FirstLight Astronomy Club

33°29.6'N / 117°06.8'W / 1190 ft.

Season of the Eclipse

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During June, Planet Earth had a solar eclipse and a lunar eclipse. And now again, on July 1st, we'll get yet another solar eclipse. 

Usually this is the perfect time for an article about what we will see and when we will see it. But not for us in Southern California, not this time around. We are 0 for 3 in this last month's worth of eclipses. We have been shut out entirely. 

But instead of crying about it, let's look at why we even have this wave of eclipses in the first place, and why the next one won't be until the end of the year.

Most readers here already know that eclipses happen when the sun, moon, and Earth all line up. If the order is sun-Earth-moon, then the Earth gets to cast its enormous shadow all over the moon, and we get a lunar eclipse.

If the order is sun-moon-Earth, then our little buddy might manage to cast its tiny shadow on us, and block out the sun for some Earth residents. That would be a solar eclipse.

But the Moon goes around us every month. We should have these eclipse things all the time! Well, not really.

We are assuming that the three of us are on the same "plane." Here's what I mean.

Imagine a huge, round table with a sun planted firmly in the middle. Around the far edge of our table a tiny Earth travels in orbit around our centerpiece sun. Most of us see the Moon as being on that table, too, blissfully rolling around the Earth each month. 

If that were so then we would indeed get eclipses every time the Moon went between the Earth and sun, or travelled around to the far side.

But the moon's orbit is not on that table. It has its own orbital plane which takes it above the table for a couple weeks, then down below it. Not by much, but enough.

Because of that, the Moon often passes in front of the sun just too high or just too low to make a shadow on us. Or it passes on the other side just too high or low for us to make a shadow on it. 

Due to this orbital inclination, the moon is only "on the table" and aligned to be a part of our Shadow Game every six months. Not coincidentally, that is when we have a swarm of eclipses, and that is why astronomers refer to those times as "eclipse seasons." 

We are ending a season now. We will be eclipse-free until the moon lines up again in about six months, when the Earth is on the other side of our table. In fact, although we in Southern California will again miss the next solar eclipses, we will just squeak out a lunar eclipse in the wee hours of December 10th, six months from the one we just had. 

And if you miss that one, no worries, wait another 6 months or so. They'll keep coming.

June

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The calendar and the skies are and always have been intimately linked. Having said that, let's look at a couple sky-related events that take place in June.

Let's start off with a little etymology, and explain where the name June comes from.

The prevailing thought appears to be that the month is named in honor of the Roman goddess Juno, the goddess of marriage and fertility. That would certainly offer up a reason why June is such a popular month for weddings. 

June has imbedded in it, just past mid-month, the summer solstice. Most of us just know that day as the "longest day of the year" or the "first day of summer." But why? And why the term "solstice"?

Regular readers here know that the tilt of the earth with respect to the sun gives us all kinds of interesting phenomena, like our whole array of seasons, and huge temperate regions so more of us have a nice place to live. Both those are related to the changing, daily circuit of the sun across the sky. 

We are now tilted just about as far towards the sun as we comfortably can be, thus it is higher in the sky and out longer. It will reach its highest point this year on the 21st. It is then that the sun will travel no higher in the sky; it will stop and from that date on travel lower and lower across the sky. 

This "stopping of the sun" has a Latin word for it - solstice.

Even though the sun is highest in the sky around solstice and the daytimes are longest, the weather lags behind a wee bit and we won't feel the full effects of all this extra sunlight until the blistering months of July and August. 

One more bit of sky trivia for June. The sun is actually nestled in a constellation of the zodiac right now. We can't see the constellation because our daytime atmosphere bleaches out the rest of the universe for us. 

Right now the sun is in Taurus, slowly making its way over to Gemini. That's not what the horoscope formulators want you to think. They have the sun in Gemini for most of June, on its way to the constellation Cancer.

Now, to be sure, the sun was once in Gemini during June, but that was about 2500 years ago! Since then the earth has wobbled, or "precessed." The constellations have moved over a little, so the sun is no longer in Gemini at this time. That's just one reason why scientists regard astrology as a pseudo-science.

Have a great June! Until next time, clear skies!
Temecula Valley High School / Temecula, CA · Some images © Gemini Observatory/AURA Contact Me