Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.aaa.org/EyepieceFiles/aaa/2015_12_December_Eyepiece.pdf Дата изменения: Mon Dec 7 20:51:50 2015 Дата индексирования: Sun Apr 10 03:48:00 2016 Кодировка: Поисковые слова: р р р с р с р р р с р с р р р с с р р с р с р р рер рере

NASA/JHUAPL/SwRI

New Horizons' false color image shows subtleties of Pluto's regions. Final maneuvers in Nov were made for a 2019 Kuiper Belt Object visit.

Journal of the Amateur Astronomers Association of New York
December 2015 V
olume 64 Number 12; ISSN 0146-7662

Our Solo Sun Stranded without Star Siblings
AAA LECTURE SERIES By Rafael Ferreira Double-sun planets like Tatooine from Star Wars are no longer the stuff of science fiction ­ thanks to Kepler. That exoplanet-hunting space telescope has discovered planets in multiple star systems, like Kepler-16b. So, is our Sun's single status unusual? On Nov 6, Stella Offner from the University of Massachusetts presented "Our L onely S un: Ex ploring W hy Many Stars are Born with Siblings" a s pa r t of the AAA Lecture Series, explaining how unique our Sun really is. Before we can understand our unusual Sun, we must first look at the overall picture of stellar formation. Stars form in Giant Molecular Clouds (GMCs). GMCs contain enough Stella Offner dense gas and dust Mizar in Ursa Major is a quadruple star systo form hundreds tem. Most stars similar in mass to our Sun formed with companions, but the Sun is single. of thousands of Sun-like stars. GMCs are very cold, and their density is very high, about 1,000 to 10,000 atoms per cubic centimeter on average. By way of comparison, average density in interstellar space is just one hydrogen atom per cubic centimeter. To make the dense core of a star like our Sun, you need 10 6 cm3 hydrogen atoms occupying a given space within the GMC. So how do you increase density by two orders of magnitude? Gravity! Yes, the gravity that you experience on Earth every day is the key component to making stars. Once a clump of gas within the GMC reaches a certain density, gravity takes over and works its magic. The force of outward gas pressure that could fight gravity is weak, because the GMC temperature is so cold. The dense clump, or core, reaches a critical point where the gravity wins and a runaway collapse forms a protostar. Ultimately, the gas becomes hot enough to prevent further gravitational collapse. An accretion disk of
Our Solo Sun (cont'd on Page 4)

The Giants of Black Holes and the Information Paradox
UNDERSTANDING THE UNIVERSE By Alan Rude For three decades, Stephen Hawking and his colleague Jacob Bekenstein were either collaborators or adversaries. The friendly fights of Hawking and Bekenstein, who passed away this year, changed our understanding of black holes . Their greatest work was in connection with what is called the Black Hole Information Paradox (BHIP). BHIP reflects the conflict between the two main theories of the universe: quantum mechanics and general relativity. The "Theory of Everything," a Holy Grail for physicists, seeks to unite the two. Due to its very nature, quantum mechanics cannot be used to make precise predictions. It can only determine the probability that a particular thing will happen. Information about objects or systems is encoded in a wave function; therefore, inf orm ation is nev er truly lost. Einstein's theory of general relativity, which celebrated its 100th anniversary last month, concerns gravity and space-time. Unlike quantum mechanics, it predicts exactly what will happen. General relativity determined that extremely compact and massive objects would form black holes. Gravity is immensely strong in their vicinity, warping space-time dramatically. An object drawn that gets too close and crosses the black hole's event horizon will never be able to escape. That object and all its in- NASA/M. W eiss (Chandra X-ray Center) formation becomes lost, Hawking believes he can solve the black hole information paradox. violating quantum theory. In 1972, Bekenstein suggested that black holes should have a well-defined entropy, the degree of disorder for a thermodynamic system. He defined the entropy of a black hole as proportional to its event horizon. Hawking initially opposed Bekenstein on the grounds that a black hole could not radiate energy, so it could not have entropy. But two years later, Hawking determined that black holes did emit a very small amount of particle radiation, known as Hawking Radiation.
Black Holes (cont'd on Page 4)

THIS MONTH: A A A W int er C lass b egins Dec 2 and A A A L ect ur e Ser ies cont inues on Dec 6


