Blue Moon on New Year's Eve

Party planners take note. For the first time in almost twenty years, there's going to be a Blue Moon on New Year's Eve.

"I remember the last time this happened," says professor Philip Hiscock of the Dept. of Folklore at the Memorial University of Newfoundland. "December 1990 ended with a Blue Moon, and many New Year's Eve parties were themed by the event. It was a lot of fun."

Don't expect the Moon to actually turn blue, though. "The 'Blue Moon' is a creature of folklore," he explains. "It's the second full Moon in a calendar month."

The full moon of Dec. 2, 2009, over Turan, Italy. Photographer Stefano De Rosa notes that the blue colors are cast by Christmas lights surrounding the pictured church.

Most months have only one full Moon. The 29.5-day cadence of the lunar cycle matches up almost perfectly with the 28- to 31-day length of calendar months. Indeed, the word "month" comes from "Moon." Occasionally, however, the one-to-one correspondence breaks down when two full Moons squeeze into a single month. Dec. 2009 is such a month. The first full Moon appeared on Dec. 2nd; the second, a "Blue Moon," will come on Dec. 31st.

This definition of Blue Moon is relatively new.

If you told a person in Shakespeare's day that something happens "once in a Blue Moon" they would attach no astronomical meaning to the statement. Blue moon simply meant rare or absurd, like making a date for the Twelfth of Never. "But meaning is a slippery substance," says Hiscock. "The phrase 'Blue Moon' has been around for more than 400 years, and during that time its meaning has shifted."

The modern definition sprang up in the 1940s. In those days, the Farmer's Almanac of Maine offered a definition of Blue Moon so convoluted that even professional astronomers struggled to understand it. It involved factors such as the ecclesiastical dates of Easter and Lent, and the timing of seasons according to the dynamical mean sun. Aiming to explain blue moons to the layman, Sky & Telescope published an article in 1946 entitled "Once in a Blue Moon." The author James Hugh Pruett cited the 1937 Maine almanac and opined that the "second [full moon] in a month, so I interpret it, is called Blue Moon."

That was not correct, but at least it could be understood. And thus the modern Blue Moon was born.
Blue moon has other connotations, too. In music, it's often a symbol of melancholy. According to one Elvis tune, it means "without a love of my own." On the bright side, he croons in another song, a simple kiss can turn a Blue Moon pure gold.

The modern astronomical Blue Moon occurs in some month every 2.5 years, on average. A Blue Moon falling precisely on Dec. 31st, however, is much more unusual. The last time it happened was in 1990, and the next time won't be until 2028.

So cue up that old Elvis record and "enjoy the extra moonlight on New Year's Eve," says Hiscock. "It only happens once in a Blue Moon."

Partial Lunar Eclipse of 31 December 2009

Headline:
The last eclipse of 2009 occurs on New Year’s Eve. This minor Partial Lunar Eclipse takes place in Gemini, and is visible primarily from the Eastern Hemisphere. Greatest eclipse takes place at 19:23 UT when the eclipse magnitude will reach 0.0763. (The information below was observed by Dragon X’s Eclipse Observation & Investigation System)

Eclipse Viewer:
On 31 December 2009, Thursday night, there will be a Partial Lunar Eclipse occurs in our Earth’s shadow. The eclipse will be occurring at the Ecliptic Conjunction of 19:13:51.1 TD (19:12:45.1 UT), and the Greatest Eclipse of 19:23:45.9 TD (19:22:39.9 UT). At the moment, the Penumbral Magnitude will be at 1.0555, P. Radius of 1.2997° and the Gamma of 0.9766. The Umbral Magnitude will be at 0.0763, U. Radius of 0.7575° and the Axis of 0.9921°.

