Monday, April 26, 2010

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Saturday, October 18, 2008

7. The Unblind Workings of Chance (Only A Trillion, 1957)

Readers, feel free to comment about this essay and share info on new ways of looking at the same topic!

Opening paragraphs
The question for discussion is exactly how much luck was involved in the development, on Earth, of life from non-living substances, and, as a corollary, what chance there is of finding life on any other Earth-like planet.

To go about this systematically, let us first decide what (from a chemical standpoint) non-life is, and what (from a chemical standpoint), life is, and then, perhaps, we can see how non-life may turn into life.

End paragraphs
But let's see, is there life on Mars?

Despite all the odds against it, despite the poorness of the planet, the answer seems to be: possibly yes. At least, the green areas on Mars seem to signify some kind of vegetation. The vegetation might be very primitive and undiversified, nothing like the teeming life of Earth, but it would be life.

And if Mars can do it, then it is my belief that any Earth-like planet can do it.

Topic
As Asimov so directly states in his opening paragraphs, this essay discusses how much luck is involved in the creation of life. He argues that "blind chance" has nothing to do with the liklihood of how life was formed on Earth, and may be formed on other planets.

He makes the point that random factors would make it impossible for life to develop, except that the development of life isn't random...certain atoms will combine with other atoms in a handul of ways, but no more than that. Thus, if you stick your hand in a vatful of marbles, chances are you will pick out one of each kind, but if you stick your hand in a vatful of atoms, you'll draw out several of the same kind or like groupings, because certain atoms will combine, but they will only combine in a limited number of ways. (For example, 2 hydrogen and 1 oxygen atoms unite to form water.) (Okay, Asimov explained it better.)

Quotes
To paraphrase a famous saying: Nucleoprotein is the whole of life, all else is commentary.

Note
In the 1976 edition, Asimov provides a note at the end of this essay:

Since July 1956, when this essay was first written [For Amazing], chemists have continued the kind of work Miller initiated and have shown in great detail the manner in which even some quite complicated chemicals can be formed without the intervention of cellular life, although they have come nowhere near life itself even yet.

Tiny traces of organic materials of the kind pointing toward life have been found in meteorites: and these show signs of having been formed without the intervention of living cells. In the 1970s, astronomers detected simple organic molecules in the dust-clouds of outer space. Apparently, the kind of molecules that seem to point toward life form whenever they are given the slightest chance to do so.)

Thursday, October 16, 2008

6. Planets Have An Air About Them (Only A Trillion 1957)

THe sixth essay in the Only A Trillion collection is, Planets Have An Air About Them, which talks about planets and their atmospheres, and what Asimov thinks they might be like based on current knowledge.

Opening paragraph
Ever since it wa recognized that other planets existed besides our own, there has been considerable speculation concerning the possibility of life on these planets and on the kind of life that could be possible on them. Intimately bound up with such speculation are considerations of the kind of atmosphere that might be expected to surround a given planet. What do we actually know, or what can we reasonably speculate concerning planetary atmosphere?

End paragraphs
Imagine a planet the size of Uranus in the position of Mars. It has just managed to hang on to enough hydrogen to allow it to be a major component of the atmosphere, along with ammonia, methane and carbon dioxide, and yet the planet is just warm enough to allow the presence of liquid water.

Plant life on such a world might split water to hydrogen and oxygen. ?It would then combine oxygen and methane (which it breathes) to form starch, liberating the hydrogen into the atmosphere. The methane would be replaced by hydrogen, the carbon dioxide would be reduced to methane and then replaced by hydrogen, the ammonia would stay put. The atmosphere of the world would end as only hydrogen and ammonia.

Animals would eat the starch, breathe the hydrogen, recombine the oxygen of the starch with the hydrogen to form water, and breathe out methane gas.

Our situation exactly, but in reverse.

With which thought, I'll step out of the backyard to take a deep, invigorating breath of oxygen and stare fondly at the grass which is so busy making more of it.

The book I have was revised and updated in 1976, and Asimov includes a note:
In the twenty years since this was first written (July 1956) astronomers have discovered more about the details of planetary atmospheres than they had in all the time prebiously - thanks to the coming of the space age and of the launching of satellites and probes. However, the material in this article is essentially correct. ...

The article
Asimov gives a table of atoms abundant in the universe (Hydrogen leading the way, sulfur at the bottom of a 10-item list, with "all others" at the end.

Which of those materials are suitable for atmosphere making, Asimov then questions. He goes on to explain how each one combines with others and what they would produce, with yet more tables...

Surface temperatures of planets of the solar syatem
Boiling points of the common elements
Boiling points of the common compounds
Molecular weights of possible atmospheric components
Atom abundance of oxygen and possible substitutes
Temperature ranges for gas-liquid-solid states of various substances

Quotes
Nothing particular quote-worthy in this essay.

Wednesday, October 15, 2008

The Abnormality of Being Normal (Only A Trillion, 1957)

Readers! Feel free to share opinions or knowledge on Asimov's essays in the Comments section of this blog entry!

First couple of paragraphs
A common-catch-phrase is the one that goes, "There's no such thing as a normal person."

The question, though, is this: Why is there no such thing as a normal person?

Last 2 paragraphs
Still, as long as psychologists use the words 'normal' and 'abnormal' in the way that they do, we will always be able to make statements like: "It is normal to be a little abnormal." and "It is highly abnormal to be completely normal."

And, after all, such statements, while confusing, are also comforting.

Topic
Asimov discusses the meaning of normal and abnormal, and segues into the types of atoms that are found in the human bod where he talks about probabilities.

He also explains what "perfect gases" are.

Notes
Nothing really quotable or of more than general interest in this essay.

