понедельник, 31 декабря 2018 г.

Hubble Paved the Way for the New Horizons Mission to Pluto and Ultima Thule

NASA –  New Horizons Mission patch.

December 31, 2018

New Year’s Ultima Thule encounter

Years before a team of researchers proposed a mission called New Horizons to explore the dwarf planet Pluto, NASA’s Hubble Space Telescope had already made initial observations of the world at the dim outer fringes of our celestial neighborhood. Over many years, Hubble’s pioneering observations repeatedly accomplished what ground-based telescopes could not — imaging features on Pluto’s surface, finding new Plutonian moons, and tracking down a destination to visit after Pluto — an even tinier, icy object in a vast region of small worlds beyond the orbit of Neptune called the Kuiper Belt.

Image above: NASA’s Hubble Space Telescope has explored the universe since the early 1990s, gathering visible, near-ultraviolet, and near-infrared imagery and spectra. From its location in space, the telescope avoids the distortion produced by Earth’s atmosphere, enabling it to take images in higher resolutions at greater distances than possible with ground-based telescopes. Image Credit: NASA.

Thus began a decades-long relationship between Hubble and NASA’s New Horizons mission: A legendary space-based telescope and a pioneering space probe hurtling through space at about 32,000 miles (51,500 kilometers) per hour.

In 1990, Hubble produced the first image that illuminated Pluto and its large moon Charon. After Hubble’s optical repair in 1993, scientists captured even sharper images. New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado, led the imaging projects while co-investigator Marc Buie, now at SwRI Boulder but then at Lowell Observatory where Pluto was discovered, led the data analysis.

Where is New Horizons? Image Credit: JHUAPL

“We got eight pixels of Pluto in 1994. Each pixel represented more than 150 square miles of Pluto’s surface. Fast forward to 2002 and we got even fewer pixels per image. We had to wring every bit of information from each pixel possible,” Buie said. “It was a time- and computer-intensive process, but we were able to create the first maps of Pluto’s surface, and they were truly spectacular for their time.”

Those crude but valuable maps provided the best evidence that Pluto was not simply a homogenous ball of ices, but has a complex, variegated surface — a promising aspect for close-up inspection by a visiting spacecraft. Hubble’s cameras revealed nearly a dozen distinctive bright features, none of which had ever been seen before, including a “ragged” northern polar cap bisected by a dark strip, a puzzling high-contrast bright spot seen rotating with the planet, a cluster of dark spots, and a bright linear marking. That bright spot feature, unusually rich in carbon monoxide frost, became the prime target for New Horizons to examine up close after NASA funded the mission in 2002.

Image above: This is the first detection of Ultima Thule using the highest resolution mode of the Long Range Reconnaissance Imager (LORRI) aboard the New Horizons spacecraft. Three separate images, each with an exposure time of 0.5 seconds, were combined to produce the image. All three images were taken on Dec. 24, when Ultima was 4 billion miles (6.5 billion kilometers) from the Sun and 6.3 million miles (10 million kilometers) from the New Horizons spacecraft.(Click for full caption). Image Credits: NASA/JHUAPL/SwRI.

Although Charon was discovered in 1978 using ground-based telescopes, Hubble detected all four of Pluto’s other moons: Nix and Hydra in 2005, Kerberos in 2011, and Styx in 2012. These moons were spotted in the Hubble images by New Horizons team members, most notably Project Scientist Hal Weaver of the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, and co-investigator Mark Showalter of the SETI Institute in Mountain View, California. By the time the latter two moons were discovered, New Horizons was in the final years of its almost decade-long, 3-billion-mile sprint from Earth to Pluto.

Image above: Illustration of NASA’s New Horizons spacecraft encountering 2014 MU69 – nicknamed “Ultima Thule” – a Kuiper Belt object that orbits one billion miles beyond Pluto. Set for New Year’s 2019, New Horizons’ exploration of Ultima will be the farthest space probe flyby in history. Image Credits: NASA/JHUAPL/SwRI.

The discovery of these four small satellites was critical to overall Pluto flyby planning by identifying potential hazards, verifying the optimal spacecraft trajectory, and establishing the need for time to include observations of them as part of the flyby observing sequence. Without Hubble, New Horizons would have discovered these moons only a few months before the encounter — too late to effectively plan for their detailed study. To examine the possibility for an extended mission into the Kuiper Belt, the New Horizons team used Hubble in 2014 to conduct a needle-in-a-haystack search for a suitable Kuiper Belt Object that New Horizons could visit after passing Pluto. Hubble’s sensitive telescope allowed it to look for fainter KBOs than ground-based telescopes can see. Hubble took deep exposures on 20 areas of the sky and found three suitable KBO targets about one billion miles beyond Pluto. Following NASA approval for a mission extension in 2016, Stern selected 2014 MU69, since nicknamed Ultima Thule, as the target for its January 2019 flyby. In the years since, Hubble has measured the target’s red color and refined its orbit with dozens of additional observations.

