Here's the review from Physics Today (http://physicstoday.org/pt/vol-55/iss-7/p55.html)
(c) American Instute of Physics
Wolfram on Cellular Automata; A Clear and Very Personal Exposition
A New Kind of Science
Stephen Wolfram
Wolfram Media, Champaign, Ill., 2002. $44.95 (1197 pp.).
ISBN 1-57955-008-8
Reviewed by Leo P. Kadanoff
Early in the 1980s, Stephen Wolfram began to work in earnest on cellular automata, a class of computer model that can be visualized as a set of memory locations, each containing one bit. The bits are updated in a succession of time steps. In each step, the new value of each bit depends on the values of neighboring bits. Wolfram particularly studied the class of automata in which all the bits are arranged in a line, and each bit is updated using the very same functional dependence on its value and that of its two nearest neighbors. There are 256 different automata of that type. Wolfram made it his business to conduct a systematic study of all those different automata using extensive computer simulations, and to think about and generalize from what he thereby uncovered. A New Kind of Science, written and published by Stephen Wolfram, is the outcome of those and related studies.
A New Kind of Science is several things at once. First, it is an excellent pedagogical tool for introducing a reader, even one who has no knowledge of advanced mathematics, to some of the concepts of modern computer science, mathematics, and physics. Space-time diagrams of the bits generated by the model show four separate patterns: dull uniformity, periodic time-dependence, fractal behavior, and truly complex nonrepetitive patterns. A discussion of this classification, which I think is originally due to Wolfram, enables the author to introduce modern concepts of complexity. Using these concepts he can discuss fractals (as they were introduced by Benoit Mandelbrot), the idea of universal computation (as it was developed by Alan Turing, Alonzo Church, and others), and the generation of complex patterns in a context in which one can actually see what is going on. The teaching continues with the description of several kinds of computers and of the conceptualization of natural processes as some kind of computation. This is a tour de force of clarity and simplicity.
Since the book covers so huge a territory, it should not be surprising to find a few errors in it. For example, in my own area of phase transitions: Wolfram says on page 981 that phase transitions involve a discontinuity in the partition function, and on page 983 that symmetries are usually not important in phase transition problems. Both statements are incorrect. Errors like these will no doubt be ironed out in subsequent editions.
A New Kind of Science is a very personal book. In it Wolfram tells the reader again and again how he discovered some new fact about automata, or used the automata to construct a new illustration of old ideas, or used his knowledge of these systems to construct the beginning of new hypotheses about mathematics or science. These descriptions of the personal events in the development of Wolfram's understanding are valuable both for the insights they give into the science involved and for the revelations they offer about the author himself. This aspect of the book is truly unique.
However, the reporting of history is spotty and sometimes quite weak. That weakness is partially structural, in that the author has not allowed himself any footnotes in the text. Instead, at the back of the book, there are 350 pages of notes that include both history and additional information about the topics in the text; any given topic might be covered in several different places. These notes do not contain any references either; they simply give authors, and sometimes dates. To find original sources one must look up a Web site; I did not choose to do this. Because of this structure, and an overuse of the words "discover" or "discovery," it is hard to distinguish among things that were explained previously by Wolfram and coauthors, well-k
There is a US experiment on Mars Express, part of the ASPERA-3 (Analyzer of Space Plasma and Energetic Atoms, http://www.aspera-3.org/) instrument package. I'm a member of the science team for this instrument, and you can see some of my computer simulations of the interaction of energetic space plasmas with the Mars environment at http://www.aspera-3.org/model.pdf.
Here's an email I got yesterday:
Dear colleagues,
We are very close to our target! On Dec. 19 Beagle - 2 will be separated and on Dec. 25 Mars Orbit Insertion executed. ESA is going to cover both events on live TV on the ESA television and, of course, Internet. Below follows a short time table for the main events.
All times are in CET (Central European Time ) = UT + 1
December 19 07:51 go/no-go decision to proceed with Beagle-2 ejection 08:21 spacecraft slew starts 08:51 spacecraft slew ends 09:31 first confirmation of separation
ESA TV sending 09:00 - 09:32 approx. (Internet 09:09 - 09:32) First sequence 11:25 - 11:47 approx. (Internet 11:25 - 11:47) Second sequence 12:00 - 12:10 approx. (Internet 12:00 - 12:10) Third sequence
December 24 21:00 MOI "go / no go"
December 25 02:47 MOI execution 02:50 Beagle 2 landing 05:15 Beagle 2 contact with Mars Odyssey
I will inform you about exact times of ESA TV live sending for December 25 later.
The permanent ESA channel: Astra 2C at 19 degrees East Transponder 57, horizontal, MPEG-2, MCPC Frequency 10832 MHz, Symbol Rate 22000 MS/sec, FEC=5/6 Service name: ESA TV
Merry Christmas, Stas
and another one...
Check out ESA's picture of Beagle-2 now separated from Mars Express.
Slashdot Mirror
Um, let's see ...
3 years ago I rented a hotel room in Nice, France for US$85 per night.
