суббота, 13 апреля 2019 г.

ancientart: Lagomarsino Canyon, one of the largest rock art…






ancientart:



Lagomarsino Canyon, one of the largest rock art sites in Nevada, USA. Majority of the motifs appear to be 4-5,000 years old, although some could be as old as 10,000 years.


Photos taken by Ken Lund.



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Bronze Age Burial Mounds Photoset 1, Moor Divock Prehistoric Complex, Cumbria,...







Bronze Age Burial Mounds Photoset 1, Moor Divock Prehistoric Complex, Cumbria, 10.4.19.


The site of Moor Divock features an extensive series of prehistoric mounds.


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Bronze Age Burial Mounds Photoset 2, Moor Divock Prehistoric Complex, Cumbria, 10.4.19.








Bronze Age Burial Mounds Photoset 2, Moor Divock Prehistoric Complex, Cumbria, 10.4.19.


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‘Carreg Samson’ Prehistoric Burial Chamber, Castlelaw, Pembrokeshire,...




‘Carreg Samson’ Prehistoric Burial Chamber, Castlelaw, Pembrokeshire, 13.4.19.


Here be monsters! Sometimes big can be beautiful!


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Fluorite | #Geology #GeologyPage #Mineral Locality: Bingham,…


Fluorite | #Geology #GeologyPage #Mineral


Locality: Bingham, Socorro County, New Mexico, United States of America


Size: 3.4 × 1.9 × 1.5 cm


Photo Copyright © Viamineralia /e-rocks. com


Geology Page

www.geologypage.com

https://www.instagram.com/p/BwL9TmUgN0i/?utm_source=ig_tumblr_share&igshid=1n3u9erg1v74g


Krubera Cave, The World’s Deepest Cave | #Geology #GeologyPage…


Krubera Cave, The World’s Deepest Cave | #Geology #GeologyPage #Cave #Georgia


Krubera Cave is the deepest known cave on Earth. It is located in the Arabika Massif of the Gagra Range of the Western Caucasus, in the Gagra district of Abkhazia, a breakaway region of Georgia.


Read more & More Photos: http://www.geologypage.com/2016/05/krubera-cave-the-worlds-deepest-cave.html


Geology Page

www.geologypage.com

https://www.instagram.com/p/BwL9cZJgRC_/?utm_source=ig_tumblr_share&igshid=qnf5ltrot5qa


Jeremejevite | #Geology #GeologyPage #Mineral Locality:…


Jeremejevite | #Geology #GeologyPage #Mineral


Locality: Emmelberg Mountain, Daun, Eifel, Rhineland-Palatinate, Germany


Size: 1 × 1.3 × 0.9 cm


Photo Copyright © Mintreasure /e-rocks. com


Geology Page

www.geologypage.com

https://www.instagram.com/p/BwL9kzzgDSE/?utm_source=ig_tumblr_share&igshid=b65ik9u9jzph


Linarite | #Geology #GeologyPage #Mineral Locality: King Arthur…


Linarite | #Geology #GeologyPage #Mineral


Locality: King Arthur Mine, Kirki, Thraki, Greece


Size: 4.6 × 2.2 × 1.5 cm


Photo Copyright © Greek rocks /e-rocks. com


Geology Page

www.geologypage.com

https://www.instagram.com/p/BwL9uAQgIW8/?utm_source=ig_tumblr_share&igshid=16w2fwn5753us


worldhistoryfacts: Xianbei belt buckle from the 3rd-4th century…


worldhistoryfacts:



Xianbei belt buckle from the 3rd-4th century CE. The Xianbei were a nomadic group that lived to the north and west of China proper. They reached their apex during late antiquity, after the fall of the Han Dynasty. The Xianbei were a key conduit of culture and trade between the disunited Chinese kingdoms and the rest of the world, bringing central Asian culture (including Buddhism) into China. The XIanbei slowly integrated themselves more  and more into China, eventually ruling parts of northern China during the Northern Wei dynasty and changing parts of their culture to be more Chinese.



