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Hi, im quite confused about 'earthshine'. On the contrary, i agree with quantumgravity that
Earthshine is the reflection and not the refraction of the sunlight
, and i read that earthshine is only visible not during eclipses. After all, it is most clearly seen in a crescent moon, where the outline of the whole moon can be seen. However, weixing says otherwise.
Hi,
On my second message, I state what cause the red moon during total lunar eclipse. It is different from earthshine... sorry about the confusion... :oops: I was also a little bit confuse.
Below is taken from a website about earthshine: Earthshine occurs due to a double reflection of sunlight. Light from the Sun is reflected off of the Earth onto the Moon. Some of this light is then reflected off of the Moon back towards the Earth. Because of this we see part of the Moon illuminated by the Sun and the rest of the Moon dimly illuminated by this doubly reflected light (which we call earthshine). Each time light reflects off a surface (like a planet), it gets dimmer because some of the light is absorbed by the reflecting surface. This means that earthshine is dimmer than moonlight because earthshine is sunlight that has been reflected twice and moonlight is sunlight that has been reflected only once (off the surface of the moon). In addition, the reflectivity of the moon (its "albedo") is less than that of the Earth, which makes earthshine even dimmer.
The moonlight of a full moon, for example, is so bright that, even if it were positioned correctly to reflect light back toward Earth, it would completely overpower earthshine. In fact, we only see earthshine during the cresent phases of the Moon because during these phases:
1) only a small part of the Moon is lit up, and moonlight doesn't outshine earthshine, and
2) the moon is in the right position to reflect light back to the Earth.
Another question: Does earthshine occur during a non-total lunar eclipse??
I think may be partially. Anyone want to comments on this??
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
I don't think earthshine would occur during a partial lunar eclipse, as the moon is still behind earth and the earthshine might not reach the moon once again. However, I'm not too sure either...
Leaves me with one question. As the moon wanes, we see the crescent getting smaller and the "earthshine" portion getting bigger. Then it is logical to assume that during the new moon, the crescent can no longer be seen and the whole moon is now covered in earth shine as seen from earth. Does this mean if we look carefully, we can see a black earth-shined disk moving across the sky ?
The Boldly Go Where No Meade Has Gone Before Captain, RSS Enterprise NCC1701R United Federation of the Planets
Does this mean if we look carefully, we can see a black earth-shined disk moving across the sky ?
You mean the moon is not there?? Of course not lah!! If the moon is not there, the light reflected by earth have nothing to reflect back for us to see.
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
Does this mean if we look carefully, we can see a black earth-shined disk moving across the sky ?
You mean the moon is not there?? Of course not lah!! If the moon is not there, the light reflected by earth have nothing to reflect back for us to see.
Have a nice day.
hi weixing
since the moon don't just disappear...I suspect its still there but now the sunlight is directly behind, so we only see the earthshine on the "Dark" moon...is that right?
rich
The Boldly Go Where No Meade Has Gone Before Captain, RSS Enterprise NCC1701R United Federation of the Planets
Hi,
Sorry.. didn't see the words "new moon", so didn't understand your previous question. :oops:
During the new moon, the earthshine can be seen cover the whole moon, but this last only minutes (not sure exactly how long, but I think very short) before sun rise. Once the sun is up, it will be too bright for us to see the earthshine or the moon.
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance." 
