"The young man knows the rules, but the old man knows the exceptions."
[Oliver Wendell Holmes, Sr.]

Quote of the Day, from brainyquote.com (2020/09/28)

Article of the Day

Rigel (on left)
Rigel (on left)

Rigel is a blue supergiant star in the constellation of Orion, approximately 860 light-years (260 pc) from Earth. It is the brightest and most massive component of a star system of at least four stars that appear as a single blue-white point of light to the naked eye. A star of spectral type B8Ia, Rigel is calculated to be anywhere from 61,500 to 363,000 times as luminous as the Sun, and 18 to 24 times as massive. Its radius is over 70 times that of the Sun, and its surface temperature is 12,100 K. Rigel varies slightly in brightness, its apparent magnitude ranging from 0.05 to 0.18. It is classified as an Alpha Cygni variable. It is generally the seventh-brightest star in the night sky and is usually the brightest star in Orion, though it is occasionally outshone by Betelgeuse. With an estimated age of 7 to 9 million years, Rigel has exhausted its core hydrogen fuel, expanded and cooled to become a supergiant. It will end its life as a type II supernova. (Full article...)

  • Article of the Day

Image of the Day

150502 Strelitzer Straße bei Nacht.jpg
Source: Wikimedia Commons.

On this day: September 28

September 28: Meskel in Ethiopia and Eritrea (2020)

Juan Rodríguez Cabrillo
Juan Rodríguez Cabrillo

Knowledge about Earth

Facts and Figures

  • Age of Earth: ~ 4.568 billion years
  • World Population: 7.3 billion (July 2015)
  • Continents: 7 (Asia, Africa, North America, South America, Antarctica, Europe, and Australia)
  • Mean Radius: 6371.0 km
  • Axial Tilt: 23,44°

Image Source: Wikipedia - License: Public Domain (thanks to NASA)

Our Solar System

Our solar system consists of
1 star (Sun) and 8 planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune).

  • 1 AU (astronomical unit) is roughly the distance between Earth and the Sun (about 150 million kilometres).
  • The space probe Voyager 1 was launched by the NASA in 1977 and is meanwhile (autumn 2015) about 133 AU away from Earth.

Image Source: Wikipedia - License: CC BY-SA 3.0

Why you should extend your general knowledge:

There are many reasons why one should or wants to extend his knowledge.
First you should consider that "general knowledge" is knowledge which a group of humans - who belong together regional, temporal or otherwise - owns. Thus, it describes a basic understanding of specific categories of knowledge.

As the English philosopher Francis Bacon said before: "Wisdom is Power" [Bacon 1597].