Posted on by Fraser Cain

Greenland is Melting Faster

Decreasing levels of ice thickness from Greenland. Image credit: NASA/JPL. Click to enlarge.
In the first direct, comprehensive mass survey of the entire Greenland ice sheet, scientists using data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (Grace) have measured a significant decrease in the mass of the Greenland ice cap. Grace is a satellite mission that measures movement in Earth’s mass.

In an update to findings published in the journal Geophysical Research Letters, a team led by Dr. Isabella Velicogna of the University of Colorado, Boulder, found that Greenland’s ice sheet decreased by 162 (plus or minus 22) cubic kilometers a year between 2002 and 2005. This is higher than all previously published estimates, and it represents a change of about 0.4 millimeters (.016 inches) per year to global sea level rise.

“Greenland hosts the largest reservoir of freshwater in the northern hemisphere, and any substantial changes in the mass of its ice sheet will affect global sea level, ocean circulation and climate,” said Velicogna. “These results demonstrate Grace’s ability to measure monthly mass changes for an entire ice sheet ? a breakthrough in our ability to monitor such changes.”

Other recent Grace-related research includes measurements of seasonal changes in the Antarctic Circumpolar Current, Earth’s strongest ocean current system and a very significant force in global climate change. The Grace science team borrowed techniques from meteorologists who use atmospheric pressure to estimate winds. The team used Grace to estimate seasonal differences in ocean bottom pressure in order to estimate the intensity of the deep currents that move dense, cold water away from the Antarctic. This is the first study of seasonal variability along the full length of the Antarctic Circumpolar Current, which links the Atlantic, Pacific and Indian Oceans.

Dr. Victor Zlotnicki, an oceanographer at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., called the technique a first step in global satellite monitoring of deep ocean circulation, which moves heat and salt between ocean basins. This exchange of heat and salt links sea ice, sea surface temperature and other polar ocean properties with weather and climate-related phenomena such as El Ninos. Some scientific studies indicate that deep ocean circulation plays a significant role in global climate change.

The identical twin Grace satellites track minute changes in Earth’s gravity field resulting from regional changes in Earth’s mass. Masses of ice, air, water and solid Earth can be moved by weather patterns, seasonal change, climate change and even tectonic events, such as this past December’s Sumatra earthquake. To track these changes, Grace measures micron-scale changes in the 220-kilometer (137-mile) separation between the two satellites, which fly in formation. To limit degradation of Grace’s satellite antennas due to atomic oxygen exposure and thereby preserve mission life, a series of maneuvers was performed earlier this month to swap the satellites’ relative positions in orbit.

In a demonstration of the satellites’ sensitivity to minute changes in Earth’s mass, the Grace science team reported that the satellites were able to measure the deformation of the Earth’s crust caused by the December 2004 Sumatra earthquake. That quake changed Earth’s gravity by one part in a billion.

Dr. Byron Tapley, Grace principal investigator at the University of Texas at Austin, said that the detection of the Sumatra earthquake gravity signal illustrates Grace’s ability to measure changes on and within Earth’s surface. “Grace’s measurements will add a global perspective to studies of large earthquakes and their impacts,” said Tapley.

Grace is managed for NASA by JPL. The University of Texas Center for Space Research has overall mission responsibility. GeoForschungsZentrum Potsdam, or GFZ, Potsdam, Germany, is responsible for German mission elements. Science data processing, distribution, archiving and product verification are managed jointly by JPL, the University of Texas and GFZ.

Imagery related to these latest Grace findings may be viewed at: http://www.nasa.gov/vision/earth/lookingatearth/grace-images-20051220.html .

For more information on Grace, visit: http://www.csr.utexas.edu/grace or http://www.gfz-potsdam.de/grace .

Original Source: NASA News Release

Posted on by Fraser Cain

Pluto Mission is Around the Corner

NASA’s New Horizons spacecraft. Image credit: NASA/KSC Click to enlarge
NASA is preparing to launch the first spacecraft to distant Pluto and its moon Charon. The January 2006 launch of New Horizons will complete the initial reconnaissance of the planets in the solar system.

“New Horizons will study a unique world, and we can only imagine what we may learn. This is a prime example of scientific missions that complement the Vision for Space Exploration,” said Mary Cleave, associate administrator for NASA’s Science Mission Directorate.

The Vision for Space Exploration is a bold new course into the cosmos, a journey that will return the space shuttle safely to flight, complete the construction of the International Space Station, take humans back to the moon and eventually to Mars and beyond.

