Jika anda ternampak muka saya tengah TT (Teh Tarik) ni, bermakna anda telah selamat mengharungi 3 hari bumi tak jadi bergelap, dan tarikh 21hb Dis yang penuh tragis dan huru-hara (kononlah).
Nak ceritanya, Falak Online telah pun berpindah rumah. Bermula sekarang silalah kemaskini link ke WWW.FALAKONLINE.NET , tak perlulah letak apa-apa selepas tu, kerana ia akan redirect ke muka hadapan BARU yang sepatutnya.
Laman lama (yang anda lihat sekarang ni), InsyaAllah akan kekal untuk beberapa bulan mendatang. Ia akan menyenaraikan KESEMUA artikel lama saya di FO, bagi rujukan anda semua. Maka, kalau anda nak masih nak marah-marah kat saya berkenaan artikel "3 hari bergelap tu" , masih boleh berbuat demikian, saya terima dengan hati terbuka! :-)
Apa pun, InsyaAllah 2013 mendatang akan terdapat beberapa pembaharuan yang saya dan rakan-rakan Personaliti Astronomi lain usahakan, demi kemajuan bidang Astronomi di Malaysia.
Jom dan Selamat Datang Ke Tahun Baru 2013.
Jemput masuk ---> WWW.FALAKONLINE.NET
Astronomers have detected a high-speed, long-lasting gas streamer spewing from the active galactic nucleus of NGC 5548. This discovery might provide new insights into how supermassive black holes influence their host galaxies.
Scientists have had their eyes on NGC 5548 for decades, but an international team of astronomers monitoring this galaxy last summer observed some unexpected behavior — namely, they discovered a new gas outflow streaming from NGC 5548's active galactic nucleus (AGN).
NGC 5548 is an archetypal Type-I Seyfert, which are (usually spiral) galaxies with a bright nucleus powered by a supermassive black hole rapaciously devouring matter. As they blaze with radiation, the accretion disks around the black holes that fuel AGNs can blow off powerful winds of ionized gas. Astronomers have observed many AGNs spewing out streams of gas, but NGC 5548 is the first galaxy whose gas streamer has actually moved into our line of sight, partially blocking our view of the bright core.
NGC 5548 is a lenticular galaxy 245 million light-years away that hosts a 39-million-solar-mass black hole. Previous high-resolution X-ray and ultraviolet observations showed a persistent outflow of gas from the AGN (expected for these objects), but in June 2013 astronomers observed a new, clumpy stream of ionized gas obscuring the AGN that had never been seen before. Whereas the persistent outflow starts 10 to 15 light-years from the black hole and flows outward at 1,000 kilometers per second (2 million miles per hour), the new streamer originates mere light-days from the black hole and blows five times faster.
Jelle Kaastra (Netherlands Institute for Space Research) and colleagues identified the peculiar gas streamer by combining observations from five X-ray space observatories, an ultraviolet spectrograph on the Hubble Space Telescope, and two ground-based optical telescopes. From May 2013 to September 2013 and December 2013 to February 2014, Kaastra’s team conducted an extensive multiwavelength monitoring campaign. Last June, they found that the AGN’s low-energy X-ray emission was 25 times weaker than astronomers measured in 2002. Simultaneous ultraviolet observations revealed that the persistent outflow around the AGN was also significantly cooler than when it was observed in 2011. After putting together the various observations, the team concluded that some new obscuring matter was blocking 90% of the X-ray emission.
Given the dates of the team’s observations and archival observations that the astronomers consulted, this obscuration has lasted between 2 ½ and 6 years. Because such a long-lasting outflow must be consistently replenished, the team suspects it originates near the accretion disk.
Observations of the NGC 5548 gas streamer provide the first direct evidence of a shielding process that could regulate the growth of black holes. As matter spirals into a supermassive black hole, it emits ultraviolet radiation that can induce powerful winds, which carry away gas that would have otherwise been gobbled up by the black hole. But if the gas is too saturated by X-ray radiation, then it gets “cooked” and loses its ability to absorb the ultraviolet radiation that launches it away, Kaastra explains. The new streamer in NGC 5548 shields both the more distant, persistent outflow and other gas closer to the accretion disk from the powerful X-ray radiation emitted near the black hole, allowing winds to sweep gas away from the galaxy’s core.
Although the winds billowing out from NGC 5548 are not powerful enough to significantly affect the galaxy’s evolution, the new study does improve our understanding of how this mechanism could influence galaxies that host more powerful AGNs.
Astronomers have only observed a few Seyfert galaxies with gaseous outflows like the one in NGC 5548, but luminous quasars, which host AGN powered by much more massive black holes, have been known to spew gaseous winds at several tenths the speed of light. Such powerful outflows can significantly affect the host galaxy’s evolution. Seyfert galaxies are easier to study than quasars because they are closer to us, explains Mike Eracleous (Pennsylvania State University). So by examining gaseous outflows from galaxies like NGC 5548, we might establish parallels between Seyfert galaxies and quasars that help us understand how more powerful outflows impact galactic evolution.