December 2015

WHAT'S UP IN THE SKY
AAA Observers' Guide
By Tony Faddoul

The 2015 Gemenids
The Geminid Meteor Shower is one of the most stable shooting star events each year. This year, it peaks on a moonless December night and will provide a spectacular show of about a hundred meteors per hour. When is the Peak? The Geminids will peak in the early hours of Dec 14. The best viewing window is late night on Dec 13 until morning twilight. Under perfect conditions (clear, dark skies), you'll be able to view over 100 shooting stars every hour at the peak. The nights before and after will have similar numbers of visible meteors. The moon will set before midnight, allowing for a perfect show. Who can see the Geminids? This bright meteor shower favors the skies of the northern hemisphere. Those who live further south will see fewer meteors. The southern hemisphere can see about 25 meteors per hour at peak under dark skies. What color are the Geminids? Geminid meteors hit Earth's upper atmosphere at 80,000 mph and vaporize in a multi-colored display. Approximately 65% of the shooting stars are white, 25% yellow, and the remaining 10% are blue, red and green. How do I view the meteor shower? Looking north to northeast, the meteors will seem to originate from the constellation Gemini, but you don't need to locate their radiant ­ the Geminids appear to strike everywhere across the sky. Find a dark spot, as far away as possible from light pollution, and hope for clear skies. There is no need for any equipment. Just look up, and enjoy. What is the mythology behind the Geminids? Castor and Pollux were the twin sons of Tyndareus and Leda, King and Queen of Sparta. Castor was a mortal, but Pollux was a demigod. He was the result of a union between Leda and the god Zeus, who disguised himself as swan one night. Pollux was a fighter, and Castor was a horseman who were among the heroes who sailed with Jason and the Argonauts. Extraordinarily brave, they were inseparable and always fought as a team. One day, they got into a quarrel with their cousins, and Castor was killed. Devastated by his brother's death, Pollux was offered a choice by Zeus to keep his immortality or share it with Castor and save him. He chose the latter, and Zeus placed them together forever in the sky as stars. You can see the constellation Gemini manly during fall and winter. Sources: timeanddate.com; wiki; earthsky.org.
Follow veteran sky watcher Tony Faddoul each month, as he points our minds and our scopes toward the night sky.

December's Evening Planets: Neptune is in Aquarius
the Water Bearer until 11 PM and setting earlier every night until 9 PM by the end of the month. Uranus is in Pisces the Fish until 2 AM and setting earlier until midnight by the end of the month. Jupiter will be between in Leo the Lion and Virgo the Virgin as of midnight rising earlier every night until 10 PM by the end of the month.

December's Evening Stars: Spot The Winter Triangle: Sirius, the brightest star viewed from Earth, in Canis Major the Great Dog, Betelgeuse in Orion the Hunter, and Procyon in Canis Minor the Small Dog as of 8 PM. Find Castor and Pollux in Gemini the Twins, Rigel in Orion, Aldeberan in Taurus the Bull, and bright Capella in Auriga the Charioteer. See the stars of constellations Andromeda, Cassiopeia, Perseus, Cepheus, Draco, Aries, Taurus, and Ursa Major and Ursa Minor (the Big and Little Dippers) .

December's Morning Planets: Find bright Venus
between Virgo and Libra the Balance around 4 AM until sunrise. Mars will be in Virgo, and Jupiter will be between Leo and Virgo until sunrise. Mercury is in Sagittarius the Archer around 5 PM for about one hour during the second half of December. Saturn will be in Scorpio the Scorpion for one hour before sunrise in the second half of the month.

December's Morning Stars: The Winter Triangle of
Sirius, Betelgeuse, and Procyon will be up until morning. Find Capella in Auriga, Arcturus in BoЖtes the Herdsman, Spica in Virgo, and Aldeberan in Taurus until the morning. See the stars of Leo, Gemini, Orion, Cassiopeia, Cepheus, Draco, Perseus, Ursa Major, and Ursa Minor .

December "Skylights"
Dec 3 Dec 5 Last Quarter Moon at 2:40 AM Moon at apogee (251,530 miles away)

Dec 11 New Moon at 5:30 AM Dec 14 Geminid Meteor Shower peaks, pre-dawn Dec 18 First Quarter Moon at 10:14 AM Dec 21 Winter Solstice at 11:49 PM Moon at perigee (228,920 miles away) Dec 25 Full Moon at 6:11 AM Dec 31 Moon near bright Jupiter, pre-dawn
Times given in EST.

