EI Knows… Astronomy


Around the Moon in 28 Days – A Parent’s Guide to Lunar Phases

If it happens to be clear where you are tonight, take a look up at the night sky and you’ll see… nothing! Wait a minute? Where’d the moon go?

Not to worry… it’ll be back. In exactly 29.53 days. Yes, tonight starts the first phase of the new lunar cycle. Lunar cycle, you ask, with cartoon question marks in your eyes? Again, not to worry. We’re here with a quick refresher on exactly what’s happening out there… in space.

Remember that as the Earth makes its annual trip around the sun, the moon is also circling the Earth. Now the moon doesn’t actually put off any light of its own. It only reflects sunlight. So, while the entire moon is always there, we can only see the part of the moon that is facing the sun at any certain time. For example, at certain times of each month we can see the entire lit up side of the moon. That’s what we call a full moon. Other times, like tonight, we can’t see any of it. That’s called a new moon. Here’s a bit more about each of the eight phases of the moon and what you’ll see (or not see) in each:

New Moon – The beginning of the lunar cycle is the new moon. This phase occurs when the moon is directly between the Earth and the sun. The moon is basically blocking any light that would illuminate it, so we can’t see it. (But we swear it’s still there.)

Waxing Crescent – The next lunar phase, waxing crescent, occurs when less than one quarter of the moon is being lit by the sun, but illumination is increasing. This phase looks like a crescent roll 😊

First Quarter – When the moon looks like it’s been cut in half vertically, that’s the first quarter moon. The sun is shining on exactly one quarter of the moon.

Waxing Gibbous – Almost there! Waxing gibbous occurs when the moon is almost completely illuminated by the sun, but not quite.

Full Moon – When the sun shines fully on one side of the moon, lighting the entire side up, we’ve got a full moon.

Waning Gibbous – Just like a waxing gibbous, a waning gibbous is the name for an almost entirely lit moon – but this time the bit that’s not lit is on the other side.

Third Quarter – The third quarter lunar phase occurs when one full half of the moon is lit – the opposite half than what you saw in the first quarter.

Waning Crescent – Ditto the waxing crescent, but this time the crescent roll is on the other side of the plate.

After the waning crescent phase, the moon turns away from the shining sun to create another new moon, and the cycle begins again. And again. And again! Spending a few minutes scoping out the phases of the moon is a really easy way to start your kiddos down the path to science. If you don’t have a scope stashed away, EI’s got a full range of affordable telescopes to choose from – check them out today!

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