March 12, 2010
Big Bang for beginners-1: The nature of matter
(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)
I was recently asked by a relative to provide a simple explanation of the Big Bang theory 'in words of one syllable', i.e., without using jargon or esoteric scientific concepts and in a way that it could be understood by non-scientists. So here goes my attempt at fulfilling that request. In doing so I have tried to follow a paraphrase of Einstein's dictum that says that when explaining something we should make things as simple as possible, but not simpler. In other words don't distort in the search for simplicity. In trying to achieve this goal, I have created a multi-part series. (I promised my relative that my explanation would be simple, not short!)
But it is inevitable that in explaining a sophisticated scientific theory like the Big Bang to non-scientists, in essence telling it in the form of a story, some distortions will creep in, not the least because this is not my area of specialization and so I may simply not be as up-to-date as I should be. An excellent site for more current and authoritative information is one put together by Professor Edward Wright of UCLA. In particular he has put together a tutorial and a valuable FAQ page that enables one to quickly find answers to questions, and I have helped myself from that resource so generously provided.
I will readily acknowledge that I will also consciously introduce some distortions by taking the kind of liberties that film makers do when adapting books to create a screenplay, by omitting those characters that are peripheral to the story in order to maintain focus and brevity. My main omissions will consist of some elementary particles of matter that do not add anything to the basic story. Those who want a highly readable yet more accurate treatment of the basics of the theory are well advised to seek out what I think is still one of the best popular treatments of this subject, and that is Steven Weinberg's The First Three Minutes (1988). Though it does not have anything about the more recent observations and refinements (such as dark matter, dark energy, and cosmic inflation), the basic paradigm it presents is still valid.
The Big Bang theory seeks to explain how the physical universe that we now inhabit came about. Since it now consists of lots of stuff, one needs to first start by looking at what that stuff (i.e., ordinary matter) consists of. This exercise turns out to be like peeling an onion. As each layer of matter is examined, it reveals another layer below it.
Most everyday stuff (plants, animals, plastics, etc.) is made up of tiny but complex entities called molecules that give them their distinctive properties and which are held together by attractive forces. To separate matter into individual molecules, we need to apply an external force that is sufficient to overcome the force that binds a molecule to its neighbors. Doing so requires us to expend some energy as well.
Each individual molecule is in turn made up of simpler entities that we call atoms, which are also held together by attractive forces. Atoms are the units of matter that distinguish one element from another, and there are a little over a hundred such elements, oxygen, hydrogen, iron, carbon, being a few of the well-known ones. The periodic table lists all of them. A very simple molecule is that of water, which consists of just three atoms, two atoms of hydrogen and one atom of oxygen, held together by attractive forces. Other molecules, like the DNA that exist in the core of our body's cells and contain our genes, consist of millions of atoms joined together.
Atoms were once considered the most basic units of matter. They were thought to be indivisible but we know now that that is not true and that they too are composite objects, consisting of a tiny central core (called the nucleus) and electrons outside the nucleus, again held together by attractive forces. Electrons do seem to be truly fundamental particles that cannot be broken up into any smaller constituents.
The nucleus of an atom, however, turns out to be yet another composite object that consists of still smaller entities called protons and neutrons.
The protons and neutrons are now known to be composite objects too, consisting of even smaller entities called quarks and gluons.
So to summarize, when we peel off the layers of matter, the component units of which it is made are, in order of decreasing size:
This is where things stand now.
Are the quarks and gluons (and electrons) the ultimate constituents of matter? We don't know for sure but given past history with the onion-like nature of matter, we should not be too surprised if searches reveal yet another layer beneath the current one.
Why is it that we do not know if quarks and gluons are the ultimate components of matter? The reason comes down to the fact that it takes force and energy to separate matter into its smaller constituents, and the force and energy required increases rapidly as one moves down the chain of matter. It takes a small amount of energy to separate molecules into atoms. It takes much more energy to separate atoms into nuclei and electrons. (Some electrons can be removed from atoms by just rubbing materials together, which is the source of what we call 'static' electricity.) It takes much greater energy to separate nuclei into protons and neutrons, which is why we need huge and expensive accelerators to do so. When it comes to separating protons and neutrons into quarks and gluons we seem to have reached the limits of our ability. We have not actually been able to create quarks and gluons as free objects but instead can only study them while they are still inside nuclei.
The reason that we cannot produce free quarks and gluons is thought to be due to the fact that the forces holding them together in protons and neutrons are like the forces exerted by rubber. When you try to separate two objects that are joined by a piece of elastic, the force you need to apply keeps increasing as the objects move apart. With real rubber bands, the band breaks at some point and the two objects break free of each other. But with the rubber band-like forces holding quarks and gluons together, we have not been able as yet to create forces that can break the bands, leaving us unsure whether they can be broken if only we could to make the forces large enough, or whether they simply cannot be broken, ever.
Next: The nature of energy
POST SCRIPT: Harry Markopolos
In my series on financial frauds, I wrote about the Bernie Madoff scandal and how Harry Markopolos's repeated warnings that Madoff was running a scam were ignored by the regulatory authorities and the media. He appeared recently on The Daily Show to repeat those charges.
|The Daily Show With Jon Stewart||Mon - Thurs 11p / 10c|