Easy Capture (1):
Ecliptic Conjunction = 19:13:51.1 TD (19:12:45.1 UT)
Greatest Eclipse = 19:23:45.9 TD (19:22:39.9 UT)

Penumbral Magnitude = 1.0555
P. Radius = 1.2997°
Gamma = 0.9766

Umbral Magnitude = 0.0763
U. Radius = 0.7575°
Axis = 0.9921°

Sun at Greatest Eclipse (Geocentric Coordinates):
When the eclipse occur, the Sun will be in the Right Ascension for 18hours 44minutes 37.2seconds. The Declination of the Sun will be in -23°02’33.1”, Apparent Semi-Diameter of 00°16’15.9”, and the Horizontal Parallax of 00°00’08.9”.

Easy Capture (2):
R.A. = 18h44m37.2s
Dec. = -23°02’33.1”
S.D. = 00°16’15.9”
H.P. = 00°00’08.9”

Moon at Greatest Eclipse (Geocentric Coordinates):
When the eclipse occur, the Moon will be in the Right Ascension for 06hours 45minutes 22.4seconds. The Declination of the Sun will be in +24°01’10.5”, Apparent Semi-Diameter of 00°16’36.6”, and the Horizontal Parallax of 01°00’57.6”.

Easy Capture (3):
R.A. = 06h45m22.4s
Dec. = +24°01’10.5”
S.D. = 00°16’36.6”
H.P. = 01°00’57.6”

Umbra Occur:

Eclipse Occur Duration:
When the eclipse occur on the day, it will passed the Penumbral Shadow for the Semi Duration of 02hours 05minutes 34seconds, and the Umbral Shadow for the Semi Duration of 00hours 29minutes 59seconds. So for the total time for the eclipse to take time(s) is 02hours 35minutes 33seconds.

Easy Capture (4):
Penumbral = 02h05m34s
Umbral = 00h29m59s
Total Occur = 02h35m33s

Best Visible:
ΔT = 66.0s
Rule = CdT (Danjon)
Eph. = VSOP87/ELP2000-85

Information Box:
Local Date(s):
31 December 2009 ~ 01 January 2009

Local Time(s):
09:37:15pm ~ 12:12:48am

Duration Occur(s):
02hours 35minutes 33seconds

Types/Percentage Occur(s):
8.0% Umbral

Best Visible From(s):
Europe, Africa, Asia

Eclipse Contacts:
On that night, the Lunar Eclipse will occur step by step by passing through the Earth’s shadow. It will started by the Penumbral Eclipse that will begins at 17:17:07 UT, then followed by the Partial Umbral Eclipse that will begins at 18:52:44 UT, next by the Partial Umbral Eclipse that will ends at 19:52:42 UT, and finally resume by the penumbral Eclipse that will be ends at 21:28:15 UT.

Easy Capture (5):
P1 = 17:17:07 UT
U1 = 18:52:44 UT
U4 = 19:52:42 UT
P4 = 21:28:15 UT

Voyager Makes an Interstellar Discovery

The solar system is passing through an interstellar cloud that physics says should not exist. In the Dec. 24th issue of Nature, a team of scientists reveal how NASA's Voyager spacecraft have solved the mystery.

"Using data from Voyager, we have discovered a strong magnetic field just outside the solar system," explains lead author Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. "This magnetic field holds the interstellar cloud together and solves the long-standing puzzle of how it can exist at all."

Voyager flies through the outer bounds of the heliosphere en route to interstellar space. A strong magnetic field reported by Opher et al in the Dec. 24, 2009, issue of Nature is delineated in yellow.

The discovery has implications for the future when the solar system will eventually bump into other, similar clouds in our arm of the Milky Way galaxy.

Astronomers call the cloud we're running into now the Local Interstellar Cloud or "Local Fluff" for short. It's about 30 light years wide and contains a wispy mixture of hydrogen and helium atoms at a temperature of 6000 C. The existential mystery of the Fluff has to do with its surroundings. About 10 million years ago, a cluster of supernovas exploded nearby, creating a giant bubble of million-degree gas. The Fluff is completely surrounded by this high-pressure supernova exhaust and should be crushed or dispersed by it.

"The observed temperature and density of the local cloud do not provide enough pressure to resist the 'crushing action' of the hot gas around it," says Opher.

