Take a look through any book on our Solar System, and you’ll see beautiful photographs of every planet – except one. Eight of our nine planets have been visited up close by a spacecraft, and we’ve got the breathtaking photos to prove it. Pluto’s the last holdout, revealing just a few fuzzy pixels in even the most powerful ground and space-based telescopes. But with the launch of New Horizons in January, bound to arrive at Pluto in 9 years, we’re one step closer to completing our planetary collection – and answering some big scientific questions about the nature of objects in the Kuiper Belt. Alan Stern is the Executive Director of the Space Science and Engineering Division, at the Southwest Research Institute. He’s New Horizon’s Principal Investigator.
Continue reading “Podcast: There Goes New Horizons”
A Closer Look at Telesto
A false colour view of the Trojan moon Telesto. Image credit: NASA/JPL/SSI Click to enlarge
These views show surface features and color variation on the Trojan moon Telesto. The smooth surface of this moon suggests that, like Pandora, it is covered with a mantle of fine, dust-sized icy material.
The monochrome image was taken in visible light (see PIA07696). To create the false-color view, ultraviolet, green and infrared images were combined into a single black and white picture that isolates and maps regional color differences. This “color map” was then superposed over a clear-filter image. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy soil.
Tiny Telesto is a mere 24 kilometers (15 miles) wide.
All images were acquired with the Cassini spacecraft narrow-angle camera on Dec. 25, 2005 at a distance of approximately 20,000 kilometers (12,000 miles) from Telesto and at a Sun-Telesto-spacecraft, or phase, angle of 58 degrees. Image scale is 118 meters (387 feet) 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
Mega Solar Systems Discovered
An illustration comparing the size of a gargantuan star and its dusty disk with our solar system. Image credit: NASA/JPL Click to enlarge
NASA’s Spitzer Space Telescope has identified two huge “hypergiant” stars circled by monstrous disks of what might be planet-forming dust. The findings surprised astronomers because stars as big as these were thought to be inhospitable to planets.
“These extremely massive stars are tremendously hot and bright and have very strong winds, making the job of building planets difficult,” said Joel Kastner of the Rochester Institute of Technology in New York. “Our data suggest that the planet-forming process may be hardier than previously believed, occurring around even the most massive stars that nature produces.”
Kastner is first author of a paper describing the research in the Feb. 10 issue of Astrophysical Journal Letters.
Dusty disks around stars are thought to be signposts for present or future planetary systems. Our own sun is orbited by a thin disk of planetary debris, called the Kuiper Belt, which includes dust, comets and larger bodies similar to Pluto.
Last year, astronomers using Spitzer reported finding a dust disk around a miniature star, or brown dwarf, with only eight one-thousandths the mass of the sun ( http://www.spitzer.caltech.edu/Media/happenings/20051129/). Disks have also been spotted before around stars five times more massive than the sun.
The new Spitzer results expand the range of stars that sport disks to include the “extra large.” The infrared telescope detected enormous amounts of dust around two positively plump stars, R 66 and R 126, located in the Milky Way’s nearest neighbor galaxy, the Large Magellanic Cloud. Called hypergiants, these blazing hot stars are aging descendents of the most massive class of stars, referred to as “O” stars. They are 30 and 70 times the mass of the sun, respectively. If a hypergiant were located at the sun’s position in our solar system, all the inner planets, including Earth, would fit comfortably within its circumference.
Astronomers estimate that the stars’ disks are also bloated, spreading all the way out to an orbit about 60 times more distant than Pluto’s around the sun. The disks are probably loaded with about ten times as much mass as is contained in the Kuiper Belt. Kastner and his colleagues say these dusty structures might represent the first or last steps of the planet-forming process. If the latter, then the disks can be thought of as enlarged versions of our Kuiper Belt.
“These disks may be well-populated with comets and other larger bodies called planetesimals,” said Kastner. “They might be thought of as Kuiper Belts on steroids.”
