History of Astronomy/Concepts of Earth Flashcards
Help prepare for Dantes Exam
In the development of _______________ thought, certain original and imaginative individuals began to make systematic observations of celestial objects to formulate theories and explain their behavior.
Astronomical. Ancient observers assumed the Earth was vast, immobile, and the center of the universe. Only when scientific procedures were developed did man’s concept of the universe begin to change.
The _______________ must call upon all his resources of ingenuity and employ more clever devises than the most astute detective to solve the problems of his business.
Astronomer. Astronomy is the science of the universe, and the laboratory for this science is afar and untouchable, other than the observations of fallen meteorites.
The first significant development of astronomy as a science took place in ancient _____________.
Greece. China, India, Mesopotamia, and Egypt had also made celestial observations, even before the Greeks. But the Greeks were the ones who explored a reservoir of ideas and inspirations, and carried out experiments and observations that contributed to the development of astronomy as a science.
The earliest Greek scientists were the ______________, who lived in what is now Asia Minor.
Ionians. The foremost astronomers of the Ionians were Thales and Anaximander. Thales introduced the concept of geometry and surveying. Anaximander may have been the first to speculate on the relative distances of the sun, moon, and planets.
_________________ was originally an Ionian in belief, but later founded a school of thought of his own regarding the shape of the planets.
Pythagoras. Pythagoras pictured a series of concentric spheres in which each of the seven moving objects, the planets, the sun and the moon, was carried by a separate sphere from the one that carried the stars, so that the motions of the planets resulted from independent rotations of the different spheres about the Earth.
A member of the Pythagorean school, ______________ was the first to introduce the concept that the Earth is in motion.
Philolaus. His concept proved to be erroneous in that he believed that there were two earths and that they each revolved equidistant from a central fire. However, he had set the “moving earth” concept in motion.
One of the most famous of the Greek philosophers was ________________.
Aristotle. He wrote encyclopedic treatises on nearly every field of human endeavor during his time. Unfortunately, his expositions in astronomy were less sound than some of his other work. The greatest of the Greek accomplishments in the fields of physics and astronomy came post-Aristotle.
The shape of the _________ in the sky depends simply on how much of its daylight hemisphere is turned to our view.
Moon. The phases of the moon and of eclipses are the results of illumination by sunlight. The moon itself is not luminous (it does not emit its own light).
_______________ of Samos was the first astronomer of the Alexandrian school and devised an ingenious method to find the relative distances from the Earth to the sun and moon.
Aristarchus. His procedure rests on the three assumptions that the moon goes about the Earth in a perfectly circular orbit, that the moon’s orbital velocity is perfectly uniform, and that the sun is near enough that its rays travel along diverging paths to different parts of the moon’s orbit. Although all three of these assumptions are incorrect, he pioneered a scientific approach that could be used to determine the distances from the Earth to the sun and moon.
Aristarchus also devised an ingenious technique to determine the relative ___________ of the sun, moon, and Earth.
Sizes. Although the data obtained and used by him were inaccurate and his results somewhat far from the truth, at least they were better than any available before and the first objective measures of astronomical dimensions based on logical reasoning.
The _________________ hypothesis states that the Earth orbits the sun and the Earth is not the center of the universe.
Heliocentric. Aristarchus was the first to profess this belief. This is opposed to the geocentric model of the universe, which states that the Earth is at the center of the universe and all objects revolve around it. Aristotle and Ptolemy were believers in the geocentric model.
The greatest astronomer of ancient times was _________________.
Hipparchus. His studies are credited with the development of both plane and spherical trigonometry, highly accurate observations, the use of old observations to determine changes, and the invention of a geometrical representation describing the motions of the sun and moon more precisely than ever before.
Another Greek astronomer, Cladius ______________, compiled a series of thirteen volumes on astronomy known as the Almagest.
Ptolemy or Ptolemeus. Most of the Almagest is a compilation of the astronomical achievements of the past, especially Hipparchus. However, it does contain some of his own contributions including the measurement of the distance to the moon by a technique essentially identical to the one used today.
Nicolas _______________ was born in Thorn on the Vistula in Poland. His forte was mathematics.
Copernicus. His great contribution to science was a critical reappraisal of the existing theories of cosmology and the development of a new model of the solar system.
Copernicus’s excellence as a mathematician and astronomer gave him the information to determine values for the distances of the various ____________ from the sun.
Planets. He lived from 1473 – 1543, yet his calculations (as shown by the table below) compared to modern calculations show how advanced he was in his observations and mathematical genius.
After beginning training for a medical career, ______________ found that he had little interest in the subject and later switched to mathematics.
Galileo. His refusal to accept dogmatic statements without proof allowed his mathematic abilities to proliferate. In 1589, he became professor of mathematics and astronomy at the university at Pisa.
Galileo’s greatest contributions were in the field of ______________.
Mechanics. Galileo experimented with pendulums, with balls rolling down inclined planes, with light and mirrors, with falling bodies, and many other objects. Galileo showed that if a heavy and light object were dropped together, even from a great height, both would hit the ground at practically the same time.
Galileo has often been called the ___________ of modern astronomy.
Father. Galileo probably has been the person most widely recognized as the “father of modern astronomy”, although there are many historians that have given the title to Nicholas Copernicus or Johannes Kepler.
The actual first telescope that attracted much notice was built by the Dutch spectacle maker ______ _____________ in 1608, but was only about three power.
Hans Lippershey. Historians generally credit Lippershey with the invention of the telescope, as he was the first to apply for a patent for a design. There is uncertainty about whether others had built telescopes earlier in the past.
Galileo was the first known astronomer to build a telescope for the specific purpose of observing and recording celestial bodies. His telescope was about __________ power.
Thirty. Hans Lippershey invented the telescope in 1608, intending it for use as a military device. Having heard of the discovery of Hans Lippershey, it was in 1609 that Galileo constructed a much improved refracting telescope of his own. He is the first person credited with using the telescope for looking at the stars. With the aid of his telescope, he was able to make keen observations that were recorded in his book Message from the Stars.
