вторник, 12 февраля 2019 г.

5 Facts About Earth’s Radiation Donuts 🍩

Did you know that our planet is surrounded by giant,

donut-shaped clouds of radiation?


image

Here’s what you need to know.


1. The radiation

belts are a side effect of Earth’s magnetic field


image

The Van Allen radiation belts exist because fast-moving charged

particles get trapped inside Earth’s natural magnetic field, forming two

concentric donut-shaped clouds of radiation. Other planets with global magnetic

fields, like

Jupiter
, also have radiation belts.


2. The radiation

belts were one of our first Space Age discoveries


image

Earth’s radiation belts were first

identified in 1958
by Explorer 1, the first U.S. satellite. The

inner belt, composed predominantly of protons, and the outer belt, mostly

electrons, would come to be named the Van Allen Belts, after James Van Allen,

the scientist who led the charge designing the instruments and studying the

radiation data from Explorer 1.


3. The Van Allen

Probes have spent six years exploring the radiation belts


image

In 2012, we launched the twin Van Allen Probes to

study the radiation belts. Over the past six years, these spacecraft have

orbited in and out of the belts, providing brand-new data about how the

radiation belts shift and change in response to solar activity and other

factors.


4. Surprise! Sometimes

there are three radiation belts


image

Shortly after launch, the Van Allen Probes detected a

previously-unknown third

radiation belt
, created by a bout of strong solar activity. All the

extra energy directed towards Earth meant that some particles trapped in our

planet’s magnetic field were swept out into the usually relatively empty region

between the two Van Allen Belts, creating an additional radiation belt.


5. Swan song for the

Van Allen Probes


image

Originally designed for a two-year mission, the Van Allen

Probes have spent more than six years collecting data in the harsh radiation

environment of the Van Allen Belts. In spring 2019, we’re changing their orbit to bring the perigee — the part of the

orbit where the spacecraft are closest to Earth — about 190 miles lower. This

ensures that the spacecraft will eventually burn up in Earth’s atmosphere,

instead of orbiting forever and becoming space junk.


Because the Van Allen Probes have proven to be so hardy,

they’ll continue collecting data throughout the final months of the mission

until they run out of fuel. As they skim through the outer reaches of Earth’s

atmosphere, scientists and engineers will also learn more about how atmospheric

oxygen can degrade satellite measurements — information that can help build

better satellites in the future.


Keep up with the latest on the mission on Twitter, Facebook

or nasa.gov/vanallenprobes.


2019 February 12 Plane Crossing a Crescent Moon Image Credit…


2019 February 12


Plane Crossing a Crescent Moon
Image Credit & Copyright: Olivier Staiger (Binounistan.com)


Explanation: No, this is not a good way to get to the Moon. What is pictured is a chance superposition of an airplane and the Moon. The contrail would normally appear white, but the large volume of air toward the setting Sun preferentially knocks away blue light, giving the reflected trail a bright red hue. Far in the distance, well behind the plane, is a crescent Moon, also slightly reddened. Captured a month ago above Valais, Switzerland, the featured image was taken so soon after sunset that planes in the sky were still in sunlight, as were their contrails. Within minutes, unfortunately, the impromptu sky show ended. The plane crossed the Moon and moved out of sight. The Moon set. The contrail became unilluminated and then dispersed.


∞ Source: apod.nasa.gov/apod/ap190212.html


Meteorite Dropping Fireball photographed from a Plane

Few weeks ago, we shared with you this amazing photo of a meteor taken from a plane by IMO member Filipp Romanov on a Moscow-Vladivostok flight on October, 31th, 2018):


Aurora Borealis from airplane and meteor (Flight Moscow-Vladivostok, October 31, 2018) over Russia. Canon EOS 60D: f/3.5, ISO-5000, 18 mm, 8 sec. exposure. Without tripod. The track of the meteor is visible at the 00:23 second of this video https://www.youtube.com/watch?v=pc-Edl2C5Ro (time-lapse; from Canon EOS 60D) from the same author.

This week, we received another amazing photo (2 photos actually) of a meteor taken from a plane. But this time, this is not a random meteor, the photo shows the meteorite dropping fireball that occurred over Cuba on Friday, February 1st, 2019! Cruz Maria Ruiz was on her way to San Jose, Costa Rica from Orlando, FL (Spirit Airlines 923) when she took a photo of the fireball and another one of the resulting smoke trail.


