Panzermann Posted September 26, 2016 Author Share Posted September 26, 2016 move over Arecibo radio telescope: World's largest radio telescope begins operationsSource: Xinhua 2016-09-25 15:18:08 GUIYANG, Sept. 25 (Xinhua) -- The world's largest radio telescope was put into use on Sunday in a mountainous region of southwest China's Guizhou Province.Shortly after noon, in a karst valley in Pingtang County, hundreds of astronomers and astronomy enthusiasts witnessed the official launch of the Five-hundred-meter Aperture Spherical Telescope's (FAST) mission to explore space and hunt for extraterrestrial life.Work on the nearly 1.2-billion-yuan (180 million U.S. dollars) project started in 2011, 17 years after it was proposed by Chinese astronomers.The installation of the telescope's main structure -- a 4,450-panel reflector as large as 30 football pitches -- was finished in early July."(The telescope) will certainly generate enthusiasm, bring people into science, and make China important in the world of science," Joseph Taylor, a Nobel Prize-winning astronomer at Princeton University, told Xinhua.The astronomer was awarded the Nobel Prize in physics in 1993 for discovering indirect proof of gravitational waves with the assistance of Puerto Rico's Arecibo Observatory, home to a radio telescope that is 350 meters in diameter.Taylor expects FAST to be a "productive" project, even if he is unsure whether any of its discoveries will lead to a Nobel Prize.In fact, FAST has already had a good start. In a recent trial observation, it received a set of high-quality electromagnetic waves sent from a pulsar about 1,351 light-years away, said Qian Lei, an associate researcher with the National Astronomical Observation (NAO) under the Chinese Academy of Sciences, which built the project.FAST's tasks include observation of pulsars as well as exploration of interstellar molecules and interstellar communication signals.To ensure the telescope's performance, more than 8,000 locals are being resettled from their homes to make way for the project, which requires radio silence within a 5-kilometer radius. Visitors to the zone must turn off their mobile phones.The telescope's leading engineer Wang Qiming said the telescope, designed and built by Chinese scientists, will remain the global leader for the next 10 to 20 years.Yan Jun, head of the NAO, said China will roll out more "world-class" telescope projects in five to 10 years.http://news.xinhuanet.com/english/2016-09/25/c_135712337.htm Link to comment Share on other sites More sharing options...
sunday Posted September 26, 2016 Share Posted September 26, 2016 Scientists discover a dark Milky Way http://news.yale.edu/2016/08/25/scientists-discover-dark-milky-way Considering how much dark matter there is one wonders why dark galaxies aren't the norm. We cannot see the dark matter. That is why it is called dark. For the estimated values of mass in the universe there must be lots of dark galaxies. So very probably there are many. Or there are none, and dark matter is only the contemporary ether, used to try to explain an unexplained phenomenon. Link to comment Share on other sites More sharing options...
Ssnake Posted September 27, 2016 Share Posted September 27, 2016 They recently discovered a "dark galaxy" - one that is very faint, yet with a very strong gravity pull. Also, the gravity wave observation: Two black holes collided with about 30 sun masses each. Something that should be incredibly rare according to the standard cosmological model. So maybe we were incredibly lucky. Or there are far more (isolated) black holes than we think (e.g. because the big bang created far more singularities all over the place right from the start). Both observations are hints that there is something to the whole dark matter thing, except that observation #1 suggests that dark matter actually exists, but may not be a pervasive thing. Maybe it's actually concentrated, e.g. in the form of small clusters that are usually just too faint to observe.Or, #2, the gravity pull of all galaxies is stronger than the observable number of stars suggest because there are far more black holes than we think. Future gravity wave observations will give us a clue about that (which is why I'm all for setting up the interferometry satellites ASAP). In the meantime the particle physicists have massively shrunk the energy envelope where WIMPS may actually exist (if they exist), which are important steps in the falsification process (unless they actually find something, after all). Link to comment Share on other sites More sharing options...
