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Rømer's observations of the occultations of Io

The speed of light in vacuum, denoted $c$ , is a physical constant that is exactly equal to 299,792,458 metres per second (approximately 186,282 miles per second, or one foot per nanosecond). According to standard modern physics, visible light and all other electromagnetic radiation moves at this constant speed in vacuum, and $c$ is the fastest speed at which matter, energy or any signal carrying information can travel through space. Ole Rømer first demonstrated in 1676 that light does not travel instantaneously by studying the apparent motion of Jupiter's moon Io (diagram shown). In an 1865 paper, James Clerk Maxwell proposed that light was an electromagnetic wave, and therefore travelled at the speed $c$ . According to the theory of special relativity, which interrelates space and time, all observers will measure the speed of light as being the same, regardless of the inertial reference frame of the observer or the velocity of the object emitting the light. (Full article...)

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Did you know ...

Hank Goldberg

... that after Hank Goldberg (pictured) was dismissed from WIOD for publicly disregarding his program director's instructions, he joined its struggling rival, which ultimately surpassed WIOD in the ratings?
... that Turkey's newly acquired fourth drillship, Abdülhamid Han, is able to drill up to 12,200 m (40,000 ft) and in a maximum water depth of 3,665 m (12,024 ft)?
... that Kyaymyin Mibaya was King Mindon's youngest, last and richest queen?
... that according to researchers including Stephen Hargarten, the slogan "guns don't kill people, people kill people" is "scientifically inaccurate"?
... that the coin used by Gaelic football referee Sean Hurson bears his initials and was presented to him by one of his umpires shortly before the latter died?
... that This Tender Land is a retelling of Adventures of Huckleberry Finn set in the 1930s and incorporating elements of Homer's Odyssey?
... that Russell Strong pioneered multiple techniques for liver transplantation, including splitting a donor liver between multiple recipients?
... that during the 2022 National Arena League season, a player hit a referee?

In the news

Salman Rushdie

A church fire in Giza, Egypt, kills 41 people, including at least 18 children.
Salman Rushdie (pictured), author of The Satanic Verses, is critically injured after a stabbing at a speech in the United States.
A mass mortality event involving fish, beavers and other wildlife occurs in the Polish part of the river Oder, causing a health and environmental crisis.
A mass shooting in Cetinje, Montenegro, leaves 11 people dead and 6 others injured.

On this day

August 16

Ringo Starr

1819 – Around 15 people were killed and 400 to 700 others injured when cavalry charged into a crowd demanding the reform of parliamentary representation in Manchester, England.
1942 – The Holocaust: During the deportation of Jews from Slovakia, President Jozef Tiso gave a speech describing Jews as "parasites" and "the eternal enemy".
1945 – The Stanley Internment Camp in Hong Kong was liberated following the announcement of the surrender of Japan in World War II.
1962 – The English rock band the Beatles fired their drummer Pete Best, replacing him with Ringo Starr (pictured).
1986 – Typhoon Wayne formed over the South China Sea, going on to become one of the longest-lived tropical cyclones in the north-western Pacific, lasting 21 days.

Ranavalona I (d. 1861)
Georgette Heyer (b. 1902)
Marian Rejewski (b. 1905)

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Today's featured picture

The double-barred finch (Stizoptera bichenovii) is a species of estrildid finch found in dry savanna, tropical (lowland) dry grassland, and shrubland habitats in northern and eastern Australia. It is sometimes referred to as Bicheno's finch or the owl finch, the latter owing to the dark ring of feathers around the face. This double-barred finch perching on a branch was photographed in Glen Davis, New South Wales.

Photograph credit: John Harrison

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