2


December 2015

Urban Astrophotography AAA Style
AAA AROUND TOWN & FOCUS ON THE UNIVERSE By Stan Honda Who says New York City is no place for astrophotography? AAA members have been turning their telescopes to the sky from balconies and rooftops across town, photographing night sky objects. They post their spectacular images and share their experiences on AAA-Astrophotography Google Groups, which anyone can join. Sign up and prepare to be wowed by the work of our members! Michael Krypel recently shared a stunning image of M42, the Orion Nebula, taken on Nov 4. It showed detail from the core, all the way out to its fringes of reddish gas. Although M42 is one of the most photographed deep sky objects, Michael's photo is especially remarkable, because he shot it from the roof of his apartment building on East 65 th Street and Second Avenue in Manhattan. How did he do it? "I hav e w anted to photograph the Orion N ebula since I first saw pictures of it as a child," Micha el sa id. "I am a beginner astrophotographer, and this was my first attempt at stacking images to photograph a deep sky object. I have seen the Orion Nebula many times through a telescope so I knew that it was bright and visible from New York City. It seemed like a good object with which to start. It was a clear night here, so I set up just after sunset on my roof. While I was waiting for Orion to rise, I practiced taking pictures of the Andromeda galaxy, the Pleiades star cluster, the Double Cluster and the M15 globular cluster. Once Orion rose, I focused on it. The images of the Orion Nebula became clearer as it rose further from the horizon. As this was my first time, I wasn't sure whether any of the images would come out well or be good enough to stack. I think I lucked out." All astrophotographers will attest that the closer an object gets to the zenith, the better the image. Michael's best shots were taken between midnight and Michael Krypel The Orion Nebula (M42) imaged from Manhattan. 1:00 AM. His set up included a Takahashi FSQ85 -ED refractor telescope, Celestron AVX mount, and a Canon 60Da camera (digital SLR factory-modified to be sensitive to the hydrogen alpha wavelength), with ISO 800 for 30-second exposures. As for processing the image, Michael said, "Out of the 80 frames [I shot during the night] only 34 seemed good enough to stack; in the others the stars were somewhat oblong instead of round. So the total exposure time for this image is 17 minutes. I ended up aligning these manually in Photoshop, stacking them using a median filter and then applying the Levels and Curves adjustment layers." 3

The lovely composition of Michael's image is very different from how M42 is normally shown: "I aligned the im age in this way because I was hoping to also capture the Running Man Nebula and place it to the left of the Orion Nebula. Unfortunately, I wasn't able to pick up enough signal to image it this time -- that's okay, though, I'm still learning!" Meanwhile, across the East River, Stephen DiCasa posted an image taken on Oct 19 of an object closer to home ­ the Moon: "Celestron retweeted this tweet n DiCasa of mine. It's a StepheThe Moon from a balcony in Queens. shot of the moon I took a few nights ago from my balcony in Astoria. " New to AAA, Stephen only purchased his telescope in July. The beautiful shot from a day before first quarter shows an almost 3-dimensional view of the Moon's craters and other features near the terminator. "I took this w hile I w as on Periscope with my telescope. Thought it was a cool idea, and people seemed to like it. If you're not aware, Periscope is a live-streaming app where you broadcast right from your phone. At first I tried to hold the phone up to the eyepiece, but it worked out much better attaching the DSLR to the telescope and showing people the LCD screen (on the back of the camera). I snapped the shot, tweeted it out about an hour later, and Celestron retweeted it. I picked the moon because really, that's the only object that can show up well enough for Periscope, at least for right now." Setting his Celestron Nexstar Evolution 8 -inch reflector telescope (2000mm, f10) to prime focus, Stephen shot with a Canon 5D Mark III camera, using 1/250 shutter speed at ISO 1250. The Canon 5D full-frame digital SLR camera provides a high level of sharpness and detail. "I did som e w ork to it in post [processing] . Brought up the blacks and [brought] down the highlights to make it as dynamic as possible without making it look weird and distorted. I was attempting to just make it look in the picture how it does to your eye." More of Michael's photos can be found at http:// www.aaa.org/gallery-2/astrophotography/michael-krypelgallery/. Follow Stephen on Twitter/Periscope at https:// twitter.com/DiCasaFilm/status/656271100716949504 . From a Manhattan rooftop to a Queens balcony, AAA Members prove that New York City is a great place for astrophotography. To join the AAA -Astrophotography Google Groups, email me at stanhonda@gmail.com.

Explore more night sky photography at

www.stanhonda.com.
Submit your photography questions to

stanhonda@gmail.com.

Stan Honda is a professional photographer. Formerly with Agence France-Presse, Stan covered the Space Shuttle program. In his "Focus on the Universe" column, he shares his night sky images and explores his passions for astronomy and photography.


December 2015 Our Solo Sun (cont'd from Page 1) Black Holes (cont'd from page 1)