So how does the Fluff survive? The Voyagers have found an answer.
"Voyager data show that the Fluff is much more strongly magnetized than anyone had previously suspected—between 4 and 5 microgauss*," says Opher. "This magnetic field can provide the extra pressure required to resist destruction."

An artist's concept of the Local Interstellar Cloud, also known as the "Local Fluff."

NASA's two Voyager probes have been racing out of the solar system for more than 30 years. They are now beyond the orbit of Pluto and on the verge of entering interstellar space—but they are not there yet.

"The Voyagers are not actually inside the Local Fluff," says Opher. "But they are getting close and can sense what the cloud is like as they approach it."

The Fluff is held at bay just beyond the edge of the solar system by the sun's magnetic field, which is inflated by solar wind into a magnetic bubble more than 10 billion km wide. Called the "heliosphere," this bubble acts as a shield that helps protect the inner solar system from galactic cosmic rays and interstellar clouds. The two Voyagers are located in the outermost layer of the heliosphere, or "heliosheath," where the solar wind is slowed by the pressure of interstellar gas.

Voyager 1 entered the heliosheath in Dec. 2004; Voyager 2 followed almost 3 years later in Aug. 2007. These crossings were key to Opher et al's discovery.

The anatomy of the heliosphere. Since this illustration was made, Voyager 2 has joined Voyager 1 inside the heliosheath, a thick outer layer where the solar wind is slowed by the pressure of interstellar gas.

The size of the heliosphere is determined by a balance of forces: Solar wind inflates the bubble from the inside while the Local Fluff compresses it from the outside. Voyager's crossings into the heliosheath revealed the approximate size of the heliosphere and, thus, how much pressure the Local Fluff exerts. A portion of that pressure is magnetic and corresponds to the ~5 microgauss Opher's team has reported in Nature.

The fact that the Fluff is strongly magnetized means that other clouds in the galactic neighborhood could be, too. Eventually, the solar system will run into some of them, and their strong magnetic fields could compress the heliosphere even more than it is compressed now. Additional compression could allow more cosmic rays to reach the inner solar system, possibly affecting terrestrial climate and the ability of astronauts to travel safely through space. On the other hand, astronauts wouldn't have to travel so far because interstellar space would be closer than ever. These events would play out on time scales of tens to hundreds of thousands of years, which is how long it takes for the solar system to move from one cloud to the next.

"There could be interesting times ahead!" says Opher.

To read the original research, look in the Dec. 24, 2009, issue of Nature for Opher et al's article, "A strong, highly-tilted interstellar magnetic field near the Solar System."

Colliding Auroras Produce Explosions of Light

A network of cameras deployed around the Arctic in support of NASA's THEMIS mission has made a startling discovery about the Northern Lights. Sometimes, vast curtains of aurora borealis collide, producing spectacular outbursts of light. Movies of the phenomenon were unveiled at the Fall meeting of the American Geophysical Union today in San Francisco.

"Our jaws dropped when we saw the movies for the first time," says space scientist Larry Lyons of UCLA, a leading member of the team that made the discovery. "These outbursts are telling us something very fundamental about the nature of auroras."

Colliding auroras photographed by THEMIS all-sky imagers (ASIs) on Feb. 29, 2008. [short movie with labels] [full-length movie]

The collisions occur on such a vast scale, isolated observers on Earth with limited fields of view had never noticed them before. It took a network of sensitive cameras spread across thousands of miles to get the big picture.

NASA and the Canadian Space Agency created such a network for THEMIS, short for "Time History of Events and Macroscale Interactions during Substorms." THEMIS consists of five spacecraft launched in 2006 to solve a long-standing mystery: Why do auroras occasionally erupt in an explosion of light called a substorm? Twenty all-sky imagers (ASIs) were deployed across the Alaskan and Canadian Arctic to photograph auroras from below while the spacecraft sampled charged particles and electromagnetic fields from above. Together, the cameras and spacecraft would see the action from both sides and be able to piece together cause and effect—or so researchers hoped.
It seems to have worked.