The National Academy of Sciences has ranked the exploration of Pluto-Charon and the Kuiper Belt among the highest priorities for space exploration, citing the fundamental scientific importance of these bodies to advancing understanding of our solar system.

Different than the inner, rocky planets (like Earth) or the outer gas giants, Pluto is a different type of planet known as an “ice dwarf,” commonly found in the Kuiper Belt region billions of miles from the sun.

“Exploring Pluto and the Kuiper Belt is like conducting an archeological dig into the history of the outer solar system, a place where we can peek into the ancient era of planetary formation,” said Alan Stern, New Horizons principal investigator, Southwest Research Institute Department of Space Studies, Boulder, Colo.

Designed and built at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., pending launch approval, New Horizons is set to launch from Cape Canaveral Air Force Station, Fla., no earlier than Jan. 17, 2006. The launch window extends until Feb. 14, 2006.

The compact, 1,050-pound piano-sized probe will launch aboard an Atlas V expendable launch vehicle, followed by a boost from a kick-stage solid propellant motor. New Horizons will be the fastest spacecraft ever launched, reaching lunar orbit distance in just nine hours and passing Jupiter 13 months later.

Launch before Feb. 3 allows New Horizons to fly past Jupiter in early 2007 and use the planet’s gravity as a slingshot toward Pluto. The Jupiter flyby trims the trip to Pluto by five years and provides opportunities to test the spacecraft’s instruments and flyby capabilities on the Jupiter system.

The New Horizons science payload, developed under direction of Southwest Research Institute, includes imaging infrared and ultraviolet spectrometers, a multi-color camera, a long-range telescopic camera, two particle spectrometers, a space-dust detector and a radio science experiment. The dust counter was designed and built by students at the University of Colorado, Boulder.

Depending on its launch date, New Horizons could reach the Pluto system as early as mid-2015, conducting a five-month-long study possible only from the close-up vantage of a spacecraft. It will characterize the global geology and geomorphology of Pluto and Charon, map their surface compositions and temperatures, and examine Pluto’s atmospheric composition and structure. New Horizons also will study the small moons recently discovered in the Pluto system.

The spacecraft will “sleep” in electronic hibernation for much of the cruise to Pluto. Operators will turn off all but the most critical electronic systems and monitor the spacecraft once a year to check out critical systems, calibrate instruments and perform course corrections, if necessary.

The spacecraft will send back a beacon signal each week to give operators an instant read on spacecraft health. The entire spacecraft, drawing electricity from a single radioisotope thermoelectric generator, operates on less power than a pair of 100-watt household light bulbs.

For more information about NASA and the New Horizons mission on the Web, visit: http://www.nasa.gov/newhorizons

Original Source: NASA News Release

Update: Is Pluto still a planet? No.

Posted on by Fraser Cain

Have the Constants of Physics Remained Unchanged?

The Robert C. Byrd Green Bank Telescope. Image credit: NRAO Click to enlarge
An international team of astronomers has looked at something very big — a distant galaxy — to study the behavior of things very small — atoms and molecules — to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation’s Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time.

“The fundamental constants of physics are expected to remain fixed across space and time; that’s why they’re called constants! Now, however, new theoretical models for the basic structure of matter indicate that they may change. We’re testing these predictions.” said Nissim Kanekar, an astronomer at the National Radio Astronomy Observatory (NRAO), in Socorro, New Mexico.

So far, the scientists’ measurements show no change in the constants. “We’ve put the most stringent limits yet on some changes in these constants, but that’s not the end of the story,” said Christopher Carilli, another NRAO astronomer.

“This is the exciting frontier where astronomy meets particle physics,” Carilli explained. The research can help answer fundamental questions about whether the basic components of matter are tiny particles or tiny vibrating strings, how many dimensions the Universe has, and the nature of “dark energy.”

The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant.

These values, considered fundamental physical constants, once were “taken as time independent, with values given once and forever” said German particle physicist Christof Wetterich. However, Wetterich explained, “the viewpoint of modern particle theory has changed in recent years,” with ideas such as superstring theory and extra dimensions in spacetime calling for the “constants” to change over time, he said.

The astronomers used the GBT to detect and study radio emissions at four specific frequencies between 1612 MHz and 1720 MHz coming from hydroxyl (OH) molecules in a galaxy more than 6 billion light-years from Earth, seen as it was at roughly half the Universe’s current age. Each of the four frequencies represents a specific change in the energy level of the molecule.