material surrounds the protostar to fuel the potential star. The law of conservation of angular momentum comes into play, and as the core draws in material, it spins faster, like a figure skater pulling in his or her arms. Offner's job is to model the extreme conditions that occur within GMCs and look at the physics affecting the formation of protostars. During the collapse process, instability can cause a protostar to fragment either in its core or accretion disk. This can lead to multiple protostars that create a binary, triple, or quadruple star system. Disk fragmentation usually occurs for stars with 10 or more solar masses. Core fragmentation occurs when the extended structure around its equator, causes the core split. For some reason, fragmentation did not occur during the formation of our Sun. According to Offner, most star systems are single or binary; triple and quadruple systems are more rare. Massive stars of 10 solar masses or more are more likely to form in GMCs. They have a higher tendency to have siblings, so multiple star systems are common. About 60% of observed stars similar to our Sun have a stellar companion. Stars less massive than the Sun tend to be single. But scientists like Offner struggle to be able to observe star formation and the fragmentation process in GMCs. That's where the Atacama Large Millimeter Array (ALMA) can help. An interferometer, ALMA's array of antennas work together as one telescope, collecting multiple images and data that can be pieced together. It is particularly useful for fine resolution of luminous objects like close binary stars. ALMA will be able to probe the light within the cold, dense GMCs to see star formation, but it is not yet fully operational. Offner's role is to provide theory to fill in the gaps from the limited observations ALMA makes now. She starts with the basic physical variables in GMCs such as mass, density, velocity, temperature, and position and then makes predictions about what ALMA's full array may observe. Until ALMA is fully operational, observations from the Kepler Space Telescope can help identify multiple star systems. It sees light dips from the transit of planets crossing in front of a star. Kepler has discovered several multiple star systems, even a quadruple star system. Some binary systems have been found with a protoplanetary disk ­ actual Tatooines in the making! The observations made so far and the theoretical work by scientists like Offner suggest that our Sun is unique to be a star without a sibling. Most of the stars being formed in stellar nurseries like GMCs do have stellar companions. ALMA may be able to confirm that ALMA (ESO/NAOJ/NRAO) some day soon, and The high resolution and sensitivity of the Atacama Large Millimeter Array in the Chile- shed some light on how these multiple an Andes may detect star birth during the early universe and detailed imaging of local star systems are star and planet formation. formed. 4

Hawking not only showed that black holes emit particle radiation, but also that they will eventually radiate themselves out of existence. But this presented a new problem: w here does the information in the black hole go once the black hole evaporates? If it disa ppea r s a long with the bla ck hole, tha t again violates quantum mechanics. But if the information leaves with the radiation, that violates general relativity, which holds that nothing, not even light, can escape a black hole. Herein lies the black hole information paradox. Hawking's calculations showed that Hawking Radiation did not preserve the information inside an evaporating black hole. For three decades, Hawking's position was clear: there was no paradox. Quantum theory must be incomplete, and a new and improved version will one day show that matter and information can be completely destroyed when a black hole evaporates. But quantum mechanics has remained solid over the years, so several physicists began to think that it was general relativity that needed altering. In 1992, Leonard Susskind, Larus Thorlacius, and Gerard 't Hooft introduced the notion of "complementarity." Complementarity relies on "holography," whereby threedimensional equations inside a black hole that factor in gravity become two-dimensional quantum equations just above the event horizon that don't. One physics mysteriously transforms into another. Information is both inside and outside of the black hole, depending on your perspective. Outside, an observer sees it accumulate at the event horizon where it is stored until it leaves with Hawking Radiation. Observers falling into a black hole see the information inside. Complementarity preserves quantum theory, but it does require some fine tuning to general relativity. In 2005, Hawking came around to this point of view that information in black holes is not lost. But complementarity doesn't answer everything. There are no equations yet that can describe the subtle evaporation process. Joseph Polchinski and his colleagues made an attempt and discovered a flaw in complementarity. It breaks down when a black hole is half-way evaporated. At that point, too much information has radiated away for holography to hold up for the interior. With no interior, an observer cannot fall into a black hole. In fact, he would burn to a crisp just outside the event horizon at a place called a "firewall." But, no such site should exist. General relativity states than the event horizon is merely a point of no return and nothing else should happen there. For complementarity to work, general relativity would need a major overhaul. This has caused a lot of consternation for physicists. There just aren't enough equations to describe how evaporation and firewalls work. This summer, Hawking embraced holography and the idea that information is stored in 2D at the event horizon, evaporating away with Hawking Radiation. He plans to publish soon, but he will still have to modify general relativity to prove that information is not lost. Despite all this confusion, the essential properties of black holes remain the same. And certainly, if you fell in, you wouldn't be able to get out.
Sources: profmattstrassler.com; cnn.com; huffingtonpost.com; "Guest Post: Joe Polchinski on Black Holes, Complementarity, and Firewalls; Cosmic Variance," blog.discovermagazine.com; nature.com, nytimes.com.


