Daily Archives: 15 April 2014

April 15, 1857 (a Wednesday)

On this date, a 3-kg carbonaceous chondrite fell at Kaba, near Debrecen, Hungary. The arrival of this meteorite was described as follows in the book The Geologist (1859) by Samuel Joseph Mackie (pp. 285-6):

About 10 pm an inhabitant of Kaba, sleeping in the open air, was awakened by a noise, different from that of thunder, as he described it, and perceived in the serene sky a luminous globe, of dazzling brightness, following a parabolic course during four seconds. This phenomenon was observed by several inhabitants of the same place. As one of them was riding out the next morning, his horse was frightened by the sight of a black stone, deeply bedded in the soil of the road, the ground around it being depressed and creviced. When dug out the meteorite weighed about 7 pounds. The finder broke off some fragments, and the remainder, weighing 5-1/4 lbs., was deposited in the Museum of the Reformed College at Debreczin.

Samples of the Kaba meteorite and the Cold Bokkeveld meteorite were examined and found to contain organic substances by Friedrich Wöhler, who inferred a biological origin. Ironically, it was Wöhler who had shown that it was possible to make organic chemicals by inorganic means. However, it was only later appreciated that complex carbon molecules can be manufactured in space by purely chemical processes.

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April 15, 1452

Leonardo's self portrait

On this date, Leonardo da Vinci was born at Anchiano near Vinci in the Florence area of Italy. It is well known that in one of his unpublished notebooks, Leonardo concluded that some fossil sea shells were the remains of shellfish.

Although “fossil” is now a common and widely used word, whose meaning is known to practically everyone, the general acceptance of the idea that fossils are the remains of ancient organisms required millennia to achieve. One reason for this is that the great age of Earth also was not widely appreciated until relatively recently. Without an Earth eons old the idea of ancient life and the idea of fossils are meaningless.

The use of fossils in understanding the distant past can be traced back to at least the sixth century B.C.E., when Xenophanes of Colophon lived. Xenophanes described the occurrence of clam shells in rocks outcropping in mountainous parts of Attica. He recognized that these lithified clam shells were closely similar to clams that were then living along the coastline of the Aegean Sea. To account for the occurrence of these lithified clam shells far from the present sea, he argued that they were the preserved remains of clams that had lived at an earlier time when Attica was covered by an ocean. Hippolytus of Rome (c. 170 – c. 236) in his Refutation of all Heresies (1.14.5-6) records that Xenophanes studied the fossils to be found in quarries:

Xenophanes declared that the sea is salty because many mixtures flow together in it… He believes that earth is being mixed into the sea and over time it is being dissolved by the moisture, saying that he has the following kind of proofs, that sea shells are found in the middle of the earth and in mountains, and the impressions of a fish and seals have been found at Syracuse in the quarries, and the impression of a laurel leaf in the depth of the stone in Paros, and on Malta flat shapes of all marine life. He says that these things occurred when all things were covered with mud long ago and the impressions were dried in the mud.

However, in 750 BCE there were no quantitative methods for verifying this hypothesis, and so Xenophanes’ rather modern-sounding explanation for these clams could not be tested, and disappeared from view. This interpretation of fossils did not reappear in history until Leonardo da Vinci, although he did not contribute to the understanding of fossils since his views were never published.

April 15, 1989 (a Saturday)

Hu Yaobang (r.) and Deng Xiaoping – Sept 1981

On this date, former Chinese Communist Party General Secretary Hu Yaobang, deposed in 1987, died of a massive heart attack. People began to gather in Tiananmen Square to commemorate Hu and voice their discontents. This was the beginning of events that would lead to the Tiananmen Square massacrein June.

Hu Yaobang was a reformist, who served as General Secretary from 1980 to 1987. He advocated rehabilitation of people persecuted during the Cultural Revolution, greater autonomy for Tibet, rapprochement with Japan, and social and economic reform. As a result, he was forced out of office by the hardliners in January of 1987, and made to offer humiliating public “self-criticisms” for his allegedly bourgeois ideas.

Chinese Students Demonstrate After Hu Yaobang’s Death, photo dated 21-22 April 1989.

One of the charges leveled against Hu was that he had encouraged (or at least allowed) wide-spread student protests in late 1986. As General Secretary, he refused to crack down on such protests, believing that dissent by the intelligentsia should be tolerated by the Communist government.

Official media made just brief mention of Hu’s death, and the government at first did not plan to give him a state funeral. In reaction, university students from across Beijing marched on Tiananmen Square, shouting acceptable, government-approved slogans, and calling for the rehabilitation of Hu’s reputation. Bowing to this pressure, the government decided to accord Hu a state funeral after all.