Corinthian Posted September 27, 2016 Share Posted September 27, 2016 http://www.nasa.gov/press-release/nasa-s-hubble-spots-possible-water-plumes-erupting-on-jupiters-moon-europa Astronomers using NASA's Hubble Space Telescope have imaged what may be water vapor plumes erupting off the surface of Jupiter's moon Europa. This finding bolsters other Hubble observations suggesting the icy moon erupts with high altitude water vapor plumes.The observation increases the possibility that missions to Europa may be able to sample Europa’s ocean without having to drill through miles of ice.“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”The plumes are estimated to rise about 125 miles (200 kilometers) before, presumably, raining material back down onto Europa's surface. Europa has a huge global ocean containing twice as much water as Earth’s oceans, but it is protected by a layer of extremely cold and hard ice of unknown thickness. The plumes provide a tantalizing opportunity to gather samples originating from under the surface without having to land or drill through the ice. Link to comment Share on other sites More sharing options...
BansheeOne Posted September 29, 2016 Share Posted September 29, 2016 The Geomagnetic Blitz of September 1941 Seventy-five years ago next week, a massive geomagnetic storm disrupted electrical power, interrupted radio broadcasts, and illuminated the night sky in a World War II battle theater. By Jeffrey J. Love and Pierdavide Coïsson 15 September 2016 Seventy-five years ago, on 18–19 September 1941, the Earth experienced a great magnetic storm, one of the most intense ever recorded. It arrived at a poignant moment in history, when radio and electrical technology was emerging as a central part of daily life and when much of the world was embroiled in World War II, which the United States had not yet officially entered. Auroras danced across the night sky as voltage surged in power grid lines. A radio blackout interrupted fan enjoyment of a baseball game, while another radio program was interrupted by private phone conversations. Citizens, already on edge, wondered if neon lights were some sort of antiaircraft signal. And far away in the North Atlantic, the illuminated night sky exposed an Allied convoy to German attack. These effects raised awareness within the scientific community and among the public of the societal significance of the effects that the Sun and outer space can have on the Earth—what we now call space weather. Solar-Terrestrial Interaction On 10 September 1941, during the declining phase of solar cycle 17, astronomers saw an unusually large, low-latitude group of sunspots on the eastern limb of the Sun. The spots had formed, as they all do, with the buoyant emergence of a concentrated bundle of magnetic field lines from the Sun’s interior through the photosphere. Over the course of the next week the spots grew, and the Sun’s rotation brought them near the center of the solar disk as viewed from Earth [e.g., Richardson, 1941]. The sunspot group was large enough to be seen with the naked eye. At 08:38 universal time (UT) on 17 September 1941, the Greenwich Observatory spectrohelioscope recorded a solar flare above this sunspot group [Newton, 1941]. The emitted ultraviolet and X-ray radiation abruptly enhanced the ionization of the Earth’s atmosphere, causing a sharp perturbation known as a “crochet” in dayside ground-based recordings of the geomagnetic field and temporarily interfering with high-frequency radio communication. Subsequently, scientists at the Mount Wilson Observatory in California observed another solar flare at 16:26 UT [Richardson, 1941]. On the basis of daily sunspot reports supplied by the U.S. Naval Observatory, the Department of Terrestrial Magnetism at the Carnegie Institution of Washington formally issued a warning to radio operators that they could expect significant disturbances to ionospheric and geomagnetic conditions beginning on about 18 September [McNish, 1941a]. This prediction, which turned out to be accurate, is a noteworthy development in the historical development of methods for reliably forecasting space weather. Less than 20 hours after the flare was reported by Greenwich, a magnetic storm commenced at 0412 UT on 18 September with the arrival at Earth of a coronal mass ejection. This mass ejection abruptly compressed the magnetopause and generated a magnetic impulse that was recorded by observatories around the world [Newton, 1941]. The magnetic superstorm that followed was complex, intense, and of long duration. A magnetic observatory in Cheltenham, Md., operated by the U.S. Coast and Geodetic Survey, registered six separate occurrences of geomagnetic storms