Talk:Tropic of Cancer

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Google Earth draws the line at 23 degrees 27 minutes. On Mexican Federal Highway 1 there's a monument marking the location of the Tropic of Cancer.

The Encyclopedia of Astronomy and Astrophysics gives a value of 23 degrees 26 minutes 21 seconds ... but also notes that the real value is plus or minus 9 arcseconds.


The tropic of cancer is currently moving south at a speed of 14.8 meters per year, at least according to [1].

Does anyone know what year it will turn around and start heading north again?

see Axial tilt --Tauʻolunga 05:59, 4 June 2006 (UTC)

It would also be nice to know when it turned around and started heading south. -- ProveIt (talk) 15:05, 3 March 2006 (UTC)

Here [2] it is thought to be 14.4 meters / year.
see also Milutin Milanković & Milankovitch cycles

It appears that nutation has an effect - - but the general trend would be south due to the long term change in the earth's axial tilt - I think it might go slightly retrograde (north) every 9 years due to the wobble of nutation.

northern solstice[edit]

This solstice entered Taurus from Gemini in December 1989 see ecliptic --Tauʻolunga 02:36, 2 June 2006 (UTC)


The countries commonly referred to as "China" and "Taiwan" are described in the articles People's Republic of China and Republic of China, respectively. China talks about the civilization and culture of both countries, and Taiwan talks just about the island (and not the other territories of the country). I believe the links to the countries are most appropriate for the list.

Puerto Rico and U.S. Virgin Islands[edit]

I removed the reference to Puerto Rico and the U.S. Virgin Islands. The Tropic of Cancer does not pass through their territories. Indeed, it passes through the Bahamas, which are a good 500 miles north of P.R. Not home 14:48, 12 August 2007 (UTC)

Political Correctness[edit]

I'm not even going to bother logging in. As a rule, I don't contribute all too frequently. And I wont take it upon myself to make changes now.I just question whether it is appropriate to give Myanmar recognition or if if would be more appropriate to list it as Burma. Just a thought. (talk) 13:07, 28 May 2008 (UTC)kevinpedia

Not sure what that's got to do with political correctness, but we should probably give both names. Bazonka (talk) 16:11, 28 May 2008 (UTC)

Location and Geodesic Datum[edit]

The article says that the tropic is 23° 26′ 22″ north of the Equator, but should not the location be different according to the reference Elipsoid?-- (talk) 02:03, 28 February 2009 (UTC)

Why is it called the "Tropic of Cancer?"[edit]

I'm curious as to where the names Tropic of Cancer and Tropic of Capricorn came from. I am aware that the ecliptic, or path of the Sun often deviates north and south of the Celestial Equator. But as far as I can tell, the northern- and southern-most lattitudes of the Sun don't occur when the Sun is in either the house of Cancer or Capricorn, respectively. Were the tropics named so far in the distant past that precession has rendered their names meaningless, or is there some other factor that I'm missing? Pine (talk) 22:08, 21 October 2009 (UTC)

"Were the tropics named so far in the distant past that precession has rendered their names meaningless?"

Indeed, that's exactly what has happened.
"The Tropic of Cancer is so named because about 2,000 years ago the sun was entering the constellation Cancer at the June solstice. In modern times the sun appears in the constellation Gemini during this time. The change is due to precession of the equinoxes. The word "tropic" itself comes from the Greek tropos, meaning turn, referring to the fact that the sun appears to "turn back" at the solstices."
Rephrased from Tropic of Capricorn
Hope this help.
As far as I know, the Greek word tropos does not mean turn. The correct word must be tropi.
-- Greek commentator

  Set Sail For The Seven Seas  340° 25' 30" NET   22:41, 21 October 2009 (UTC)

Inaccurate reference to the 1st day of summer[edit]

The phrase "the sun is directly overhead the Tropic of Cancer on the first day of summer in the Northern Hemisphere" is inaccurate because summer does not always start on the solstice - it varies by culture/jurisdiction. I plan to remove this reference and rewrite / rearrange the lead section unless anyone objects. Wally1972b (talk) 06:26, 2 March 2010 (UTC)

