deepstash

Beta

Four amazing astronomical discoveries from ancient Greece

The first astronomical calculator

The Antikythera Mechanism is the word's oldest surviving mechanical calculator. The device was discovered in an ancient shipwreck in 1900 and dates between the 3rd and 1st centuries BC.

When manually rotated by a handle, the gears span dials on the exterior showing the Moon's phases, the timing of lunar eclipses, and the positions of the five planets then known (Mercury, Venus, Mars, Jupiter, and Saturn) at different times of the year.

24 SAVES


This is a professional note extracted from an online article.

Read more efficiently

Save what inspires you

Remember anything

IDEA EXTRACTED FROM:

Four amazing astronomical discoveries from ancient Greece

Four amazing astronomical discoveries from ancient Greece

https://theconversation.com/four-amazing-astronomical-discoveries-from-ancient-greece-136197

theconversation.com

5

Key Ideas

Strange discovery from early history

In the Histories by Herodotus (484BC to 425BC), Herodotus recounts the story of Phoenician sailors who were dispatched by King Neco II ofEgypt (about 600BC), to sail clockwise around continental Africa, starting in the Red Sea.

The voyage took years. As they rounded the southern tip of Africa, and following a westerly course, the sailors observed the Sun as being on their right-hand side, above the northern horizon. Because they still thought the Earth was flat, the observation did not make sense at the time.

The planets orbit the Sun

The earliest known heliocentric theory of the solar system came from Aristarchus of Samos (310BC to 230BC). He argued that the Sun was central. He also placed all the then known planets is their correct order of distance around the Sun. His original text was unfortunately lost to history.

Nicolaus Copernicus rediscovered the theory in the 16th century. He acknowledged Aristarchus during the development of his own work.

The size of the Moon

In one of Aristarchus' books that did survive, he laid out the earliest known attempted calculations of the sizes and distances to the Sun and Moon.

From solar eclipses, where the Moon passes in front of the Sun, they realised that the Sun was further away. Aristarchus estimated that the size of the Moon was approximately one-third that of the Earth, based on the careful timing of lunar eclipses. He was surprisingly accurate in determining the ratio of the size of the Earth to the Moon. (the Moon has a diameter 0.27 times that of Earth).

The Earth’s circumference

  • Eratosthenes (276BC to 195BC) relied on measuring the different lengths of shadows cast by poles stuck vertically into the ground, at midday on the summer solstice, at different latitudes. The difference in the shadows demonstrated how much the Earth's surface curved. Eratosthenes estimated the Earth's circumference as approximately 40,000km.
  • Another scientist called Posidonius (135BC to 51BC) who lived on the island of Rhodes, arrived at almost exactly the same answer. He observed the bright star Canopus would lie very close to the horizon, but when in Alexandria, in Egypt, Canopus would ascend to some 7.5 degrees above the horizon. 7.5 degrees is 1/48th of a circle, and multiplying the distance from Rhodes to Alexandria by 48, arrived at approximately 40,000km.

The first astronomical calculator

The Antikythera Mechanism is the word's oldest surviving mechanical calculator. The device was discovered in an ancient shipwreck in 1900 and dates between the 3rd and 1st centuries BC.

When manually rotated by a handle, the gears span dials on the exterior showing the Moon's phases, the timing of lunar eclipses, and the positions of the five planets then known (Mercury, Venus, Mars, Jupiter, and Saturn) at different times of the year.

EXPLORE MORE AROUND THESE TOPICS:

SIMILAR ARTICLES & IDEAS:

The scientific revolution

Human history is often framed as a series of episodes, representing sudden bursts of knowledge. The Agricultural Revolution, the Renaissance, and the Industrial Revolution are a few examples where ...

Pseudo-Science 

Much of the knowledge about the natural world during the middle ages dates back to the teachings of the Greeks and Romans. Many did not question these ideas, despite the many flaws.

  • Aristotle taught everything beneath the moon was comprised of four elements: earth, air, water, and fire.
  • Greek astronomer Claudius Ptolemy thought that heavenly bodies such as the sun, moon, planets and various stars all revolved around the earth in perfect circles.
  • The ancient Greeks and Romans held to the idea that illnesses were the result of an imbalance of four basic substances and was related to the theory of the four elements.
Rebirth and Reformation
  • During the Renaissance, there was a renewed interest in the arts and literature. It led to a shift toward more independent thinking.
  • In 1517, Martin Luther nailed his 95 theses to the door of the Roman Catholic Church. Luther promoted his thoughts by printing and distributing them, encouraging churchgoers to read the Bible for themselves. This led to the Protestant Reformation.
  • In the process, the criticism and reform led to placing the burden of proof ahead in understanding the natural world, paving the way for the scientific revolution.

4 more ideas

Astrology and cultural acceptance

Astrology is currently enjoying a broad cultural acceptance through the Internet. It is a content business as well as a traditional spiritual practice.

Many people are explaining themselv...

Popularity of astrology

The rise of astrology is explained as a result of the decline of organized religion and the insecurity of the economy and politics. 

People want some stability in a world of chaos where they wonder what is going on in their lives.

Astrology

At the center of astrology is the pattern of a person’s life that corresponds to the planetary pattern at the moment of his birth.

Astrology has helped people decide when to plant crops or go to war. It is used to predict a person's life and interpret his character. For some, astrology can explain everything, from earthquakes to the rise of social media.

3 more ideas

Living in the age o doubt
Living in the age o doubt

We live in a time when all scientific knowledge (the safety of fluoride, vaccines, climate change, moon landing, etc.) faces coordinated and vehement resistance.

The acces...

We now face risks we can’t easily analyze

Our existence is invaded by science and technology as never before. For many of us, this brings comfort and rewards, but this existence is also more complicated and sometimes agitated.

Our lives are full of real and imaginary risks, and distinguishing between them isn’t easy. We have to be able to decide what to believe and how to act on that.

Marcia McNutt  - Geophysicist
Marcia McNutt - Geophysicist

“Science is not a body of facts. Science is a method for deciding whether what we choose to believe has a basis in the laws of nature or not.”

6 more ideas