Archive for the ‘science’ Category

Aristotle (-384 to -322) was a Greek philosopher, the founder of the Peripatetics, one of the five schools of Greek philosophy in ancient times. His teacher was Plato and he in turn taught Alexander the Great. Although Plato has been more important through most of the history of the West, Aristotle’s philosophy was on top from about 1250 to 1650, a period that saw the birth of Western science.

Aristotle was more down to earth than Plato. Unlike Plato, he trusted his senses and did not see this world as only the shadow of some higher reality. But like Plato he saw reason as the royal road to the truth.

For Aristotle a field of science starts with a set of axioms – statements whose truth is self-evident. One builds on top of this by observation and reason. This was how science was done until the time of Galileo nearly two thousand years later.

Aristotle saw the earth as a place of ceaseless change, birth and destruction. The heavens, however, were perfect, changeless and eternal.

The universe is made up of five elements: earth, water, air, fire and quintessence. Earth is the heaviest element so it sinks to the middle of the universe. That is how the earth itself came to be. Water is the next heaviest, making the seas, then comes the air. Above the air is a region of fire and above that are the heavens made of quintessence. Quintessence moves in perfect circles.

That is why the sun, moon, planets and stars all go round the earth.

Aristotle said that nothing could be physically infinite, that it was impossible for anything real to go on forever. That meant that the chain of causes that make up the universe cannot go on forever. There must be some starting point. That first uncaused cause he called the Prime Mover. Aquinas would later develop this argument into his proof of God.

Aristotle said that each physical thing or substance, like a man or a horse or a table, is made up of essence and accidents.

An essence are the parts of a thing that belong to its definition. Man, for example, is a rational animal. So his reason and animal body are part of his essence. He could not be a man without them. Accident, on the other hand includes those things that make one man different from the next, like his colour or weight, but which do not make him something other than a man.

This is only some of what he taught. He also wrote about the soul, virtue, reason, cause, motion, being, animals, the earth, government, rhetoric, theatre and much else.

Aristotle came down to the West chiefly through the Arabs. When his works appeared in Europe in the 1100s the Catholic Church at first saw him as a threat. But in the 1200s Aquinas was able to explain Christian theology, even the Eucharist, in terms of Aristotle’s philosophy. This in turn laid the groundwork for the rise of Western science.

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Thomas Kuhn (1922-1996) was an American philosopher of science. He said that science progresses not by the slow, orderly increase of facts and theories – fact building on fact, theory building on theory – but by one theory overthrowing another.

He called the conquering theory a paradigm and the overthrow a paradigm shift.

Kuhn found this out when he read Copernicus: Copernicus and Ptolemy had the same set of facts, more or less, yet while Ptolemy said the planets went round the earth, Copernicus said they all went round the sun. Copernicus did not “build” on Ptolemy’s theory: he ground it into the dust.

He is not the exception, as it turns out: Dalton did not build on Lavoisier, Darwin did not build on Lamarck and Einstein did not really build on Newton. They each had a new paradigm: a new way of looking at the facts that everyone already knew.

What makes a paradigm powerful is that it not only explains the known facts better, it predicts something surprising that turns out to be true. It also gains followers by opening up new roads into the unknown, just as Copernicus opened up new roads for Galileo, Kepler, Tycho and Newton.

Although the new paradigm has fact and reason on its side, it wins less by persuading the grey hairs and more by winning glory, honour and top positions for the young bloods. In time the grey hairs die off and the young bloods, by middle age, have all the top positions. By this point the paradigm has become the reigning truth. Paradigms win not by sweet reason, but by death and fashion.

Yet after a time new facts start to come in that do not quite fit. The paradigm becomes like a faithful old shoe that has seen its day and is starting to show holes. At first the new facts are not taken seriously, but then more are discovered. It seems like every five years or so someone finds out something new that does not quite fit.

Then a genius comes along with a new way of looking at it all – a new paradigm. He is able to explain the new facts as well as the old.

Then the whole thing starts over again.

Science was not always like this. Greek science certainly was not. Neither are the so-called “soft” sciences like those political and social. Not even computer science.

How to tell philosophy and soft science from true science:

  1. Theories sound good but cannot be proved to be true or false.
  2. The existence of different schools of thought.
  3. In school you read the “great works” of the field.
  4. There is no overarching theory – just a lot of rules that work.

In political science, for example, you may read Aristotle, but in physics no one thinks to read Galileo, as great as he was. Why? Because physics, as a true science, has progressed far beyond its founders, political science has not.

When a field gets its first paradigm it then becomes a true science.

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Science is our body of knowledge of the natural world. It is more than just a long list of facts: it includes the theories that fit the facts together and explain them. Facts tell us what is so, theories tell us why it is so.

Science used to be called natural philosophy because it was the branch of philosophy that explained the natural world. But no one calls it that now because science no longer works the way philosophy does. It has become something halfway between philosophy and geometry.

These days science almost always means Western science. There were other sciences: Greek science, Arab science, Chinese science and so on.

Western science is built on Greek science but it takes it much further. What distinguishes the two are the rules that they follow.

Science is not just theories and facts: it is also a set of rules about how to do science.

Greek science had three rules:

  1. Observation: gather the facts.
  2. Theory: apply reason to the facts to come up with a theory that explains them.
  3. You may use no gods in your theory.

Before the Greeks everyone explained nature by gods and spirits. The Greeks, however, starting with Thales, attempted to explain nature as a system that kept on going without help from the gods. Gods may have created nature and may act within it, but they do not keep it in operation. It goes on by itself.

Because gods can explain everything, they explain nothing. Also, god theory gives man no means to control nature by himself. It does not lead to invention, but to prayer and sacrifice.

