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We appreciate everyone's very enthusiastic participation in the Space Community.

In order to keep this community focused on proper scientific facts, historical or contemporary space related stories, photos or videos and more broadly pertinent, general interest space posting, we encourage all of our members to keep in mind a few recommendations and community rules:

The Space Community is not intended for posts about non-scientific Ufology, Religion, Speculative Alienology and/or Conspiracy Theories.

Further, posting of fictional space art imagery or videos, especially without attribution, credits and/or explanation, (unless strongly contextualized and properly credited), and other forms of photo shopped "fake" space imagery (i.e. wallpapers) without any proper context, rhyme or reason as well as other forms of "space resembling" fictional art is strongly discouraged.

There are many other, more appropriate communities out there for those sort of posts.

For more information, please refer to the Community Policy section of this Community.


Also read this few, important words by our fellow moderator +Jason Major :

"Just a quick note (PLEASE READ) – if you post an article here that has already been shared recently, especially multiple times, OR if you post an image or video (even space-related) with no content, description, or attribution, it will be removed.

Thank You - Management"

Please refer to the Community Policy at left for more information. Thank you.
It's About Respect 
One of the things we do a lot as moderators of the Space community is remind posters to give proper attribution and link-backs to the authors and artists whose work they're sharing with everybody. Though the rules are pretty simple - put the name of the content creator in your post, if the work is copyrighted put the name of the organization that owns the copyright (if different from the author) in your post, and include a link back to the original source - they're often not heeded. The moderating team understands that even these simple rules are significantly stricter  than what people find in most of social media, and so we try to give people ample warning and reminders of the expectations here. 
If we know the rules surrounding sharing are stricter than in other communities, why do we have them?  If the copyright boogymen aren't coming for you on Facebook, Pinterest, Tumblr, or even elsewhere on Google+, isn't it safe to just share freely with the Space community? 
Well, simply put, yes. Unless you're posting something that's explicitly and blatantly illegal, the legal ramifications of your sharing a quote, or an image, or what have you are nil. Nobody's coming to get you. 
But that's not the point. It's not about the law. We're not trying to cover our behinds, and we're not reminding you to cover yours. In fact, many of the images we're all sharing are in the public domain, and are not protected by copyright laws. 
It's about respect. 
By naming the scientist, author, artist, photographer, videographer, director, producer, or whoever it is that has created this work that you feel is worth sharing in your post and including a link back to the original source, you are showing your respect. You are showing your respect to the creator of that work, and, perhaps more importantly, you are showing your respect to the other members of this community. 
As moderators, we want to build a community that is built on respect, and one of the most significant ways we can show respect is to give credit where credit is due. We want to foster an attitude around content sharing that is respectful, that is not exploitative of artists and authors, and that does not take the members of this community for granted. 
As a denizen and frequent user of social media, you may not care about giving credit, and as a content creator yourself, you may not care if you get credit. In the end, however, it isn't about you, nor is it about what you care about. It's about this community as a whole, and what kind of community we all want it to be. What we want is a community that does care. 
We want a community that cares about attribution because it's curious about where things come from, and because it's respectful toward others.

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Apply now for a #NASASocial event at our Jet Propulsion Laboratory in California on Sept 14-15 for the triumphant end of NASA’s Cassini mission to Saturn after nearly 20 years in space. Details:

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Y por si éramos pocos... llega el «Planeta 10»

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6 panel of Chandra & Hubble, full field.

This comparison between the Chandra (left) and Hubble (right) images of the Crab Nebula shows 3 sets of full field views.

About the Image:
NASA press release
NASA caption
Id: opo0224b
Type: Collage
Release date: 19 September 2002, 19:00
Size: 963 x 1763 px

Credit: NASA/ESA/CXC/ASU/J. Hester et al., HST/ASU/J. Hester et al.

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This infrared view of Orion is literally cool; gas at hundreds of degrees rather than the thousands of degrees gas seen in optical light.
Exploring the Orion Nebula in infrared light for an upcoming project. This view, from the WISE mission, clearly shows the "bowl" carved by the stars of the trapezium. It also shows how the cool gas underlies the nebula and connects between Orion and the Running Man Nebula above it. It also extends down along a dense filament of cold gas that is dark at visible wavelengths. Multi-wavelength astronomy shows us diverse views that teach us so much more about the universe.

Credit: NASA/JPL-Caltech/WISE Team

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Source: RIKEN
Massive stars end their lives in gigantic explosions, so-called supernovae. Within millions of years of stable evolution, these stars have built up a central core composed of mostly iron. When the core reaches about 1.5 times the mass of the Sun, it collapses under the influence of its own gravity and forms a neutron star. Enormous amounts of energy are released in this catastrophic event, mostly by the emission of neutrinos. These nearly massless elementary particles are abundantly produced in the interior of the new-born neutron star, where the density is higher than in atomic nuclei and the temperature can reach 500 billion degrees Kelvin.