Spitzer detected the disks during a survey of 60 bright stars thought to be wrapped in spherical cocoons of dust. According to Kastner, R 66 and R 126 “stuck out like sore thumbs” because their light signatures, or spectra, indicated the presence of flattened disks. He and his team believe these disks whirl around the hypergiant stars, but they say it is possible the giant disks orbit unseen, slightly smaller companion stars.
A close inspection of the dust making up the disks revealed the presence of sand-like planetary building blocks called silicates. In addition, the disk around R 66 showed signs of dust clumping in the form of silicate crystals and larger dust grains. Such clumping can be a significant step in the construction of planets.
Stars as massive as R 66 and R 126 don’t live very long. They burn through all of their nuclear fuel in only a few million years, and go out with a bang, in fiery explosions called supernovae. Their short life spans don’t leave much time for planets, or life, to evolve. Any planets that might crop up would probably be destroyed when the stars blast apart.
“We do not know if planets like those in our solar system are able to form in the highly energetic, dynamic environment of these massive stars, but if they could, their existence would be a short and exciting one,” said Charles Beichman, an astronomer at NASA’s Jet Propulsion Laboratory and the California Institute of Technology, both in Pasadena.
Other authors of this work include Catherine L. Buchanan of the Rochester Institute of Technology, and B. Sargent and W. J. Forrest of the University of Rochester, N.Y.
The Jet Propulsion Laboratory manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech. JPL is a division of Caltech. Spitzer’s infrared spectrograph, which made the new observations, was built by Cornell University, Ithaca, N.Y. Its development was led by Jim Houck of Cornell.
An artist concept of a hypergiant and its disk, plus additional graphics and information, are available at http://www.spitzer.caltech.edu/spitzer.
Original Source: NASA News Release
DVD Review: Dune – Extended Edition
Frank Herbert wrote the book ‘Dune’ in 1965, while the Apollo program was yet to deliver on its promise of landing humans on the Moon. Since then, over 20 million copies were printed. In answer to a clamour from science fiction fans, David Lynch wrote the screen play for and brought to life a cinematic version. This, however, was not greatly appreciated by the general theatre audience. Nevertheless, science fiction fans kept asking for it and eventually a lengthened version was prepared for television viewing. From this, today, there is the longer Dune ? Extended Edition with 40 more minutes of film than in the original theatrical feature.
One can better understand this movie by considering the times. By 1965, humans had only just discovered space flight. Perhaps because of this, Herbert’s novel mostly focuses on human interactions as well as strange new worlds. Though the movie was made in 1984, there’s little to suggest the improved knowledge of space from the nearly 20 intervening years. Also, Lynch made his movie before computerized visual effects became main stream. Thus, achieving a believable visualisation of alien landscapes and space flight was a matter of using models, skilful depth perception and on screen trickery. Yet, there are many locations on Earth which can easily look like another planet. As well, adept cinematographers have been beguiling audiences for many years. So the capability existed to create a vision of humans far away in space and time.
Using this capability, Lynch does make the planet Dune into a special, alien world. Vistas of stars and multiple moons help the audience leave behind Earth. A driving score by Toto keeps the movie flowing, and the audience’s attention focused. Unfortunately, the premise of the movie, even with an extra 40 minutes, still doesn’t come clear. Having read and enjoyed Herbert’s book, a viewer can piece together most of the parts of the movie. Without having done this, the movie can’t stand on its own. The plot isn’t an adventure or a romance or some political suspense thriller. It is of a messiah coming to terms. Yet, the basis for being a messiah and the correlation with the people of Dune isn’t obvious in the film. The significance of some characters is vague to the point where one questions their inclusion. Even the most magical part, the folding of space to allow for interstellar travel, isn’t immediately obvious. The fact that a narrator has a voice over every now and again demonstrates this film’s disjoint nature.