As good as it was, Greek science had a weakness: There was no way to prove a theory right or wrong so long as it kept within the bounds of fact and reason, which any serious theory did. The choice between theories became a matter of taste. Science was divided into schools of thought just like the philosophy from which it sprang.

To mend this Western science added two new rules:

  1. Occam’s razor: the simplest theory that explains the most facts is the best.
  2. Experiment: A theory must have a test, often called an experiment, by which it can be proved false.

A good theory will not only explain the known facts but also predict something surprising, a previously unknown fact. If it turns out to be false, the theory is rejected. If it turns out to be true, it will gain followers, win awards and in time be written up in school books as the truth.

The great age of Greek science ran from the time of Thales, about –600, till 200. By 200 most of what could be done in Greek science had already been done. The Arabs were able to take it a bit further, but that was all.

It was not till the time of Galileo, about 1600, with the rise of Western science that another great age of science came. We live in that age.

– Abagond, 2006.

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Eris is the largest and farthest away of the three known dwarf planets. It is larger than even Pluto, though not by much. It was discovered in 2005 when it was named 2003 UB313. The discoverers called it Xena, after a television warrior princess.

Eris is sometimes closer to the Sun than Pluto but most of the time it is much farther away. It takes 560 years for Eris to go round the Sun. Where Pluto is 30 to 49 times farther away from the Sun than the Earth, Xena is 38 to 98 times farther away.

Eris has a moon named Dysnomia.

Unlike the Sun, Moon and ordinary planets it does not follow the Zodiac when it crosses the sky. Even Pluto mostly follows the Zodiac.

The farther away a planet is, the slower it moves, which makes it harder to find. Although anyone with a good telescope who knows where to look can see it, Eris would never have been discovered without using cameras and computers.

The picture of Eris was taken by a telescope on top of a mountain in California in 2003. But it took nearly a year and a half before a computer spotted it as a possible planet. It almost missed it.

Ten computers at Caltech look through countless pictures of the night sky for anything moving against the background of stars. Most pictures turn up nothing. But a few do: astronomers then check these out for themselves.

Eris was discovered by Mike Brown, Chad Trujillo and David Rabinowitz on January 5th 2005 at 17:20 UTC.

They named it Xena, not after some forgotten goddess (that came later), but after a character from a television show about a warrior princess. They had always wanted to name something Xena.

They regarded it as a planet and so did NASA, the American government’s space department. So for a while it was known as the tenth planet in certain circles.

In other circles, however, some argued that Xena and even Pluto were not true planets at all: they were too small – smaller than the Moon even. In the 1990s all sorts of things – lost moons, would-be comets and so on – were found in the same region of space beyond Neptune.

To settle the argument, astronomers from all over the world met in 2006 and came up with the definition of what a planet is. In the end Pluto and Eris did not make the cut: now they were mere “dwarf planets”. While they are large enough to be round (the “planet” part) they were too small to remove other smaller bodies from their orbits (the “dwarf” bit).

It was because of all this strife that Xena got the name of Eris, the Greek goddess of strife, also known as Discordia. She was the daughter of Night (Nyx) and the sister of the god of war (Mars). She had a daughter named Dysnomia.

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On Tuesday Pluto was the ninth planet and now it is not. Pluto is two-thirds the size of the moon and takes almost 248 years to circle the sun. It is 40 times farther from the sun than the earth. Discovered in 1930, it was long considered to be the ninth planet till 2006.

In 2006 astronomers from all over the world met and came to the decision that Pluto is a mere dwarf planet: it is big enough to be round (the planet part) but not big enough to clear other bodies out of its orbit about the sun (the dwarf part).

In the 1990s astronomers found out that Pluto is just one of many other such bodies just beyond Neptune. The region is now known as the Kuiper belt. Pluto is in the middle of it and many other smaller bodies have been discovered there. In 2006 one of them, Eris (then known as Xena), was found to be larger than Pluto! The Kuiper belt is full of huge pieces of rock and ice that never managed to form themselves into a true planet, but sometimes they become comets.

Even when it was considered a planet it seemed more like a lost moon of Neptune than a true planet: it seemed very much like Triton, it is sometimes closer to the sun than Neptune, the eighth planet, and it does not always travel along the Zodiac like the other planets.

Pluto is so far away that light from the sun takes five hours to get there!

Pluto is so cold that our air would become snow there. Yet Pluto has seasons, it has very thin air and it is not completely covered by snow and ice: it is partly dark red – no one knows why. Parts of Pluto are grey, and, because of the thin clouds, parts are yellow and pink.

Most of Pluto is covered with what looks like large pieces of
, very pretty. That is nitrogen ice. On Earth most of what we breathe is nitrogen!

You cannot see Pluto with the naked eye in Earth’s night sky, even if you know where to look. In fact, even with telescopes, no one would have found it before the invention of photography. It was found almost by accident by comparing pictures of the same piece of the night sky taken days apart.

Pluto has at least three moons: Charon, which is half the size of Pluto and very close, and two much smaller moons discovered in 2005, Nix and Hydra. Because it is so close, Charon looks very large in the sky, though half of Pluto never sees it.

At its closest Pluto is 30 AUs from the sun (one AU is the distance between the earth and the sun), as it was in 1989, and at its farthest it is 50, as it will be in 2113. By then the sun will be three times fainter than it is now.

In 2006 the Americans sent a machine to Pluto, New Horizons. It should fly by Pluto in July 2015 (and start taking pictures that January).

– Abagond, 2006.

Update (July 14th 2015): Two more moons have been discovered: Styx and Kerberos. New Horizons is about to fly by Pluto! Check that post for updates. 

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