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worldhistoryfacts: Twelfth century chess pieces from Nishapur,…


worldhistoryfacts:



Twelfth century chess pieces from Nishapur, Iran. In place of the modern queen, medieval Persians played with viziers (chief ministers for the Caliph); bishops were elephants. Chess came to Persia from India, where it was invented in the 6th century. Many sets in the Islamic world used abstract figurines like these because of the religious prohibition on creating human and animal images.



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Armenians vs Georgians

Armenians and Georgians are ethnic groups that live side by side in the south Caucasus, or Transcaucasia. By all accounts, they’ve both been there since prehistoric times and they’re very similar in terms of overall genetic structure.
However, they speak languages from totally unrelated families: Indo-European and Kartvelian, respectively. How did this happen and might the answer lie in the small genetic differences that do exist between them?
To investigate this issue, I ran a series of qpAdm formal mixture models of present-day Armenians and Georgians using hundreds of ancient reference populations. To come up with as straightforward and meaningful results as possible, I constrained myself to two-way models. I then discarded the runs that produced “tail probs” under 0.1 and retained less than 400K SNPs. Only a handful models passed muster, including these two:



Armenian
Mycenaeans_&_Empuries2 0.233±0.041
Kura-Araxes_Kaps 0.767±0.041

chisq 18.422
tail prob 0.142151
Full output
Georgian
Globular_Amphora 0.071±0.025
Kura-Araxes_Kaps 0.929±0.025

chisq 18.419
tail prob 0.142266
Full output



At the most basic level, the results suggest that both Armenians and Georgians are overwhelmingly derived from populations of Bronze Age Transcaucasia associated with the Kura-Araxes archeological culture, albeit with minor ancestries from somewhat different sources from the west. As far as I can see, when using more than 400K SNPs and a wide range and large number of outgroups (or right pops), neither Armenians nor Georgians can pass perfectly for any one ancient population in my dataset.
The best proxies for the minor but significant western ancestry in Armenians are Mycenaeans of the Bronze Age Aegean region and Greek colonists from Iron Age Iberia (Empuries2). Obviously, and perhaps importantly, these are both attested Indo-European-speaking groups. On the other hand, the very minor western ancestry in Georgians is best characterized as gene flow from Middle to Late Neolithic European farmers rich in indigenous European forager ancestry. It’s practically impossible to say what language or languages these farmers spoke. How about something Kartvelian?
In any case, for me, the perplexing thing about present-day Armenians is that they harbor very little steppe ancestry. By and large, no more than a few per cent. Compare that to the currently available samples from what is now Armenia dating to the Middle to Late Bronze Age, which show ratios of steppe ancestry of up to 25%. For now, I’m guessing that what we’re dealing with here is the classic bounce back of older ancestry layers that has been documented for different parts and periods of prehistoric Europe.
See also…
Steppe ancestry in Chalcolithic Transcaucasia (aka Armenia_ChL explained)
Catacomb > Armenia_MLBA
Late PIE ground zero now obvious; location of PIE homeland still uncertain, but…

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2019 April 13 Rigil Kentaurus and Sandqvist 169 Image Credit…


2019 April 13


Rigil Kentaurus and Sandqvist 169
Image Credit & Copyright: Roberto Colombari


Explanation: Rigil Kentaurus is the bright star near the top of this broad southern skyscape. Of course it’s probably better known as Alpha Centauri, nearest star system to the Sun. Below it sprawls a dark nebula complex. The obscuring interstellar dust clouds include Sandqvist catalog clouds 169 and 172 in silhouette against the rich starfields along the southern Milky Way. Rigil Kent is a mere 4.37 light-years away, but the dusty dark nebulae lie at the edge of the starforming Circinus-West molecular cloud about 2,500 light-years distant. The wide-field of view spans over 12 degrees (24 full moons) across southern skies.


∞ Source: apod.nasa.gov/apod/ap190413.html


Hubble Peers at Cosmic Blue Bauble


NASA – Hubble Space Telescope patch.


April 12, 2019



Globular clusters are inherently beautiful objects, but the subject of this NASA/ESA Hubble Space Telescope image, Messier 3, is commonly acknowledged to be one of the most beautiful of them all.


