There can be no doubt that solar and lunar eclipses are some of the most fascinating sights for the “naked” eye. (And I say “naked” under the assumption that you know never to look directly at the sun without approved protection!)
Unless it’s during totality. Then you can take those glasses off.
But what I mean is, solar and lunar eclipses don’t require telescopes or binoculars to be seen. You don’t need to use any special equipment. You just need your eyes, and in the case of a solar eclipse, some form of protection—like solar glasses.
You may have noticed that when a solar eclipse comes up—or even a lunar eclipse—it’s all the rage. Suddenly, the media is swamped with safety warnings and calendar countdowns to the big event.
The United States just about lost its mind over the solar eclipse of August 21, 2017. And I have a feeling the next total solar eclipse to pass over the US, in seven years, will be just as dramatic.
But you might also be wondering…how do we know when these incredible sights are going to happen?
We see them all the time. When we look up at the moon in the sky, we’re bound to notice that it looks just a little bit different from the last time we saw it. It changes from a slivery crescent to a full circle, and then wanes back to the crescent phase again.
The moon has behaved the same way in the sky for billions of years, ever since a Mars-sized space rock collided with the newborn Earth and the debris collected into our own personal satellite.
For that long, the moon has watched over us and captivated scientists and amateur skywatchers alike.
But what are the secrets behind its monthly changes?
You may have heard of a common pseudoscience—astrology. Astrology is a pseudoscience because it’s a set of beliefs that seem to be based on scientific ideas, but really, it fails to obey even the most basic rules of science.
The ecliptic, as astronomers call it, is the apparent path of the sun against the background of the stars in the sky.
It’s useful because it tells us how to find the planets in the sky. They can be hard to spot if you don’t know where to look, but they will always be somewhere along one imaginary line that arcs across the sky—the ecliptic.
This pattern never changes. The planets don’t follow the ecliptic exactly, but it’s useful for getting an idea of where they should be.
But why does it work—and what exactly does it mean, when it’s obvious we can’t see the sun among the stars of the night sky?