with a K index of 9 (the most intense value possible). Five of these occurred consecutively over a 24-hour period. In terms of a related global index , the level of geomagnetic activity over a 24-hour period has not since been matched [e.g., Cliver and Svalgaard, 2004]. An Auroral Light Show On 18–19 September 1941, the Moon was nearly new, ideal for seeing the auroral light that the magnetic storm produced in many nighttime skies. The observer in charge at the Cheltenham, Md., observatory [Ludy, 1941] reported a brilliant auroral display of rays and moving drapery of pink, green, and lavender. He also described an auroral corona, where light appears to stream down from directly overhead, a phenomenon rarely seen at midcontinental latitudes. Weather Service observers reported seeing auroras in New Mexico [Cameron, 1941]. Letters to Sky and Telescope [1941] described the auroras seen around the United States. One amateur astronomer from Rhode Island [Boss, 1941] wrote a detailed description of the “celestial pyrotechnics,” and he apparently stayed up all night watching the spectacle, until the paperboy delivered the morning newspaper with the headline “Auroral Display Watched by Thousands.” The popular press provided vivid accounts of the auroras. The Brooklyn Eagle [1941] described celestial “neon lights.” The Chicago Tribune [1941a] reported that a “cosmic brush painted the Chicago sky with light” and that motorists parked on the highways had caused a traffic jam as they sought a clear view of the celestial spectacle. According to the Washington Post [1941a], some people wondered if the celestial events had something to do with national defense: “Was it an antiaircraft search battery?” These were, after all, difficult times. The United States was already being drawn into World War II [e.g., Heinrichs, 1988], and many citizens anticipated even greater involvement. [...] Radio Silence and Spice The National Bureau of Standards [1941] reported a great ionospheric disturbance starting at about 06:00 UT on 18 September, 2 hours after the sudden commencement of the magnetic storm. We might retrospectively infer that this was caused by substorm precipitation of charged particles into the Earth’s auroral zone. This would have disrupted over-the-horizon radio signals that are normally calibrated for a set level of ionospheric reflectivity. And, sure enough, as a result of the 18–19 September storm, widespread interference was reported for radio transmissions around the world [e.g., General Electric, 1941; Conklin, 1941]. As part of these developments, two amusing happenings were reported in the New York Times [1941a, 1941b], Newsweek [1941], and Time [1941], paraphrased here. First, on the afternoon of 18 September, the Pittsburgh Pirates hosted the Brooklyn Dodgers in a game of baseball. Red Barber, a well-known sports commentator, was calling the game for WOR Radio. In the fourth inning, with the score tied at 0–0, the broadcast lost signal for 15 minutes. By the time the broadcast resumed, the Pirates had 4 accumulated runs. Irate Brooklyn fans phoned the radio station to complain, but they found “little satisfaction” with the “explanation that the sun,” sunspots, and the related magnetic storm were to blame for the outage. To top it off, the Dodgers went on to lose to the Pirates, 5-6. The next morning, radio station WAAT was broadcasting a program of Bing Crosby songs. Suddenly, during “Where the Blue of the Night (Meets the Gold of the Day),” a phone conversation between two men discussing their previous night’s amours could be heard in background. Workers at the radio station tried without success to clear up what was apparently some sort of silly mix-up of signals. Station representatives later claimed that although the conversation was “strong,” it was also “not particularly objectionable.” When the men’s phone conversation did finally fade, it was replaced by what was described in the language of the time a “spicy” conversation between two young women talking about a blind date: “I fixed it for Eddie to pick up a guy for you.” Before station operators could mute the conversation, the colorful “crosstalk had faded, and decorum was again supreme” on the airwaves. Communications engineers for the Radio Corporation of America attributed the trouble to sunspots and the magnetic storm. Wartime Event in the Atlantic Far away from those innocent events in the United States, in the frigid North Atlantic Ocean east of southern Greenland, several German U-boats of the Brandenburg wolf pack were lurking. They operated there, out of reach of Iceland-based Royal Air Force maritime patrols, in search of eastbound ships that were keeping Britain supplied