Fireball and Smoke Trail from an Airplane – Feb, 1 2019 – Credit: Cruz Maria Ruiz

Thank you Cruz Maria Ruiz!

Please, don’t hesitate to share you photos with us!


Source link


Human habitation in the Rockies older than originally thought

An archaeological site near Golden, Colorado, was occupied by humans thousands of years earlier than originally understood, according to new research conducted by the Denver Museum of Nature & Science in partnership with the Paleocultural Research Group (PCRG) and the University of Kansas Odyssey Archaeological Research Program (OARP).











Human habitation in the Rockies older than originally thought
University of Kansas Odyssey Archaeological Research Program participant Rolfe Mandel (in the excavation unit),
Mark Mitchell and Michele Koons examine the different layers in the profile of an excavation unit.
A buried soil with associated artifacts nearly two meters below the surface yielded the
new dates for the site [Credit: © Denver Museum of Nature & Science]

The site, nicknamed Magic Mountain, served as a campground for nomadic hunter-gatherers for millennia. The Museum, PCRG and OARP have conducted fieldwork there for the past few summers. The site was also excavated in the 1950s and 1990s. Previous excavations and radiocarbon dates revealed that the oldest occupation was roughly 5,500 to 5,000 years ago.


New radiocarbon dates from buried soil and its associated artifacts date to 8,000 radiocarbon years BP, or roughly 9,000 calendar years ago. The samples were collected and dated by Dr. Rolfe Mandel, director of OARP.


“The new dates push back the earliest occupation of the site by several millennia, into a period about which we know very little. Only a few sites in the Denver Basin preserve archaeological deposits from that period,” said Dr. Mark Mitchell of PCRG and co-director of the Magic Mountain project.


“The fact that we’ve identified an early Holocene and potentially Late Paleoindian occupation at Magic Mountain only magnifies the site’s importance for understanding the ancient history of the region. The new dates are also significant for our understanding of how the natural landscape around the site changed over time.”











Human habitation in the Rockies older than originally thought
Archaeologist Michele Koons holds up a rock chip at Magic Mountain archaeological site on May 25, 2017
[Credit: Seth McConnell, YourHub]

Magic Mountain is a prime locale to better understand mobility patterns, seasonal use, and site activities by early humans. Recent excavations have unearthed numerous rock-filled hearths and roasting ovens that were possibly once inside structures, countless fragments of grinding stones, various projectile points and other stone tools, and a handful of gray cord-marked ceramic fragments. Dr. Michele Koons, curator of archaeology at the Museum and co-director of the project, is overseeing the cleaning, sorting, cataloging and analysis of the collected material.
“The new dates are very exciting. Our research up until now had mainly focused on the Early Ceramic Period (200 – 1000 CE) occupation at the site. These new dates open up a potential new avenue of inquiry into early Coloradan life along the Front Range,” said Koons.


For the last two summers, more than 3,000 members of the general public have attended free tours and participated in excavation activities at Magic Mountain. A grant from the Colorado State Historical Fund is supporting the project. The project will take a break from fieldwork in 2019 as analysis continues and helps form research questions for the future.


Source: Denver Museum of Nature & Science [February 07, 2019]



TANN



Archive


Reconstructed Model of a Roman Villa, Senhouse Roman Museum, Maryport, Cumbria, 9.2.19.

Reconstructed Model of a Roman Villa, Senhouse Roman Museum, Maryport, Cumbria, 9.2.19.







Source link


NASA’s MAVEN Spacecraft Shrinking its Mars Orbit to Prepare for Mars 2020 Rover


NASA – MAVEN Mission patch.


Feb. 11, 2019


NASA’s 4-year-old atmosphere-sniffing Mars Atmosphere and Volatile Evolution (MAVEN) mission is embarking on a new campaign today to tighten its orbit around Mars. The operation will reduce the highest point of the MAVEN spacecraft’s elliptical orbit from 3,850 to 2,800 miles (6,200 to 4,500 kilometers) above the surface and prepare it to take on additional responsibility as a data-relay satellite for NASA’s Mars 2020 rover, which launches next year.


“The MAVEN spacecraft has done a phenomenal job teaching us how Mars lost its atmosphere and providing other important scientific insights on the evolution of the Martian climate,” said Jim Watzin, director of NASA’s Mars Exploration Program. “Now we’re recruiting it to help NASA communicate with our forthcoming Mars rover and its successors.”