The exact frequency emitted or absorbed when the molecule undergoes a transition from one energy level to another depends on the values of the fundamental physical constants. However, each of the four frequencies studied in the OH molecule will react differently to a change in the constants. That difference is what the astronomers sought to detect using the GBT, which, Kanekar explained, is the ideal telescope for this work because of its technical capabilities and its location in the National Radio Quiet Zone, where radio interference is at a minimum.

“We can place very tight limits on changes in the physical constants by studying the behavior of these OH molecules at a time when the Universe was only about half its current age, and comparing this result to how the molecules behave today in the laboratory,” said Karl Menten of the Max-Planck Institute for Radioastronomy in Germany.

Wetterich, a theorist, welcomes the new capability, saying the observational method “seems very promising to obtain perhaps the most accurate values for such possible time changes of the constants.” He pointed out that, while some theoretical models call for the constants to change only in the early moments after the Big Bang, models of the recently-discovered, mysterious “dark energy” that seems to be accelerating the Universe’s expansion call for changes “even in the last couple of billion years.”

“Only observations can tell,” he said.

This research ties together the theoretical and observational work of Wetterich and Carilli, this year’s winners of the prestigious Max Planck Research Award of the Alexander von Humboldt Foundation and the Max Planck Society in Germany. Menten and Carilli have collaborated on research in this area for years, and Kanekar has pioneered the OH molecular technique.

Kanekar, Carilli and Menten worked with Glen Langston of NRAO, Graca Rocha of the Cavendish Laboratory in the UK, Francoise Combes of the Paris Observatory, Ravi Subrahmanyan of the Australia Telescope National Facility (ATNF), John Stocke of the University of Colorado, Frank Briggs of the ATNF and the Australian National University, and Tommy Wiklind of the Space Telescope Science Institute in Sweden. The scientists reported their findings in the December 31 edition of the scientific journal Physical Review Letters.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Original Source: NRAO News Release

Posted on by Mark Mortimer

Book Review: Women in Space

Being female makes for some basic biological differences. But as proven time and again, women have proven themselves capable to undertake and satisfactorily complete the same tasks as done by men. Given that piloting vehicles is less about strength and more about coordination and intuition, some would happily wager that women should excel in this role. However, because flight grew up as a tool of war and war has been a strictly male domain, women have always been at the periphery looking in. The insipient space industry also arose from a military foundation, hence, again men made decisions and prepared designs for themselves. Thus, though many women had the capability and desire to contribute, few opportunities arose for their participation in space.

Even though much could be said on the participation, or lack thereof, of women in space, Shayler and Moule’s book focuses solely on the achievements. The little seagull, Valentina Tereshkova, was the first woman to fly into space, but predecessors abounded. In acknowledging this, Shayler and Moule take the reader on a history lesson. They go to the 1700’s, when women astronomers were making their mark by flying in Montgolfier styled balloons. Parachuting, gliding and powered flight quickly succumbed to their skills. As most of these accomplishments could be achieved by an individual, women could and did do as they wished. This history review, though brief, amply demonstrates the ability of women.

In a juxtaposition, the book shows how, once society’s morality came into play, women were no longer equal players. That is, they were involved because of their sex, principally shown by the USSR in their program. The authors, however, stay with the facts by noting cosmonaut selection and training. After providing the backgrounds of many of these hopefuls, and the successful Valentina herself, Shayler and Moule switch back to the program of the United States. In an attempt to be broadly inclusive or perhaps to fill in a sorry lack of participation, they broaden their extent of achievements. There’s the female computers doing orbital trajectories as well as seamstresses who sewed flight suits and Skylab’s reflector. However, in using old phone books for identification, the authors let slip the narration and in consequence the book transposes into a series of lists rather than a discussion of accomplishments.

For example, much is made of Nichelle Nichols, better known as Uhura of Star Trek fame. True, she was prominent in early outreach programs for females but she did not directly contribute. There’s also description of the families and spouses of male astronauts. It wasn’t until the space shuttle era that women entered the mainstream. Sadly, here again, the authors trivialize their work by filling up much of the remainder of the book with data sheets. Using NASA Query Book and Press Kit factoids, they list every female who has flown on the space shuttle (or Soyuz), their technical background and their mission tasks. They go so far as identifying which shuttle seat they occupied during launch and return. Listing of minor roles, such as organizing flight shirts, clearly shows that the authors let NASA’s dogma dictate the contents. They neglect their own narrative abilities, which they ably showed in the earlier chapters.

