page_title: Tropic of Cancer
section_title: Drift
hierarchical_section_title: Tropic of Cancer / Drift
caption_attribution_description: Español: De todos los cruces del Trópico de Cáncer con las carreteras federales mexicanas, éste es el único lugar donde la línea está marcada con absoluta precisión y además se puede visualizar el desplazamiento anual entre los años 2005 y 2010. English: Of all crossings of the Tropic of Cancer with Mexican federal highways, this is the only place where the line is marked with precision and history of the annual movement since 2005. Publicada originalmente en Trópico en movimiento
context_page_description: The Tropic of Cancer, which is also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. This occurs on the June solstice, when the Northern Hemisphere is tilted toward the Sun to its maximum extent. It also reaches 90 degrees below the horizon at solar midnight on the December Solstice. Using a continuously updated formula, the circle is currently 23°26′11.8″ north of the Equator.
  Its Southern Hemisphere counterpart, marking the most southerly position at which the Sun can be directly overhead, is the Tropic of Capricorn. These tropics are two of the five major circles of latitude that mark maps of Earth, the others being the Arctic and Antarctic Circles and the Equator. The positions of these two circles of latitude are dictated by the tilt of Earth's axis of rotation relative to the plane of its orbit, and since the tilt changes, the location of these two circles also changes.
context_section_description: The Tropic of Cancer's position is not fixed, but constantly changes because of a slight wobble in the Earth's longitudinal alignment relative to the ecliptic, the plane in which the Earth orbits around the Sun. Earth's axial tilt varies over a 41,000-year period from 22.1 to 24.5 degrees, and as of 2000 is about 23.4 degrees, which will continue to remain valid for about a millennium.  This wobble means that the Tropic of Cancer is currently drifting southward at a rate of almost half an arcsecond (0.468″) of latitude,  or 15 metres, per year. The circle's position was at exactly 23° 27′N in 1917 and will be at 23° 26'N in 2045.  Distance between Antarctic Circle and Tropic of Cancer is essentially constant as they move in tandem.
  See axial tilt and circles of latitude for additional details.
caption: Carretera 83 (Vía Corta) Zaragoza-Victoria, km 27+800. Of all crossings of the Tropic of Cancer with Mexican federal highways, this is the only place where the latitude is marked with precision and where the annual drift between the years 2005 and 2010 can be appreciated.
exif: {"Image ImageDescription": "", "Image Make": "SONY", "Image Model": "DSC-H7", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2008:03:23 10:10:13", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "2300", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 51, 48, 48, 0, 0, 2, 0, 2, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0]", "Image Padding": "[]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "1/96", "Thumbnail YResolution": "1/96", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "13450", "Thumbnail JPEGInterchangeFormatLength": "3838", "EXIF ExposureTime": "1/500", "EXIF FNumber": "4", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "125", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2008:03:23 10:10:13", "EXIF DateTimeDigitized": "2008:03:23 10:10:13", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "23/8", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "252/5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3264", "EXIF ExifImageLength": "2448", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "13298", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF Padding": "[]", "EXIF OffsetSchema": "4128"}