If you’ve ever stood in the totality of a solar eclipse, you’ve seen something astonishing: the full width of the moon’s dark shadow blocking out the sun, perfectly encircled by the dim, wispy rays of the sun’s corona. And if you’ve also stood outside during a lunar eclipse, you might know that the effect is somewhat less dramatic. As Earth’s shadow falls on the moon, it quickly swallows the smaller orbiting rock. The effect of the moon glowing bloody red with Earth’s refracted twilight is beautiful, but the effect doesn’t fully convey the scale of the astronomical phenomenon at work in the same in-your-face way as happens during a solar eclipse. The moon, much smaller than Earth’s shadow, never shows the whole thing on its surface.

Signs. Portents. Omens. There’s something primal about the Moon. Even in this enlightened age, its glow can evoke a mystical experience. Little wonder so much mythology surrounds it.

A lunar eclipse is nothing unusual. Usually. But the one due on July 28 is somewhat different. It will fall under the Earth’s shadow for four hours.