December 2015

Where Do We Go From Here?
BOTH SIDES NOW

Let's Go to an Asteroid!
By Stanley Fertig Really, I mean it! An asteroid is by far our best bet for the next celestial body where humans should set foot. Why, you ask? Well, asteroids offer several tangible advantages over other potential targets for manned exploration. Think of the science we can learn, the resources we can find, and the money we can make. First, by examining asteroids close-up, we can study the very origins of the Solar System and the Earth. After all, our planet began as a large asteroid. Asteroids today are like the leftover building materials from a construction project. From them, we can learn a great deal about the Solar System's formation and composition, and by extrapolation, about those processes in exoplanet systems. More specifically, going to an asteroid can help us uncover the source of the water that today covers two thirds of our planet. The Rosetta mission recently disqualiTouchstone Pictures fied comets simiAsteroid drilling depicted in Armageddon. lar to 67P as the source by analyzing isotopes in its water. A similar analysis needs to be done on asteroids. The largest asteroid, Ceres, is estimated to possess more subsurface water than is found in all the oceans of Earth combined! At present, asteroids are the prime suspects for bringing H2O to early Earth and enabling life as we know it. As a matter of fact, it is possible that asteroids seeded the that life itself by panspermia, delivering microorganisms or the chemical building blocks of life. We won't know unless we go find out. Of course, you say, all that could be done via robotic exploration. It is true that we require special transportation and life support, but humans are better explorers, quicker and more discerning than machines. Humans could do much more at an asteroid than just analyze water and organics. Asteroids are rich not only in water, but also in valuable metals and minerals. It's not simply altruism or scientific curiosity that drives companies like Planetary Resources to want to visit near-Earth asteroids ­ they aim to capture and mine them. A relatively small rock, say 500 meters in diameter, can contain tens of billions of dollars worth of materials. That's before you even take into account the fact that a kilogram of something in space is worth far more than a kilogram of the same material on Earth, due to the cost involved in acquiring it. Asteroid mining could arguably fund itself or potentially pay off all of Earth's collective space programs combined, and still make a profit. 5

There are additional benefits to mining asteroids. Once you've bored a hole in a near-Earth asteroid with a tunnelboring machine and removed the valuable water and minerals, a n Sta par t T an or the hollowed-out inte- WBshingtortha,te iDethementgof str-dspmtation tunnel" ig Be "s lar e ia eter rior can then provide boring machine at 57.5 feet across. a safe place to construct a colony or space station. The exterior of the asteroid can provide unmatched protection against both meteorites and radiation. Now, attach a rocket engine to your asteroid -cumspace-station, and you've got yourself a robust, interplanetary spaceship that could possibly travel to Mars or beyond. This would kill several birds with one stone. A spaceship that lives in space saves on the enormous costs of lifting a large vessel off the Earth and into space. No need. It's already there. Unfortunately, the asteroid giveth, and it taketh away. Ask any dinosaur. Oh wait, you can't. One thing we know for sure is that somewhere, some time, some asteroid has got our number. It's not a matter of if but rather of when a large asteroid will impact the Earth again and potentially cause humans to suffer the same fate as the dinosaurs. But unlike those early reptilian inhabitants of Earth, humans possess the ability to track asteroids and perhaps prevent such a catastrophe. Various technological solutions have been proposed, including ablation via large mirrors and sunlight or with lasers, or by exerting gravitational tugs with rockets in close proximity. But it is critical that we test such technologies in advance so that we have the solution ready when needed. By visiting an asteroid, we can have an in situ laboratory to conduct those tests. Let's figure out how to nudge an asteroid and save the world!

Adolphis, will come dangerously close to Earth in 2029.

Although most asteroids lie in the Asteroid Belt beyond Mars, more than 10,000 near-Earth asteroids have been located. An estimated million more are yet to be discovered. We closely monitor those that we have identified for obvious reasons. But those same potential threats can become potential targets for manned missions. At distances not much further away than the Moon, near Earth asteroids offer a great destination for exploration that is much easier to get to than any planet. And because asteroids are small and have low gravity, takeoff for a return trip home is easier too. So, look out Bruce Willis, here we come!
Sources: planetaryresources.com; abundantplanet.com; space.com; nasa.gov.


December 2015

Make the Moon a Priority
By Richard Brounstein The next venture astronauts make into space should be to visit an old friend, the Moon. This destination makes the most sense for continued human exploration of the Solar System. Despite over 50 years of human activity in space, including six successful landings on the Moon in the 1960s and 1970s, we still don't know how to establish a permanent, self sustained presence on another world. Let's finish what we started! Launching to and landing heavy objects on the Moon is difficult, but we know how to do it. We've done it before. However, current space technology is still lacking in many of the areas necessary for building a permanent settlement off Earth. The challenges of colonizing another celestial body are many: we must protect against deadly cosmic radiation, produce abundant and various foods, harness water from ice and rocks, extract oxygen, prospect, mine, and refine materials for construction and repairs, manufacture fuel for vehicles, and keep humans healthy and safe in a low-gravity environment without assistance from Earth. The International Space Station is currently making advancements in some of these areas. But the ISS is an Earth dependent system. It has no access to materials that aren't brought there from Earth. In order to learn how to gather resources in situ, we need to practice in a place where local materials exist. The Moon is the best place for this. The lunar poles have deep craters that almost certainly have trapped water ice. Rare Earth elements like europium, lanthanum, and cerium, used in electronic devices and energy plants, are found in large quantities on the Moon. As these minerals become more rare and prohibitively expensive to mine safely and in an environmentally-friendly manner on Earth, an alternate source like the Moon is worth considering.

there. Rare ture nuclear no waste or greatest ener

on Earth, Helium-3 gas could potentially fuel fufusion power plants. Efficient and with virtually radiation, Helium-3 fusion reactors could be the gy source in all of history.

