redmoon alert 30/8/04 8:02

MooEy · Post by **MooEy** » Mon Aug 30, 2004 8:02 pm

quick quick go see the big big redmoon

~MooEy~

carlogambino · Post by **carlogambino** » Tue Aug 31, 2004 3:34 pm

interesting...

Btw, im still not sure of the reason why it looks 'red'. Read from previous forum posts that this is due to earthshine, but I read that earthshine(reflection of the earth's albedo) causes us to be able to view the unlit part of the moon behind the terminator as a outline against the backdrop of the nightsky. (e.g in a crescent moon, the outline of the whole moon can be seen clearly in a scope or in an overexposed photograph).

As for the refraction of the red spectrum of visible light to the moon, I'm not sure how it occurs. I thought this only occurs during moon eclipses, when the light from the sun is refracted by the earth's atmosphere and red light is refracted onto the moon's surface.

As a result, I'm quite confused. Can anybody explain? Thanks.

MooEy · Post by **MooEy** » Tue Aug 31, 2004 8:42 pm

must be the ghost are angry, people didn't offer enuff paper money and incense.

~MooEy~

QuantumGravity · Post by **QuantumGravity** » Tue Aug 31, 2004 9:11 pm

Hi all,

Just a question. If earthshine is the the Earth's albedo, then during a lunar eclipse, how does the earthshine reach the moon. The moon would be behind the earth, hence i doubt any earthshine would be able to somehow reach there, as the earthshine comes from the "litted" side of earth.

Or is it that the moon appearing red in lunar eclipse due to the refraction of light through the earth atmosphere?

Thanks

MooEy · Post by **MooEy** » Tue Aug 31, 2004 9:14 pm

2nd night of the redmoon *continue burning paper money and incense*

~MooEy~

carlogambino · Post by **carlogambino** » Tue Aug 31, 2004 9:38 pm

hence i doubt any earthshine would be able to somehow reach there, as the earthshine comes from the "litted" side of earth.

Hi, I didnt mention that earthshine had anything to do with the lunar eclipses. During lunar eclipses, there is no earthshine at all.(obvious) What im talking about is during a total/annular eclipse of the moon, some of the light from the sun is refracted onto the surface of the moon through the earth's atmosphere, which is why it looks red during the eclipse. The Moon does not become invisible, though, because there is still residual sunlight that is deflected towards it by the Earth's atmosphere, most of which is light in the red part of the spectrum.

Think about it: if light is not refracted onto the moon, it would be totally in darkness, not looking red right?(picture attached)

What im puzzled about is abt the instances where the redmoon is visible even without the eclipse. Could it be dust scattering light in the air?

QuantumGravity · Post by **QuantumGravity** » Tue Aug 31, 2004 9:48 pm

Hi again,

Hmm... Sorry, I wasn't sure what i was reading. My bad.

Anyway, can someone take a picture of that red moon? I have a science fair competition these few days and reach home too late to catch the red moon.

Thanks

Post by **weixing** » Tue Aug 31, 2004 9:58 pm

Hi,

During lunar eclipses, there is no earthshine at all.

When near full lunar eclipses, you will be able to see earthshine. You will also be able to see earthshine during cresent phases.

What im talking about is during a total/annular eclipse of the moon, some of the light from the sun is refracted onto the surface of the moon through the earth's atmosphere, which is why it looks red during the eclipse.

The light from the sun is reflected to the moon by earth atmosphere... and this is call earthshine.

What im puzzled about is abt the instances where the redmoon is visible even without the eclipse. Could it be dust scattering light in the air?

Get the below from a website:
When light from an astronomical object passes through the Earth's atmosphere, it scatters off of particles in the latter. It turns out that these particles like to scatter blue light more than they do red light; so "bluer" photons (those with shorter wavelengths) tend to get scattered, and "redder" photons (those with longer wavelengths) pass through. So, astronomical objects look redder from Earth than they would from space, because the redder wavelengths from the objects penetrate the atmosphere better than the bluer ones. Incidentally, this is why the sky is blue: blue light from the Sun is scattered in all directions on its way to the Earth. You may have noticed that they always occur when the Sun or Moon is close to the horizon. If you think about it, sunlight or moonlight must travel through the maximum amount of atmosphere to get to your eyes when the Sun or Moon is on the horizon (remember that that atmosphere is a sphere around the Earth). So, you expect *more* blue light to be scattered from Sunlight or Moonlight when the Sun or Moon is on the horizon than when it is, say, overhead; this makes the object look redder. In other words, the Sun or Moon tends to look orange or red when it is rising or setting because that's the time when the light has to travel through the most atmosphere to get to you

Have a nice day.

QuantumGravity · Post by **QuantumGravity** » Tue Aug 31, 2004 11:05 pm

Hi wei xing,

I'm lazy to quote so let's just refer back to your post. Anyway, the red moon during the lunar eclipses can't be caused by earthshine. Earthshine is the reflection and not the refraction of the sunlight. If the moon is in earth's shadow, there is no possibility that the reflected light off the litted side can reach the moon.

Anyway, is the red moon lately observed at the horizon?

Post by **weixing** » Wed Sep 01, 2004 1:04 am

Hi,
I do a search on the web and below is what most website said:
Particles in the atmosphere cause the light rays coming from the sun to bounce around. Some are refracted, or bent. They get redirected through the atmosphere and out around behind Earth and onto the moon, which is blocked only from direct sunlight.
Thus, the moon is still visible in the sky. However, the refracted rays of sunlight doing the illuminating turn the moon a strange reddish. That’s because of all the bouncing around those rays had to go through on their way through the atmosphere. The more atmosphere that sunlight travels through, the more the blue and green parts of the spectrum are scattered.

Anyway, all the red moon I had observe occur when the moon is quite low.

Have a nice day.