While MAVEN’s new orbit will not be drastically shorter than its present orbit, even this small change will significantly improve its communications capabilities. “It’s like using your cell phone,” said Bruce Jakosky, MAVEN principal investigator from the University of Colorado, Boulder. “The closer you are to a cell tower, the stronger your signal.”


A strong telecommunications antenna signal is not the only benefit of a tighter orbit. Coming in nearly 1,000 miles (about 1,500 kilometers) closer also will allow the MAVEN orbiter to circle Mars more frequently — 6.8 orbits per Earth day versus 5.3 previously — and thus communicate with the Mars rovers more frequently. While not conducting relay communications, MAVEN will continue to study the structure and composition of the upper atmosphere of Mars. “We’re planning a vigorous science mission far into the future,” Jakosky said. 


The MAVEN mission was designed to last two years in space, but the spacecraft is still operating normally. With the mission managing its fuel to last through 2030, NASA plans to use MAVEN’s relay capability as long as possible. The MAVEN orbiter carries an ultra high-frequency radio transceiver — similar to transceivers carried on other Mars orbiters ­­— that allows it to relay data between Earth and rovers or landers on Mars. The MAVEN spacecraft already has served occasionally as NASA’s communication liaison with the Curiosity rover.


Over the next few months, MAVEN engineers will use a navigation technique known as aerobraking — like applying the brakes on a car — to take advantage of the drag of the Red Planet’s upper atmosphere to slow the spacecraft down gradually, orbit by orbit. This is the same drag you would feel if you put your hand out of the window of a moving car.



Image above: Aerobraking plan for MAVEN. (left) Current MAVEN orbit around Mars: 6,200 kilometers (~3,850 miles) at highest altitude, and an orbit period of about 4.5 hours. (center) Aerobraking process: MAVEN performs a series of “deep dip” orbits approaching to within about 125 kilometers (~78 miles) of Mars at lowest altitude, causing drag from the atmosphere to slow down the spacecraft. Over roughly 360 orbits spanning 2.5 months, this technique reduces the spacecraft’s altitude to about 4,500 kilometers (~2,800 miles) and its orbit period to about 3.5 hours. (right) Post-aerobraking orbit, with reduced altitude and shorter orbit period.
Image Credits: NASA’s Scientific Visualization Studio/Kel Elkins and Dan Gallagher.


Based on the tracking of the spacecraft by the navigation team at NASA’s Jet Propulsion Laboratory in Pasadena, California, and at Lockheed Martin in Littleton, Colorado, engineers will begin carefully lowering the lowest part of the spacecraft’s orbit into the Martian upper atmosphere over the next couple of days by firing its thrusters. The spacecraft will circle Mars at this lower altitude about 360 times over the next 2.5 months, slowing down slightly with each pass through the atmosphere. While it may seem like a time-consuming process, aerobraking is the most efficient way to change the spacecraft’s trajectory, said Jakosky: “The effect is the same as if we fired our thrusters a little bit on every orbit, but this way, we use very little fuel.”



Image above: This illustration shows the MAVEN spacecraft and the limb of Mars. Image Credit: NASA’s Goddard Space Flight Center.


Fortunately, the team has ample experience operating the spacecraft at these lower altitudes. On nine previous occasions throughout the mission, MAVEN engineers have dipped the orbiter into the same altitude targets for aerobraking to take measurements of the Martian atmosphere. As a result of these “deep dips” and other measurements, NASA has learned that solar wind and radiation had stripped Mars of most of its atmosphere, changing the planet’s early climate from warm and wet to the dry environment we see today. MAVEN also discovered two new types of auroras on Mars and the presence of charged metal atoms in its upper atmosphere that tell us that a lot of debris is hitting Mars that may affect its climate.


MAVEN’s principal investigator is based at the University of Colorado’s Laboratory for Atmospheric and Space Physics, Boulder. The university provided two science instruments and leads science operations, as well as education and public outreach, for the mission. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN project and provided two science instruments for the mission. Lockheed Martin built the spacecraft and is responsible for mission operations. The University of California at Berkeley’s Space Sciences Laboratory also provided four science instruments for the mission. NASA’s Jet Propulsion Laboratory in Pasadena, California, provides navigation and Deep Space Network support, as well as the Electra telecommunications relay hardware and operations.