This leads to the greatest short comings of this DVD, the lack of input from David Lynch himself. A few minutes of him explaining his goal and direction would have been a real coup. Instead, there are other bits, interesting but not as beneficial. Some stand alone deleted scenes are in the package, as well as short reviews of visual designs, sketches and techniques for special effects. Equally interesting are the reviews of the costume designer and how material was more scrounged than invented. This adds to the value of learning how to make a film but not of making the Dune film. Because of this short coming, this edition is a longer version rather than a definitive description of the film and its making.
However, even with these short comings, the film is grand. Wide open spaces, opulent throne rooms, and a tendency for oration rather than dialogue captures the image of a messiah. My review hardware was a standard television with its own small speakers. To do justice, this film needs a large screen with surround sound so the viewers’ senses are overtaken as they enter the intergalactic intrigue of 8000 years in the future. Even with the three hour running time of the extended edition, there’s a lot to keep a viewer’s interest.
Science fiction challenges a person to grapple with the normalities of the present. It lets them envision other worlds, other living beings, and other physical laws. In the movie Dune ? Extended Edition, David Lynch includes these and more in a perspective of political intrigue in another place at another time. After all, envisioning the future through science fiction gives us ideas with which to plan, while ignoring the future may put us out of even a messiah’s reach.
Review by Mark Mortimer
Hubble View of a Pinwheel-Shaped Galaxy
Spiral galaxy NGC 1309. Image credit: Hubble Click to enlarge
Looking like a child’s pinwheel ready to be set a spinning by a gentle breeze, this dramatic spiral galaxy is one of the latest viewed by NASA’s Hubble Space Telescope. Stunning details of the face-on spiral galaxy, cataloged as NGC 1309, are captured in this color image.
Recent observations of the galaxy taken in visible and infrared light come together in a colorful depiction of many of the galaxy’s features. Bright blue areas of star formation pepper the spiral arms, while ruddy dust lanes follow the spiral structure into a yellowish central nucleus of older-population stars. The image is complemented by myriad far-off background galaxies.
However, this galaxy image is more than just a pretty picture. It is helping astronomers to more accurately measure the expansion rate of the universe. NGC 1309 was home to supernova SN 2002fk, whose light reached Earth in September 2002. This supernova event, known as a Type Ia, resulted from a white dwarf star accreting matter from its companion in a binary star system. When the white dwarf collected enough mass and was no longer able to support itself, the star detonated, becoming the brightest object in the galaxy for several weeks.
Nearby Type Ia supernovae like SN 2002fk in NGC 1309 are used by astronomers to calibrate distance measures in the universe. By comparing nearby Type Ia supernovae to more distant ones, they can determine not only that the universe is expanding, but that this expansion is accelerating. However, this method only works if the distance to the host galaxies is known extremely well.
That’s where the Hubble Telescope comes into play. Since NGC 1309 is relatively close to us, the high resolution of Hubble’s Advanced Camera for Surveys can help accurately determine the distance to the galaxy by looking at the light output of a particular type of variable star called a Cepheid variable. Cepheids are well studied in our own galaxy, and vary regularly in brightness at a rate that is directly related to their total intrinsic brightness. By comparing their variation rate with how bright they appear, astronomers can deduce their distance. In this way, the Cepheids in NGC 1309 allow astronomers to accurately measure the distance to NGC 1309, and thus to SN 2002fk. The expansion of the universe was discovered by Edwin Hubble, the Hubble Space Telescope’s namesake, nearly a century ago, but the accelerating expansion is a recent discovery which has interesting consequences for cosmological models.
These Hubble images were taken in August and September 2005. NGC 1309 resides 100 million light-years (30 Megaparsecs) from Earth. It is one of about 200 galaxies that make up the Eridanus group of galaxies.
