Wednesday, October 23, 2013

The Venus and the scientist

I want to tell you the story of ordeals of a scientist, who wanted to measure distance to the Sun. What I admire is his strength. Despite of the many misfortunes, he stood firm and continued his work.
This story is narrated in the book ‘A Brief History of Almost Everything’ by Bill Bryson.
Before I tell you the story, you should know what the Transit of Venus is. Sometimes, when you see from earth, the planet Venus appears to be passing over Sun. This is called transit of Venus.
The transits are very rare. They come twice in eight years, then do not happen for more than 100 years. The last two happened in 2004 and 2012. Next one will be in 2117, but few of us can hope to see it.
Now, two hundred and fifty years ago, in 1761 there was a transit of Venus, and many scientists were eager to observe it. They wanted to take some measurements, and use them in calculating the distance from earth to Sun.
(In 1761, Marathas were still big rulers, British had just begun to spread in India and there was no Telephone; it would be invented only after 100 years).
One of these scientist was Le Gentil from France. He wanted to observe the transit from India. He started his journey one year in advance. But on the day of the transit he was still on his ship. The ship was horribly unsteady and it was impossible to measure anything.
Gentil was not discouraged. He reached India and started preparing for the next transit that would come eight years later. After a long preparation, he was perfectly ready. On the day of the transit, as he began his measurements, a cloud slid in front of the Sun and remained there for almost the entire time of the transit.
Bryson writes:
“Stoically, Le Gentil packed up his instruments and set off for the nearest port, but en route he contracted dysentery and was laid up for nearly a year. Still weakened, he finally made it onto a ship. It was nearly wrecked in a hurricane of the African coast. When at last he reached home, eleven and a half years after setting off, and having achieved nothing, he discovered that his relatives have declared him dead and enthusiastically plundered his estate.”
(The most useful measurement was taken by Captain James Cook, who later discovered Australia. Using his measurement, the distance to the Sun was estimated as 15 crore kilometres.)

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