Space · Living in space and watching the sky
The lunar eclipse
The Earth casting a shadow on the Moon
You can see it with your eyes
Finding it in the sky
When to look
It happens only when the Moon is full, and not every month. It comes a couple of times a year, and when it does the Moon stays in shadow for an hour or more, often in the middle of the night.
How to recognize it
You do not need to search for it: it is the usual full Moon, in the part of the sky where it would be anyway. You watch its face darken on one side, then turn red all over.
To get an idea
That red is the light of all the Earth's sunrises and sunsets put together.
A lunar eclipse can be seen from the whole half of the world that has the Moon above the horizon at that moment.
Fun facts
These are not in the book: there was no room on paper.
On the way out it goes through the same stages in reverse, passing through the penumbra again.
The total phase of a lunar eclipse can last up to one hundred minutes.
It is the most watched kind of lunar eclipse, exactly because of how long it lasts and its color.
You can watch it safely with the naked eye: no filter is needed and there is no risk at all.
When it happens it can be seen from the whole half of the world that has the Moon above the horizon.
The Moon crosses the cone of shadow at about twice the speed of the Earth's spin.
Test yourself
The first question is the one printed under the QR code, with the answer the book did not give. The other four only exist here.
Question 1 of 5★ is the one from your book
What happens in a lunar eclipse?
Question 2 of 5
In what phase can it happen?
Question 3 of 5
What color does the Moon turn?
Question 4 of 5
Where does that red come from?
Question 5 of 5
Do you need protection to watch it?
Riddles
To make me happen, three bodies have to line up, and I come only when your companion is fully lit. Then I turn her red without touching her. What am I?
The color you see during me does not come from the Moon: it comes from all the sunrises and all the sunsets of your planet, all together at the same moment. What am I?
You need no filter to watch me, no protection and no hurry: I can last more than a whole hour, and you can follow me comfortably with your own eyes from start to finish. What am I?
Try it yourself
Photograph it with a phone resting on something steady: the red Moon is bright enough to work even without special gear.
With a lamp, a big ball and a small ball you can recreate it all on the table: the big ball in the middle casts a shadow on the small one.
The words
- refraction
- The bending of light as it passes from one material into another.
Sources: Wikidata (Q45922), Wikipedia (Eclissi lunare).