The breakthrough came earlier this year when UCLA researcher Toshi Nishimura completed the Herculean task of assembling continent-wide movies from the individual ASI cameras.

Twenty all-sky imagers (ASIs) were deployed by researchers from the University of California Berkeley, the University of Calgary, and the University of Alaska in support of the THEMIS mission. This map shows their locations and field of view. Image

"It can be a little tricky," Nishimura says. "Each camera has its own local weather and lighting conditions, and the auroras are different distances from each camera. I've got to account for these factors for six or more cameras simultaneously to make a coherent, large-scale movie."

The first movie he showed Lyons was a pair of auroras crashing together in Dec. 2007.

"It was like nothing I had seen before," Lyons recalls. "Over the next several days, we surveyed even more events. Our excitement mounted as we became convinced that the collisions were happening over and over."

The explosions of light, they believe, are a sign of something dramatic happening in the space around Earth—specifically, in Earth's "plasma tail." Millions of kilometers long and pointed away from the sun, the plasma tail is made of charged particles captured mainly from the solar wind. Sometimes called the "plasma sheet," the tail is held together by Earth's magnetic field.

The same magnetic field that holds the tail together also connects it to Earth's polar regions. Because of this connection, watching the dance of Northern Lights can reveal much about what's happening in the plasma tail.

A schematic diagram of Earth's magnetosphere. Earth is the circle near the middle and the plasma tail is denoted in yellow.

By examining many collisions, Lyons and Nishimura have identified a common sequence of events. It begins with two elements: (1) a broad curtain of slow-moving auroras and (2) a smaller knot of fast-moving auroras, initially far apart. The slow curtain is quietly glowing over the Arctic when the speedy knot rushes in from the north. The two auroras collide and an eruption of light ensues.

How does this sequence connect to events in the plasma tail?

"It took some creative thinking to come up with an answer, but I believe this team has done it," says THEMIS project scientist Dave Sibeck of the Goddard Space Flight Center.

Lyons believes that the fast-moving knot is associated with a stream of relatively lightweight plasma jetting through the plasma tail. The stream gets started in the outer regions of the plasma tail and moves rapidly inward toward Earth. The fast knot of auroras moves in synch with this stream.

Meanwhile, the broad curtain of auroras is quietly hanging over the Arctic, gently glowing, more or less minding its own business. This curtain is connected to the stationary inner boundary of the plasma tail and is fueled by plasma instabilities there.

Auroras poised to collide. Click on the image to view a labeled sequence of events.

When the lightweight stream reaches the inner boundary of the plasma tail—bang!--there is an eruption of plasma waves and instabilities. This collision of plasma is mirrored by a collision of auroras over the poles.

National Science Foundation radars located in Alaska and Greenland confirm this basic picture. They have detected echoes from streams of material rushing through Earth's upper atmosphere just before the auroras collide and erupt.
The five THEMIS spacecraft also agree. They have been able to fly through the plasma tail and confirm the existence of lightweight material rushing toward Earth.

"By putting together data from ground-based cameras, ground-based radar, and the THEMIS spacecraft themselves, we now have a nearly complete picture of what causes explosive auroral substorms," says Sibeck.And what a picture it is. Click here for movies.

A Flash of Light from Titan

NASA's Cassini spacecraft has photographed a flash of sunlight reflecting from a lake on Saturn's moon Titan, confirming the presence of liquid hydrocarbons on a part of the moon dotted with many lake-shaped basins.

Cassini scientists had been looking for the glint, also known as a specular reflection, since the spacecraft began orbiting Saturn in 2004. But until recently Titan's northern hemisphere, where most of the lakes are located, had been veiled in winter darkness. Now, however, the seasons are changing and sunlight has returned to the north, allowing Cassini to capture this serendipitous image:

This image, obtained using Cassini's Visual and Infrared Mapping Spectrometer (VIMS), shows the first observed flash of sunlight reflected off a lake on Saturn's moon Titan.