By staying narrowly focussed on achievements, the author’s missed writing a great book rather than the good book they did write. They should have surmised on the precepts of a society that kept females in support roles while men achieved the glory. They alluded to but did not support the premise that shuttle crews would no longer include females so society would grieve less should another disaster occur. Does this mean men are more expendable? Sadly, their book never rises to this occasion.

There is no doubt that in most fields women are every bit as capable as men. The aerospace frontier is no exception. Women in Space by David Shayler and Ian Moule lists the women and their achievements as they and space flight increased in capability. From flying in balloons to piloting the space shuttle, they’re all in this book with great praise to their contributions.

Review by Mark Mortimer

Read more reviews online, or purchase a copy from Amazon.com.

Posted on by Fraser Cain

Rhea Hiding Behind the Rings

Saturn’s icy F ring. Image credit: NASA/JPL/SSI Click to enlarge
The searing arc of light seen here is Saturn’s icy F ring, seen nearly edge-on. In the background, Rhea (1,528 kilometers, or 949 miles across) is lit by reflected light from Saturn and the rings, with only the slightest sliver of light at its bottom being from direct sunlight.

The faint material surrounding the F ring likely lies in the planet’s equatorial plane, extending radially farther out and in from the main F ring core. A smaller fraction of this material could be vertically extended, and Cassini’s investigations should help to clarify this.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Oct. 30, 2005, at a distance of approximately 689,000 kilometers (428,000 miles) from Saturn. The image scale is approximately 4 kilometers (2 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Posted on by Fraser Cain

Enceladus is Creating one of Saturn’s Rings

Enceladus plume. Image credit: NASA/JPL/UA Click to enlarge
Cassini observations by several instruments have revealed the source of Saturn’s broadest and faintest ring. Recent observations show that tiny particles of frozen water ice are streaming outward into space from the south polar region of the moon Enceladus.

The source of geological activity on Enceladus is a mystery. “We’re amazed to see ice geysers on this little world that was thought to be cold and dead long ago,” commented Dr. Dale Cruikshank of NASA Ames Research center, a member of the visual and infrared mapping spectrometer team. “Some unexpected process is vigorously heating the interior of Enceladus, especially the south polar region, and causing the ejection of the plumes of ice particles.”

As the icy plumes jet out from the moon, the larger particles probably follow paths that mostly bring them back to the surface, while the smaller particles are nudged by sunlight into orbits around Saturn.

“Most of these small particles probably re-impact the moon, but the smallest ones eventually disperse as a result of radiation (light) pressure and interactions with Saturn’s magnetosphere to form the broad E ring,” said Dr. Mark Showalter of the SETI Institute, Mountain View, Calif. Thus, the E ring is currently being regenerated by some kind of geological activity in the interior of Enceladus.

During the Cassini spacecraft’s flyby on Nov. 26, the visual and infrared mapping spectrometer instrument measured the spectrum of the polar plumes of Enceladus. “We see a very clear signature of small ice particles in the plume data, in the form of a strong absorption band at 2.9 microns in an otherwise featureless spectrum,” said Dr. Phil Nicholson, professor of astronomy at Cornell University, Ithaca, N.Y. Nicholson is a member of the visual and infrared mapping spectrometer science team.

The visual and infrared mapping spectrometer images of Enceladus show not only the plume over the south pole, but also the dark side of the moon, silhouetted against a foggy background of light from the E Ring. Measurements of the spectrum show a very similar signature of small ice particles to that in the plumes, confirming earlier expectations that Enceladus is indeed the source of the E ring.

Preliminary analyses suggest that the average size of the particles in the plume is about 10 microns (1/100,000 of a meter), whereas the particles in the E ring are about three times smaller. The sunlit surface of Enceladus itself is also composed of water ice, but with a much larger grain size than the plume.

Original Source: NASA/JPL/SSI News Release

Posted on by Fraser Cain

What’s Up This Week – December 19 – December 25, 2005

NGC 1300. Image credit: Hilary Mathis/NOAO/AURA/NSF. Click to enlarge.
Monday, December 19 – ‘Tis the season for freezin’, but you won’t be cold for long as you head towards the furnace of Fornax to discover one of the most awesome structured galaxies around – NGC 1300.

Located about a fistwidth north-northeast of Alpha Fornacis in the constellation of Eridanus, NGC 1300 is definitely one of the best barred spiral galaxies that can be viewed with the average telescope. Cataloged and studied by both Herschels, just the central bar in this 75 million light year distant beauty is larger in diameter than our own Milky Way – it spans an incredible 150,000 light years. As a topic of scientific study, the speed at which NGC 1300’s clouds of gas and stars rotate has been measured to help understand how this type of galaxy forms.

