Galileo Galilei - Part 1

Galileo's Telescope
- Observations of Venus, Saturn's rings, and sunspots.
- Context: NATS1745 - History of Astronomy, York University.

Kepler's Publication
- Title: Harmony of the Worlds.
- Demonstrated the spacing between planets corresponds to musical intervals (leading to his 3rd law).
Planetary Frequencies
- Orbital period expressed in 'orbits per time.'
  - Earth: 1 revolution/year.
  - Mars: 0.5 revolutions/year.
Reference:
- [NRICH](https://nrich.maths.org/problems/tuning-and-ratio#:~:text=The octave corresponds to 2,' and 'fifth' etc.)

Observation: Harmony exists among adjacent planets except for Mars and Jupiter.
Speculation: A planet might have existed between Mars and Jupiter that is now gone.

Order of Planets:
- Mercury, Venus, Earth, Mars, Asteroid Belt, Jupiter, and Trojans.

Kepler's Contribution
- Created the Rudolphine Tables, the most accurate tables for planetary coordinates derived from his laws of motion.

Historical Context
- Known as the father of experimental science, lived from 1564-1642.
Education & Position
- Chair of Mathematics at University of Pisa, later moved to University of Padua.
Rediscovery of Heliocentrism
- Not the inventor of the telescope; faced persecution for heliocentric beliefs.
Legal Consequences
- Banned from heliocentrism, tried for heresy, placed under house arrest for 9 years.
Common Myths Addressed: Not jailed specifically for heliocentrism.

Personal Conflict
- Initially accepted heliocentrism privately but feared public assertion due to persecution of others (e.g., Copernicus).
Correspondence with Kepler
- Expressed concern over the repercussions of advocating heliocentrism publicly.

Historical Figure
- Called the first martyr of science, a Dominican friar advocating heliocentrism.
Beliefs
- Believed stars are like the sun with their own planetary systems.
- Executed in 1600 for charges including diabolism.
Critique of Draper’s Work
- Draper’s writings popularized myths about science and religion, criticized as lacking scholarly rigor.

Invention Timeline
- Telescopes first invented in 1608 by Dutch lens makers.
- Galileo improved upon the original design after hearing about it in 1609 and earned a lectureship at Padua.

Etymology
- The term 'telescope' comes from Greek roots: 'tele' (far) and 'scopos' (to see).
Functionality
- Telescopes make distant objects appear closer.

Fundamental Concepts
- Refraction is the bending of light as it passes through different media.
- Telescopes utilize this phenomenon to collect more light, enhancing visibility.

Operation of Refracting Telescope
- Lens bends incoming light rays to converge at the focus.
- An inverted image is produced, which is viewed through an eyepiece.
Focal Length
- Distance where light rays converge is termed the focal length.

Galileo's Observations
- Observed the imperfections of the moon with his telescope in December 1609.
- Published findings in Sidereus Nuncius (Starry Messenger) in 1610.

Galileo’s Findings
- The moon is not a perfect sphere but has mountains and valleys, contradicting Aristotelian views.
- Observed traces of geological features similar to Earth.

Lunar Phenomena
- Identified features on the moon: mountains, maria (dark patches), and described them as not having a smooth surface.
- Stated that the moon consists of vast prominences and uneven terrain, challenging previous beliefs.