Containing an incredible half-million stars, this 8-billion-year-old cosmic bauble is one of the largest and brightest globular clusters ever discovered. However, what makes Messier 3 extra special is its unusually large population of variable stars — stars that fluctuate in brightness over time. New variable stars continue to be discovered in this sparkling stellar nest to this day, but so far we know of 274, the highest number found in any globular cluster by far. At least 170 of these are of a special variety called RR Lyrae variables, which pulse with a period directly related to their intrinsic brightness. If astronomers know how bright a star truly is based on its mass and classification, and they know how bright it appears to be from our viewpoint here on Earth, they can thus work out its distance from us. For this reason, RR Lyrae stars are known as standard candles — objects of known luminosity whose distance and position can be used to help us understand more about vast celestial distances and the scale of the cosmos.


Messier 3 also contains a relatively high number of so-called blue stragglers, which are shown quite clearly in this Hubble image. These are blue main sequence stars that appear to be young because they are bluer and more luminous than other stars in the cluster. As all stars in globular clusters are believed to have formed together and thus to be roughly the same age, only a difference in mass can give these stars a different color. A red, old star can appear bluer when it acquires more mass, for instance by stripping it from a nearby star. The extra mass changes it into a bluer star, which makes us think it is younger than it really is.


Messier 3 is featured in Hubble’s Messier catalog, which includes some of the most fascinating objects that can be observed from Earth’s Northern Hemisphere. See the NASA-processed image and other Messier objects at: https://www.nasa.gov/content/goddard/hubble-s-messier-catalog.



Hubble Space Telescope (HST)

For more information about Hubble, visit:


http://hubblesite.org/


http://www.nasa.gov/hubble


http://www.spacetelescope.org/


Text Credits: ESA (European Space Agency)/NASA/Rob Garner/Image, Animation, Credits: ESA/Hubble & NASA, G. Piotto et al.


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met-africa-oceania: Two Flat Stamps, Arts of Africa, Oceania,…


met-africa-oceania:



Two Flat Stamps, Arts of Africa, Oceania, and the Americas


The Michael C. Rockefeller Memorial Collection, Bequest of Nelson A. Rockefeller, 1979

Metropolitan Museum of Art, New York, NY
Medium: Ceramic


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met-africa-oceania: Headdress Ornament, Arts of Africa,…


met-africa-oceania:



Headdress Ornament, Arts of Africa, Oceania, and the Americas


Bequest of Jane Costello Goldberg, from the Collection of Arnold I. Goldberg, 1986

Metropolitan Museum of Art, New York, NY
Medium: Silvered copper, shell, turquoise


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historyarchaeologyartefacts: Assyrian soldier within siege…


historyarchaeologyartefacts:



Assyrian soldier within siege tower pours down the water on its side extinguishing the flames, scene from siege of the Lachish, Assyria 701 B.C.[40×560]



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Are brown dwarfs failed stars or super-planets?

Brown dwarfs fill the “gap” between stars and the much smaller planets – two very different types of astronomical objects. But how they originate has yet to be fully explained. Astronomers from Heidelberg University may now be able to answer that question. They discovered that the star ν Ophiuchi in the Milky Way is being orbited by two brown dwarfs, which in all probability formed along with the star from a gas and dust disk, just as planets do. The research results were published in Astronomy & Astrophysics.











Are brown dwarfs failed stars or super-planets?
Artist rendering of a brown dwarf. They are more massive and hotter than planets but lack the nuclear fusion in their
 core as in normal stars. Two such “failed” stars were detected orbiting the star ? Ophiuchi. They were probably
 formed in the earlier protoplanetary disk of the star [Credit: NASA/JPL-Caltech]

Brown dwarfs orbit either one star or travel in isolation in the vast expanse of the Milky Way. Their mass – they are at least 13 times heavier than the planet Jupiter – is sufficient to generate, at least temporarily, energy in their core through nuclear fusion. They are not sufficiently massive, however, to ignite hydrogen in their cores and hence to create their own light. The heat they continue to radiate after formation is how astronomers are able to locate them. It is estimated that up to 100 billion brown dwarfs make their home in the Milky Way. Yet it remains unclear how they form – whether they are “failed” stars or possibly even super-planets.
The recent discoveries made at the Centre for Astronomy of Heidelberg University (ZAH) could provide an answer. Prof. Dr Andreas Quirrenbach and his team at the Königstuhl State Observatory of the ZAH analysed the variations in radial velocity of the star ν Ophiuchi. Using telescopes in the USA and Japan, the Heidelberg astronomers and others measured the velocity of the star for 11 years. The star has a mass slightly greater than two and half times that of the Sun, and is located approximately 150 light years from Earth in the constellation Ophiuchus.











