The solar eclipse that will cross America this week has a narrow path and short duration. As a result, observers within the track will not get to see much of its beauty. But the eclipse will still be visible, and those who are able to see it should consider themselves lucky.
The eclipse path races from west to east because the Moon is in an elliptical orbit, which means that it has a very short distance to travel between the Earth and the Sun. This means that the shadow it casts has a very short duration, too. This is why a total solar eclipse only lasts for two hours, and it only occurs when the Moon passes directly in front of the Sun.
But the Moon is in a constant motion. When it is closest to the Earth, it forms its umbra, and people within the umbra can experience a partial eclipse in which only the center of the Sun is covered by the Moon. People outside the umbra, however, see a different kind of eclipse: one in which the entire Sun is obscured by the Moon, with only a ring of sunlight around its edges.
Until recently, eclipses were viewed with fear and suspicion. But as the ability to predict them spread, that fear slowly transformed into excitement and a willingness to experiment with eclipses in order to understand them better. This change in perspective can be traced to the work of scientists and philosophers like fifth-century B.C. Greek Anaxagoras, who sought to explain the Sun and the Moon through physics and astronomy rather than as omens or as the will of gods.