Easily reached by small telescopes, this 10th magnitude galactic giant will reveal its bright core area and the beginnings of resolution to larger aperture. No matter which hemisphere you observe from, this hot galaxy is definitely very “cool!”

Tuesday, December 20 – Tonight is the peak of Delta Arietid meteor shower. While most showers are best after midnight, this is a both hemispheres, early evening shower that must be viewed before the radiant sets. The fall rate is modest – about 12 per hour – but with early evening dark skies, your chance of success is good.

Today marks the founding of the Mt. Wilson Solar Observatory, which officially opened its doors in 1904. We also celebrate the birth of Walter S. Adams on this date. Born in 1876, Adams was an astronomer at Mt. Wilson who revealed the nature of Sirius B, the first known white dwarf star. Sirius B was first seen by Alvan Clark in 1862 abd hust recently, the Hubble Space Telescope precisely measured the mass of B for the first time.

While Sirius is far too low at an early hour to study its white dwarf, we can have a look at a similar star when we view Omicron 2 Eridani located roughly a handspan west of Rigel. As the southernmost of the Omicron pair, it is sometimes known as 40 Eridani and you’ll find it to be an interesting multiple star system that’s very worthy of your time.
Discovered by William Herschel in 1783, this 16 light year distant system is the eighth nearest of the unaided visible stars. Well spaced from the primary, the companion star is also a double for high powers and will reveal a red dwarf discovered by Otto Struve. Now, look closely at the 9th magnitude B star. This is the only white dwarf that can be considered “easy” for the backyard telescope. Its diameter is only about twice the size of Earth and its mass is about that of our Sun. Power up and locate the 11th magnitude companion…for it’s one of the least massive stars known!

Wednesday, December 21 – Today marks the official beginning of winter for the northern hemisphere. For the USA at 1:35 p.m. EST, the Sun will stand directly over the Tropic of Capricorn and meet its most southern extension. This time of solstice is also a good time to create your own shadow marker, so you may follow as the Sun changes positions in the sky. Anything can be used as a marker – be it a fencepost or simply a stake driven into the ground. At local noon, measure the distance between your marker and the end of the shadow. Every so often, repeat the process and watch the changes in shadow length in the weeks ahead!

Tonight let’s have a look at an open cluster best suited to binoculars or telescopes at very low power – Collinder 62. Located about two fingerwidths south of Alpha Auriga – Capella – this scattered collection of mixed magnitude stars is often overlooked in favor of the Messier objects. While its small groupings of roughly 8th magnitude stars occupy an area about the size of the full Moon, it fares well under tonight’s darker skies. Be sure to look for its brightest member in a zig-zag formation of stars.

Thursday, December 22 – Up early? Fantastic! In the pre-dawn hours of this morning, we have a treat for you – the Ursid meteor shower. Cruising around the Sun about every thirteen and a half years, Comet 8P/Tuttle sheds a little skin. Although it never passes inside of Earth’s orbit, some six years later we pass through its debris stream. Not so unusual? Then think again, because it takes as much as six centuries before any one meteoroid’s orbit is affected enough by Jupiter’s gravitation to pass into our atmosphere.

With only a little interference from the Moon while watching this northern circumpolar meteor shower, the hours before dawn could see activity of up to 12 per hour. By keeping watch on the constellation of Ursa Major, you just might spot one of these slow moving, 600 year old travelers that make their path only halfway between us and Selene!
While you’re out, be sure to have a look at Jupiter and see if you can spot Mercury as well. You’ll find the swift inner planet around a handspan and a half further east along the ecliptic plane. Don’t confuse it with the lower Antares!

Friday, December 23 – This will be a morning worth getting up early for – as almost all of the North American continent will be treated to an event when the Moon occults Beta Virginis. Be sure to check this IOTA page for a listing of times and locations in your area. Best of luck!

After sunset tonight, be sure to have a look at the rapidly slimming crescent of Venus. At this time, its orbital track is carrying it past the Earth and it will begin its “retrograde” – or reverse – motion as it heads off on its journey around the Sun.