Are brown dwarfs failed stars or super-planets?
Periodic variations of the radial velocity of ν Ophiuchi over a period of about ten years caused by two circulating
brown dwarfs. The blue, green and red data points come from telescopes in California, Japan and Chile. The
 regular movement in the rhythm of approximately 530 days is caused by the inner brown dwarf. At the third
and ninth time a particularly high speed is reached – this points to the existence of the outer brown dwarf,
which has exactly six times the circulation time [Credit: A. Quirrenbach (ZAH/LSW)
and T. Trifonov (MPIA)]

The Heidelberg team noticed a certain pattern in the measurements, similar to those caused by orbiting planets or binary stars, which is usually nothing out of the ordinary. But in this case, in-depth analysis of the data revealed something extraordinary: apparently, ν Ophiuchi is being orbited by two brown dwarfs with an orbital period of approximately 530 and 3,185 days, which puts them in a 6:1 resonant configuration. So, the brown dwarf closest to ν Ophiuchi orbits its star exactly six times while the other, more distant brown dwarf completes only one orbit.
This discovery sheds completely new light on the evolution of brown dwarfs. Do they develop exclusively like normal stars in interstellar clouds, or can they also form in the so-called protoplanetary disk of gas and dust that surrounds the parent star in the early phase of its formation? “The 6:1 resonance is a strong indication for the latter scenario,” explains Prof. Quirrenbach. “Only then could the orbits of the newly developing brown dwarfs adjust to a stable resonance over millions of years.”


That is what the extensive dynamic analyses for possible configurations of the ν Ophiuchi system suggest, reports the researcher. This superplanetary system is the first of its kind as well as the first sure sign that brown dwarfs can form in a protoplanetary disk, Prof. Quirrenbach stresses. The researcher and his team hope for other such discoveries that may one day allow them to clarify how many of the “failed” stars are actually more massive siblings of Jupiter and Saturn.


Source: University of Heidelberg [April 09, 2019]




TANN



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Curiosity Tastes First Sample in ‘Clay-Bearing Unit’


NASA – Mars Science Laboratory (MSL) logo.


April 12, 2019


Scientists working with NASA’s Curiosity Mars rover have been excited to explore a region called “the clay-bearing unit” since before the spacecraft launched. Now, the rover has finally tasted its first sample from this part of Mount Sharp. Curiosity drilled a piece of bedrock nicknamed “Aberlady” on Saturday, April 6 (the 2,370th Martian day, or sol, of the mission), and delivered the sample to its internal mineralogy lab on Wednesday, April 10 (Sol 2374).



Curiosity’s First Clay Unit Drill Hole

Animation above: The Mast Camera, or Mastcam, on NASA’s Curiosity Mars rover captured this set of images before and after it drilled a rock nicknamed “Aberlady,” on Saturday, April 6 (the 2,370th Martian day, or sol, of the mission). The rock and others nearby appear to have moved when the drill was retracted. This was the first time Curiosity has drilled in the long-awaited “clay-bearing unit.” Animation Credits: NASA/JPL-Caltech/MSSS.


The rover’s drill chewed easily through the rock, unlike some of the tougher targets it faced nearby on Vera Rubin Ridge. It was so soft, in fact, that the drill didn’t need to use its percussive technique, which is helpful for snagging samples from harder rock. This was the mission’s first sample obtained using only rotation of the drill bit.



Curiosity Surveys the Clay-Bearing Unit

Image above: The Mast Camera (Mastcam) on NASA’s Curiosity Mars rover captured this mosaic as it explored the clay-bearing unit on February 3, 2019 (Sol 2309). This landscape includes the rocky landmark nicknamed “Knockfarril Hill” (center right) and the edge of Vera Rubin Ridge, which runs along the top of the scene. Image Credits: NASA/JPL-Caltech/MSSS.