Original Source: Hubble News Release
The Case of the Stolen Stars
The central part of Messier 12. Image credit: ESO Click to enlarge
Based on observations with ESO’s Very Large Telescope, a team of Italian astronomers reports that the stellar cluster Messier 12 must have lost to our Milky Way galaxy close to one million low-mass stars.
“In the solar neighbourhood and in most stellar clusters, the least massive stars are the most common, and by far”, said Guido De Marchi (ESA), lead author of the study. “Our observations with ESO’s VLT show this is not the case for Messier 12.”
The team, which also includes Luigi Pulone and Francesco Paresce (INAF, Italy), measured the brightness and colours of more than 16,000 stars within the globular cluster Messier 12 with the FORS1 multi-mode instrument attached to one of the Unit Telescopes of ESO’s VLT at Cerro Paranal (Chile). The astronomers could study stars that are 40 million times fainter than what the unaided eye can see (magnitude 25).
Located at a distance of 23,000 light years in the constellation Ophiuchus (The Serpent-holder), Messier 12 got its name by being the 12th entry in the catalogue of nebulous objects compiled in 1774 by French astronomer and comet chaser Charles Messier. It is also known to astronomers as NGC 6218 and contains about 200,000 stars, most of them having a mass between 20 and 80 percent of the mass of the Sun.
“It is however clear that Messier 12 is surprisingly devoid of low-mass stars”, said De Marchi. “For each solar-like star, we would expect roughly four times as many stars with half that mass. Our VLT observations only show an equal number of stars of different masses.”
Globular clusters move in extended elliptical orbits that periodically take them through the densely populated regions of our Galaxy, the plane, then high above and below, in the ‘halo’. When venturing too close to the innermost and denser regions of the Milky Way, the ‘bulge’, a globular cluster can be perturbed, the smallest stars being ripped away.
“We estimate that Messier 12 lost four times as many stars as it still has”, said Francesco Paresce. “That is, roughly one million stars must have been ejected into the halo of our Milky Way.”
The total remaining lifetime of Messier 12 is predicted to be about 4.5 billion years, i.e. about a third of its present age. This is very short compared to the typical expected globular cluster’s lifetime, which is about 20 billion years.
The same team of astronomers had found in 1999, another example of a globular cluster that lost a large fraction of its original content (see ESO PR 04/99).
The scientists hope to discover and study many more clusters like these, since catching clusters while being disrupted should clarify the dynamics of the process that shaped the halo of our home galaxy, the Milky Way.
High resolution images and their captions are available on this page.
A press release on this is also issued by INAF in Italian and is available at www.inaf.it/comunicati_stampa/cs070206/Inaf-04-06.html.
Original Source: ESO News Release
Young Enceladus
Saturn’s moon Enceladus. Image credit: NASA/JPL/SSI Click to enlarge
For Enceladus, wrinkles mean the opposite of old age. This view of a crescent Enceladus shows a transition zone between a wrinkled and presumably younger region of terrain and an older, more heavily cratered region. The moon’s geologically active southern polar region is seen at bottom.
The lit terrain shown here is on the side of Enceladus (505 kilometers, or 314 miles across) that faces away from Saturn. North is up and rotated 20 degrees to the right.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 24, 2005 at a distance of approximately 108,000 kilometers (67,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 102 degrees. Image scale is 646 meters (2,118 feet) 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
Book Review: Saturn V
The Saturn V richly deserves the many superlatives heaped upon it. The most apt is it being described as nearly 6 million pounds of explosive fuel waiting for a match to set it alight. Striking as this sounds, it was the control of the resulting exothermic reactions that gently pushed man and machine into the space age. However, where the car industry could continually make corrections to correct design flaws, these rockets had to perform nearly flawlessly every time. This ensured the safety of the people and the achievement of the assigned mission. As well, these rockets were at the centre of a race between nations, thus there was an impassioned need to build, test and use them as quickly as possible. Thus, judicious testing ensured that each Saturn V rocket was ready to perform when called upon.