The picture, which shows sunlight reflecting from the smooth surface of a liquid on July 8, 2009, was presented today at the Fall meeting of the American Geophysical Union in San Francisco.

"This one image communicates so much about Titan -- a thick atmosphere, surface lakes and an otherworldliness," says Bob Pappalardo, Cassini project scientist, based at NASA's Jet Propulsion Laboratory. "It's an unsettling combination of strangeness yet similarity to Earth. This picture is one of Cassini's iconic images."

Titan, Saturn's largest moon, has captivated scientists because of its many similarities to Earth. Scientists have theorized for 20 years that Titan's cold surface hosts seas or lakes of liquid hydrocarbons, making it the only other planetary body besides Earth believed to have liquid on its surface. While data from Cassini have not indicated any vast seas, they have revealed what appeared to be large lakes near Titan's north and south poles.

In 2008, Cassini scientists using infrared data confirmed the presence of liquid in Ontario Lacus, the largest lake in Titan's southern hemisphere. But they were still looking for the smoking gun to confirm liquid in the northern hemisphere, where the basins are larger and more numerous.

Katrin Stephan, of the German Aerospace Center (DLR) in Berlin, an associate member of the Cassini visual and infrared mapping spectrometer team, was processing the initial image and was the first to see the glint on July 10, 2009.

"I was instantly excited because the glint reminded me of an image of our own planet taken from orbit around Earth, showing a reflection of sunlight on an ocean," Stephan said. "But we also had to do more work to make sure the glint we were seeing wasn't lightning or an erupting volcano."

A false-color radar map of putative methane lakes in Titan's northern hemisphere.

Team members at the University of Arizona in Tucson processed the image further. They were able to pinpoint the reflection at the southern shoreline of a lake called Kraken Mare. The sprawling Kraken Mare covers about 400,000 square kilometers (150,000 square miles), an area larger than the Caspian Sea, the largest lake on Earth.

By comparing this new image to radar and near-infrared images acquired since 2006, scientists were able to show that the shoreline of Kraken Mare has been stable over the last three years and that Titan has an ongoing hydrological cycle that brings liquids to the surface. Of course, in this case, the liquid in the hydrological cycle is methane rather than water, as it is on Earth."These results remind us how unique Titan is in the solar system," says Ralf Jaumann, who leads the scientists at the DLR who work on Cassini. "They also show us that liquid has a universal power to shape geological surfaces in the same way, no matter what the liquid is."

When to See Mercury in December 2009

Headline:
In December 2009, there will be many space events to see during this school end holidays. Once of the event is the Milky Way Galaxy first planet, Mercury will be seen on 18 December 2009? Mercury is the first planet in our solar system named, the Milky Way Galaxy. On 18 December 2009, we can see Mercury as a bright star in the sunset and sunrise. The Mercury will be seen as a bright star in the evening sky, 1 hour before sunset.

How to See the Mercury in the Evening Sky:
Look at the sun at 6.00pm (Malaysia Time), 6.00am (Orlando Florida Time). You can find the Mercury in the horizon line to the sun, and then look up onto 20 degrees angle from the line; you will found the bright star which is take place as Mercury. The Mercury will be in the Earth area by 6 weeks after the date given. But for the information, in the 6 weeks duration, on 18 December 2009 only that you can see the Mercury as visible as you can.

See The Mercury Needs Any Preparation?
Actually, see the Mercury in the evening sky doesn’t need any preparation or equipments. Some of the people said that seeing the Mercury in the evening sky needs the binocular and telescope to see it clearly. That is not actually wrong, but for seeing the Mercury, you can also don’t need the equipments for seeing it clearly. Even though the position of Mercury is so nearly to the Sun, when you used the binocular or the telescope to see it, it will damage your eyes. So, Dragon X Space Agency warn that when the Mercury is occur, do not used any equipments to see it, you can even see it with your naked eyes. This is safe for your eyes’ system.

Information Box:
Local Date(s):
18 December 2009, Friday

Local Time(s):
1 hour before sunset

Visible Position(s):
Horizon line to the Sun, 20 degrees above