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Flash
168032.  Fri Apr 20, 2007 3:58 am Reply with quote

eggshaped wrote:
But by your "Stephen won't be able to get the answer out" logic, surely this is worse - first he would have to describe the big-balls experiment, then the equation, then the fact that it doesn't work with planets sans lune.


Well, I had in mind that he would just say "because they don't have moons - for every planet except those two you can work out the mass by analysing the orbit of its moons, thanks to Cavendish's experiment". It could be an autocued link.

I don't say it's brilliant, mind, and I certainly don't say it's funny. But I hadn't heard of it before, and I have the impression that it was something that not even Dr Bob had thought about till now.

 
dr.bob
168054.  Fri Apr 20, 2007 4:22 am Reply with quote

Flash wrote:
But I hadn't heard of it before, and I have the impression that it was something that not even Dr Bob had thought about till now.


That's true. Like many of these astronomical facts and figures, you don't always think about how they were measured. It was certainly quite interesting to me that you had to wait until the space race to know how massive Venus and Mercury were.

 
Gray
168060.  Fri Apr 20, 2007 4:31 am Reply with quote

Apparently, it's possible to calculate the masses by simply watching them move past each other (and knowing some exceptionally crafty mathematics):
Quote:
For planets without observable natural satellites, we must be more clever. Although Mercury and Venus (for example) do not have moons, they do exert a small pull on one another, and on the other planets of the solar system. As a result, the planets follow paths that are subtly different than they would be without this perturbing effect. Although the mathematics is a bit more difficult, and the uncertainties are greater, astronomers can use these small deviations to determine how massive the moonless planets are.

Source

 
Flash
168113.  Fri Apr 20, 2007 5:42 am Reply with quote

On the subject of Cavendish, Fred the Monk raised in a meeting his use of the "Scale of Pain" to measure electricity - ie assessing the current on the basis of how much it hurt him. If we do use that, then the note should mention that there is indeed a method used to measure pain which is currently in use: the Visual Analogue Scale (VAS).

You're shown a line 100mm long with "No pain" written at one end and "Very Severe Pain" at the other, and invited to put a mark on the line to represent your current state. This is then measured in mm from the left. The idea is that this method captures a continuous spectrum of possible states, rather than trying to assign discrete step changes. As the measurement is highly subjective it's regarded as more useful for tracking a single patient's progress than it is for comparing one patient with another.
http://www.blackwellpublishing.com/specialarticles/jcn_10_706.pdf

Also:
Quote:
The McGill Pain Questionnaire consists primarily of 3 major classes of word descriptors--sensory, affective and evaluative--that are used by patients to specify subjective pain experience. It also contains an intensity scale and other items to determine the properties of pain experience. The questionnaire was designed to provide quantitative measures of clinical pain that can be treated statistically. This paper describes the procedures for administration of the questionnaire and the various measures that can be derived from it. The 3 major measures are: (1) the pain rating index, based on two types of numerical values that can be assigned to each word descriptor, (2) the number of words chosen; and (3) the present pain intensity based on a 1-5 intensity scale.


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=PubMed&list_uids=1235985&dopt=medline

 
dr.bob
168202.  Fri Apr 20, 2007 7:52 am Reply with quote

Gray wrote:
Apparently, it's possible to calculate the masses by simply watching them move past each other


Well, yes, before the space race the mass of Venus and Mercury was estimated by measuring the perturbations they caused in the orbits of the Earth (for Venus) and Venus (for Mercury). However, as you point out:

Quote:
the uncertainties are greater


Certainly the reading I did implied that the error bars were pretty large, so it was only when they could chuck satellites around them that scientists were able to make accurate measurements of their masses.

 
Gray
168206.  Fri Apr 20, 2007 7:55 am Reply with quote

Could have some fun with:

http://en.wikipedia.org/wiki/Beck_Hopelessness_Scale

 
Flash
168212.  Fri Apr 20, 2007 8:09 am Reply with quote

Quote:
Apparently, it's possible to calculate the masses by simply watching them move past each other

I do that by sitting in the window of my club observing the masses as they wend their dreary way to their dismal jobs through the pouring rain. It's priceless, I tell you.

 
Gray
168224.  Fri Apr 20, 2007 9:07 am Reply with quote

Surely there's a lumpenness scale you could use.

 
Molly Cule
168258.  Fri Apr 20, 2007 10:23 am Reply with quote

A computer geek called Gilbert Bohuslav had a very advanced computer for it’s time (1980’s) called DEC 11/70, it was a chess master so the engineer thought he would be able to teach it to write Westerns. He fed in every Western movie he had ever come across. DEC told the following;

“Tex Doe, the marshal of Harry City, rode into town. He sat hungrily in the saddle, ready for trouble. He knew that his sexy enemy, Alphonse the Kid, was in town. The Kid was in love with Texas Horse Marion. Suddenly the kid came out of the upended Nugget Saloon. “Draw Tex” he yelled madly. Tex reached for his girl, but before he could get it out of his car, the Kid had fired, hitting Tex in the elephant and the tundra. As tex fell he pulled out his chess board and shot the Kid 35 times. The Kid dropped in a pool of whisky. I hated to do it but he was on the wrong side of the Queen.”

S The world’s greatest mistakes by nigel blundell

 
eggshaped
168265.  Fri Apr 20, 2007 10:29 am Reply with quote

**BUZZ**

I spotted the elephant in the room.

 

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