The author’s goal is to recover and present the manufacturing steps and test results of the Saturn V stages. They admirably do so. In a manner that would warm many engineers’ hearts, though perhaps bore the average reader, the authors list relevant dates, locations and events for each stage produced. That is, there’s a review of the 19 S-IC stages, the 27 S-II stages, and, the 26 S-IVB stages. The stages are listed in a numeric, hence chronological, sequence and all reviews follow the same format. There’s a short, one paragraph summary of the stage’s eventual use, a description of its manufacturing history and a listing of the testing of the complete stage, usually focusing on the all up test that included static firing of the engines. The test results get listed immediately after, as are any abnormalities. With this expansive coverage of the testing, the book well meets its goal of providing a record of Saturn V’s manufacturing and tests.
Supporting this compilation is a quick survey of some support elements. There’s a review of the J-2 and F-1 engines, the Pregnant Guppy and Super Guppy cargo aircraft, the barges and the relevant development centres. Of interest, the J-2 may be produced again for the Crew Launch Vehicle’s upper stage. These short asides are brief but useful additions to help the reader understand the enormity of the project.
Though the book provides extensive information, it’s not exhaustive. As the authors note, there’s a massive quantity of records in storage, with little to no organization to aid in searching through it. As such, problems encountered while testing are simply stated, such as ‘a minor bearing overheating problem was encountered during the move’. There are even slight traces of levity, such as the comment �the failure was due to the inability to abort 3.2 million pounds of water�. But humour isn’t the goal; this book is a collection of information and facts solely.
Accompanying this book’s sound review is an excellent potpourri of photographs, videos and historical documents. The book has a centre section with many colour plates of test firings, stage construction or simple transportation. Black and white pictographs are sprinkled throughout the text. The videos and support documentation are in the enclosed DVD. One can easily enjoy the sonic reverberations kicking through the speakers when viewing really close up images of the engine tests!
Though the book is large, the manufacturing and test record pages are a bit less than half. The remainder are reprints of two historical NASA publications, the Saturn V News Reference and the Saturn V Payload Planner’s Guide. Both these documentations provide background information. The first provides a ready review of the details of the Saturn V’s design, while the later is a marketing brochure that advertises the rockets capabilities, in the unfulfilled hope that many more would be built. By adding these, the book becomes an excellent reference for Saturn V enthusiasts as well as those interested in engineering test programs or large equipment handling and manufacturing.
Though the Saturn was a rocket, it was also a system. Millions of individual pieces, each serving their own function, had to operate in unison. Alan Lawrie and Robert Godwin in their book Saturn V recover all the manufacturing steps and test results that together gave the confidence to the engineers to say that this system was worthy to send a human on a journey into space.
Review by Mark Mortimer
Copies are available for purchase from Countdown Creations.
What’s Up This Week – February 6 – February 12, 2006
Download our free “What’s Up 2006” ebook, with entries like this for every day of the year.
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Apollo 16. Image credit: NASA. Click to enlarge.
Monday, February 6 – On this day in 1971, astronaut Alan Shepherd became the first “lunar golfer” to tee off on the Moon’s surface. While the Apollo 14 landing site is just on the other side of the terminator tonight, we can still go “crater hopping” to catch another. Close to the terminator and about one third of the way from the southern cusp are the ancient walls of huge previous studied Albategnius. Directly to its lunar east, and about the same distance as Albategnius’ is wide, look for a trio – small western Andel, larger eastern Descartes, and larger still southern Abulfeda. Power up! Between Andel and Descartes is the small pockmark of Dolland. North of Dolland is a ruined, unnamed crater with a pronounced set of rings on its northwestern shore. On the eastern edge of the relatively smooth floor, the remains of the Apollo 16 mission still shine on!
Tonight we’ll finish up our sweep for stardust through Auriga. Start at Theta and head due south five degrees (half a fist). On most nights, M37 gives an extraordinarily dense and complex view of more than 100 stars to small scopes, but lunacy will prevent that. Power up to darken the field.
