Monday, August 31, 2009

Possible destruction of the universe?


From Techfreep: By accelerating protons toward each other at 99.999999% the speed of light the LHC can recreate conditions similar to those that resulted from the Big Bang, ultimately alighting a great deal about the particles and forces that comprise our Universe. A press release from CERN better illuminates their intent for the project. Another interesting article in Radiant Reality.
Dark Rosted Blend has very good photographs. It quotes some additional material worth speculating.
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CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research.

Sunday, August 30, 2009

Are you interested in possibilities?

I wanted to tell you that logical possibility is a subset of a wider kind known as subjunctive possibilities. Basically, subjunctive possibilities express wishes, commands, emotion, possibility, judgment, opinion, necessity, or statements that are contrary to fact at present.

So, we have:

*Logical possibility is usually considered the broadest sort of possibility; a proposition is said to be logically possible if there is no logical contradiction involved in its being true. "Dick Cheney is a bachelor" is logically possible, though in fact false.

* Metaphysical possibility is either equivalent to logical possibility or narrower than it. For instance, "Water is H2O" is metaphysically necessary but not logically necessary.

* Nomological possibility is a possibility under the actual laws of nature. Most philosophers since David Hume have held that the laws of nature are metaphysically contingent -i.e., that there could have been different natural laws than the ones that actually obtain. If so, then it would not be logically or metaphysically impossible, for example, for you to travel to Alpha Centauri in one day; it would just have to be the case that you could travel faster than the speed of light. But of course there is an important sense in which this is not possible; given that the laws of nature are what they are, there is no way that you could do it.

* Temporal possibility is a possibility given the actual history of the world. Barack Obama could have chosen a degree in Accounting rather than Law, but there is an important sense in which he cannot do it now. So, the "could have" expresses the fact that there is no logical, metaphysical impossibility involved in Obama's having a degree in Accounting instead of Law; the "cannot now" expresses the fact that that possibility is no longer open, given that the past is as it actually is.

Laws of nature and origins of the universe

As per our discussion last week about laws of nature, read here. I think the most important laws are conservation laws, mass energy equivalence, and chemical laws, such as chemical equilibrium, First Law and Second Law of thermodynamics, and what is known as Classical Electromagnetism.

As per how these laws can change (a point one of you suggested in class), read this Wikipedia article:

Experiments and observations suggest that the Universe has been governed by the same physical laws and constants throughout its extent and history. The dominant force at cosmological distances is gravity and general relativity is currently the most accurate theory of gravitation.

I think for the sake of our future discussions it would be a good idea to check out the origins of the universe.
Here is a PBS presentation entitled NOVA. Click "launch interactive."

What's the age of the universe? Click here for a brief discussion of the time-line of cosmology.