A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving slowly across the face of the Sun. A transit is similar to a solar eclipse by the Moon, but while the diameter of Venus is more than three times that of the Moon it is much further from Earth and so appears smaller and generally takes longer (up to eight hours) to travel across the solar disk. Transits of Venus are among the rarest of predictable astronomical phenomena—they occur in a pattern that repeats every 243 years, with pairs of transits eight years apart separated by long gaps of 121.5 years and 105.5 years. The next transit of Venus occurs on 5 and 6 June 2012, and will be the last Venus transit this century. Historically, Venus transits were of great scientific importance as they were used to gain the first realistic estimates of the size of the solar system. A transit of Venus can be safely observed by taking the same precautions used when observing the partial phases of a solar eclipse.
Read more: https://en.wikipedia.org/wiki/Transit_of_Venus
_______________________________ Today's selected anniversaries:
1832:
The June Rebellion, an anti-monarchist uprising of students, broke out in Paris. https://en.wikipedia.org/wiki/June_Rebellion
1849:
A new constitution was introduced in Denmark, establishing a constitutional monarchy and the Rigsdag, a bicameral parliament consisting of the Landsting and the Folketing. https://en.wikipedia.org/wiki/Denmark
1941:
Second Sino-Japanese War: During one sortie in a five-year bombing campaign on Chongqing, 4,000 people died of asphyxiation when the tunnel they were hiding in became blocked. https://en.wikipedia.org/wiki/Bombing_of_Chongqing
1981:
The Centers for Disease Control recorded a cluster of Pneumocystis pneumonia cases among homosexual men in Los Angeles, the first reported cases of AIDS. https://en.wikipedia.org/wiki/AIDS
2001:
Tropical Storm Allison made landfall in southeast Texas, causing $5.5 billion in damage to make it the costliest tropical storm in US history. https://en.wikipedia.org/wiki/Tropical_Storm_Allison
_____________________________ Wiktionary's word of the day:
vulgarian: A vulgar individual, especially one who emphasizes or is oblivious to their vulgar qualities. https://en.wiktionary.org/wiki/vulgarian
___________________________ Wikiquote quote of the day:
Words ought to be a little wild, for they are the assault of thoughts on the unthinking. --John Maynard Keynes https://en.wikiquote.org/wiki/John_Maynard_Keynes