during the war. Kapitänleutnant Eitel-Friedrich Kentrat of U-74 recorded the ensuing events in his war diary [Morgan and Taylor, 2011, pp. 119–123]: “September 18, 1941, visibility 4–6 nautical miles, a number of smoke plumes on the horizon, vessels seem well strung out.” Kentrat had spotted SC-44, a Canadian convoy of cargo ships. For protection, a destroyer and small antisubmarine warships known as corvettes escorted SC-44 along its journey. At 22:30 UT, Kentrat issued a radio dispatch to headquarters and the other Brandenburg U-boats, “Alpha. Alpha. Enemy convoy in sight. Quadrant AD9761. Course NE, moderate speed. U-74.” Unsure whether his compatriots received his message, he recorded in his diary that since 04:30 UT on 18 September, “short-wave radio reception has been very poor and it gradually cuts out altogether. We try absolutely everything but without success. I hope the other Brandenburg boats can receive me.” Unbeknownst to Kentrat, his radio problems were caused by the magnetic storm and the ionospheric disturbance that followed. As the Sun set, the sea haze lifted. Under such conditions, a wartime convoy would normally have been relatively securely hidden in the dark of night. But not this night. The sky was ablaze with the aurora borealis. Kentrat described the conditions as being “as bright as day.” Ironically, in a postwar interview [Johnston, 2008, p. 38], a crewman on board a ship in the convoy, the SC44 corvette HMCS Lévis, recalled seeing the aurora on that evening and remarking to a fellow crewman, “What a night for a torpedoing.” This bit of dark humor would turn out to be prophetic. At 01:00 UT on 19 September, Kentrat tried several times to maneuver U-74 into attack position on the starboard side of the convoy, only to be “driven off” each time by SC-44’s defending corvettes. They didn’t pursue for long, but Kentrat became concerned that his own U-boat was too visible “in these conditions.” (In those days, submarines were only occasionally submerged.) He decided to maneuver “to the port side of the convoy, where the Northern Lights [were] less bright.” At 03:50 UT, Kentrat radioed, “Brandenburg boats report in immediately.” (He did not know at the time that the other U-boats had been receiving his radio messages; he just hadn’t been receiving theirs.) At 05:03 UT, from the unusually long distance of 3 kilometers, Kentrat ordered four torpedoes fired in spread formation at the convoy. Afterward, U-74 quickly turned around to escape, and Kentrat ordered a fifth torpedo fired from the stern. Monitoring the results through his periscope, Kentrat reported a direct hit, “a plume” and “green light.” A torpedo had struck the stern of the Lévis, nearly cutting her in two. Afterward, Kentrat recorded detecting a desperate Morse code signal: “help.” Hours later, the Lévis sank. Of the ship’s complement, 18 died and 40 were rescued. [...] https://eos.org/features/the-geomagnetic-blitz-of-september-1941 Link to comment Share on other sites More sharing options...
Panzermann Posted October 13, 2016 Author Share Posted October 13, 2016 We have miscounted the number of galaxies. slightly. heic1620 Science ReleaseObservable Universe contains ten times more galaxies than previously thought13 October 2016 Astronomers using data from the NASA/ESA Hubble Space Telescopes and other telescopes have performed an accurate census of the number of galaxies in the Universe. The group came to the surprising conclusion that there are at least 10 times as many galaxies in the observable Universe as previously thought. The results have clear implications for our understanding of galaxy formation, and also help solve an ancient astronomical paradox - why is the sky dark at night? One of the most fundamental questions in astronomy is that of just how many galaxies the Universe contains. The Hubble Deep Field images, captured in the mid 1990s, gave the first real insight into this. Myriad faint galaxies were revealed, and it was estimated that the observable Universe contains between 100 to 200 billion galaxies [1] . Now, an international team, led by Christopher Conselice from the University of Nottingham, UK, have shown that this figure is at least ten times too low. Conselice and his team reached this conclusion using deep space images from Hubble, data from his teams previous work, and other published data[2] . They painstakingly converted the images into 3D, in order to make accurate measurements of the number of galaxies at different times in the Universes history. In addition, they used new mathematical models which allowed them to infer the existence of galaxies which the current generation of telescopes cannot observe. This led to the