For more information on the MAVEN mission, visit: https://www.nasa.gov/maven or http://lasp.colorado.edu/home/maven/


Images (mentioned), Text, Credits: NASA/Svetlana Shekhtman/GFSC/Nancy Jones/Lonnie Shekhtman.


Best regards, Orbiter.chArchive link


Skeletons from Eighty Years’ War found at Den Bosch, Netherlands

Three skeletons were found during archaeological excavations in Den Bosch. The skeletons are believed to be soldiers who died during the siege of the city in the Eighty Years’ War in the 17th century. Two skeletons were excavated during the past few days. The third skeleton is in the process of being excavated on Thursday, NOS reports.











Skeletons from Eighty Years' War found at Den Bosch, Netherlands
Credit: NOS/Trudy van Rijswijk

The soldiers likely formed part of the army of Frederik Hendrik, who besieged Den Bosch in 1629’s – Hertogenbosch was in the hands of the Spaniards at the time. The city was seen as an almost impregnable fortress, because the surrounding areas were flooded.











Skeletons from Eighty Years' War found at Den Bosch, Netherlands
Credit: © Roy Lazet

Between April and September 1629, Frederik Hendrik succeeded in surrounding and besieging the city by laying a line of dikes, mills and pumping stations, with which he pumped the water away. The capture of Den Bosch is considered the greatest victor of Frederik Hendrik and his young Republic.











Skeletons from Eighty Years' War found at Den Bosch, Netherlands
Credit: NOS/Trudy van Rijswijk

The skeletons were found at the Isabellaveld in Vught, where there used to be a Spanish fort. Houses are now being built on the field. Traces of lead were found on one skeleton, indicating that this person was shot to death. The archaeologists also found weapons, hundreds of lead musket bullets and the remains of trenches and cart tracks.











Skeletons from Eighty Years' War found at Den Bosch, Netherlands
Credit: NOS/Trudy van Rijswijk

While victims of the Eighty Years’ War are often found during excavations, this is the first time that it happened in Den Bosch.


Author: Janene Pieters | Source: NLTimes [February 08, 2019]



TANN



Archive


Spacesuits, Life Science and Robotic Assistant Work Start the Week


ISS- Expedition 58 Mission patch.


February 11, 2019


Spacesuit work, robotic assistants as well as exercise and biology studies took up the majority of the Expedition 58 crew’s schedule on Monday. The rest of February at the International Space Station will be primarily science work before March ramps up with crew and cargo missions and spacewalks.


Flight Engineer Anne McClain of NASA opened up the Fluids Integrated Rack and set up protein crystal samples inside a specialized microscope for photographing. The research is supporting a series of Biophysics experiments exploring potential pharmaceutical benefits for humans on and off Earth.



Image above: Astronaut David Saint-Jacques of the Canadian Space Agency takes pictures of the Earth below from inside the International Space Station’s “window to the world,” the seven-windowed cupola. Image Credit: NASA.


After lunch, McClain spent the rest of the afternoon emptying and refilling water in the U.S. spacesuit cooling loops. She also verified the spacesuits’ ability to transfer high-speed data during usage. NASA is currently targeting the end of March to begin a trio of maintenance spacewalks.



International Space Station (ISS). Animation Credit: NASA

Canadian Space Agency astronaut David Saint-Jacques strapped himself into an exercise bike today to measure his breathing and aerobic capacity. He attached breathing tubes and sensors to himself to help doctors understand the effects of microgravity on pulmonary function and physical exertion.


In the afternoon, he set up a docking station where tiny free-flying robots can mount themselves in Japan’s Kibo laboratory module. Powered by fans and guided by a vision system, the Astrobee autonomous assistants may free up more science time for astronauts and allow mission controllers better monitoring capabilities.


Related links:


Expedition 58: https://www.nasa.gov/mission_pages/station/expeditions/expedition58/index.html


Biophysics experiments: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/search.html?#q=biophysics&i=57_58&p=&c=&g=&s=


Exercise bike: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=821


Breathing: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=103


Aerobic capacity: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=644


Kibo laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory


Astrobee: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1891


Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html


International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html


Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.


Best regards, Orbiter.chArchive link


SOFIA finds dust survives obliteration of Supernova 1987A


Artist’s concept illustrating Supernova 1987A as the powerful blast wave passes through its outer ring and destroys most of its dust, before the dust re-forms or grows rapidly. SOFIA observations reveal that this dust — a building block of stars and planets — can re-form or grow immediately after the catastrophic damage caused by the supernova’s blast wave. Image credits: NASA/SOFIA/Symbolic Pictures/ The Casadonte Group.

