence?

Time will naturally answer these questions. It is my suspicion that revolutions of the scale I have mentioned aren’t extinct, nor have they been replaced by steady technological developments. Using Kuhn’s criteria for scientific revolution being based on a paradigm shift, these steady technological achievements do nothing to change the paradigm; they are just the natural implication of the paradigm shift 100 years ago. We have yet to fully explore all the possible implications of the recent revolutions in science and it may be a full century after those implications are realized before another revolution greets humanity. Technology has yet to reach the limits of the laws of physics as we understand them. When technology does reach that limit, as I suspect it will once nano-technology is fully understood and utilized, the ground will have been laid for the next revolution. Don’t hold you breath though.