The physical processes that trigger and drive the explosion have been an unsolved puzzle for more than 50 years. One of the theoretical mechanisms proposed invokes the neutrinos, because they carry away more than hundred times the energy needed for a typical supernova. Leaking out from the hot interior of the neutron star, a small fraction of the neutrinos are absorbed in the surrounding gas. This heating causes violent motions of the gas, similar to those in a pot of boiling water on a stove. When the bubbling of the gas becomes sufficiently powerful, the supernova explosion sets in as if the lid of the pot were blown off. The outer layers of the dying star are expelled into circumstellar space, and with them all the chemical elements that the star has assembled by nuclear burning during its life. But also new elements are created in the hot ejecta of the explosion, among them radioactive species such as 44Ti (titanium with 22 protons and 22 neutrons in its atomic nuclei) and 56Ni (28/28 neutrons/protons), which decay to stable calcium and iron, respectively. The thus released radioactive energy makes a supernova shine bright for years.

Because of the wild boiling of the neutrino-heated gas, the blast wave starts out nonspherically and imprints a large-scale asymmetry on the ejected stellar matter and the supernova as a whole (Fig. 1), in agreement with the observation of clumpiness and asymmetries in many supernovae and their gaseous remnants. The initial asymmetry of the explosion has two immediate consequences. On the one hand, the neutron star receives a recoil momentum opposite to the direction of the stronger explosion, where the supernova gas is expelled with more violence. This effect is similar to the kick a rowing boat receives when a passenger jumps off. On the other hand, the production of heavy elements from silicon to iron, in particular also of 44Ti and 56Ni, is more efficient in directions where the explosion is stronger and where more matter is heated to high temperatures. "We have predicted both effects some years ago by our three-dimensional (3D) simulations of neutrino-driven supernova explosions", says Annop Wongwathanarat, researcher at the RIKEN Astrophysical Big Bang Laboratory and lead author of the corresponding publication of 2013, at which time he worked at MPA in collaboration with his co-authors H.-Thomas Janka and Ewald Müller. "The asymmetry of the radioactive ejecta is more pronounced the larger the neutron star kick is", he adds. Since the radioactive atomic nuclei are synthesized in the innermost regions of the supernova, in the very close vicinity of the neutron star, their spatial distribution reflects explosion asymmetries most directly.

Journal Reference:
Annop Wongwathanarat, Hans-Thomas Janka, Ewald Müller, Else Pllumbi, Shinya Wanajo. Production and Distribution of 44Ti and 56Ni in a Three-dimensional Supernova Model Resembling Cassiopeia A. The Astrophysical Journal, 2017; 842 (1): 13

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Source: NASA/Goddard Space Flight Centre
At any given moment, as many as 10 million wild jets of solar material burst from the sun’s surface. They erupt as fast as 60 miles per second, and can reach lengths of 6,000 miles before collapsing. These are spicules, and despite their grass-like abundance, scientists didn’t understand how they form. Now, for the first time, a computer simulation — so detailed it took a full year to run — shows how spicules form, helping scientists understand how spicules can break free of the sun’s surface and surge upward so quickly.

This work relied upon high-cadence observations from NASA’s Interface Region Imaging Spectrograph, or IRIS, and the Swedish 1-meter Solar Telescope in La Palma, in the Canary Islands. Together, the spacecraft and telescope peer into the lower layers of the sun’s atmosphere, known as the interface region, where spicules form.

“Numerical models and observations go hand in hand in our research,” said Bart De Pontieu, an author of the study and IRIS science lead at Lockheed Martin Solar and Astrophysics Laboratory, in Palo Alto, California. “We compare observations and models to figure out how well our models are performing, and to improve the models when we see major discrepancies.”

Observing spicules has been a thorny problem for scientists who want to understand how solar material and energy move through and away from the sun. Spicules are transient, forming and collapsing over the course of just five to 10 minutes. These tenuous structures are also difficult to study from Earth, where the atmosphere often blurs our telescopes’ vision.


Journal Reference: J. Martínez-Sykora, B. De Pontieu, V. H. Hansteen, L. Rouppe Van Der Voort, M. Carlsson, T. M. D. Pereira. On the generation of solar spicules and Alfvénic waves. Science, 2017

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Horsehead Nebula - Distance From Earth, Location, Name Meaning, Composition, Facts

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Rotating Gas Cloud

An excerpt from an article by Phil Plait:

IC1396 is a huge cloud of gas and dust, a star-forming factory 100 light years across. Massive, hot, young stars in the center have blown an enormous cavity in the center of the nebula, their fierce stellar winds and blasting ultraviolet light eating the cloud away from the inside out.

J-P Metsävainio is a Finnish astrophotographer who took several images of this sprawling cloud, broke them up into layers, made a computer surface model of the structure, then remapped it all into different frames seen from different angles. The finished product is this jaw-dropping three-dimensional animation. I’ll note this is an approximation to the real structure of the nebula, an educated guess. But it gives an incredible feel to the object and a real sense of what it must really be like.

IC 1396 is a stunning emission nebula that mixes glowing cosmic gas and dark dust clouds in the high and far off constellation of Cepheus.
Among the intriguing dark shapes within IC 1396, the winding Elephant's Trunk nebula lies just below center

Image credit: J-P Metsävainio

Image source>>

#universe, #3D_animation, #IC1396, #emission_nebula, #astronomy, #astrophotography
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