Columbia, MD–Febriuary 11,2019. : Researchers using NASA’s SOFIA airborne telescope have found that cosmic dust, a building block of planets, forms in the wake of a supernova blast wave.


Cosmic dust, a building block of stars and planets, can form in the wake of a violent stellar explosion called a supernova, according to a new study using the Stratospheric Observatory for Infrared Astronomy, SOFIA. These surprising findings provide clues to an astronomical mystery surrounding cosmic dust.


Dust particles form as dying red giant stars throw off material and become part of interstellar clouds of various sizes, densities and temperatures. This cosmic dust is then destroyed by supernova blast waves, which propagate through space at more than 6,000 miles per second (10,000 km/sec)!


Supernova explosions are among the most powerful events in the universe, with a peak brightness equivalent to the light from billions of individual stars. The explosion also produces a blast wave that destroys almost everything in its path, including dust in the surrounding interstellar medium, the space between the stars. Current theories predict when a supernova blast sweeps through a region of space, much of the dust would be destroyed, so there should be little dust left.


Observations with SOFIA, however, tell a different, mysterious story — revealing more than 10 times the dust expected. This suggests that dust is much more abundant in the wake of a blast wave than theories estimate.


The new study is based on observations of a nearby supernova explosion, called Supernova 1987A. When it was discovered in 1987, it was one of the brightest supernovae seen in 400 years! Due to its close proximity, astronomers have been able to monitor its impact on the surrounding environment continuously for the past 30 years.


SOFIA’s observations of the iconic supernova suggest dust may actually be forming in the wake of the powerful blast wave. These results are helping astronomers solve the mystery surrounding the abundance of dust in our galaxy.


“We already knew about the slow-moving dust in the heart of 1987A,” said Mikako Matsuura, a senior lecturer at Cardiff University, in the United Kingdom, and the lead author on the paper. “It formed from the heavy elements created in the core of the dead star. But the SOFIA observations tell us something new about a completely unexpected dust population.”




Supernova 1987A has a distinctive set of rings that are part of a cavity created in an earlier, pre-explosion phase of the star’s evolution. The fast-expanding blast wave has passed through these ring structures. Astronomers thought that any dust particles in these rings would have been destroyed, but recent observations from SOFIA show emission consistent with a growing population of dust in the rings. The results indicate that dust particles can re-form or grow rapidly, even after the catastrophic damage caused during the passage of the blast wave, suggesting that although this might be the end of a chapter in the life cycle of dust, it does not appear to be the end of the story.


The dust detected by SOFIA could result from either significant growth of the existing dust particles or the formation of a new dust population. These new observations compel astronomers to consider the possibility that the post-blast environment might be ready to form or re-form dust immediately after the blast wave passes — a new clue that may be pivotal in resolving the discrepancy between dust destruction models and observations.


From ground-based telescopes on Earth, observing cosmic dust particles in the infrared is difficult — or impossible — due to strong absorption, primarily from water and carbon dioxide in the Earth’s atmosphere. By flying above most of the obscuring molecules, the airborne observatory SOFIA provides access to portions of the infrared spectrum not available from the ground. In particular, SOFIA’s Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST) is a powerful instrument for understanding warm dust in particular.


“FORCAST is the only instrument that can observe at these critical wavelengths and detect this newly-forming population of warm dust,” said James De Buizer, the USRA manager for science operations at the SOFIA Science Center and co-author on the study. “We plan to continue monitoring with FORCAST to gain more insight into dust creation and evolution in supernova remnants.”


In the future, NASA’s James Webb Space Telescope will examine this dust in further detail, looking for clues about its origins and composition.


SOFIA is a Boeing 747SP jetliner modified to carry a 106-inch diameter telescope. It is a joint project of NASA and the German Aerospace Center, DLR. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science and mission operations in cooperation with the Universities Space Research Association, or USRA, headquartered in Columbia, Maryland, and the German SOFIA Institute (DSI) at the University of Stuttgart. The aircraft is maintained and operated from NASA’s Armstrong Flight Research Center Hangar 703, in Palmdale, California.


Contact:

Suraiya Farukhi
Director, External Communications
sfarukhi@usra.edu
410-740-6224





Archive link


Greatest Hits — Craters We Love

Our solar system was built on impacts — some big, some small — some fast, some slow. This week, in honor of a possible newly-discovered large crater here on Earth, here’s a quick run through of some of the more intriguing impacts across our solar system.


