[meteorite-list] New find Phoenix
Found a 204 gram stoney specimen in the Phoenix area. I've tried to post pics, then links to pics to no avail. It's been a long time since I've been plugged into the meteorite community. I would like someone to at least have a look. Thanks. Todd Dziuk Phoenix, AZ Sent from my iPhone __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] Asteroid 2014 JO25 to Fly Safely Past Earth on April 19
https://www.jpl.nasa.gov/news/news.php?feature=6807 Asteroid to Fly Safely Past Earth on April 19 Jet Propulsion Laboratory April 6, 2017 A fairly large asteroid discovered nearly three years ago will fly safely past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance from Earth to the moon. Although there is absolutely no chance that the asteroid will collide with our planet, this will be a very close approach for an asteroid of this size. The asteroid, known as 2014 JO25, was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona -- a project of NASA's NEO Observations Program in collaboration with the University of Arizona. (An NEO is a near-Earth object). Contemporary measurements by NASA's NEOWISE mission indicate that the asteroid is roughly 2,000 feet (650 meters) in size, and that its surface is about twice as reflective as that of the moon. At this time very little else is known about the object's physical properties, even though its trajectory is well known. The asteroid will approach Earth from the direction of the sun and will become visible in the night sky after April 19. It is predicted to brighten to about magnitude 11, when it could be visible in small optical telescopes for one or two nights before it fades as the distance rapidly increases. Asteroids pass within this distance of Earth around two to seven times a week, but this upcoming close approach is the closest by any known asteroid of this size, or larger, since asteroid Toutatis approached within about four lunar distances in September 2004. The next known encounter of an asteroid of comparable size will occur in 2027 when the half-mile-wide (800-meter-wide) asteroid 1999 AN10 will fly by at one lunar distance, about 236,000 miles (380,000 kilometers). The April 19 encounter provides an outstanding opportunity to study this asteroid, and astronomers plan to observe it with telescopes around the world to learn as much about it as possible. Radar observations are planned at NASA's Goldstone Solar System Radar in California and the National Science Foundation's Arecibo Observatory in Puerto Rico, and the resulting radar images could reveal surface details as small as a few meters. The encounter on April 19 is the closest this asteroid has come to Earth for at least the last 400 years and will be its closest approach for at least the next 500 years. Also on April 19, the comet PanSTARRS (C/2015 ER61) will make its closest approach to Earth, at a very safe distance of 109 million miles (175 million kilometers). A faint fuzzball in the sky when it was discovered in 2015 by the Pan-STARRS NEO survey team using a telescope on the summit of Haleakala, Hawaii, the comet has brightened considerably due to a recent outburst and is now visible in the dawn sky with binoculars or a small telescope. JPL manages and operates NASA's Deep Space Network, including the Goldstone Solar System Radar, and hosts the Center for Near-Earth Object Studies for NASA's Near-Earth Object Observations Program, an element of the Planetary Defense Coordination Office within the agency's Science Mission Directorate. More information about asteroids and near-Earth objects can be found at: http://cneos.jpl.nasa.gov http://www.jpl.nasa.gov/asteroidwatch For more information about NASA's Planetary Defense Coordination Office, visit: http://www.nasa.gov/planetarydefense For asteroid and comet news and updates, follow AsteroidWatch on Twitter: twitter.com/AsteroidWatch News Media Contact DC Agle Jet Propulsion Laboratory, Pasadena, Calif. 818-393-9011 a...@jpl.nasa.gov 2017-100 __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] Ceres' Temporary Atmosphere Linked to Solar Activity
https://www.jpl.nasa.gov/news/news.php?feature=6802 Ceres' Temporary Atmosphere Linked to Solar Activity Jet Propuslion Laboratory April 6, 2017 Scientists have long thought that Ceres may have a very weak, transient atmosphere, but mysteries lingered about its origin and why it's not always present. Now, researchers suggest that this temporary atmosphere appears to be related to the behavior of the sun, rather than Ceres' proximity to the sun. The study was conducted by scientists from NASA's Dawn mission and others who previously identified water vapor at Ceres using other observatories. "We think the occurrence of Ceres' transient atmosphere is the product of solar activity," said Michaela Villarreal, lead author of the new study in the Astrophysical Journal Letters and researcher at the University of California, Los Angeles. Ceres is the largest object in the asteroid belt that lies between Mars and Jupiter. When energetic particles from the sun hit exposed ice and ice near the surface of the dwarf planet, it transfers energy to the water molecules as they collide. This frees the water molecules from the ground, allowing them to escape and create a tenuous atmosphere that may last for a week or so. "Our results also have implications for other airless, water-rich bodies of the solar system, including the polar regions of the moon and some asteroids," said Chris