“Curiosity has been on the road for nearly seven years,” said Curiosity Project Manager Jim Erickson of NASA’s Jet Propulsion Laboratory in Pasadena, California. “Finally drilling at the clay-bearing unit is a major milestone in our journey up Mount Sharp.”


Scientists are eager to analyze the sample for traces of clay minerals because they usually form in water. NASA’s Mars Reconnaissance Orbiter (MRO) spied a strong clay “signal” here long before Curiosity landed in 2012. Pinpointing the source of that signal could help the science team understand if a wetter Martian era shaped this layer of Mount Sharp, the 3-mile-tall (5-kilometer-tall) mountain Curiosity has been climbing.


Curiosity has discovered clay minerals in mudstones all along its journey. These mudstones formed as river sediment settled within ancient lakes nearly 3.5 billion years ago. As with water elsewhere on Mars, the lakes eventually dried up.



Curiosity Sees Waves in the Clay Unit (Click on the image for enlarge)

Image above: The hills and troughs in this little valley, carved between a ridge and cliffs higher up Mount Sharp, almost look like undulating waves. The Mast Camera (Mastcam) on NASA’s Curiosity Mars rover captured this mosaic as it explored the clay-bearing unit on Jan. 23, 2019 (Sol 2299). Image Credits: NASA/JPL-Caltech/MSSS.


The clay beacon seen from space brought the rover here, but the region clearly has several other stories to tell. Now that Curiosity is searching this area, scientists can peer around as geological tourists, finding a landscape both ancient and new. There are several kinds of bedrock and sand, including active sand ripples that have shifted in the past year. Pebbles are scattered everywhere – are they eroding from the local bedrock? Several eye-catching landmarks, such as “Knockfarril Hill,” stick out as well.





Mars Science Laboratory (MSL) or Curiosity rover. Image Credits: NASA/JPL-Caltech

“Each layer of this mountain is a puzzle piece,” said Curiosity Project Scientist Ashwin Vasavada of JPL. “They each hold clues to a different era in Martian history. We’re excited to see what this first sample tells us about the ancient environment, especially about water.”


The Aberlady sample will give the team a starting point for thinking about the clay-bearing unit. They plan to drill several more times over the course of the next year. That will help them understand what makes this region different from the ridge behind it and an area with a sulfate signal up higher on the mountain.


More information about Curiosity is at: https://mars.nasa.gov/msl/


More information about Mars is at: https://mars.nasa.gov/


Animation (mentioned), Images (mentioned), Text, Credits: NASA/JPL/Andrew Good.


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Rocket break-up provides rare chance to test debris formation


ESA – Clean Space logo.


12 April 2019


The discarded ‘upper stage’ from a rocket launched almost ten years ago has recently crumbled to pieces.


“Leaving a trail of debris in its wake, this fragmentation event provides space debris experts with a rare opportunity to test their understanding of such hugely important processes”, explains Tim Flohrer, ESA’s Senior Space Debris Monitoring Expert.



Rocket body fragments

Fragmentation events like this one – either break ups or collisions – are the primary source of debris objects in space in the range of a few millimetres to tens of centimetres in size. Travelling at vast speeds, these bits of technological trash pose a threat to crucial space infrastructure, such as satellites providing weather and navigation services, and even astronauts on the ISS.


A remarkable video captured by the Deimos Sky Survey in Spain shows the stream of newly-made debris objects as they rush across the sky.


In the clip, a number of small point-like fragments can be seen spread horizontally across frame. As the observatory moves with the debris objects, the background stars are seen as white streaks.


The remnant piece is clearly visible as the largest and brightest point at the centre of about 40-60 smaller pieces, many larger than 30 cm in size, and has been traced back to the upper stage of a rocket launched in September 2009.



Example of the Atlas V Centaur upper stage

Originally an Atlas V Centaur upper stage, this rather large nearly cylindrical object would have measured about 12.5 metres in length and three metres in diameter, with a mass of more than two tonnes.


Given the international code 2009-047B, this rocket remnant had been flying in an eccentric orbit around our planet for just under a decade – flung as far as 34 700 km from Earth at the most distant point in its orbit and just 6675 km at the closest.


For an as-yet-unknown reason, the rocket body fragmented some time between 23 to 25 March.