The same hotel room on my trip this year is US$250 per night.
What's that about the Canadian dollar?
Here's the review from Physics Today (http://physicstoday.org/pt/vol-55/iss-7/p55.html) (c) American Instute of Physics Wolfram on Cellular Automata; A Clear and Very Personal Exposition A New Kind of Science Stephen Wolfram Wolfram Media, Champaign, Ill., 2002. $44.95 (1197 pp.). ISBN 1-57955-008-8 Reviewed by Leo P. Kadanoff Early in the 1980s, Stephen Wolfram began to work in earnest on cellular automata, a class of computer model that can be visualized as a set of memory locations, each containing one bit. The bits are updated in a succession of time steps. In each step, the new value of each bit depends on the values of neighboring bits. Wolfram particularly studied the class of automata in which all the bits are arranged in a line, and each bit is updated using the very same functional dependence on its value and that of its two nearest neighbors. There are 256 different automata of that type. Wolfram made it his business to conduct a systematic study of all those different automata using extensive computer simulations, and to think about and generalize from what he thereby uncovered. A New Kind of Science, written and published by Stephen Wolfram, is the outcome of those and related studies. A New Kind of Science is several things at once. First, it is an excellent pedagogical tool for introducing a reader, even one who has no knowledge of advanced mathematics, to some of the concepts of modern computer science, mathematics, and physics. Space-time diagrams of the bits generated by the model show four separate patterns: dull uniformity, periodic time-dependence, fractal behavior, and truly complex nonrepetitive patterns. A discussion of this classification, which I think is originally due to Wolfram, enables the author to introduce modern concepts of complexity. Using these concepts he can discuss fractals (as they were introduced by Benoit Mandelbrot), the idea of universal computation (as it was developed by Alan Turing, Alonzo Church, and others), and the generation of complex patterns in a context in which one can actually see what is going on. The teaching continues with the description of several kinds of computers and of the conceptualization of natural processes as some kind of computation. This is a tour de force of clarity and simplicity. Since the book covers so huge a territory, it should not be surprising to find a few errors in it. For example, in my own area of phase transitions: Wolfram says on page 981 that phase transitions involve a discontinuity in the partition function, and on page 983 that symmetries are usually not important in phase transition problems. Both statements are incorrect. Errors like these will no doubt be ironed out in subsequent editions. A New Kind of Science is a very personal book. In it Wolfram tells the reader again and again how he discovered some new fact about automata, or used the automata to construct a new illustration of old ideas, or used his knowledge of these systems to construct the beginning of new hypotheses about mathematics or science. These descriptions of the personal events in the development of Wolfram's understanding are valuable both for the insights they give into the science involved and for the revelations they offer about the author himself. This aspect of the book is truly unique. However, the reporting of history is spotty and sometimes quite weak. That weakness is partially structural, in that the author has not allowed himself any footnotes in the text. Instead, at the back of the book, there are 350 pages of notes that include both history and additional information about the topics in the text; any given topic might be covered in several different places. These notes do not contain any references either; they simply give authors, and sometimes dates. To find original sources one must look up a Web site; I did not choose to do this. Because of this structure, and an overuse of the words "discover" or "discovery," it is hard to distinguish among things that were explained previously by Wolfram and coauthors, well-k
There is a US experiment on Mars Express, part of the ASPERA-3 (Analyzer of Space Plasma and Energetic Atoms, http://www.aspera-3.org/) instrument package. I'm a member of the science team for this instrument, and you can see some of my computer simulations of the interaction of energetic space plasmas with the Mars environment at http://www.aspera-3.org/model.pdf.
...
Here's an email I got yesterday:
Dear colleagues,
We are very close to our target! On Dec. 19 Beagle - 2 will be separated
and on Dec. 25 Mars Orbit Insertion executed. ESA is going to cover both
events on live TV on the ESA television and, of course, Internet. Below
follows a short time table for the main events.
All times are in CET (Central European Time ) = UT + 1
December 19
07:51 go/no-go decision to proceed with Beagle-2 ejection
08:21 spacecraft slew starts
08:51 spacecraft slew ends
09:31 first confirmation of separation
ESA TV sending
09:00 - 09:32 approx. (Internet 09:09 - 09:32) First sequence
11:25 - 11:47 approx. (Internet 11:25 - 11:47) Second sequence
12:00 - 12:10 approx. (Internet 12:00 - 12:10) Third sequence
December 24
21:00 MOI "go / no go"
December 25
02:47 MOI execution
02:50 Beagle 2 landing
05:15 Beagle 2 contact with Mars Odyssey
I will inform you about exact times of ESA TV live sending for December
25 later.
The permanent ESA channel:
Astra 2C at 19 degrees East
Transponder 57, horizontal, MPEG-2, MCPC
Frequency 10832 MHz, Symbol Rate 22000 MS/sec, FEC=5/6
Service name: ESA TV
Merry Christmas,
Stas
and another one
Check out ESA's picture of Beagle-2 now
separated from Mars Express.
http://www.esa.int/export/esaCP/index.html
Cheers,
Rick