ESA/Forster + Partners

Artist's rendering of a 3-D printing robot adding a protective layer to the inflatable dome shell of a lunar base.

NASA/SAIC/Pat Rawlings

Artist's concept of a lunar mining facility harvesting oxygen from the volcanic soil of the eastern Mare Serenitatis.

In fact, the greatest reason to settle on the Moon may be the economic value it offers Earth. Space agencies already struggle to find support for expensive manned missions from their home nations, and governments will likely refuse to keep funding unprofitable endeavors. We could end up with another 50 years of exploration stagnation. But, a lunar base could partially pay for itself. In addition to the valuable rare earth elements that can be mined there, Helium-3 is abundant 6

An initial lunar colony doesn't have to be a thriving metropolis of thousands of relocated Earthlings. It can serve more as a science and refueling station. On lunar outposts, scientists and engineers can work for months or years and still be able to return to home to Earth. There, they can develop and test the technologies and skills needed to maintain a self-sufficient space colony, which could be used for future colonies on an asteroid, Mars, or elsewhere in the Solar System. Much of the Moon remains unexplored, and there is a great deal of science to accomplish there. Aside from what we can learn about the Moon itself, its location offers us an opportunity to learn about other celestial bodies. The Moon is a great place to house observatories. It has virtually no atmosphere to interfere with a telescope. An observatory on the lunar surface offers the advantages of a space telescope with the access and maintainability of ground -based observatory. A lunar base could also serve as a waystation to resupply and refuel spacecraft travelling throughout the Solar System. It is cheaper and easier to launch from the surface of the Moon than from the surface of Earth. Today, it costs about $10,000 a pound to launch a payload from Earth. Vehicles that touch down on the Moon would be able to replenish food, fuel, and essential supplies and return to space more quickly. A lunar base could sell fuel and even booster rockets manufactured there. It would be our first gas station in space. Meanwhile, manned missions sent from a lunar colony could be deployed to repair satellites and space telescopes. The ISS could be a customer of a lunar outpost repair service. And of course, lunar tourism would be very popular for wealthy private explorers. The infrastructure of a lunar base would be a boon to the lunar tourism industry Once we've mastered the skills we need for colonization on the Moon, we will have a model to establish new permanent human colonies elsewhere in the Solar System. Perfecting those systems first on a cheaper and less risky prospect like the Moon, we could then focus on the challenges of sending humans to Mars. As technologies will inevitably improve over time, a lunar base will become more independent, and living in space will seem routine. The Moon is our stepping-stone to long-term living that is out of this world.
Sources: popsci.com; space.com; nbcnews.com; nasa.gov; wiki.


December 2015

Mad for Mars
Solar Wind Killed the Martian Climate Launched in 2013, NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft entered Mars' orbit last year and discovered the culprit behind its climate change ­ the Sun. Ancient Mars was a warm water world; valleys and mineral deposits today NASA Goddard Space Flight Center indicate the presence of rivCharged solar particles hit Mars' ers and lakes and maybe upper atmosphere. With no proIts tecting magnetic field, they pile up oceans in Mars' past. atmosphere was thick enough in a bow shock. During solar storms, they push into the atmos- to support liquid water on the phere and accelerate ion escape. surface. But billions of years ago, Mars began to lose its atmosphere, and it became a cold, dry place. So, how did that happen? Mars also lost its global magnetic field long ago and became unprotected from solar wind. The stream of particles that flows out from the Sun's atmosphere achieves speeds of one million mph. As that solar wind races by unprotected Mars, it generates an electric field that hits Mars' upper atmosphere with an energy equivalent to a million tons of TNT an hour, accelerates ions there and shooting them into space. "T hat's one large nuclear w eapon per hour, if you like," sa id MAVEN tea m member J a sper Halekas. Results show that ion loss occurs in three regions at a rate of 0.25 lbs. per second. 75% escapes down the "tail" of solar wind flowing behind Mars; another 25% leaves through polar plumes and a small amount from an extended cloud of gas surrounding Mars. During solar storms, atmosphere erosion will increase 10 to 20 times, losing as much as five lbs. of ions a second. AMW Source: mars.nasa.gov; nytimes.com.