Image above: NASA’s Hubble Space Telescope discovered the next target for the New Horizons spacecraft — 2014 MU69, nicknamed Ultima Thule — in June 2014. Seen in these five overlaid images, the object resides more than one billion miles beyond Pluto in the frigid outer reaches of the Kuiper Belt. New Horizons will reach Ultima Thule on New Year’s Day 2019. Image Credits: NASA/STScI/JHUAPL/SwRI.

“Without Hubble there would be no flyby of Ultima Thule,” said Stern. “And without Hubble, New Horizons would not have been as productive studying Pluto’s small moons. In fact, without Hubble’s early images revealing how interesting Pluto’s surface markings are, there might have never been a mission to explore this fascinating dwarf planet.”

New Horizons Beyond Pluto

The New Horizons spacecraft is now on course to fly by Ultima Thule — the farthest object ever explored by humankind — on New Year’s Day, Jan. 1, at 12:33 a.m. EST. Follow New Horizons to Ultima Thule at http://pluto.jhuapl.edu/Mission/Where-is-New-Horizons.php.

For more information on the New Horizons mission, including fact sheets, schedules, video and images, visit: https://www.nasa.gov/newhorizons

Images (mentioned), Video, Text, Credits: NASA/JHUAPL.

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Planetary Defense: Tonight begin the Bennu Experiment

NASA – OSIRIS-REx Mission patch.

Dec. 31, 2018

On Dec. 3, after traveling billions of kilometers from Earth, NASA’s OSIRIS-REx spacecraft reached its target, Bennu, and kicked off a nearly two-year, up-close investigation of the asteroid. It will inspect nearly every square inch of this ancient clump of rubble left over from the formation of our solar system. Ultimately, the spacecraft will pick up a sample of pebbles and dust from Bennu’s surface and deliver it to Earth in 2023.

Image above: This artist’s concept shows the Origins Spectral Interpretation Resource Identification Security – Regolith Explorer (OSIRIS-REx) spacecraft contacting the asteroid Bennu with the Touch-And-Go Sample Arm Mechanism or TAGSAM. The mission aims to return a sample of Bennu’s surface coating to Earth for study as well as return detailed information about the asteroid and it’s trajectory. Image Credits: NASA’s Goddard Space Flight Center.

The spacecraft’s first orbital insertion is scheduled for Dec. 31 (today), and OSIRIS-REx will remain in orbit until mid-February 2019, when it exits to initiate another series of flybys for the next survey phase. During the first orbital phase, the spacecraft will orbit the asteroid at a range of 0.9 miles (1.4 km) to 1.24 miles (2.0 km) from the center of Bennu — setting new records for the smallest body ever orbited by a spacecraft and the closest orbit of a planetary body by any spacecraft.

Generations of planetary scientists will get to study pieces of the primitive materials that formed our cosmic neighborhood and to better understand the role asteroids may have played in delivering life-forming compounds to planets and moons.

But it’s not just history that the mission to Bennu will help uncover. Scientists studying the rock through OSIRIS-REx’s instruments in space will also shape our future. As they collect the most detailed information yet about the forces that move asteroids, experts from NASA’s Planetary Defense Coordination Office, who are responsible for detecting potentially hazardous asteroids, will improve their predictions of which ones could be on a crash-course with our planet.

Here is how the OSIRIS-REx mission will support this work:

How scientists predict Bennu’s whereabouts

About a third of a mile, or half a kilometer, wide, Bennu is large enough to reach Earth’s surface; many smaller space objects, in contrast, burn up in our atmosphere. If it impacted Earth, Bennu would cause widespread damage. Asteroid experts at the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Pasadena, California, project that Bennu will come close enough to Earth over the next century to pose a 1 in 2,700 chance of impacting it between 2175 and 2196. Put another way, those odds mean there is a 99.963 percent chance the asteroid will miss the Earth. Even so, astronomers want to know exactly where Bennu is located at all times.

Animation above: This series of images taken by the OSIRIS-REx spacecraft shows Bennu in one full rotation from a distance of around 50 miles (80 km). The spacecraft’s PolyCam camera obtained the thirty-six 2.2-millisecond frames over a period of four hours and 18 minutes. Animation Credits: NASA’s Goddard Space Flight Center/University of Arizona.

Astronomers have estimated Bennu’s future trajectory after observing it several times since it was discovered in 1999. They’ve turned their optical, infrared and radio telescopes toward the asteroid every time it came close enough to Earth, about every six years, to deduce features such as its shape, rotation rate and trajectory.

“We know within a few kilometers where Bennu is right now,” said Steven Chesley, senior research scientist at CNEOSand an OSIRIS-REx team member whose job it is to predict Bennu’s future trajectory.