1. Mercury: A Basin Bigger Than Texas


image

Mercury does not have a thick atmosphere to protect it from space debris. The small planet is riddled with craters, but none as spectacular as the Caloris Basin. “Basin” is what geologists call craters larger than about 186 miles (300 kilometers) in diameter. Caloris is about 950 miles (1,525 kilometers) across and is ringed by mile-high mountains.


For scale, the state of Texas is 773 miles (1,244 kilometers) wide from east to west.


2. Venus: Tough on Space Rocks


image

Venus’ ultra-thick atmosphere finishes off most meteors before they reach the surface. The planet’s volcanic history has erased many of its craters, but like almost any place with solid ground in our solar system, there are still impact scars to be found. Most of what we know of Venus’ craters comes from radar images provided by orbiting spacecraft, such as NASA’s Magellan.


Mead Crater is the largest known impact site on Venus. It is about 170 miles (275 kilometers) in diameter. The relatively-flat, brighter inner floor of the crater indicates it was filled with impact melt and/or lava.


3. Earth: Still Craters After All These Years


image

Evidence of really big impacts — such as Arizona’s Meteor Crater — are harder to find on Earth. The impact history of our home world has largely been erased by weather and water or buried under lava, rock or ice. Nonetheless, we still find new giant craters occasionally.


A NASA glaciologist has discovered a possible impact crater buried under more than a mile of ice in northwest Greenland.


This follows the finding, announced in November 2018, of a 19-mile (31-kilometer) wide crater beneath Hiawatha Glacier – the first meteorite impact crater ever discovered under Earth’s ice sheets. 


If the second crater, which has a width of over 22 miles (35 kilometers), is ultimately confirmed as the result of a meteorite impact, it will be the 22nd largest impact crater found on Earth.


4. Moon: Our Cratered Companion


image

Want to imagine what Earth might look like without its protective atmosphere, weather, water and other crater-erasing features? Look up at the Moon. The Moon’s pockmarked face offers what may be humanity’s most familiar view of impact craters.


One of the easiest to spot is Tycho, the tight circle and bright, radiating splat are easy slightly off center on the lower-left side of the full moon. Closer views of the 53-mile (85 kilometer)-wide crater from orbiting spacecraft reveal a beautiful central peak, topped with an intriguing boulder that would fill about half of a typical city block.


5. Mars: Still Taking Hits


image

Mars has just enough atmosphere to ensure nail-biting spacecraft landings, but not enough to prevent regular hits from falling space rocks. This dark splat on the Martian south pole is less than a year old, having formed between July and September 2018. The two-toned blast pattern tells a geologic story. The larger, lighter-colored blast pattern could be the result of scouring by winds from the impact shockwave on ice. The darker-colored inner blast pattern is because the impactor penetrated the thin ice layer, blasting the dark sand underneath in all directions.


6. Ceres: What Lies Beneath


image

The bright spots in Ceres’ Occator crater intrigued the world from the moment the approaching Dawn spacecraft first photographed it in 2015. Closer inspection from orbit revealed the spots to be the most visible example of hundreds of bright, salty deposits that decorate the dwarf planet like a smattering of diamonds. The science behind these bright spots is even more compelling: they are mainly sodium carbonate and ammonium chloride that somehow made their way to the surface in a slushy brine from within or below the crust. Thanks to Dawn, scientists have a better sense of how these reflective areas formed and changed over time — processes indicative of an active, evolving world.


7. Comet Tempel 1: We Did It!


image

Scientists have long known we can learn a lot from impact craters — so, in 2005, they made one themselves and watched it happen.


On July 4, 2005, NASA’s Deep Impact spacecraft trained its instruments on an 816-pound (370-kilogram) copper impactor as it smashed into comet Tempel 1.


One of the more surprising findings: The comet has a loose, “fluffy” structure, held together by gravity and contains a surprising amount of organic compounds that are part of the basic building blocks of life.


8. Mimas: May the 4th Be With You


image

Few Star Wars fans — us included — can resist Obi Wan Kenobi’s memorable line “That’s no moon…” when images of Saturn’s moon Mimas pop up on a screen. Despite its Death Star-like appearance, Mimas is most definitely a moon. Our Cassini spacecraft checked, a lot — and the superlaser-looking depression is simply an 81-mile (130-kilometer) wide crater named for the moon’s discoverer, William Herschel.


