Yesterday, Jan. 31st, the full Moon passed directly through the shadow of Earth, producing a total lunar eclipse. The shadowed Moon turned a coppery shade of orange visible in Asia, Australia and much of North America. Chirag Upreti sends this picture from New York City:
"The eclipse was gorgeous," says Upreti. "As morning twilight illuminated the landscape, the Moon was already low on the horizon. What a stunning scene to absorb on a really cold morning! Just as I was taking the picture, an airplane passed over the Statue of Liberty and a sea gull photobombed the eclipsed Moon at the same time."
On Wednesday, Jan. 31st, there's going to be a "Blue Moon"–the second full Moon in a calendar month. People who go outside to look may see a different hue: bright orange. This Blue Moon is going to be eclipsed, swallowed by copper-colored shadow of Earth for more than an hour. The eclipse will be visible from Asia, Australia, and most of North America: visibility map.
The bright orange color of the eclipse may be chalked up to volcanic activity–or rather, lack thereof. Atmospheric scientist Richard Keen from the University of Colorado explains:
"During a lunar eclipse, most of the light illuminating the Moon passes through Earth's stratosphere where it is reddened by scattering," he says. "If the stratosphere is loaded with dust from volcanic eruptions, the eclipse will be dark. The cataclysmic explosion of Tambora in 1815, for instance, turned the Moon into a dark, starless hole in sky during two subsequent eclipses."
But Earth is experiencing a bit of a volcanic lull. We haven't had a major volcanic blast since 1991 when Mt Pinatubo awoke from a 500 year slumber and sprayed ten billion cubic meters of ash, rock and debris into Earth's atmosphere. Recent eruptions have been puny by comparison and have failed to make a dent on the stratosphere. To Keen, the interregnum means one thing: "This eclipse is going to be bright and beautiful."
From "Two Centuries of Volcanic Aerosols Derived from Lunar Eclipse Records"
by R. A. Keen
Keen studies lunar eclipses because of what they can tell us about Earth's energy balance. A transparent stratosphere "lets the sunshine in" and actually helps warm the Earth below. "The lunar eclipse record indicates a clear stratosphere has contributed about 0.2 degrees to warming since the 1980s."
"Mt. Pinatubo finished a 110-year episode of frequent major eruptions that began with Krakatau in 1883," he says. "Since then, lunar eclipses have been relatively bright, and the Jan. 31st eclipse should be no exception."
In the USA, the best time to look is during the hours before sunrise. Western states are favored: The Moon makes first contact with the core of Earth's shadow at 3:48 am Pacific Time, kicking off the partial eclipse. Totality begins at 4:52 am PST as Earth's shadow engulfs the lunar disk for more than an hour. "Maximum orange" is expected around 5:30 am PST. Easternmost parts of the USA will miss totality altogether.
There's a lunar eclipse tonight, Feb. 10th, when the Moon spends almost 4 hours skimming through the shadow of Earth. If you've seen a lunar eclipse before, you might be expecting the Moon to turn red--the color of our planet's inner shadow. But no. The eclipsed Moon will look more like this:
Matt Wastell of Brisbane, Australia, took this picture during a similar lunar eclipse in April 2005. Earth's shadow darkens the upper left quadrant of the Moon, producing a gradient of luminosity across the lunar disk. Overall, the Moon remains silvery gray.
Tonight's eclipse is "penumbral." In other words, the Moon will pass through the pale outskirts of our planets shadow (the penumbra) rather than directly through its red core (the umbra). Graphic artist Larry Koehn has created an excellent animation of the event.
The best time to look is Friday night around 07:44 p.m. Eastern Time (00:44 UT Saturday). That's the time of maximum coverage when Earth's shadow creates a clear gradient of light and shadow across the lunar disk. Check out this global visibility map to see if you are in the eclipse zone:
According to folklore, a full Moon in February is called the "Snow Moon." For northerners, it often feels like the brightest Moon of the year as moonlight glistens off the white landscape. For a while on Friday night, the Snow Moon won't seem quite so bright.
On Sunday night, Sept. 27th, the supermoon passed through the shadow of Earth, producing a total lunar eclipse visible from the Americas, Europe, Africa and parts of Asia. "It was one of the darkest lunar eclipses I have ever seen," reports Kevin R. Witman, who sends this picture from Cochranville, Pennsylvania:
Other observers (see the gallery) also remarked on the darker hue of this lunar eclipse, compared to others in recent years. What caused the change? Atmospheric scientist Richard Keen of the University of Colorado offers one reason: "Supermoon eclipses should be a bit darker. Because of its closeness to Earth, a supermoon passes deeper into the shadow of our planet."
Working independently, Steve Albers of NOAA and Helio Vital of REA/Brazil have suggested another reason: aerosols in the atmosphere. "Earth's stratosphere is no longer completely clean of volcanic ashes," says Vital. "In fact, lingering aerosols from the explosion of Calbuco, five months ago, may be to blame for that excessive darkening."
Calbuco is a volcano in Chile. After it erupted in April 2015, colorful sunsets were observed around the southern hemisphere for months. Recently, Albers has noted an increase in purple and yellow sunsets around his home town, Boulder CO, and elsewhere. These are telltale colors of volcanic exhaust. "A thin veneer of aerosols from Calbuco may have now spread to the northern hemisphere," Albers says. "In addition, we could be seeing the effects of residual smoke from forest fires at high altitudes, or the general increase in sulfate pollution that has been documented on a global basis."
Richard Keen, who is a leading expert on volcanic aerosols and lunar eclipses, says "the Sept. 27th eclipse was about 0.5 magnitudes darker than expected for a clear stratosphere. A slight layer of aerosols in the upper troposphere/lower stratosphere might explain this. Also, the Moon passed through the southern part of Earth's shadow, so southern hemisphere aerosols (such as those produced by Calbuco) would have greater effect." www.spaceweather.com
This weekend's full Moon is a "supermoon," as much as 50,000 km closer to Earth than other full Moons of the year. Rising in the east at sunset, the swollen disk will look extremely beautiful... because it is going to be eclipsed. On Sunday evening, Sept. 27th, the supermoon will pass through the shadow of Earth, turning the lunar disk a cosmic shade of red. Click here to view an animation of the eclipse and to find out when to look:
What makes the eclipsed Moon turn red? A quick trip to the Moon provides the answer: Imagine yourself standing on a dusty lunar plain looking up at the sky. Overhead hangs Earth, nightside down, completely hiding the sun behind it. The eclipse is underway.
You might expect Earth seen in this way to be utterly dark, but it's not. The rim of the planet looks like it is on fire. As you scan your eye around Earth's circumference, you're seeing every sunrise and every sunset in the world, all of them, all at once. This incredible light beams into the heart of Earth's shadow, filling it with a coppery glow and transforming the Moon into a great red orb.
Red isn't the only color. Sharp-eyed observers might also spot some turquoise, shown here in a photo taken by Jens Hackman during an eclipse in March of 2007:
Its source is ozone. Atmospheric scientist Richard Keen of the University of Colorado explains: "During a lunar eclipse, most of the light illuminating the moon passes through the stratosphere where it is reddened by scattering. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer." This can be seen, he says, as a soft blue fringe around the red core of Earth's shadow.
To catch the turquoise on Sept. 27-28, he advises, "look during the first and last minutes of totality. The turquoise rim is best seen in binoculars or a small telescope."
_This section is for interesting items which are brought to my attention but which do not merit a separate article.
I welcome your comments, questions or suggestions on any topics you wish to contribute to this section.
Link to: Contact and