surprising realisation that in order for the numbers to add up, some 90% of the galaxies in the observable Universe are actually too faint and too far away to be seen - yet. It boggles the mind that over 90% of the galaxies in the Universe have yet to be studied. Who knows what interesting properties we will find when we observe these galaxies with the next generation of telescopes, explains Christopher Conselice about the far-reaching implications of the new results.In analysing the data the team looked more than 13 billion years into the past. This showed them that galaxies are not evenly distributed throughout the Universes history. In fact, it appears that there were a factor of 10 more galaxies per unit volume when the Universe was only a few billion years old compared with today. Most of these galaxies were relatively small and faint, with masses similar to those of the satellite galaxies surrounding the Milky Way. These results are powerful evidence that a significant evolution has taken place throughout the Universes history, an evolution during which galaxies merged together, dramatically reducing their total number. This gives us a verification of the so-called top-down formation of structure in the Universe, explains Conselice.The decreasing number of galaxies as time progresses also contributes to the solution of Olbers paradox - why the sky is dark at night [3] . The team came to the conclusion that there is such an abundance of galaxies that, in principle, every point in the sky contains part of a galaxy. However, most of these galaxies are invisible to the human eye and even to modern telescopes, owing to a combination of factors: redshifting of light, the Universes dynamic nature and the absorption of light by intergalactic dust and gas, all combine to ensure that the night sky remains mostly dark. Notes[1] The limited speed of light and the age of the Universe mean that the entire Universe cannot be seen from Earth. The part visible within our cosmological horizon is called the observable Universe.[2] The study uses data from Perez-Gonzalez et al. (2008), Kajisawa et al. (2009), Fontanta et al. (2004, 2006), Caputi et al. (2011), Pozzetti et al. (2009), Mortlock et al. (2011), Muzzin et al. (2013), Mortlock et al. (2015), Duncan et al. (2014), Grazian et al. (2015), Tomczak et al. (2014) and Song et al. (2015).[3] The astronomer Heinrich Olbers argued that the night sky should be permanently flooded by light, because in an unchanging Universe filled with an infinite number of stars, every single part of the sky should be occupied by a bright object. However, our modern understanding of the Universe is that it is both finite and dynamic not infinite and static.More informationThe Hubble Space Telescope is a project of international cooperation between ESA and NASA.The results are going to appear in the paper The evolution of galaxy number density at z < 8 and its implications , to be published in the Astrophysical Journal.The international team of astronomers in this study consists of Christopher J. Conselice (University of Nottingham, United Kingdom), Aaron Wilkinson (University of Nottingham, United Kingdom), Kenneth Duncan (Leiden University, the Netherlands), and Alice Mortlock (University of Edinburgh, United Kingdom)Image credit: NASA, ESALinksImages of HubbleLink to hubblesite releaseLink to science paperhttp://www.spacetelescope.org/news/heic1620/ http://www.spacetelescope.org/static/archives/releases/science_papers/heic1620/heic1620a.pdf pics to gawk at on the website Link to comment Share on other sites More sharing options...
Burncycle360 Posted October 13, 2016 Share Posted October 13, 2016 With the primary detection method for exoplanets being transit photometry, wouldn't that mean the systems we observe have to be angled such at we're looking relatively edge on to their systems invariable plane? Plus we have to be looking at exactly the right time for a planet to transit the star, and long enough to see the relative light blocked before, during and after... it seems like we're still just scratching the surface. Whatever happened to the OWL telescope? Two could be built for the price of hubble, and made into an interferometer, 100m primary with maybe 300m between them, would it be sufficient for direct atmospheric spectroscopy of an earth sized planet around a sun like star at all, and if so, out to how far? I guess the limiting factor is the the short exposures possible due to earths rotation... unless several sites can be set up to take over as the earth rotates and the data combined, though I imagine the costs would be getting silly at that point Link to comment Share on other sites More sharing options...
