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from the still-waiting-for-the-hyper-ultra-mega-turbo-moon dept.
According to a report at phys.org, The moon is about to do something it hasn't done in more than 150 years:
Three separate celestial events will occur simultaneously that night, resulting in what some are calling a super blue blood moon eclipse. The astronomical rarity hasn't happened for more than 150 years.
A super moon, like the one visible on New Year's Day, is the term for when a full moon is closest to the Earth in its orbit, appearing bigger and brighter than normal.
On Jan. 31, the moon will be full for the second time in a month, a rare occasion—it happens once every two and a half years—known as a blue moon.
To top it off, there will also be a total lunar eclipse. But unlike last year's solar eclipse, this sky-watching event isn't going to be as visible in the continental United States. The best views of the middle-of-the-night eclipse will be in central and eastern Asia, Indonesia, New Zealand and Australia, although Alaska and Hawaii will get a glimpse, too.
For the rest of the U.S., the eclipse will come too close to when the moon sets for the phenomenon to be visible.
Because of the way the light filters through the atmosphere during an eclipse, blue light is bounced away from the moon, while red light is reflected. The eclipsed moon's reddish color earned it the nickname blood moon.
Super blue blood moon?
So, an extremely noble or socially prominent moon? ;)
I wonder what differences, if any, there would be in the appearance of the Earth from a person standing on the moon, compared to a "normal" full moon?
(Score: 5, Insightful) by maxwell demon on Friday January 05 2018, @07:25PM (5 children)
Super: When the Moon is closer to the Earth, the Earth is closer to the Moon. So the person on the moon would see a lightly larger Earth than otherwise (a Super Earth?)
Blue: That's just a calendar thing; a Blue Moon looks exactly like any other full moon. And the blue Earth will not look different from any other "New Earth" (Earth showing its dark side to the moon) either.
Blood Moon: Since the red light is shining on the Moon, I expect the person on the Moon would see the ground around him as red lit as well. And of course much darker, due to the solar eclipse. However I'd expect the solar eclipse to be quite spectacular, with the border of the Earth glowing in bright red.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by NewNic on Friday January 05 2018, @07:31PM (1 child)
Exactly.
A blue moon is nothing special astronomically. It's just an artifact of the calendar that we use.
lib·er·tar·i·an·ism ˌlibərˈterēənizəm/ noun: Magical thinking that useful idiots mistake for serious political theory
(Score: 3, Informative) by realDonaldTrump on Sunday January 07 2018, @06:38AM
A lot of our magnificent Orthodox Christian friends use what they call the Julian calendar. In which Christmas is just happening now. Merry Christmas to them!
(Score: 4, Informative) by All Your Lawn Are Belong To Us on Friday January 05 2018, @10:18PM (2 children)
The redness is highly variable - it is usually more orangey or even yellow-y than red toned (it can also be a dull, burning-ember brick red). Every lunar eclipse I've observed and photographed had a VERY visible change in tone to the tangent point closest to the Earth's surface (for example http://static.snopes.com/app/uploads/2017/02/lunar_eclipse_fb.jpg [snopes.com] ). While there's lots of good speculation as to why, nobody is entirely sure why the variations exist as they do. Lots of good possible explanations have been ruled out. And also remember that the redness is entirely the light we're seeing filtered around the planet (best theory is that light is bent around the earth) and then *also* reflected back at us and again passing through our atmosphere. My guess is that on the lunar surface it would just appear as lunar "night" in terms of dimness, and probably more clearly so than the dimness of a solar eclipse on Earth. But I'm just guessing.
I wouldn't necessarily expect the border of the earth as bright red.... again because the color is from our perspective and not necessarily theirs, but especially because the Earth covers a much wider swath of the Sun's surface during the lunar eclipse than the Moon does during a solar eclipse. (See https://www.space.com/33786-lunar-eclipse-guide.html [space.com] for an idea of the scale of a lunar eclipse. A total solar eclipse, the moon barely covers the Sun's surface). But I'd expect the same edge-closest-to-sun to have a color variation. (If it's not pitch black and I don't think it necessarily would be).
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(Score: 2) by maxwell demon on Saturday January 06 2018, @01:10PM (1 child)
The effect of the light going through atmosphere when coming from the moon and heading towards our eye is in no way different from the effect during a normal full moon (or any other moon phase, for that matter). The colour change relative to the normal moon is purely because of the light that reaches the moon.
The "returning light" effect makes the apparent moon colour dependent on where on the sky the moon is seen (because, just like the sun, the lower the moon is seen, the more distance its light had to pass through the atmosphere). But that's independent of the "blood moon" effect during eclipse.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by All Your Lawn Are Belong To Us on Monday January 08 2018, @06:49PM
I think you're mostly right, and the best theory is that more red-frequency light than blue is able to pass the rim of earth (the same Rayleigh scattering that gives us blue sky I think). There would be a corona around Earth as seen from the Moon (of the same collective color temperature as the moon itself). But I'm also saying don't expect that the surface of the moon around you would appear a blood red color, or even the overall shade your eye perceived when looking at the whole moon from Earth. If you're close to the edge where the tangent is lighting it with more yellow wavelengths, you might see a yellowy surface. If you're at the opposite point it might be duller orange indeed.
Of all the lunar eclipses I've observed - low in elevation, high in elevation, early evening, midnight, late morning... None of them have been what I'd call red and all of them have had that tangent point of light yellow on one limb. (It's still totally awesome to watch the progression of the eclipse across the lunar surface through a telescope or with imaging. :) ) Others have historically observed exactly that, though. NASA suggests the redness is from the amount of dust in the atmosphere that would scatter the yellow/orange frequencies also. (Same as a dusty sunset...)
I was also enlightened by both your post and these very interesting pages: https://www.nasa.gov/mission_pages/LRO/news/dec2011-eclipse.html [nasa.gov] and https://svs.gsfc.nasa.gov/4341 [nasa.gov] . Apparently the Lunar Reconaissance Orbiter can't run camera during the eclipse period but did run a Radiometer to measure surface temperature change. And I find it fascinating (though easily understandable) that you get instant lunar "night" temperatures during the eclipse - again on those pages.
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