Now let’s talk about these three interesting open clusters. All were discovered by Giovanni Batista Hodierna before the year 1654 – more than a decade before Messier cataloged them. All are located roughly 4000 light years away from Earth. The smallest of the three, M36, spans 12 light years. That’s not much more than the distance between our Sun and Epsilon Eridani. Larger M37 and M38 span about 25 light years, or about the distance between us and Vega. We’ll come back for a look at all three later in the month.
Tonight observers in western North America and Hawaii should follow the progress of the Moon as it passes through the Pleiades!
Tuesday, February 7 – On this day in 1889, the first American national astronomy organization was born – the Astronomical Society of the Pacific.
Tonight, let’s return to the Moon and previous study Plato. To the south on the dark plains of Mare Imbrium, you will notice an almost star-like point of light, a singular peak named Mons Pico. Unique among lunar mountains, its highly reflective rocky composition makes it appear almost like a pyramid in the long shadows of sunrise. “Pyramid” Pico stands 8,000 feet above the lunar plane on a base some 18 miles wide!
After looking at a solitary mountain this evening, let’s have a look at a solitary star as well – Alpha Orionis. Although its designation lists it as Orion’s brightest star in Johann Bayer’s Uranometria of 1603, Betelgeuse is actually slightly fainter than Beta (Rigel). What makes it special is its color. To the eye, Betelgeuse appears a distinctive red-orange. This color relates directly to its spectral class of M2. Like many M-spectra stars, Betelgeuse truly is a “red giant” – a star approaching the end of its life. With an immensely swollen, low temperature, near-vacuum photosphere of hydrogen and helium gas, this star measures some 300 million miles in diameter. Placed at the Sun’s position, it would extend out beyond the orbit of Mars! At 430 light years away, Betelgeuse is not the farthest or bright stars of winter, but it is most certainly the largest.
Wednesday, February 8 – Today celebrates the birth of J.L.E. Dreyer. Born in 1852, the Danish Dreyer came to fame as the astronomer who compiled the New General Catalogue (NGC) published in 1878. As a professional, Dreyer began his observations of the night sky in the employ of Lord Rosse at Birr Castle Ireland. Later Dreyer moved to Armagh Observatory where he confirmed many of the deep sky studies compiled by William Herschel and other observers using the 10″ refractor he secured funds for and selected as his instrument of choice. Even with a wealth of astronomical catalogs to choose from, the NGC objects, and Dreyer’s abbreviated list of descriptions, still remain the most widely used today.
Let’s engage is some further lunar exploration as crater Copernicus again becomes visible tonight to even the most modest of optical aid. Small binoculars show Copernicus as a bright “ring” midway along the lunar dividing line of light and dark called the “terminator.” Telescopes will reveal its 97 km (60 mile) expanse and 120 meter (1200 ft.) central peak to perfection. Copernicus holds special appeal as it’s the aftermath of a huge meteoric impact. At 3800 meters (12,600 feet) deep, its walls are around 22 km (14 miles) thick and over the next few days, the impact ray system extending from this tremendous crater will become wonderfully apparent.
Now, let’s explore something special from J.L.E’s lifework. Let’s turn eyes, binoculars, and scopes on Orion’s Belt and the brightly scattered open cluster NGC 1981. On a dark, moonless night, NGC 1981 can be seen unaided as a small, fuzzy haze in Orion’s “sword.” Let’s start by using binoculars – or finderscope – to get a sense of how 1981 “fits in” with the area. Do you see those three 6th magnitude stars at the top? They’re part of the 1981 cluster. Now look south to 4.6 magnitude 42 Orionis – a tight, disparate double. You probably won’t see M43 further south, but M42 will be visible. Try observing multiple system Iota Orionus. After the low power tour, head back to the top of the list with a telescope and enjoy the dozen or so brightly scattered, hot young stars that make up number 1981 on J.L.E Dreyer’s celestial list!
