Astronomy, Fallacies, & 2012 Doomsday Prediction
End of the World Hoaxes, Mayan Calendar, & Astronomical Urban Myths
Oct 27, 2009
Many recent books and the major Hollywood movie, 2012, purvey alleged Mayan predictions that the world will end on the 2012 winter solstice, December 21, 2012. These claims intertwine the Mayan calendar with some rather dubious astronomy.
Mayan Calendar
Doomsday predictions based on the Mayan calendar are not being made by present day Mayans. Are the people writing 2012 end of the world scenarios based on the Mayan calendar actually knowledgeable about Mayan culture?
Like the modern calendar, the Mayan calendar contains cycles of various lengths. On December 12, 2012 multiple Mayan cycles end and restart at the same time. The most recent analogy in the modern calendar was midnight December 31, 1999, when the day, year, decade, century, and millennium cycles ended and started over on January 1, 2000. Astute readers will recall that despite all the fuss the world didn't end then either.
December 21, 2012 has no more significance in the Mayan calendar than midnight December 31, 1999 has in the modern calendar.
Astronomical Urban Myths about December 21, 2012
Doomsday predictions that the world will end on December 21, 2012 in many 2012 themed books and the movie 2012 are based on urban myths about astronomy.
Doomsday purveyors claim on the 2012 winter solstice the Earth, Sun, and center of the Milky Way galaxy will align, so the Sun eclipses the galactic center. Furthermore doomsday purveyors claim that tidal forces from this alignment will cause severe disruptive earthquakes to end the world. The same tidal forces acting on the Sun will trigger severe solar storms devastating Earth. The planets in the solar system will also allegedly align on December 21, 2012.
Sun Will Not Eclipse Galactic Center
Earth's rotational axis tilts about 23.5 degrees. The December winter solstice occurs when Earth is at the point in its orbit where the southern hemisphere most directly points towards the Sun. The Sun is then directly overhead as seen from Earth at 23.5 degrees south latitude, the Tropic of Capricorn. The Sun cannot appear further south in the sky.
To measure celestial positions, astronomers project latitude and longitude into the sky and call them declination and right ascension. The Sun's declination is about 23.5 degrees south on the winter solstice and cannot go further south.
Astronomers have identified the center of the Milky Way galaxy as the object Sgr A*. Astronomical catalogs list the declination of Sgr A* as very nearly 29 degrees south. Because the Sun cannot get this far south the Sun cannot align with the galactic center.
Tidal Forces from Galactic Center
Even if the Sun could align with the galactic center, the tidal effects would be completely negligible.
Tidal forces from astronomical objects depend on their mass and inversely on the cube of their distance. This dependence allows a simple order of magnitude estimation of the ratio of the tidal force from the galactic center to that from the Sun.
For an estimate, it suffices to use 8 light minutes (about 500 light seconds) as the distance to the Sun and about 30,000 light years (9E11 light seconds) as the distance to the galactic center. Assuming that the galactic mass (about 100 billion times the Sun's mass) is concentrated at the galactic center, overestimates the tidal force from the galactic center and simplifies the calculation.
Doing the math, the tidal force from the galactic center is about 2E17 (200000000000000000) times weaker than the tidal force from the Sun.
Such a weak tidal force will have no detectable effect whatsoever on either the Earth or Sun!
Aligned Planets
Doomsday scenarios also claim that the planets will align and their tidal forces will cause destructive earthquakes. A book called The Jupiter Effect made similar claims in the 1970s. There were no problems then either.
Computing planetary positions on December 21, 2012 with a good planetarium or ephemeris program, shows that the planets will have different positions. They will not align. If they did, the tidal forces from the planets are more than from the galactic center, but still much less than from the Sun and Moon.
Will the world end December 21, 2012? No!
Many people make considerable money spreading panic by preying on those who lack scientific knowledge. Learn about real science; keep your money.
Further Reading
Krupp, EC. "The Great 2012 Scare" Sky and Telescope, November, 2009.
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