J. Kaastra et al. "A fast and long-lived outflow from the supermassive black hole in NGC 5548," Science, 19 June 2014.
Dig into more mysteries of the cosmos with our special issue, Astronomy's 60 Greatest Mysteries.
Whether you're a seasoned observer or a novice, star parties provide the perfect opportunity to kick back and enjoy the night sky with some fellow astronomy enthusiasts.
When people think of summertime, they might imagine nights spent toasting marshmallows, listening to cricket chatter, and camping out under the stars with friends. For astronomers, that latter will include pulling out a pair of binoculars or setting up the telescope to enjoy some stargazing without the cumbersome bulk of winter wear. And when astronomers camp out under the stars, sometimes they do it with dozens or even hundreds of strangers, all drawn together by a common fascination with the night sky.
Summer is the high season for star parties, when newbies, amateurs, and professionals alike gather for astronomical observation and conversation. Many astronomy clubs and observatories host single-night star parties for club members and the local public. Some societies also organize annual regional star parties, typically held in remote locations to escape the pall of light pollution, and folks from all over the country flock to these events to set up camp for a several-night stint of stargazing.
These gatherings are great not only for astronomy enthusiasts seeking kindred spirits, but also for beginners seeking guidance from more seasoned astronomers. Though a few star parties have reputations for attracting “serious observers” — like the Mount Kobau Star Party, set on a high, cold summit in Canada nearly an hour’s bumpy drive from the nearest town — most star parties are designed to accommodate everyone from the veteran astronomer to the novice. Even the organizers of those “serious” star parties encourage ambitious beginners to join them. In many cases, you don’t even need to bring your own telescope, because so many attendees are excited to share and show off their equipment and knowledge.
During the day, many star parties host workshops on using or building telescopes, presentations by professional astronomers, and markets where astronomy venders hawk their wares. Many offer a family-friendly atmosphere with workshops for teenagers and astronomy camps and activities for kids.
Listed below is a selection of the major star parties in North America for the remainder of 2014. Also check out Sky & Telescope’s list of annual star parties, which includes some winter and spring events for advanced planning. NASA’s Night Sky Network is also an excellent resource for finding upcoming events in your area.
For detailed information on star parties and much more, including museum exhibits and talks by professional astronomers, check out our Events Calendar. (Note to club officers: make sure your events are listed and up to date!)Selected North American Star Parties in 2014EventLocationDatesTable Mountain Star PartyOroville, WAJuly 22-26Mason Dixon Star PartyWellsville, PAJuly 23-27Stellafane ConventionSpringfield, VTJuly 24-27Mount Kobau Star PartyOsoyoos, BC (Canada)July 26-Aug. 3Oregon Star Party Prineville, OR Aug. 19-24Starfest Ayton, ON (Canada) Aug. 21-24Almost Heaven Star Party Circleville, WV Aug. 22-26Nova East Star Party Haunts County NS (Canada) Aug. 22-24Idaho Star Party Mountain Home, ID Sept. 19-21Alberta Star Party Drumheller, AB (Canada) Sept. 19-21Okie-Tex Star Party Kenton, OK Sept. 20-28Astroblast Franklin, PA Sept. 23-28SJAC Fall Star Party Woodbine, NJ Sept. 25-28Astronomy Day (autumn) Everywhere! Oct. 4Bays Mountain StarFest Kingsport, TN Oct. 17-19 Chiefland Star Party Chiefland, FL Nov. 17-23
On July 5th, the Moon has a remarkably close brush with Mars, followed two nights later by a similar rendezvous with Saturn.
July starts with a bang — and I'm not just talking about Independence Day fireworks!
Even if you're just a casual skywatcher, as darkness falls on July 5th you won't fail to note the Moon perched remarkably close to a ruddy "star" — actually the planet Mars — with the bright star Spica not far away. Then, two nights later, the Moon's eastward motion will park it close by the planet Saturn.
Why are these close encounters occurring? The Moon's path through the sky closely follows the zodiac — the band of a dozen constellations home to the wanderings of the Sun and planets. As it cycles around the sky each month, the Moon glides by each of the eight planets for a brief nightly visit — called a conjunction.
The closer the conjunction and the brighter the planet the more striking the sight. I can't explain it, but few can resist the magnetic draw of two or more bright celestial objects side by side. We see beauty and meaning in these sometimes spectacular alignments.July 5th: The Moon and Mars
On July 5th, skywatchers across much of North America and Canada will see the first quarter Moon glide just 30 arcminutes (one full Moon diameter) south of fiery bright Mars in Virgo at nightfall. Their separation will vary depending on your location. Across the east-central U.S., they'll be about ½° apart — but the farther south you live, the choicer the view.
Intrepid observers up for a challenge can try spotting Mars shortly before sunset as it hovers just above the Moon's northern limb. (Hint: use binoculars.) Let me know, via a comment below, if you have success.