9. Europa: Say What?


image

The Welsh name of this crater on Jupiter’s ocean moon Europa looks like a tongue-twister, but it is easiest pronounced as “pool.” Pwyll is thought to be one of the youngest features we know of on Europa. The bright splat from the impact extends more than 600 miles (about 1,000 kilometers) around the crater, a fresh blanket over rugged, older terrain. “Fresh,” or young, is a relative term in geology; the crater and its rays are likely millions of years old.


10. Show Us Your Greatest Hits


image

Got a passion for Stickney, the dominant bowl-shaped crater on one end of Mars’ moon Phobos? Or a fondness for the sponge-like abundance of impacts on Saturn’s battered moon Hyperion (pictured)? There are countless craters to choose from. Share your favorites with us on Twitter, Instagram and Facebook.


Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com


T. rex possessed a unique flexible skull…


T. rex possessed a unique flexible skull http://www.geologypage.com/2019/02/t-rex-possessed-a-unique-flexible-skull.html


Rain destroys 16th century church in Nicosia’s buffer zone

Torrential rains in recent days caused the collapse of the bell tower and part of the wall of the derelict 16th century church of Ayios Iakovos in the Nicosia buffer zone, the Greek Cypriot head of the technical committee on cultural heritage, Takis Hadjidemetriou, said on Saturday.











Rain destroys 16th century church in Nicosia’s buffer zone
The collapsed church [Credit: Takis Hadjidemetriou/Cyprus Mail]

Hadjidemetriou announced the collapse in a post on his Facebook profile, arguing that had the committee been given permission when it requested to work on supporting the structure, the damage may have been avoided.


“Unfortunately,” Hadjidemetriou said, “we don’t always have good news.”


The church, he said, is in a hard to reach area which is under the control of the Turkish military. The church is estimated to have been built between the 15th and 16th centuries although it has several subsequent interventions such as the bell tower.


“Ayios Iakovos is included in the programme of the technical committee and we were waiting for the green light for the reinforcement works to begin,” he said.


“Unfortunately, the start was delayed on the excuse that demining was needed. We are now facing a disaster.”


I hope that this dramatic situation will allow immediate intervention and to the extent that reparation is possible.”











Rain destroys 16th century church in Nicosia’s buffer zone
Photo of Ayios Iakovos church taken last October for Europa Nostra
[Credit: Roman Robroek]

He said that the technical committee, that is scheduled to meet soon with President Nicos Anastasiades, will propose that the Ayios Iakovos church is put on the agenda of his upcoming meeting with Turkish Cypriot leader Mustafa Akinci. Anastasiades and Akinci are to have an informal meeting at the Chief of Mission’s residence in the United Nations Protected Area on February 26.


Akinci had visited the church area, Hadjidemetriou said, and it appears that he is “positively inclined”.


“After 45 years, the list of churches and monuments all over Cyprus that face collapse is very long,” he said, adding that in these cases the only obstacle is financial.


Hadjidemetriou said that the committee is looking forward to Anastasiades’ annual donation of €500,000 but also hopes for donations by anyone who “aches for the state of the monuments”.


Last November, following a conference in Nicosia on the occasion of the 5th Anniversary Conference of the 7 Most Endangered programme, Europa Nostra  appealed to the two leaders “to give the political impetus to the urgently needed reinforcement” of two churches located in the buffer zone, of Ayios Georgios and Ayios Iakovos.


“The condition of these important historic monuments is particularly alarming and it is necessary to start the rescue works without any further delay to avoid any irreparable loss,” the organisation had said.


In 2013, Europa Nostra had identified the buffer zone of Nicosia as one the most endangered heritage sites in Europe because of its symbolic and historical significance but also for its authenticity and the cultural, social and economic potential it represents.


Author: Evie Andreou | Source: Cyprus Mail [February 09, 2019]



TANN



Archive


Roman Statues, Altars, Column Stones and Plaques, Senhouse Roman Museum, Maryport,...









Roman Statues, Altars, Column Stones and Plaques, Senhouse Roman Museum, Maryport, Cumbria, 9.2.19.


Source link


Featured

    Солнечное затмение 14 декабря 2020 года  — полное  солнечное затмение  142  сароса , которое лучше всего будет видно в юго-восточной час...

Popular