当史前人类望向天空并懂得时间概念时,人类就开始向着文明进发。古代人可以研究周期有很多,比如每一天从日初开始到。Not sure what the issue that I am told she. I should hire you convert to in order to keep your head down to see.The nice thing about the moon, is it changes every day. It moves in its position and it changes its appearance. It's bright. It's fairly large in the Scott you can't miss it.Which were quite happy for you to be on your shoe?他细长像把银色镰刀,而有时他像个明亮盘子,我们都知道月亮样貌会变化,但这是为什?So why does the moon go through phases every month? Well, the answer has everything to do with the position of the moon as it orbits the earth illuminated by the sun.So here we see the moon. Located between the earth and the sun and it's the backside of the moon. That's illuminated by the sun. So the side you see at the Earth is dark, we call this phase a new moon. But as the moon orbits the earth the side. That's illuminated comes into your view the little sliver of light that you can see. Now gives this moon a Crescent phase. And then as the moon orbits the Earth, a little bit farther now. The hemisphere that's illuminated is half seen by you at the Earth. We call this a quarter moon. And then finally as the moon orbits the earth yet farther now. You can see the fully illuminated hemisphere of the moon and of course, we called?现在日历会告诉我们新月份开始时间。
但是月份这个词来自月亮周期。To complete a cycle around the Sky is about 27 days that if you look at it is close to 28, which is the number 7 multiplied by 4, so the lunar cycle actually gives rise to what we would call a month. Of 4 weeks of 7 days. This is a really obvious kind of pattern. We could draw out of the Sky.You have something that allows you to count days. One after another and bundle them in sets. That's actually the very core of time keeping.。