Russell, principal investigator of the Dawn mission, also at UCLA. "Atmospheric releases might be expected from their surfaces, too, when solar activity erupts." Before Dawn arrived in orbit at Ceres in 2015, evidence for an atmosphere had been detected by some observatories at certain times, but not others, suggesting that it is a transient phenomenon. In 1991, the International Ultraviolet Explorer satellite detected hydroxyl emission from Ceres, but not in 1990. Then, in 2007, the European Southern Observatory's Very Large Telescope searched for a hydroxide emission, but came up empty. The European Space Agency's Herschel Space Observatory detected water in the possible weak atmosphere, or "exosphere," of Ceres on three occasions, but did not on a fourth attempt. As Dawn began its thorough study of Ceres in March 2015, scientists found ample evidence for water in the form of ice. The spacecraft's gamma ray and neutron detector (GRaND) has found that the uppermost surface is rich in hydrogen, which is consistent with broad expanses of water ice. This ice is nearer to the surface at higher latitudes, where temperatures are lower, a 2016 study published in the journal Science found. Ice has been detected directly at the small bright crater called Oxo and in at least one of the craters that are persistently in shadow in the northern hemisphere. Other research has suggested that persistently shadowed craters are likely to harbor ice. Additionally, the shapes of craters and other features are consistent with significant water-ice content in the crust. Because of this evidence for abundant ice, many scientists think that Ceres' exosphere is created in a process similar to what occurs on comets, even though they are much smaller. In that model, the closer Ceres gets to the sun, the more water vapor is released because of ice sublimating near or at the surface. But the new study suggests comet-like behavior may not explain the mix of detections and non-detections of a weak atmosphere. "Sublimation probably is present, but we don't think it's significant enough to produce the amount of exosphere that we're seeing," Villarreal said. Villarreal and colleagues showed that past detections of the transient atmosphere coincided with higher concentrations of energetic protons from the sun. Non-detections coincided with lower concentrations of these particles. What's more, the best detections of Ceres' atmosphere did not occur at its closest approach to the sun. This suggests that solar activity, rather than Ceres' proximity to the sun, is a more important factor in generating an exosphere. The research began with a 2016 Science study led by Chris Russell. The study, using GRaND data, suggested that, during a six-day period in 2015, Ceres had accelerated electrons from the solar wind to very high energies. In its orbital path, Ceres is currently getting closer to the sun. But the sun is now in a particularly quiet period, expected to last for several more years. Since their results indicate Ceres' exosphere is related to solar activity, study authors are predicting that the dwarf planet will have little to no atmosphere for some time. However, they recommend that other observatories monitor Ceres for future emissions. Dawn is now in its extended mission and studying Ceres in a highly elliptical orbit. Engineers are maneuvering the spacecraft to a different orbital plane so that Ceres can be viewed in a new geometry. The primary science objective is to measure cosmic rays to help determin
[meteorite-list] Dawn Journal - March 30, 2017
http://dawn.jpl.nasa.gov/mission/journal_03_30_17.html Dawn Journal Dr. Marc Rayman March 30, 2017 Dear Leonardo dawn Vinci, Micheldawngelo and Other Artistic Readers, Now in its third year of orbiting a distant dwarf planet, a spacecraft from Earth is as active as ever. Like a master artist, Dawn is working hard to add fine details to its stunning portrait of Ceres. In this phase of its extended mission, the spacecraft's top priority is to record space radiation (known as cosmic rays) in order to refine its earlier measurements of the atomic species down to about a yard (meter) underground. The data Dawn has been collecting are excellent. [Image] Dawn saw this rugged terrain on August 15, 2016, from an altitude of 240 miles (385 kilometers). This is the southeastern end of a network of canyons in Yalode Crater called Nar Sulcus. (Nar is from a modern pomegranate feast in part of Azerbaijan. A sulcus is a set of parallel furrows or ridges.) We saw the rest of these canyons as they extend far to the northwest here. Geological structures like this have been found on some icy moons of the outer planets. The tremendous impact that formed Yalode heated the mixture of ice, rock and salt, which is a common combination on Ceres, perhaps causing a large volume to melt. When it subsequently refroze, it would have expanded (just as water does when it turns to ice in your freezer), and that may have created stresses that fractured the ground, forming Nar Sulcus. You can locate this scene in the eastern part of Yalode on this map near 41S, 281E. With a diameter of 162 miles (260 kilometers), Yalode is the second largest crater on Ceres. We have presented other photos of the crater, most recently in January. Full image and caption. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA As we explained in January, the ambitious mission has added a complex bonus to its plans. The team is piloting the ship through an intricate set of space maneuvers to dramatically shift its orbit around Ceres. They are now about halfway through, and it has been smooth sailing. Dawn is on course and on schedule. (If you happen to be one of the few readers for whom it isn't second nature to plan how to change a spacecraft's orbit around a dwarf planet by 90 degrees and then fly it under control of ion engine, last month's Dawn Journal presents a few of the details that may not be obvious. And you can follow the adventurer's orbital progress with the regular mission status updates.) If all goes well, on April 29 the new orbit will take Dawn exactly between the sun and the famous bright region at the center of Occator Crater. Named Cerealia Facula, the area is composed largely of salts. (Based on infrared spectra, the strongest candidate for the primary constituent is sodium carbonate). The probe will be at an altitude of about 12,400 miles (20,000 kilometers), or more than 50 times higher than it was in 2016 when it captured its sharpest photos of Occator (as well as the rest of Ceres' 1.1 million square miles, or 2.8 million square kilometers). But the objective of reaching a position at which the sun and Ceres are in opposite directions, a special alignment known as opposition, is not to take pictures that display more details to our eyes. In fact, however, the pictures will contain intriguing new details that are not readily discerned by visual inspection. Dawn will take pictures as it gets closer and closer to opposition, covering a range of angles. In each image, scientists will scrutinize the handful of pixels on Cerealia Facula to track how the brightness changes as Dawn's vantage point changes. [Occator Crater Image] Dawn took this photo of Occator Crater on Oct. 18, 2016, at an altitude of 920 miles (1,480 kilometers) in extended mission orbit 2. We have seen other views of Occator, from farther, from closer, with exposures optimized for the brightest areas, in color, with the crater on the limb of Ceres and more, but you can never have too many pictures of such a captivating scene. The central bright region is Cerealia Facula, and the collection of others is Vinalia Faculae. (A bright region on a planet is a facula. Here is more on these names.) These are the brightest areas on Ceres. One scenario for how they formed is that underground briny water made its way to the surface through fractures. When the water was on the ground, exposed to the cold vacuum of space, it froze and sublimated (that is, it transformed from a solid to a gas). The dissolved salt was left behind, with sodium carbonate being the likely principal constituent, and that reflective material is what we see here. We will see below that opposition surge measurements may provide evidence to support or modify this scenario. (A recent estimate is that Cerealia Facula may be some tens of millions of years younger than the crater itself. We discussed last year how ages are determined.) Since we can't have to
Re: [meteorite-list] space junk
I'd hazard that this is lightning damage, and the vitreous slag-like material is the remains of the melted shingles. There are some fragile-looking drips on the large fragment in image 4 that don't look like they could have survived high-speed impact through the roof. A Google image search for "lightning damage to roof" also shows similar holes in shingle roofs. On Thu, Apr 6, 2017 at 11:45 AM, Korotev, Randy via Meteorite-list < meteorite-list@meteoritecentral.com> wrote: > A guy sent me these photos. > > https://www.dropbox.com/sh/qcnzxol29ypwi4q/AAAWTbYOJh-LTf1L7JRFaMTsa?dl=0 > > My guess: space junk. He'd be happy to sell it because he's got $1000 > deductible on his home owner's insurance. > > Contact me off line if you want his e-mail address. > > ~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+ > Randy L. Korotev > Research Professor > Department of Earth & Planetary Sciences > Washington University in Saint Louis > > > http://eps.wustl.edu/people/randy_korotev > http://meteorites.wustl.edu/lunar/moon_meteorites.htm > > If you think you've found a meteorite, read these: > http://meteorites.wustl.edu/what_to_do.htm > http://meteorites.wustl.edu/realities.htm > > __ > > Visit our Facebook page https://www.facebook.com/meteoritecentral and the > Archives at http://www.meteorite-list-archives.com > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > https://pairlist3.pair.net/mailman/listinfo/meteorite-list > __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] space junk
A guy sent me these photos. https://www.dropbox.com/sh/qcnzxol29ypwi4q/AAAWTbYOJh-LTf1L7JRFaMTsa?dl=0 My guess: space junk. He'd be happy to sell it because he's got $1000 deductible on his home owner's insurance. Contact me off line if you want his e-mail address. ~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+~+ Randy L. Korotev Research Professor Department of Earth & Planetary Sciences Washington University in Saint Louis http://eps.wustl.edu/people/randy_korotev http://meteorites.wustl.edu/lunar/moon_meteorites.htm If you think you've found a meteorite, read these: http://meteorites.wustl.edu/what_to_do.htm http://meteorites.wustl.edu/realities.htm __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] Meteorite Picture of the Day
Today's Meteorite Picture of the Day: Portales Valley Contributed by: Gourgues Denis http://www.tucsonmeteorites.com/mpodmain.asp?DD=04/06/2017 __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
