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In Denmark his name is written "Ole Rømer". Seindal, Wednesday, April 3, 2002
My book explicitly says that he never calculated the speed of light and that the orbit of Earth and Jupiter was not known in his time. The article said differently. Lir 02:23 Nov 19, 2002 (UTC)
"Notable is also his definition of the new Danish mile. It was 24,000 Danish feet, which corresponds to 4 minutes of arc latitude, thus making navigation easier."
This is a conflation of the definitions of two different units of measure, the Danish land mile of 24,000 feet, and the geographical mile of four minutes of arc.
I'm pretty sure it hasn't always been mixed up this way in the article, so the first thing I'll do is check the history. Gene Nygaard ( talk) 01:19, 3 March 2008 (UTC)
I think those other materials re basing on Romer's strategy should be placed somewhere... This article is a biography on the person. -- Bentong Isles ( talk) 05:21, 11 November 2008 (UTC)
The paragraph below:
"Assume the Earth is in L, at the second quadrature with Jupiter (i.e. ALB is 90°), and Io emerges from D. After one orbit of Io, 42.5 hours, the Earth is in K. Rømer reasoned that if light is not propagated instantaneously, the additional time it takes to reach K, that he reckoned about 3½ minutes, would explain the observed delay."
contains a mistake. For the Earth to be 3.5 light-minutes more distant from Jupiter than it was at position L, it must move around the Sun for approximately 25 days; during this time, Io would make about 14.2 orbits of Jupiter. Not a single orbit, as the paragraph above states.
Sincerely, A Ph.D. Physicist —Preceding unsigned comment added by Tenorio40 ( talk • contribs) 01:43, 20 June 2009 (UTC)
I was hoping that someone would rewrite the entire light speed calculations part, since it is not very good, but I suppose correcting small errors is better than nothing. I shall make an attempt. DanielDemaret ( talk) 08:31, 20 June 2009 (UTC)
I made that small change. However, I think that the explanation right now still contains several irrelevant notions that should be left out, and that some more relevant details should be put in. An example of a better explanation is here: http://www.is.wayne.edu/mnissani/a&s/light.htm. If n-oone protests, no-one changes this and I feel like it sometime I shall then rewrite that small paragraph. If I feel like it. DanielDemaret ( talk) 08:47, 20 June 2009 (UTC) Since there are many different kinds of "minutes" and the articele does not specify nor make it clear which kind, it is confusing. DanielDemaret ( talk) 08:54, 20 June 2009 (UTC)
Daniel - Since your improvement of June 20, 2009 it is much better. But I agree with you, the entire light-speed calculation section could be improved further. If you don't mind doing it, please do, since the Romer measurement was very interesting and important in the history of science. This does not matter now, but in the original mistaken paragraph (with only one orbit of IO around Jupiter), the Earth would have only moved away from L by 15 light-seconds after 42.5 hours, which is 14 times less than 3.5 light-minutes. But, as I mentioned, this is now irrelevant. I encourage you to rewrite the paragraph. Thanks in advance. Richard. —Preceding
unsigned comment added by
Tenorio40 (
talk •
contribs)
18:30, 22 June 2009 (UTC)
One might add, near the end of the section, that the speed of light is nowadays defined as precisely 299,792,458 metres per second, which (the second being already well-defined) defines the length of the metre. Wikipedia will have the details. Date around 1975, I think. 94.30.84.71 ( talk) 22:28, 18 June 2022 (UTC)
In the section on the speed of light the articles says:
Then in the next paragraph it says:
What did Huygens misinterpret, the value of 22 minutes or what it means?
The article mentions that "Rømer joined the observatory of Uraniborg on the island of Hven, near Copenhagen, in 1671"; however, the article on Uraniborg mentions that "The institution was destroyed in 1601 after Tycho's death" and later "both Uraniborg and Stjerneborg were destroyed shortly after Tycho's death," without any mention of the observatory being rebuilt at any point until recently ("Uraniborg's grounds are currently being restored," which doesn't specify the date, but obviously in the 20th or 21st century).
Does anyone have any explanation for this apparent anachronism?
Thanks in advance.
CielProfond ( talk) 03:10, 19 February 2017 (UTC)
Den Store Danske Encyklopædi tells the story of Ole Rømer as follows: He worked on Tycho Brahe’s manuscript at Copenhagen University when Jean Picard came to Denmark to measure the precise location of “Uraniborg Plads” (Uraniborg square), so probably where Uraniborg used to stand. Also the Encyclopædie Britannica states similarly that Picard was interested in Uraniborg’s precise location to compare Tycho Brahe’s measurements with those made elsewhere. Donik ( talk) 07:56, 26 September 2018 (UTC)
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In Denmark his name is written "Ole Rømer". Seindal, Wednesday, April 3, 2002
My book explicitly says that he never calculated the speed of light and that the orbit of Earth and Jupiter was not known in his time. The article said differently. Lir 02:23 Nov 19, 2002 (UTC)
"Notable is also his definition of the new Danish mile. It was 24,000 Danish feet, which corresponds to 4 minutes of arc latitude, thus making navigation easier."