Celestial Selection of the Month
Galaxy Cluster Abell 1689 2.2 billion lightyears away in the constellation Virgo is one of the most massive galaxy clusters known. Abell 1689 contains over 160,000 globular clusters. Those dense, spherical objects host hundreds of thousands of stars that orbit a galactic core. About 95% NASA, ESA, STScI/AURA, J. Blakeslee (NRC Herzberg Astroof globular clusters physics Prog., Dominion Astrophysical Obs.), H. Ford (JHU) formed in the first cou- Abell 1689 galaxy cluster was imaged in visible and infrared by Hubble with a 34ple billion years after hour exposure. Gravitational lensing the Big Bang, so their magnifies distant galaxies behind it. stars are some of the oldest in the universe. 2 million light -years across, Abell 1689 is speeding away from us at 49,863 km/sec, and gasses there can reach temperatures up to 100 million degrees. Images of this enormous galaxy cluster demonstrate the effect of gravitational lensing. Einstein's theory of general relativity predicted that massive objects can bend and magnify the light that's behind it, like a lens, which lets an observer see objects that are even further away. In the Hubble image above, the yellow galaxies reside in Abell 1689, while the streaks and arcs of blue are galaxies perhaps 13 billion light -years away that are forming hot, new stars. Studying images like these not only brings the distant universe closer to us but also reveals its invisible wonders. The visible matter in Abell 1689 is responsible for only 1% of the mass required to warp space enough for this lensing, so dark matter must account for the rest. AM W Sources: spacetelescope.org; apod.nasa.gov; wiki.

Exo-citement
An Exoplanet is Born and Nearby Rocky Worlds Found Last month, astronomers using the Large Binocular Telescope in Arizona and the Magellan Telescopes in Chile saw for the first time the birth of an exoplanet . T h a n k s t o t h e K ep ler Sp a ce Telescope and other observatories, we've discovered thousands of extrasolar planets over the past 27 years, so why has it taken so long for us to see one form? Formation lasts for only a short period of a planet's life, so "it's unlik ely that y ou'll com e across a planet w hen it's still f orm ing, " said study coNASA/JPL-Caltech/R. Hurt (IPAC) leader Stephanie Sallum. They also form in regions that are full of gas and dust, obscuring observa- Exoplanet HD 219134b was tions by the transit method. The baby planet that is forming around Sun -like LkCa15, a 2-million-year- confirmed by Spitzer as our old star that is 450 light-years away, was found in a relatively empty gap between the star and a ring of nearest rocky neighbor at 21 light-years away. dust and gas. Hydrogen-alpha emissions in infrared images of the LkCa15 system indicated that hydrogen atoms were falling through the magnetic field of a hot new planet. Meanwhile, scientists using the MEarth-South telescope array in Chile announced in November the discovery of Gliese 1132b, the nearest Earth -sized rocky exoplanet at only 39 light-years away. I n J u ly, su p er -Earth HD 219134b was confirmed by the Spitzer Space Telescope as our closest rocky neighbor at only 21 light-years away. It's hot and lifeless, orbiting close to its home star. Both rocky exoplanets are ripe for study, but Gliese 1132b may be easier to examine. The light from its home star, a small, faint, red dwarf, doesn't drown out the exopla net. Red dwarfs are the most common type of star in our galaxy, and astronomers estimate about 1.4 rocky planets orbit each. And, while Gliese 1132b is also hot and uninhabitable ­ average surface temperature is 260°C ­ it is cool enough to support a substantial atmosphere. "T his w ill probably be our f irst opportunity to study the atm osphere of a rock y planet outside our S olar S y stem ," said Zach Berta-Thompson, who found Gliese 1132b. By analyzing wavelengths of light passing through the edges of its atmosphere, scientists can learn its composition. AM W Sources: arstechnica.com; spitzer.caltech.edu; techtimes.com; theverge.com. 7


December 2015

AAA Events on the Horizon
DECEMBER 2015
WED, Dec 2, 9, & 16 Continued in Jan & Feb 2016 AAA Winter Astronomy Class at Cicatelli Center ­ Manhattan, M
@ 6:30 pm ­ 8:30 pm

