The Sun in Time

Slide Show, Page 4
sun_in_time_ssm.jpg (10439 bytes)
caracol_ss.jpg (6053 bytes) 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 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 site:

Some 600 years after the heyday of the Mayan people at Chichén Itzá, Galileo Galilei, an Italian scientist,  pointed a telescope toward the Sun.
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 cycle. sunspot0_s.jpg (4862 bytes) 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.

Press Here for the Next Page

Press Here for the Previous Page

To return to Slide Show Index, click here.

To return to the Sun in Time home page, click here.

This work was paid for by the NASA IDEAS program.

Please direct comments, questions, and suggestions to:
Mitzi Adams
mitzi dot adams @ msfc dot nasa dot gov
(256) 961-7626
Last Updated: April 23, 2014