Science, Technology And Society

What astronomy teaches us.

When scientific discovery, conjecture or theory challenges belief, there will be conflict.

A classic example occurred during the middle ages

The controversy was whether or not the earth was the center of the universe.

Two models:

Ptolemaic/geocentric

Copernican/heliocentric

Geocentric—earth at center

Makes sense—it does appear that objects orbit the earth.

The geocentric model is usually attributed to

(Claudius) Ptolemy

AD 90 -- AD 168

In order for everything to orbit the EARTH, theorists needed to

be able to explainRETROGRADE MOTION.

Retrograde Motion

Some planets appear to move BACKWARDS in their orbits at times.

Retrograde Motion of Mars

http://www.lasalle.edu/~smithsc/Astronomy/retrograd.html

Ptolemy suggested that this occurred due to “epicycles”– within their orbits,

the planets had smaller orbits.

To explain the backward motions,

Each planet moved around a smaller circle as it orbited the earth.

On the other hand, if the earth is orbiting the sun

along with the other planets, it makes sense that faster, inner planets would approach, pass, and move away from slower, outer planets.

The IDEA of a sun-centered universe

Is usually credited to Aristarchus of Samos, third century BC

(310BC-230BC)

A Polish doctor, lawyer and amateur astronomer.

The first formal heliocentric model is attributed to Nikolas

Copernicus, 1473-1543

Copernicus

Thought the retrograde motion of the planets could be explained just as easily if ALL planets orbited the SUN.

Copernicus:

still used epicycles in his model

waited until near his death to publish his ideas, which received little attention for nearly 100 years.

WHY? Was the earth-centered universe accepted for almost

1400 years?The Copernican model really didn’t

describe planetary motion any better than the Ptolemaic.

There is no physical sensation of the earth orbiting.

No parallax shift

Most importantly:

1. The historical context was not one which encouraged scientific discussion. -Literacy was low.-Practically no travel, communication, written texts

2. The growing influence of the holy roman church.

The church was the dominant intellectual and political force in Europe.

The church much preferred the Aristotle/Ptolemy model.

Man, God’s great creation,

Would be at the center of all

Everything else

In the universe would be created for man, and his divine home, the earth.

So, the sun

Existed to warm the home of man.

Furthermore,

The emphasis on circular orbits and epicycles was good—the circle is a “perfect” shape, and God’s creations were perfect.

In 1517, the protestant movement began in Germany.

Martin Luther, the leader of the movement, spoke out in favor of heliocentrism.

As a result,

The Catholic church actually expressed some interest in Copernicus’ book, even though it contradicted church doctrine.

Those who spoke against church doctrine

Were labeled ‘heretics.”The could be kicked out of the church, identified as outlaws, imprisoned or put to death.

Giordano Bruno

1548-1600

Burned at stake for heresy

Bruno’s heresy:

The sun was just another star, and there were probably people elsewhere in the universe.

It is out of this context that

Experimental science was born.

The issue of the organization of the universe (solar system) came down to the introduction of new technology the collection of data

TO BE CONTINUED….