Other Astronomy Events in NYC
FRI, Dec 4 @ 7 pm Columbia Stargazing/Lecture Series at Pupin Hall ­ Manhattan, F "On the Care and Feeding of Black Holes" with Aleksey Generozov. Observing will follow, weather permitting. (outreach.astro.columbia.edu) SAT, Dec 5 @ 7 pm Our Solar System at Fort Greene Park ­ Brooklyn, FT NYC Urban Park Rangers guide naked eye observing and discuss the science, history, and folklore of the universe. (nycgovparks.org) MON, Dec 7 @ 7:30 pm AMNH Frontiers Lecture (Kaufmann Theater) ­ Manhattan, X "Dark M atter and the Dinosaurs" with Lisa Randall at the American Museum of Natural History explores an idea that connects a mass extinction event on Earth with a dark matter disk at the edge of the Solar System. (amnh.org) SAT, Dec 12 @ 6 pm Astronomy at Fort Totten Park Visitors Center ­ Queens, FT The New Moon tonight offers the best time of the month to observe faint objects such as galaxies and star clusters. (nycgovparks.org) @ 7 pm Astronomy at Van Cortlandt Park Nature Center ­ Bronx, FT Experience the Geminids Meteor Shower, which produces up to 120 multicolored meteors per hour at its peak. (nycgovparks.org) SUN, Dec 13 @ 7 pm Dark Nights, Bright Lights at Marine Park ­ Brooklyn, F NYC Urban Park Rangers guide naked eye observing and discuss the science, history, and folklore of the universe. Avenue U/E 33rd St. (nycgovparks.org) FRI, Dec 18 @ 7 pm Columbia Stargazing/Lecture Series at Pupin Hall ­ Manhattan, F "Our Magnetic Universe" with Susan Clark. Obser ving will follow, wea ther permitting. (outreach.astro.columbia.edu) SAT, Dec 19 @ 6 pm Astronomy at the Great Lawn in Central Park ­ Manhattan, FT NYC Parks Astronomy programs feature the use of telescopes and binoculars to observe the night sky. (nycgovparks.org) SUN, Dec 20 @ 6 pm Ursids Meteor Shower at Wolfe's Pond Park ­ Staten Island, FT At its peak, the shower produces 10 meteors per hour. (nycgovparks.org) TUES, Dec 29 @ 7 pm AMNH Astronomy Live (Hayden Planetarium) ­ Manhattan, X "Grand T our of the Univ erse" with Carter Emmart and Jackie Faherty explores the entire observable universe and gives a cosmic understanding of where we are and how we came to be. (amnh.org)
F: F ree; X: Tickets required (contact vendor for informat ion); T: Bring telescopes, binoculars.

The first three classes of David Kiefer's advanced course, " M easuring Distances in Space," will explor e methods used by a str onomer s to deter mine the distance to the Sun, the size of the Solar System, the distance to nearby stars, and stars' magnitude and luminosity.
Registration is closed.

FRI, Dec 4 Next: Jan 8 AAA Lecture at the American Museum of Natural History, P
@ 6:15 pm ­ 8 pm

"T he S tory of Galax y Ev olution f rom an X -ray Perspective" pr esented by Bret Lehmer from NASA. Free admission; open to the public. (In the Kaufmann Theater; Enter at 77th St)

FRI, Dec 18 AAA Observing at Floyd Bennett Field ­ Brooklyn, PTC
@ 7:30 pm ­ 9:30 pm

Fund us in the Community Garden parking lot.

MON, Dec 21 AMNH Winter Telescope Party with AAA ­ Manhattan, P
@ 7 pm

Enjoy hot chocolate and the night sky with AAA members on the Arthur Ross Terrace at the American Museum of Natural History, following a presentation in the Hayden Planetarium. (Purchase tickets at amnh.org.)
M: Members only; P: Public event; T: Bring telescopes, binoculars; C: Cancelled if cloudy.

For location & cancellation information visit www.aaa.org.

A Message from the AAA President
Hello Members, In the next month, you will be receiving an AAA membership renewal letter in the mail. Please renew as soon as you can. If you joined in just the last few months, no renewal is necessary, but a donation would be greatly appreciated. AAA's Lecture Series continues strong on Dec 4 with Bret Lehmer (NASA) presenting "T he S tory of Galax y Ev olution f rom an X-ray Perspective." F ind the full schedule of 2015-2016 lectures at: www.aaa.org/lectures. The AAA calendar updates frequently with events throughout New York, so be sure to check it often at www.aaa.org/ calendar. I would like to wish you all Happy Holidays and a very productive New Year, and I hope you will consider including AAA in your year-end giving.

Now Playing... INSIGNIFICANT
Insignificant tells th e tr u e stor ies of Cecilia P a yn e a n d Annie Jump Cannon, the pioneering women behind the stars, and their unheralded triumphs in astronomy. On Stage at the Kraine Theater (85 E 4 St) Dec 3-19

$15 Discounted Tickets for AAA Members!
Use code "L eav it t " www.infinitevarietynyc.org

Marcelo Cabrera President, AAA

Eyepiece Staff
December 2015 Issue
Editor-in-Chief: Amy M. Wagner
Copy Editor: Rich a r d Br ou n stein
Contributing Writers: R ich ar d B r ou n st ein , T on y Fad d ou l, Rafael Ferreira, Stanley Fertig, Stan Honda, and Alan Rude Eyepiece Logo and Graphic Design: R or i B ald ar i Administrative Support: J oe Delf au sse
Printing by McVicker & Higginbotha m

The Amateur Astronomers' Association of New York
Info, E vents, and Obser ving: president@aaa. org or 2 12 -535-2922 Membership: members@aaa. org Eyepiece: editor@aaa.org

Visit us online at www.aaa.org.

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