The Solar System

CHAPTER 3 | CYCLES OF THE MOON 37

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Solar Eclipses

For millennia, cultures worldwide have understood that the

sun is the source of life, so you can imagine the panic people felt

at the fearsome sight of the sun gradually disappearing in the

middle of the day. Many imagined that the sun was being

devoured by a monster (■ Figure 3-5). Modern scientists must

3-3

■ Figure 3-5

(a) A 12th-century Mayan symbol believed to represent a solar eclipse. The

black-and-white sun symbol hangs from a rectangular sky symbol, and a

voracious serpent approaches from below. (b) The Chinese representation of

a solar eclipse shows a monster usually described as a dragon fl ying in front

of the sun. (From the collection of Yerkes Observatory) (c) This wall carving from

the ruins of a temple in Vijayanagaara in southern India symbolizes a solar

eclipse as two snakes approach the disk of the sun. (T. Scott Smith)

SCIENTIFIC ARGUMENT

What would a total lunar eclipse look like if Earth had no

atmosphere?

As a way to test and improve their understanding, scientists often

experiment with their ideas by changing one thing and trying to

imagine what would happen. In this case, the absence of an atmo-

sphere around Earth would mean that no sunlight would be bent

toward the eclipsed moon, and it would not glow red. It would be

very dark in the sky during totality.

Now change a different parameter. What would a lunar eclipse

look like if the moon and Earth were the same diameter?

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■ Table 3-1 ❙ Total and Partial Eclipses of

the Moon, 2010 to 2017*

Time** of Length of Length

Mid-eclipse Totality of Eclipse†

Year (GMT) (Hr: Min) (Hr: Min)

2010 June 26 11:40 Partial 2:42

2010 Dec. 21 8:18 1:12 3:28

2011 June 15 20:13 1:40 3:38

2011 Dec. 10 14:33 0:50 3:32

2012 June 4 11:03 Partial 2:08

2013 April 25 20:10 Partial 0:28

2014 April 15 7:48 1:18 3:34

2014 Oct. 8 10:55 0:58 3:18

2015 April 4 12:02 Partial 3:28

2015 Sept. 28 2:48 72 3:30

2017 Aug. 7 18:22 Partial 1:54

*There are no total or partial lunar eclipses during 2016.

**Times are Greenwich Mean Time. Subtract 5 hours for Eastern Standard Time,

6 hours for Central Standard Time, 7 hours for Mountain Standard Time, and 8 hours

for Pacifi c Standard Time. From your time zone, lunar eclipses that occur between

sunset and sunrise will be visible, and those at midnight will be best placed.

†Does not include penumbral phase.

remains in the penumbra receives some direct sunlight, and the
glare is usually great enough to prevent your seeing the faint cop-
pery glow of the part of the moon in the umbra. Partial eclipses are
interesting, but they are not as beautiful as a total lunar eclipse.
If the orbit of the moon
carries it far enough north or
south of the umbra, the
moon may pass through only
the penumbra and never
reach the umbra. Such pen-
umbral lunar eclipses are
not dramatic at all. In the
partial shadow of the pen-
umbra, the moon is only par-
tially dimmed. Most people
glancing at a penumbral
eclipse would not notice any
diff erence from a full moon.
Total, partial, or pen-
umbral, lunar eclipses are
interesting events in the
night sky and are not diffi -
cult to observe. When the
full moon passes through
Earth’s shadow, the eclipse
is visible from anywhere on
Earth’s dark side. Consult
■ Table 3-1 to fi nd the next
lunar eclipse visible in your
part of the world.