Today in 1672, astronomer Giovanni Cassini discovered Saturn’s moon Rhea. Around four hours after local sunset you’ll find Saturn rising along the ecliptic plane and becoming more accessible to view. While a small telescope can easily resolve the largest satellite Titan, you can also see Tethys, Rhea and Dione in aperture as small as 4″. The clue is to watch carefully along the boundaries of the ring system. These moons stay in close and with good conditions you can catch their “wink” easily!

Saturday, December 24 – ‘Twas the night before Christmas and all through the house, not a creature was stirring…except for the mouse with the telescope who wants to see a multiple star system! Why don’t we join him tonight and have a look at very nice, and easily resolved, Sigma Orionis.

This particular system is easily found without a map. By identifying the three “belt” stars of Orion, go to the easternmost – Alnitak. Sigma is the first star south of it. In the telescope you will find a beautiful combination of four stars. The 3.8 magnitude white primary commands attention. With a designation of “A/B,” this super-massive and extremely bright pair is far too close (about 100 AU apart) to be split with a small scope. Looking 11″ to the southwest, you will discover the 10th magnitude white “C” star and you will see the 7.2 magnitude red “D” star 13″ to the east. Further away yet at a distance of 42″ to the east-northeast is the 6.5 magnitude blue “E” star.
Sharp-eyed observers will also note another multiple system in the same field of view to the northwest. This is Struve 761. As an “all white” system of similar magnitudes, you will see two residing east/west of each other and the third companion to the north. What we are looking at is a system that is about 1,500 light years away from us in the rich, star-forming region of Orion. Give that mouse a piece of cheese!

And even if that mouse just has a pair of binoculars, it’s in for another treat tonight as a great opportunity arises for binocular and small scope users to locate bright asteroid Vesta. Around 9:00 p.m. local time, look for the constellation of Gemini rising and identify bright Pollux – the southeastern of the pair. A little less than a fistwidth to the southwest of Pollux you will see Delta Geminorum at the “waist” of Gemini. Aim there and you will find Vesta very close to Delta! For accurate locator charts, be sure to visit Heavens-Above.

Today in 1968 Apollo 8 became the first manned spacecraft to orbit the Moon. If you should be out when the Moon rises, have a look at its beautiful cold surface for features we often see during the waxing phases – the fantastic Copernicus and the peaceful Sinus Iridum.

Sunday, December 25 – For a huge portion of the United States and Canada, this will be a Christmas morning to remember as the Moon will occult bright Spica in the hours before dawn! Please take the time to check this IOTA information page for the precise path locations and times in your area. May the morning bring you clear skies!

Like a present, Sir Isaac Newton was born on this day 1642 – Newton was the British “inventor” of calculus and a huge amount of what we now consider classical physics. Even young children are aware of his simple laws of motion and gravity. It wasn’t until the age of Einstein that things changed!

In keeping with the season, tonight’s astronomical object is a celebration of both starlight and asterism. Located 10 degrees east of Betelgeuse, NGC 2264 will be a challenging object. But thanks to the late rise of the Moon, the results will be quite worth it. Also known as “the Christmas Tree” cluster, this asterism of approximately 20 bright stars and over 100 fainter ones is embroiled in a faint nebula that will be lost to smaller scopes and binoculars, leaving only the delightful “Christmas Tree” shape adorned with stars.
The very brightest of these stars, S Monoceros, is fifth magnitude and will show clearly in the finderscope and as a double at magnification. Steady skies will reveal that the “star” at the top of our “tree” is also a visual double and home to the beautiful “Cone Nebula!” Many of the stars will also appear to have companions, as well as tints of silver and gold. The visual effect of this splendid open cluster is well worth the challenge it presents.

Thank you all for such a spectacular year. Here’s wishing everyone the most joyous of holiday seasons! Light speed… ~Tammy Plotner

Posted on by Fraser Cain

Moving the Newsletter to Feedblitz

For the 35,000 or so of you receiving Universe Today by email, things are going to seem a little strange for the next few days. I’m moving the mailing service from my webserver to a service called Feedblitz. What this does is take the last 24 hours worth of stories on Universe Today and mail them out to all the subscribers. If I’ve done everything right, the newsletter will look almost identical to the one you’ve been getting in the past; however, it will have new “unsubscribe” information down at the bottom. You’ll get an email today confirming that your address has been transfered, and future emails will be coming from [email protected], so update your address books, etc. As always, please let me know if you have any questions or comments, and I’ll help however I can. For some of you, this will be the first email you’ve received from me in a couple of months, which means I’ve figured out a solution to stop the newsletter from getting blocked.

Thanks!

Fraser Cain
Publisher
Universe Today