Sounds OK as long as we're clear about astronomical summer vs. cultural seasons. I though by definition the farthest extent of the sun is at the solstice and is at the tropic lines -- in other words that both summer and the tropic of Cancer and Capricorn are defined by the sun being at a particular highest point because of the earth's orbit and tilt. DavidH (talk) 16:51, 8 August 2010 (UTC)


File:tropic-cancer-slp-mexico.JPG used to be on this page. It was removed by user: on 14 May 2010. Granted it is not a very pretty monument, but is this a sufficient reason to remove the photo? There are not many other monuments to choose from. --Lasunncty (talk) 11:41, 26 May 2010 (UTC)

other languages[edit]

There's something broken with linking. On the English site "Tropic of Cancer" there is no Polish language to choose. And Polish "Zwrotnik raka" does not have an English link. What is interesting you can click on the German version and then you can get to the Polish site, but only in this direction. —Preceding unsigned comment added by (talk) 21:45, 5 August 2010 (UTC)

Fixed - By the way, it wasn't broken, there was just no interwiki link there yet. The relevant interwiki link has now been added. Thanks. Set Sail For The Seven Seas 344° 32' 29" NET 22:58, 5 August 2010 (UTC)

Tropic of Cancer also passes through Vietnam[edit]

Tropic of Cancer also passes through Vietnam, in the very north, around the city of Lao Cai (which is at the Chinese border). I leave it to others to add this information to the scheme in the article in the right format. Rbakels (talk) 07:57, 4 January 2011 (UTC)

Incorrect - the most northerly point of Vietnam is at about 23°23'N, which is approximately 7km south of the Tropic of Cancer. I have mentioned this in the article though. Bazonka (talk) 12:10, 4 January 2011

"annual drift"?[edit]

One of the images on this rev is captioned "this is the only place where the latitude is marked with absolute precision and where the annual drift between 2005 and 2010 can be appreciated." What is an "annual drift"? It is not defined in the article nor can I easily find this out in the Google Test. Valley2city 17:38, 16 February 2012 (UTC)

This is not a technical term; it just means the amount the tropic moves every year. The article does mention this motion and gives a link to more information in another article. --Lasunncty (talk) 07:39, 20 February 2012 (UTC)

Coordinate error[edit]


The following coordinate fixes are needed for

geo:23.433333,52.133333 When opened in Google Maps the drop pin is on the Saudi Arabia side if the border with the UAE. It is supposed to show the Tropic of Cancer in the UAE, not in KSA. (talk) 17:19, 10 October 2014 (UTC)

I have amended it. Bazonka (talk) 19:42, 10 October 2014 (UTC)

Regarding constant date changes[edit]

I see some people keep constantly posting the actual date into the article. It is right the angle does change constantly but the sun is only once a year in actual zenit over the tropic and changes are so minimal that with each day that it does not make sense to write 15th of January it was here, 16th of January there. If somebody is willing to write down the mili-second degree it changes everyday than fine by me but its has to be updated everyday but if you leave the coordinates that I looked out for the 21st of June when the Sun is in actual Zenit over the Tropic and write next to it 1st of February than it's simply wrong. So please stop changing the article all the time or calculate the position of the tropic everyday if you have ample time! I took myself the time to calculate when summer solstice is occurring and where the tropic lies at that specific moment, so if a person wanted to see the sun in Zenit in a given year the coordinates are very accurate. I hope this way you finally understand my reasoning!

Please see my talk page. I responded to you there. --Lasunncty (talk) 10:45, 3 February 2015 (UTC)

External links modified[edit]

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Bot edit seems good. But now I question if that source really is useful enough to have on this page. It seems to be mentioned as a reference for either the rate of change or the 1917 value, but neither of those figures are in the source. --Lasunncty (talk) 08:42, 29 August 2015 (UTC)