Thursday, February 9 – It’s a “Moon Gazer’s” evening as our nearest astronomical neighbor continues to light up the night sky. Don’t put away your telescopes and binoculars thinking there’s nothing to view though, because one of the most “romantic” features on the lunar surface will be highlighted tonight.
The Sinus Iridium is one of the most fascinating and idyllic regions of the Moon. At 241 km (150 miles) in diameter and ringed by the Juras Mountains, it’s known by the quiet name of “The Bay of Rainbows.” Despite this serene name, the region was actually formed by cataclysm. Astronomers speculate that a minor planet of around 200 km in diameter once impacted our newly formed Moon with a glancing strike. This caused “waves” of superheated material to wash up along a “shoreline” forming this delightful C-shaped lunar feature. The effect of looking at a bay is stunning as the smooth inner sands show soft waves called “rilles,” broken only by a few small, impact craters. This picture is completed as Promentoriums Heraclides and LaPlace rise above the surface (at 1800 meters and 3000 meters respectively) appearing as distant “lighthouses” standing at the entrance.
It’s also a great time for seeing double. Before it moves too high overhead, have a look at 41 Aurigae. The pair ? one of 5th and other of the 7th magnitude – is separated by 8 arc seconds. Notice how the companion orients almost due north of its brighter primary. The result appears as two stars moving side-by-side across the field of view! 41 Aurigae and it secondary are members of the Hyades. To locate 41, start at Beta Aurigae. Use your finderscope to center on Pi – a little more than a degree north. 41 is a slightly fainter star around five degrees northeast of Pi. It’s a challenge to locate – but it means is that you can congratulate yourself when you find it! And enjoy observing it all the more…
Friday, February 10 – Let’s return to the Moon tonight and explore an area to the south around another easy and delightful lunar feature – the crater Gassendi. At 110 km in diameter and 2010 meters deep, this ancient crater contains a triple mountain peak in its center. Once one of the most “perfect circles” on the Moon, the south wall of Gassendi has been eroded by lava flows over a 48 km expanse and offers numerous detailed features to telescopic observers on its ridge and rille covered floor. Observing with binoculars? Gassendi’s bright ring stands on the north shore of Mare Humorum…an area about the size of the state of Arkansas!
Are you ready for a tough double star? Alnitak (Zeta Orionis) is the easternmost star of Orion’s belt. It’s a double just wide enough to resolve through any telescope. However, you’ll need steady skies to show the two bright stars as distinct and tiny orbs of light separated by a mere 2.3 arc seconds. While observing this tight couple, keep in mind that both stars are some 800 light-years distant and that Zeta-A has one of the hottest photospheres among all known stars. At 31,000 degrees K, its temperature is so high that it shines primarily in the ultraviolet. Look for a third, 10th magnitude star almost 1 arc minute away from the bright pair. When you can see this one plainly, you’re ready to start looking for fainter members of the famed Trapezium found in the heart of M42.
Saturday, February 11 – On this day in 1970, Lambda 4S-5, the first Japanese satellite was launched.
The waxing Moon will dominate early evening skies, but tonight is an excellent opportunity for binoculars and telescopes to explore crater Tycho.
Named for Danish astronomer, Tycho Brahe, this fantastic impact crater is very impressive in even the most modest of optical aids. Spanning 85 km, this lunar feature will be very prominent and unmistakable in the southern hemisphere of the Moon. Tycho’s highly conspicuous ray system supports its origin as an impact crater. The rays span hundreds of kilometers across the lunar surface. Tycho is also one of the youngest of the major features at an astounding age of only 50,000,000 years old!