Mobius Posted October 15, 2016 Share Posted October 15, 2016 (edited) What are the odds that the closest star to the sun is named Proxima Centauri? it was estimated that the observable Universe contains between 100 to 200 billion galaxies [1] . Now, an international team, led by Christopher Conselice from the University of Nottingham, UK, have shown that this figure is at least ten times too low.Considering that the universe is dynamic and changing the further back one looks the number of galaxies are more numerous and smaller. So many have by now combined into larger though fewer. Edited October 15, 2016 by Mobius Link to comment Share on other sites More sharing options...
DB Posted October 15, 2016 Share Posted October 15, 2016 Burncycle360 - the VLT (Very Large Telescope (!) comprises 4 separate optical telescopes that can be combined interferometrically. http://www.eso.org/public/unitedkingdom/teles-instr/vlt/ The baseline is 130 or 140 meters, depending on how they are combined (I believe). Link to comment Share on other sites More sharing options...
Ivanhoe Posted October 21, 2016 Share Posted October 21, 2016 http://www.nydailynews.com/news/national/planet-making-sun-tilt-adding-wobble-solar-system-article-1.2838105 The mysterious, unseen Planet Nine could be causing the sun to tilt and adding a "wobble" to the solar system, according to a new study. Caltech researchers announced the findings at the American Astronomical Society's Division for Planetary Sciences meeting Wednesday — nine months after the group initially reported about the massive planet lurking at the outer reaches of our solar system. The planet is believed to have a mass about 10 times that of Earth and takes about 15,000 years to orbit the sun. Link to comment Share on other sites More sharing options...
Corinthian Posted October 21, 2016 Share Posted October 21, 2016 (edited) Should've been Planet X, but some anal-retentive idiots demoted Pluto. Edited October 21, 2016 by Corinthian Link to comment Share on other sites More sharing options...
Panzermann Posted October 21, 2016 Author Share Posted October 21, 2016 It was no demotion. Pluto received its own new category. and the status as "full" planet has always been debated. It moves around a common centre of gravity with its Moon and is rather small and not spherical. Not very planet like. There should be a movie: "Planet 9 from Outer Space" Link to comment Share on other sites More sharing options...
Ssnake Posted October 21, 2016 Share Posted October 21, 2016 It was a demotion. And by an organization that is inherently clueless about planets in the first place, the interstellar astonomers' society. Pluto is definitely round last time I looked (so is Charon), and that you have two planets circling each other ... well, I could have understood if they would have called it a bi-planetary system. What are they doing next time when we find two earth-sized planets circling each other with a center of gravity at a libration point, telling us that these aren't planets either? Link to comment Share on other sites More sharing options...
Panzermann Posted October 21, 2016 Author Share Posted October 21, 2016 (edited) So what. It was put in a different box than the other balls orbiting our central star. At 1/459 of Earth's mass it is a dwarf and in many other ways different from the other planets. *shrug* Science is a continually evovling process including definitions. Maybe in ten, thirty or hundred years the definition is changed again. Heck at first Pluto was thought to be a super heavy planet, which turned out not to be true at all. changing categories seems to be a feature of Pluto. People throwing a tantrum over it has become a meme disconnected from the actual astronomy I think. If someone thinks up a better system to sort and categorize our (or other star's) satellites that is okay with me too. The category is called plutoid at the moment instead of dwarf planet. Hey Pluto now has its very own category named after itself. Edited October 21, 2016 by Panzermann Link to comment Share on other sites More sharing options...
Corinthian Posted October 21, 2016 Share Posted October 21, 2016 (edited) The two posts above this one just reinforces the stereotype that Germans have no sense of humour nyahahahahaha! Edited October 21, 2016 by Corinthian Link to comment Share on other sites More sharing options...
Ssnake Posted October 21, 2016 Share Posted October 21, 2016 At 1/459 of Earth's mass it is a dwarf That's your metric?Just because you happen to live on this particular rock, which itself is a dwarf at 1/318 of Jupiter's? Link to comment Share on other sites More sharing options...
