/~jeffery/astro/aristotle/aristotle_cosmos.png

    Caption: If the Earth moved, the fixed stars should show stellar parallax in simple observations---unless they are flying in formation with the Earth or are very, very remote implying a very big universe.

    Features:

    1. Aristotle (384--322 BCE) thought both of the above explanations for the lack of observed stellar parallax were implausible.

      This was one of his arguments for a static Earth.

      Yours truly thinks we must agree that it is a strong argument for Aristotle's time and for later times up to the 17th century and 18th century.

    2. But, of course, it is a WRONG argument since there is stellar parallax. It is just very, very small since even the closest fixed stars are very remote by comparison to Solar System length scales. But discovering this fact was well beyond the abilities of Ancients.

    3. Galileo Galilei (1564--1642) and other Copernicans of the 17th century did try to find stellar parallax. But they could NOT Nevertheless, people in the 17th century and 18th century who accepted heliocentrism believed stellar parallax did exist and the fixed stars were just very remote making it unobservable.

      In fact, Isaac Newton (1643--1727) obtained the first stellar distance, but NOT using stellar parallax. He determined an approximate distance to Sirius using by assuming it had the same luminosity as the Sun. Comparing the Sun's brightness and Sirius' allowed a distance determination using the inverse-square law fall off of brightness with distance (No-374).

    4. Stellar parallax was discovered in 1838 by Friedrich Bessel (1784--1846) (see Wikipedia: Stellar parallax: 19th and 20th centuries; Wikipedia: Friedrich Bessel: Work)---who is also known for his Bessel functions though they were originally discovered by Daniel Bernoulli (1700--1782) (see Wikipedia: Friedrich Bessel).

    5. The size scale of observable universe as a whole was discovered in the 20th century.

    Credit/Permission: © David Jeffery, 2003 / Own work.
    Image link: Itself.
    Local file: local link: aristotle_stellar_parallax.html.
    File: Aristotle file: aristotle_stellar_parallax.html.