tingilinde

on the sympathy of two clocks

Steve points out this excellent history piece on synchronized pendulums.

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To test their hypothesis, Huygens and Bruce placed two pendulum clocks on board a ship commanded by the British admiral Robert Holmes. The idea of having multiple clocks was that if rough seas stopped one of the clocks from working, at least the other would be running at the correct frequency.

According to the instructions Huygens provided, the ship’s sailors were meant to look at the time indicated by the clocks (set to the time of the place of departure) and then determine the local time (indicated by the Sun). If the time on the clocks was later than the local time, it meant the sailors were moving east. But if the clock time was earlier, they were heading west. In both cases, each hour of difference was equivalent to 15° of longitude.

Departing from the island of St Thomas off the coast of Guinea in west Africa, Holmes’ vessel initially set off in a westerly direction. But after a few days, the master of the ship realized they were running out of drinking water. Using the time indicated by the pendulum clocks, however, Holmes was able to figure out the vessel’s location – barely 30 nautical leagues from one of the Cape Verde islands in the mid-Atlantic. Thanks to this vital information, Holmes steered the vessel towards the island and arrived safely the next day, exactly as expected from the calculations carried out using data from the clocks (1665 Phil. Trans. 1 13).

Based on this successful trial, Huygens – who was as much an entrepreneur as a scientist – drew up a business plan and started to prepare his maritime pendulum clocks for sale. Huygens also published his instructions to determine longitude at sea with these devices (1669 Phil. Trans. 4 937). There was, though, one snag with Huygens’ set-up. It’s almost impossible to build two identical pendulum clocks, which means that one will always be slower or faster than the other. So if one of the clocks were to stop due to rough seas, then even if the sailors reactivated it to match the time of the other clock, it could be substantially “out” and give a wrong longitude. Even an error of just four minutes would lead to a 1° error in the ship’s longitude, which could be disastrous.

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a ton of urine

A fun article on the discovery of elements in The New Yorker.

 

 

racism and football - 50 yrs ago

A civil rights protest involving the University of Wyoming football team. 

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The university’s athletic director had spent the previous night in Orlando watching the players — known as the “Black 14” — accept an award and explain how they had been kicked off the team in 1969 after trying to ask their coach if they could wear black armbands during an upcoming game. They had wanted to show solidarity against racism at a time when civil rights protests were common on the nation’s college campuses.

Instead, they were immediately banished, sending many of their lives into turmoil. Some transferred away from Wyoming, others left school, never to return and never to receive a degree. Burman hurt for the men as he heard how they had been villainized throughout the state as insubordinate and ungrateful, how most fans sided with their white coach and his strict “no protest” policy.

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plutokiller on the search for planet 9

Mike Brown's TED talk

jim peebles

Half of the Nobel Prize in physics for pioneering physical cosmology.  To give a sense here's a recent non-speciaiist lecture at the Perimeter Institute

100 years ago today

The 100th anniversary of the total solar eclipse that was the first verification of Einstein's General Relativity. 

 

one of the great ones leaves

Murry Gell-Mann ..  probably most famous for naming quarks, but he was one of the best physicists ever with numerous fundamental contributions.

 

a talk by kip thorne

Kip Thorne gave a non-technical talk last week on how and why he got into the gravity wave business.    He's a good speaker and it's fascinating if you're interested in one of the current revolutions in science and how they build.

 

planet nine

Mike Brown presents the history for the search for planet nine without the math,  Nicely written!

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In 1820 Alexis Bouvard, the director of the Paris Observatory, made what could have been a huge discovery. The planet Uranus, whose position he had tracked back 130 years in old star catalogs, didn’t quite go around the Sun the way that he predicted it should. It traveled along its elliptical orbit as expected, but sometimes the old observations suggested it was a little ahead of its predicted position and sometimes a little behind. Bouvard might have realized that there was something beyond Uranus, but instead he was convinced the old star catalogs were simply wrong.

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redesigning the periodic table

It's been broken for a long time, but it's still very useful.  I think the way forward is to recognize most serious users will be viewing it on a computer.  Come up with a half dozen or so well-designed specialized versions that are a click away for whatever you're using it for.