Some Radiation Information

Radiation Primer

Some revelant definitions and information:
A Sievert is a measure of radiation exposure, a millisievert is one-thousandth of a sievert, and a microsievert is one-millionth of a sievert.

Isotope: An atom with a particular neutron count in its nucleus. Whereas all the atoms of a given element will have the same number of protons present in the nucleus, the number of neutrons may vary. For example, hydrogen has one proton in its nucleus. It has three different isotopes: protium (most common form containing no neutrons), deuterium (one neutron), and tritium (two neutrons).

Iodine-131 and Cesium-137 are the most dangerous contaminants of concern so far. Iodine-131 is readily absorbed by the thyroid gland and can lead to thyroid cancer. By taking potassium iodide, one can saturate one's thyroid and effectively prevent the uptake. Since the half-life (the time it takes for half of the material to decay) of I-131 is only 8 days, this is an effective and practical method of reducing one's risk. In the case of Ce-137, however, the half-life is about 30 years and there is no effective means of reduction of risk other than physically preventing exposure. Cesium is incorporated in one's bones, primarily and can lead to bone cancer and leukemia.
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Sources of Information about Paleoclimates

Nearly everyone has heard of how tree rings can be used to indicate annual weather history. There are many other methods as well, some are even more sensitive than trees for deciphering the past. A few of these will be discussed in a series of posts to this section of the blog.

1. Clam shells

A Brief History of Gravitational Theory

Sir Isaac Newton developed the first theory of gravitation. It was universal: it explained the motion of objects near the earth and the motion of the planets and moons. Using his theory, one could predict the trajectory of a cannon ball or the positions of the moon or any other celestial body. One only needed to know the initial conditions of the objects ... [Read more]

Does Evolution Imply Progress?

Evolution isn't about progress.  It is about species adapting to local environments.  If a mutation leads to a member of a species leaving more offspring with this mutation, then the mutation will spread through the local population, whatever the size of "local" is - it might be a few square miles or thousands of square miles - it depends on the species.... [Read more...]

Thoughts on a Definition of Science

Science is the effort to provide natural explanations of natural phenomena.  The truth of any scientific proposition rests ultimately upon how well it accounts for the observations it is trying to explain, and by how well it can predict the results of experiments and/or future observations. 

Mathematics is not a branch of science.  I think it has been called the handmaiden of science; not an appellation that would make any mathematician happy, I'm sure.  Much of theoretical physics is more math than science.  Until it connects with observation and explaining how the universe works, it has no direct scientific truth value (it is neither true nor false.  Heisenberg [I believe it was he] once remarked after listening to a paper being presented that the paper wasn't even wrong, meaning that the proposition being presented could not be falsified).  It may lead to valuable insights, and it might be a valuable reformulation of an existing theory; but if it makes no new predictions that can be tested and that differentiate it from existing theory, then either it is not a scientific proposition or it is not a new scientific proposition.