Daily Knowledge

"Experience is simply the name we give our mistakes."
[Oscar Wilde]

Quote of the Day, from brainyquote.com (2026/06/15)

Makemake and its moon

Makemake is a dwarf planet orbiting the Sun beyond Neptune. It has a diameter 60% that of Pluto, and is the fourth-largest trans-Neptunian object and the largest member of the Solar System's classical Kuiper belt, a disk of icy bodies beyond Neptune's orbit. Its discovery on March 31, 2005, by American astronomers Mike Brown, Chad Trujillo and David Rabinowitz at Palomar Observatory contributed to the reclassification of Pluto as a dwarf planet in 2006. Makemake's surface, like Pluto's, is largely covered by frozen methane and stained reddish-brown by tholins. It has one known satellite, unnamed, whose orbit suggests that Makemake's rotation has a high axial tilt. Makemake shows evidence of geochemical activity and cryovolcanism, which has led scientists to suspect that it might harbor a subsurface ocean of liquid water. No high-resolution images of its surface exist because it has not been visited up close by a space probe. (This article is part of a featured topic: Solar System.)

1991 eruption of Mount Pinatubo

1520 – Leo X issued the papal bull Exsurge Domine, censuring 41 propositions from Martin Luther's Ninety-five Theses and subsequent writings, and threatening him with excommunication unless he recanted.
1896 – A magnitude-8.5 earthquake and a subsequent tsunami struck Japan, killing at least 22,000 people and destroying about 9,000 homes.
1920 – Three African-American circus workers were lynched by a mob in Duluth, Minnesota, a crime that shocked the country for having taken place in the Northern United States.
1991 – An eruption of Mount Pinatubo (pictured) in the Philippines deposited large amounts of particulate matter into the atmosphere, enough to lower global temperatures by about 0.5 °C (0.9 °F).
2006 – US president George W. Bush designated 140,000 square miles (360,000 km²) around the Northwestern Hawaiian Islands as the Papahānaumokuākea Marine National Monument, now one of the world's largest protected areas.

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 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