This is a conflation of the definitions of two different units of measure, the Danish land mile of 24,000 feet, and the geographical mile of four minutes of arc.
I'm pretty sure it hasn't always been mixed up this way in the article, so the first thing I'll do is check the history. Gene Nygaard ( talk) 01:19, 3 March 2008 (UTC)
I think those other materials re basing on Romer's strategy should be placed somewhere... This article is a biography on the person. -- Bentong Isles ( talk) 05:21, 11 November 2008 (UTC)
The paragraph below:
"Assume the Earth is in L, at the second quadrature with Jupiter (i.e. ALB is 90°), and Io emerges from D. After one orbit of Io, 42.5 hours, the Earth is in K. Rømer reasoned that if light is not propagated instantaneously, the additional time it takes to reach K, that he reckoned about 3½ minutes, would explain the observed delay."
contains a mistake. For the Earth to be 3.5 light-minutes more distant from Jupiter than it was at position L, it must move around the Sun for approximately 25 days; during this time, Io would make about 14.2 orbits of Jupiter. Not a single orbit, as the paragraph above states.
Sincerely, A Ph.D. Physicist —Preceding unsigned comment added by Tenorio40 ( talk • contribs) 01:43, 20 June 2009 (UTC)
I was hoping that someone would rewrite the entire light speed calculations part, since it is not very good, but I suppose correcting small errors is better than nothing. I shall make an attempt. DanielDemaret ( talk) 08:31, 20 June 2009 (UTC)
I made that small change. However, I think that the explanation right now still contains several irrelevant notions that should be left out, and that some more relevant details should be put in. An example of a better explanation is here: http://www.is.wayne.edu/mnissani/a&s/light.htm. If n-oone protests, no-one changes this and I feel like it sometime I shall then rewrite that small paragraph. If I feel like it. DanielDemaret ( talk) 08:47, 20 June 2009 (UTC) Since there are many different kinds of "minutes" and the articele does not specify nor make it clear which kind, it is confusing. DanielDemaret ( talk) 08:54, 20 June 2009 (UTC)
Daniel - Since your improvement of June 20, 2009 it is much better. But I agree with you, the entire light-speed calculation section could be improved further. If you don't mind doing it, please do, since the Romer measurement was very interesting and important in the history of science. This does not matter now, but in the original mistaken paragraph (with only one orbit of IO around Jupiter), the Earth would have only moved away from L by 15 light-seconds after 42.5 hours, which is 14 times less than 3.5 light-minutes. But, as I mentioned, this is now irrelevant. I encourage you to rewrite the paragraph. Thanks in advance. Richard. —Preceding
unsigned comment added by
Tenorio40 (
talk •
contribs)
18:30, 22 June 2009 (UTC)
One might add, near the end of the section, that the speed of light is nowadays defined as precisely 299,792,458 metres per second, which (the second being already well-defined) defines the length of the metre. Wikipedia will have the details. Date around 1975, I think. 94.30.84.71 ( talk) 22:28, 18 June 2022 (UTC)
In the section on the speed of light the articles says:
Then in the next paragraph it says:
What did Huygens misinterpret, the value of 22 minutes or what it means?
The article mentions that "Rømer joined the observatory of Uraniborg on the island of Hven, near Copenhagen, in 1671"; however, the article on Uraniborg mentions that "The institution was destroyed in 1601 after Tycho's death" and later "both Uraniborg and Stjerneborg were destroyed shortly after Tycho's death," without any mention of the observatory being rebuilt at any point until recently ("Uraniborg's grounds are currently being restored," which doesn't specify the date, but obviously in the 20th or 21st century).
Does anyone have any explanation for this apparent anachronism?
Thanks in advance.
CielProfond ( talk) 03:10, 19 February 2017 (UTC)
Den Store Danske Encyklopædi tells the story of Ole Rømer as follows: He worked on Tycho Brahe’s manuscript at Copenhagen University when Jean Picard came to Denmark to measure the precise location of “Uraniborg Plads” (Uraniborg square), so probably where Uraniborg used to stand. Also the Encyclopædie Britannica states similarly that Picard was interested in Uraniborg’s precise location to compare Tycho Brahe’s measurements with those made elsewhere. Donik ( talk) 07:56, 26 September 2018 (UTC)
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