Saturday, October 4, 2008

Victory on Paper (March 1955) (Only A Trillion, 1957)

Victory on Paper was published in March, 1955. Asimov doesn't say where. (The version of Only A Trillion that I'm working with was "revised and updated" in 1976. Each essay has an endnote explaining, a bit, what's gone on since the essay was originally published.

First paragraph
The key to the answer to the problem of protein structure was found by a Russia. This was Michael Tswett.

Final Paragraph
It took Sanger and his men eight years to solve the "impossible" problem of finding one arrangement out of several googols of possible arrangements. We shouldn't object to giving biochemists a few more years to see what other possibilities they can knock off.

Topic
Asimov tells how Michael Tswett discovered the principles of chromatography, but becauses he was a Russian, writing in Russian, and Germans dominated th field of biochemistry, his paper never got read, and it wasn't until 1931 that anything started happening with it.

Chromatography is the process of using filter paper. Immerse it in a liquid, the liquid creeps up the paper, until it gets to a solution you've placed on the paper. Each different component of the liquidd separates out...like substances stay with the solution you've placed on the paper, unlike substances continue their creeping. (Very rought description.)

But, using chromatography, scientists were able to discover how insulin was put together (as well as other proteins) in a quest to create artificial insulin as at th etime of this writing, iinsulin came only from the pancreas of cattle or pigs.

Synthetic insulin first appeared in 1982, and today, 2008, "Since January 2006, all insulins distributed in the U.S. and some other countries are synthetic "human" insulins or their analogs. A special FDA importation process is required to obtain bovine or porcine derived insulin for use in the U.S., although there may be some remaining stocks of porcine insulin made by Lilly in 2005 or earlier."

Friday, October 3, 2008

Hemoglobin and the Universe (Only A Trillion) 1957

Hemoglobin and the Universe was first written in 1954.

First paragraph
Even the purest and most high-minded scientist finds it expedient sometimes to assault the fortress of truth with the blunt weapon of trial and error. Sometimes it works beautifully. As evidence and as a case in point, let us bring to the front of the stage the hemoglobin molecule.

Last paragraph
The fact is that straight trial-and-error technique would have been an unbearable trial and a colossakl error. So they used other methods. There are other methods, you know.

Topic
Asimov begins by telling the story of German chemist Hans Fischer, who discovered how sidechains are attached to which positions in the porphyrin ring. He used "trial and error" by having 60 graduate students, and had them prepare protoporphyrin... only one of the synthetic protoporphyrin's matched the natural product (and since he'd assigned number 9 to that grad student group, that's why it became called Protoporphyrin IX.)

But then Asimov went on to point out that trial and error wouldn't have worked in trying to find out the exact order in which the different amino acids occur along the protein chain. "The number of different combinations tested in all tha time (300 billion years) would be about 10 to the 179th power. The chance that the right combination would have been found is 1 in 4 X 10 to the 440th power.

Quotable Asimov
Even the purest and most high-minded scientist finds it expedient sometimes to assault the fortress of truth with the blunt weapon of trial and error.

There is no question but that most or all of the secrets of life lie hidden in the details of protein structure.

Notes
Since this essay was written in July, 1954, Asimov points out in an afterword, chemists have discovered many details about the hemoglobin molecule.

Tuesday, September 30, 2008

"The Explosions Within Us" (Only A Trillion)

According to Isaac Asimov's Essays, (a site that lists them and what books they are collected in, and reviews them, but doesn't go in-depth as ths blog does), "The Explosions Within Us" first appeared in Only A Trillion , in other words it was written specifically for the book, and published for the first and only time in 1957.

The Quotable Asimov
All mathematical treatment of radioactive breakdown is statistical in nature and statistics work more poorly as the numbers grow smaller.

First Paragraph
It is all very well to speak of radioactive atoms that occur in the soil, as I have been doing in the previous chapter. There is something objective and detached about atoms exploding within rocks and soil. But plants grow in the soil and animals live on plants. Is it possible that radioactive atoms may find their way into living tissue and even into our own bodies?

It is not only possible, it is certain.

Topic
Asimov discusses the trace elements in our body, broken down by atom. (We need only a trace of cobalt to survive, but that trace actually consists of several million atoms.)

He also talks about the existence of the radioactive potassium-40 in our bodies. There is three times as much potassium-40 in our bodies as iodine.

"There is always a chance" Asimov comments "...that the unfortunate molecule that finds itself in the path of a free radical (a water molecule with a piece knocked off by a beta particle) may be one of the nucleo-protein molecules called "genes". There are several thousand genes in each cell, each gene controlling some particular facet of the cell's chemistry. If one of those genes is damaged or altered as a result of a collision with a free radical, the cell's chemical is also altered to some extent...this change is called a mutation."

He then moves on to discuss carbon-14, and how much of that is in our bodies, and why that enables us to date dead bodies (as in mummies).

Final Paragraph
This is the same as saying that if you live to be 70, the chances that a particular cell in your body will ever have experienced even a single carbon-14 breakdown in its genes is only one in 260.

So sleep in comfort!



A note
Asimov has a note at the end of this article, pointing out he''d wriiten it in November 1956. He'd wriiten an article on the same topic that had appeared in the February 1955 issue of Journal of Chemical Education. "That, I believe, was the first mention in print of the relationship of carbon-14 to genetics." He goes on to say, "In 1958, when atmospheric testing of nuclear bombs still went on wholesale, Linus Pauling published a paper in Science (Nov 14, 1958) which commented that the increase in carbon-14 content in the atmosphere would increase the incidence of undesirable mutations. Asimov states he received a letter from Pauling "which refers in most kindly fashion to my article." But he doesn't say exactly what Linus said (and if you read Yours, Isaac Asimov, a collection of Asimov's correspondence, typically Linus only wrote when he was pointing out an error in on of Asimov's articles.)