Panzermann Posted October 21, 2016 Author Share Posted October 21, 2016 At 1/459 of Earth's mass it is a dwarf That's your metric?Just because you happen to live on this particular rock, which itself is a dwarf at 1/318 of Jupiter's?By definition any category is arbitrary. I can just as well ask you why pluto is supposed to be a planet and not Eris or Cares? Pluto is categorised as an ice dwarf planet at times (together with thebotjer bigger transneptunian objects), because not all astronomers agree on the categorization as plutoid. That will take time to settle on a a widely accepted categorization system. Until hypothetical Planet X is found throwing it all out of whack again. Jupiter is a gas giant planet. Pluto an ice dwarf. Earth is the point of reference as "normal" planet. Sure it is terracentric or humancentric, but somewhere you have got to start. Link to comment Share on other sites More sharing options...
Panzermann Posted October 21, 2016 Author Share Posted October 21, 2016 The two posts above this one just reinforces the stereotype that Germans have no sense of humour nyahahahahaha! "pluto is a planet" is just not funny and I did not laugh the first time. This joke is just tired. Link to comment Share on other sites More sharing options...
Fritz Posted October 21, 2016 Share Posted October 21, 2016 At 1/459 of Earth's mass it is a dwarf That's your metric? Just because you happen to live on this particular rock, which itself is a dwarf at 1/318 of Jupiter's? Jupiterians are welcome to make their own metric based on Jupiter's size. Oh wait... Link to comment Share on other sites More sharing options...
Ivanhoe Posted October 22, 2016 Share Posted October 22, 2016 There should be a movie: "Planet 9 from Outer Space" I thought about that pun, but too easy. Link to comment Share on other sites More sharing options...
Ivanhoe Posted October 22, 2016 Share Posted October 22, 2016 The category is called plutoid at the moment instead of dwarf planet. If a gas giant digests too much ice, it gets plutoids? Link to comment Share on other sites More sharing options...
Ssnake Posted October 23, 2016 Share Posted October 23, 2016 By definition any category is arbitrary. Yay.You realize however that the convention just moved the goal posts of what a planet would be like just as the prospect came up that they would have to handle dozens of more planets like Pluto, and they somehow felt uncomfortable with it. Therefore, I can just as well ask you why pluto is supposed to be a planet and not Eris or Cares?Nope. THEY said that Pluto couldn't be a planet because it wouldn't fit their new definition of what a "planet" actually was that was tailored to exclude Pluto and other planetary bodies like it from the list. The onus is on them to explain why their move, which by the way was anything BUT unanimous, is better than to deal with the teensy incongruency that Pluto was declared a planet at a time when people thought that "this would be it". I will keep calling Pluto a planet simply for historical reasons.It matches four out of five of their categories anyway, and I won't hold it against it being a binary system with Charon. Link to comment Share on other sites More sharing options...
Mobius Posted October 24, 2016 Share Posted October 24, 2016 At 1/459 of Earth's mass it is a dwarf That's your metric?Just because you happen to live on this particular rock, which itself is a dwarf at 1/318 of Jupiter's? Jupiterians are welcome to make their own metric based on Jupiter's size. Oh wait... For now. If there is a far larger sample, say 100,000 known planets then maybe we can find a median planet size. Until then I vote earthling. Link to comment Share on other sites More sharing options...
savantu Posted October 24, 2016 Share Posted October 24, 2016 (edited) Apparently we have a 9th planet in our solar system. Puzzling how something 2x as large as Neptune ( up to 10x Earth ) managed to escape detection so far. https://www.washingtonpost.com/news/speaking-of-science/wp/2016/10/20/the-mysterious-planet-nine-might-be-causing-the-whole-solar-system-to-wobble/ And the paper itself for those interested : https://arxiv.org/pdf/1607.03963v2.pdf Edited October 24, 2016 by savantu Link to comment Share on other sites More sharing options...
Mobius Posted October 24, 2016 Share Posted October 24, 2016 It has been discussed back when it was first announced. But is was only 2 x earth's mass then. It apparently has grown in 10 months.The tilt of the planets orbit is a new wrinkle. Link to comment Share on other sites More sharing options...
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