From Miami, only 10 arcminutes separate two bodies, tight enough that both cratered lunar landscape and ruddy Martian deserts can be viewed in the same high-power telescopic field of view. By the time the sky's dark for observers on the West Coast, the Moon will have moved eastward in its orbit, putting some 1½° (three lunar diameters) between it and the Red Planet.
Jet down to Quito, Ecuador, and the Moon will completely block Mars from view during an occultation lasting up to an hour.
As the map below shows, the occultation zone extends from northern South America south of Caracas, Venezuela, across the Amazon Basin to northern Chile. For details on disappearance and reappearance times for cities across South America, check out the International Occultation Timing Association's Mars Occultation site<. Remember that the times shown there are Universal Time (UT); subtract 4 hours for EDT, 5 for CDT, 6 for MDT, and 7 for PDT.July 7th: The Moon and Saturn
Two nights later, on July 7th, the now-gibbous Moon performs an encore, passing under Saturn during evening hours across North and South America. From mid-northern latitudes, about 1° will separate Moon and planet. Once again, viewers in South America will be graced with an occultation. Click here for a map and list of cities and times.
If you think that's all the celestial sphere has on its agenda this weekend, you'd be wrong. Saturday also marks the date the brightest asteroid Vesta makes a spectacular close approach to the largest asteroid, Ceres — taking place mere degrees from the Moon-Mars duo. Check out S&T.com's companion article for a map and more info on that conjunction. Such riches!Get more great skywatching info — and the latest discoveries in astronomy — by downloading the July issue of Sky & Telescope.
It's rare that two sizable asteroids pair together in the sky as closely as Ceres (the biggest of all) and Vesta (the brightest) in early July.
For the past few months, two of the biggest and brightest asteroids — 1 Ceres and 4 Vesta — have been gliding in parallel just 2° or 3° apart in eastern Virgo. They've been visible in binoculars all that time and gradually drawing closer together in the sky.
This week their months-long dance reaches its denouement, as the king and queen of the asteroid belt appear to embrace closer than anyone has ever seen them. They'll appear just 10 arcminutes apart (a third of the Moon's apparent diameter) on the evenings of July 4th and 5th in the Americas (July 5th and 6th Universal Time). They'll remain near one another for the next few weeks, separated by 2.2° on August 1st and by 5° on September 1st.How to Spot Ceres and Vesta Tonight
If you've always wanted to view an asteroid, this is a great opportunity. Right now the Ceres-Vesta pairing is moderately high in the southwest at nightfall (30° high if you're near 40° north latitude), so you'll have time to track them down shortly after twilight ends before they become too low.
Mars and the star Spica are your starting points, as shown on the wide-field chart below. This planet-star pairing has been tightening as well: they're 5½° apart on July 1st and just 1.3° apart on July 13th, the date when they appear closest together. They'll be joined on the evening of July 5th by a just-past-first-quarter Moon that skirts especially close to Mars.
Look 10° above the planet-star combo — the width of your fist on an outstretched arm — to find the 3rd-magnitude star Zeta (ζ) Virginis, also known as Heze. It's the faint peak of a narrow, wizard-hat-shaped triangle with Mars and Spica at its base. Ceres and Vesta are inside that triangle, situated roughly side by side and just 1½° below (southwest of) Zeta.
If you carefully note the asteroids' positions, you should be able to monitor their night-to-night motion (likewise about 10 arcminutes) with respect to the surrounding stars.
These two "dwarf planets" were brightest when at opposition back in April, and since then they've lost some luster. In early July, Ceres is magnitude 8.5 and brighter Vesta is 7.2. And yet Ceres, with a diameter of 585 miles (940 km), is nearly twice as large as Vesta. It looks fainter partly because it's farther away — 46 million miles (74 million km) beyond Vesta on July 5th — and because it's farther from the Sun as well. So, while they look close together in the sky, they're really not.
Ceres also has a much darker surface. Vesta is medium gray, reflecting 42% of the sunlight striking it (a high albedo, or reflectivity, for an asteroid), while Ceres is a more typical dark gray-brown with an albedo of only 9%.
If it's cloudy or you don't have a telescope handy, you can watch the pairing of Ceres and Pallas online. Choose between Slooh's webcast (which begins July 3rd at 8 p.m. Eastern Daylight Time) or Gianluca Masi's Virtual Telescope Project (July 5th at 4:00 p.m. EDT).
Quite near the two asteroids on the sky, though utterly invisible, is NASA's Dawn spacecraft. It's en route from its successful 2011-12 mission at Vesta to its next mapping project at Ceres, where it will take up permanent orbit next March. Hubble images reveal Ceres to have a patchwork of bright and dark markings — hints of interesting landscapes awaiting Dawn.
Keep tabs on major celestial happenings throughout the year with SkyWatch 2014.
The post Milky Way Rising over the Solar Array at Cal Tech’s OVRO appeared first on Sky & Telescope.
The post The Pleiades, Venus, and Crescent Moon at Dawn – June 24, 2014. appeared first on Sky & Telescope.
The post NGC 2264, The Christmas Tree Cluster, Fox Fur Nebula, and Cone Nebula appeared first on Sky & Telescope.
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