An international effort


During a meeting of the International Academy of Astronautics (IAA) on 26 March, ESA’s space debris team met their counterparts from Russia, who informed the international community of fragments detected orbiting in the sky.


Just hours later, the Zimmerwald Observatory in Switzerland scheduled immediate observations of the cloud of fragments, and by 26 March had acquired the first views.



Zimmerwald Observatory gets the first look

The animation to the left shows the first series of exposures taken by the 0.8 metre telescope, ZimMAIN, which followed the debris cloud. It reveals several small dots, each a fragment larger than a few tens of centimetres, with background stars again appearing as long streaks.


Not long after, the Deimos Sky Survey followed up with observations of the event from 26-28 March (lead animation in this article), using the ‘Antsy’ optical sensor in Spain, which is adapted for tracking objects in low-Earth orbit.


While Zimmerwald continues to observe the cloud in close collaboration with Russian and ESA experts, ESA’s own 1-metre telescope at the Optical Ground Station at Tenerife, Spain, has joined the observation campaign, detecting a large number of fragments down to 10-20 cm in size.


Modeling the mess


ESA keeps an eye on events like this and continually updates the international community through its public database, enabling researchers to find patterns and come up with mitigation strategies for spacecraft in all variety of shapes, sizes and orbits. The database also allows operators of satellites and spacecraft to determine the changing risk to their missions from specific fragmentation events.


Once detected and observed, events like these are put into ‘space debris environment models’, allowing teams to compare the fragmentation of real-life debris with predictions – a rare but crucial opportunity to validate or improve models as necessary.


Developing models of the space debris environment allows ESA to design spacecraft that can withstand impacts from small objects, and design systems to avoid collisions. These models are the baseline for predicting not just the present, but our future space debris environment, which is essential to developing efficient space debris mitigation guidelines.



Our human-made space environment (debris not to scale)

International collaboration is essential to exchanging data and models, which takes place via a technical body called the Inter-Agency Space Debris Coordination Committee, which comprises all major European and international space agencies.


“As this example shows, international collaboration is essential if we want to respond quickly to debris creating events”, concludes Holger Krag, Head of ESA’s Space Safety Office.


“Incidents like this are rare, so to have such rich observations and data from across the globe is a unique opportunity to better understand the human-made environment around Earth, in which our satellites live out their lives”.



Space Safety & Security at ESA

To find out more about ESA’s space safety and security activities, including the work being done by the Planetary Defence and Space Weather Offices, click here: http://www.esa.int/Our_Activities/Operations/Space_Safety_Security/Space_Safety_Security


Related links:


Deimos Sky Survey: http://www.elecnor-deimos.com/portfolio/deimos-sky-survey/


‘Space debris environment models’: https://sdup.esoc.esa.int/


ESA public database: https://fragmentation.esoc.esa.int/


Zimmerwald Observatory: http://www.aiub.unibe.ch/research/zimmerwald_observatory/index_eng.html


ESA’s space debris team: http://www.esa.int/Our_Activities/Operations/Space_Safety_Security/Space_Debris


International Academy of Astronautics (IAA): https://www.iaaweb.org/


ESA reentry predictions: https://reentry.esoc.esa.int/


ESA Space Environment Report 2018 (PDF): https://www.sdo.esoc.esa.int/environment_report/Space_Environment_Report_latest.pdf


Collision warning: http://www.esa.int/Our_Activities/Operations/Space_Safety_Security/Rocket_break-up_provides_rare_chance_to_test_debris_formation


Space debris: http://www.esa.int/Our_Activities/Operations/Space_Safety_Security/Rocket_break-up_provides_rare_chance_to_test_debris_formation


Clean space: http://www.esa.int/ESA_Multimedia/Images/2019/03/Clean_Space


Space Safety & Security: http://www.esa.int/Our_Activities/Operations/Space_Safety_Security


Image, Animations, Text, Credits: ESA/Deimos Sky Survey/NASA/Roy Allison/Zimmerwald Observatory, AIUB/CC BY-SA 3.0 IGO.


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‘The Cop Stone’ Prehistoric Waymarker, Moor Divock Prehistoric Complex,...

‘The Cop Stone’ Prehistoric Waymarker, Moor Divock Prehistoric Complex, Cumbria, 10.4.19.




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