click on image for a larger version
(18 kB jpeg image)
Photo is courtesy of Tom Sever.
El Caracol at Chichén Itzá is another example of Maya
ingenuity, which resembles a modern day observatory. Windows,
located at various heights and
positions, were very probably used to sight the Sun...as well as the planet Venus.
Indeed, four alignments in the building point to eight year extremes of the planet
Venus. The purposeful construction of this structure resulted from observations of
the sky over many, many years. Just as scientists today build upon work done in
prior years, so did the Mayan astronomers of Chichén Itzá.
To learn about solar folklore, visit this
Some 600 years after the heyday of the Mayan people at Chichén
Itzá, Galileo Galilei, an Italian scientist, pointed a telescope toward the Sun.
NEVER, NEVER LOOK AT THE SUN WITHOUT THE USE OF SPECIALIZED FILTERS. VIEWING THE SUN THROUGH A TELESCOPE CAN PERMANENTLY DAMAGE YOUR EYES!!
Around the time period 1609-1611 C.E., Galileo discovered spots on
the surface of the Sun. At that time, learned individuals in Europe believed that everything in the sky was perfect; therefore, the Sun could not possibly have "blemishes" such as those
Galileo claimed he saw. A debate raged in which some asserted that the spots were planets in orbit about the Sun. Galileo however, continued to
assert that the spots were actually a part of the Sun and even used them to
calculate the Sun's rotation rate. So, as a result of observations with
the telescope, Galileo guided the world toward a philosophical change in the way we think about the universe. Instead of believing
the Sun to be perfect, scientists began to use optical instruments to probe the nature of this heavenly body. Further, with the discoveries of Galileo,
scientists began to use mathematics as a tool to predict the positions of the
Sun instead of naked eye observations and architecture.
For more information about Galileo and some sunspot
activities, visit this site:
Modern astronomy allows us to
study the different layers of the Sun's atmosphere. The image to the right, shows
the photospheric layer of the solar atmosphere, the layer that Galileo would have seen,
with sunspots. The appearance of sunspots on the solar disk is cyclic, with an
eleven year period. At the beginning of a cycle, at minimum when there are few
sunspots, the polarity1 of spots of the new cycle will be
reversed with respect to those of the previous cycle. That is, if the positive
polarity of the previous cycle leads2 in a sunspot group, the
negative polarity will lead in the current cycle. Another change of the cycle is the
position of the sunspots north or south of the Sun's equator. Early in the
cycle, the spots appear in the middle latitudes and move toward the equator during the
click on image for a larger version
(15 kB jpeg image)
To learn more about the sunspot cycle, go to this site:
1 polarity -- Sunspots are like dipole
magnets, they have a north and south pole, or a positive and
negative pole. The polarity of the sunspot refers to either the positive or negative pole.
2 leading/following spots -- The leading spot
in a sunspot group will be the one which is closest to the western edge (or the right side of this image), of the Sun. The following spot will be closest to the eastern edge, or limb, of the Sun.
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This work was paid for
by the NASA IDEAS program.
Please direct comments, questions, and suggestions to:
mitzi dot adams @ msfc dot nasa dot gov
April 23, 2014