I’ve read that a lunar eclipse is what makes the moon appear red in the sky, because only light of certain wave lengths passing through our atmosphere. Would it also be red when viewed not from earth? It would still be the same light reaching it but bouncing back to our eyes not through the atmosphere. I’m not sure I’ve fully understood, I’d very much appreciate a science lesson. Thanks
In: 24
Broadly, yes. Think about it. A lunar eclipse is the Earth’s shadow blocking the direct path of light from the Sun to the Moon. Yet we, on Earth, see red light coming from it. So what’s that light?
We know that the Moon doesn’t visibly glow in its own right, and starlight is way too weak to illuminate it. That leaves sunlight. How? The short answer is, it’s light that got bent by the Earth’s atmosphere. But the atmosphere bends different colours to different degrees – and most of the light that actually gets to the Moon is red ([nice NASA diagram here](https://www.hindustantimes.com/science/nasa-explains-why-the-moon-turns-red-during-a-lunar-eclipse-watch-101667616724643.html)).
So, basically, during a lunar eclipse, the Moon is still being lit by sunlight, and that light is predominantly red. Which means that, if you’re in a position to see a significant amount of that light after it’s reflected off the Moon, a red tinge is what you can expect to see – whether you’re on Earth or in space.
(In space, if that diagram is reasonably accurate, you’ll potentially start seeing more yellow light as well if you’re further away from the centre line to the Earth’s shadow, because the parts of the Moon’s surface directly facing you are increasingly being illuminated by light of other wavelengths. So the precise colour will vary according to where you are. But it’s still going to be dominated by light from the red end of the spectrum.)
Latest Answers