On January 9, 1968 Surveyor 7 – the last lunar robot of its kind – landed quietly at lunar sunrise on Tycho’s slopes. Because previous Surveyor missions provided the Apollo program with all data necessary for manned missions, Surveyor 7’s presence was scientific only. Two weeks later, when the Sun set on the landing site, Surveyor 7 had provided over 21,000 photographs, determined physical and chemical properties associated with the Southern Highland area, and detected laser beams aimed at it from two separate Earth observatories.
With the Moon lighting the skies, tonight will give you and opportunity to see just how much effect it has on studies. In the spirit of investigation, have a look at the Great Nebula in Orion. Not quite the glorious sight you remember, huh? But while in M42, power up a little and have a look at those four stars in its midst. We will be back…
Sunday, February 12 – Tonight the Moon will command the skies and give naked-eye observers an opportunity to use their imaginations!
Since the dawn of mankind, we have been gazing at the Moon and seeing fanciful shapes in large lunar features. Tonight, as the Moon rises, is your chance to catch an AL lunar challenge – “The Rabbit in the Moon.” The “Rabbit” is a compilation of all the dark maria. The Oceanus Procellarum forms the “ear” while Mare Humorum makes the “nose.” The “body” is Mare Imbrium and the “front legs” appear to be Mare Nubium. Mare Serenitatis is the “backside” and the picture is complete where Mare Tranquillitatis and Mare Fecunditatis shape the “hind legs” with Crisium as the “tail.”
See the Moon with an imaginative mind and new eyes — and find the “Rabbit.” It’s already out of the hat and in the heavens…
For telescopes and binoculars, the lunar surface will provide a bright but superior view of crater Grimaldi. Named for Italian physicist and astronomer, Francesco Grimaldi, this deep grey oval is one of the darkest features on the Moon – only reflecting about 6% of the light. Approximately 430 km (140-145 miles) long, it’s easy to spot along the terminator and just slightly south of the center of the lunar limb. Tonight is the best time to view its mountained walls, for later they will disappear and Grimaldi will take on the appearance of a small mare in the light of the full Moon.
Before then, let’s look at another fine double star – Eta Orionus. Eta is the 3.4 magnitude star a little over 6 degrees north-northeast of Rigel. Like Alnitak, Eta has a bright, closely spaced companion. Look for a much fainter 9.4 magnitude star that may not be part of the system. Like Alnitak, almost any size telescope can split the pair, but it will take a still sky to fully distinguish each star clearly.
May all your journeys be at light speed… ~Tammy Plotner. Contributing writer – Jeff Barbour @ astro.geekjoy.com
Hot Halo Surrounds Distant Galaxy
The massive spiral galaxy NGC 5746. Image credit: NASA Click to enlarge
Chandra observations of the massive spiral galaxy NGC 5746 revealed a large halo of hot gas (blue) surrounding the optical disk of the galaxy (white). The halo extends more than 60,000 light years on either side of the disk of the galaxy, which is viewed edge-on.
The galaxy shows no signs of unusual star formation, or energetic activity from its nuclear region, making it unlikely that the hot halo is produced by gas flowing out of the galaxy. Computer simulations and Chandra data show that the likely origin of the hot halo is the gradual inflow of intergalactic matter left over from the formation of the galaxy.
Spiral galaxies are thought to form from enormous clouds of intergalactic gas that collapse to form spinning disks of stars and gas. One prediction of this theory is that massive spiral galaxies should be immersed in halos of hot gas left over from the galaxy formation process.
Hot gas has been detected around spiral galaxies in which vigorous star formation is ejecting matter from the galaxy, but until now, hot halos due to infall of intergalactic matter had not been detected. Indeed, the extensive hot gas halo around NGC 5746 is faint and would be very difficult to detect without a powerful X-ray telescope such as Chandra. Also, the galaxy’s special orientation and large mass increased the chance of detection.
The discovery of a hot halo around NGC 5746 was welcome news to astronomers because it shows that the “missing” hot halos predicted by computer models in fact exist.
Original Source: Chandra X-Ray Observatory