Why Bennu’s future trajectory predictions get fuzzy

Scientists have estimated Bennu’s trajectory around the Sun far into the future. Their predictions are informed by ground observations and mathematical calculations that account for the gravitational nudging of Bennu by the Sun, the Moon, planets and other asteroids, plus non-gravitational factors.

Given these parameters, astronomers can predict the next four exact dates (in September of 2054, 2060, 2080 and 2135) that Bennu will come within 7.5 million kilometers (5 million miles or .05 astronomical units) of Earth. That’s close enough that Earth’s gravity will slightly bend Bennu’s orbital path as it passes by. As a result, the uncertainty about where the asteroid will be each time it loops back around the Sun will grow, causing predictions about Bennu’s future orbit to become increasingly hazy after 2060.

In 2060, Bennu will pass Earth at about twice the distance from here to the Moon. But it could pass at any point in a 30-kilometer (19-mile) window of space. A very small difference in position within that window will get magnified enormously in future orbits and make it increasingly hard to predict Bennu’s trajectory.

As a result, when this asteroid comes back near Earth in 2080, according to Chesley’s calculations, the best window we can get on its whereabouts is 14,000 kilometers (nearly 9,000 miles) wide. By 2135, when Bennu’s shifted orbit is expected to bring it closer than the Moon, its flyby window grows wider, to 160,000 kilometers (nearly 100,000 miles). This will be Bennu’s closest approach to Earth over the five centuries for which we have reliable calculations.

“Right now, Bennu has the best orbit of any asteroid in our database,” Chesley said. “And yet, after that encounter in 2135, we really can’t say exactly where it is headed.”

Animation above: This picture shows the OSIRIS-REx spacecraft’s view of Bennu during the final phase of its journey to the asteroid. From Aug. 17 through Nov. 27 the spacecraft’s PolyCam camera imaged Bennu almost daily as the spacecraft traveled 1.4 million miles (2.2 million km) toward the asteroid. The final images were obtained from a distance of around 40 miles (65 km). During this period, OSIRIS-REx completed four maneuvers slowing the spacecraft’s velocity from approximately 1,100 mph (491 m/sec) to 0.10 mph (0.04 m/sec) relative to Bennu, which resulted in the slower approach speed at the end of the video. Animation Credits: NASA’s Goddard Space Flight Center/University of Arizona.

There’s another phenomenon nudging Bennu’s orbit and muddying future impact projections. It’s called the Yarkovsky effect. Having nothing to do with gravity, the Yarkovsky effect sways Bennu’s orbit because of heat from the Sun.

“There are a lot of factors that might affect the predictability of Bennu’s trajectory in the future, but most of them are relatively small,” says William Bottke, an asteroid expert at the Southwest Research Institute in Boulder, Colorado, and a participating scientist on the OSIRIS-REx mission. “The one that’s most sizeable is Yarkvovsky.”

This heat nudge was named after the Polish civil engineer who first described it in 1901: Ivan Osipovich Yarkovsky. He suggested thatsunlight warms one side of a small, dark asteroid and some hours later the heat radiates away as the asteroid rotates its hot side into cold darkness. This thrusts the rock pile a bit, either toward the Sun or away from it, depending on the direction of its rotation.

In Bennu’s case, astronomers have calculated that the Yarkovsky effect has shifted its orbit about 284 meters (0.18 miles) per year toward the Sunsince 1999. In fact, it helped deliver Bennu to our part of the solar system, in the first place, from the asteroid belt between Mars and Jupiter over billions of years. Now, Yarkovsky is complicating our efforts to make predictions about Bennu’s path relative to Earth.

Getting face-to-face with the asteroid will help

The OSIRIS-REx spacecraft will use its suite of instruments to transmit radio tracking signals and capture optical images of Bennu that will help NASA scientists determine its precise position in the solar system and its exact orbital path. Combined with existing, ground-based observations, the space measurements will help clarify how Bennu’s orbit is changing over time.

Additionally, astronomers will get to test their understanding of the Yarkovksy effect on a real-life asteroid for the first time. They will instruct the spacecraft to follow Bennu in its orbit about the Sun for about two years to see whether it’s moving along an expected path based on gravity and Yarkovsky theories. Any differences between the predictions and reality could be used to refine models of the Yarkovsky effect.

But even more significant to understanding Yarkovsky better will be the thermal measurements of Bennu. During its mission, OSIRIS-REx will track how much solar heat radiates off the asteroid, and where on the surface it’s coming from—data that will help confirm and refine calculations of the Yarkovsky effect on asteroids.

The spacecraft also will address some open questions about the Yarkovsky theory. One of them, said Chesley, is how do boulders and craters on the surface of an asteroid change the way photons scatter off of it as it cools, carrying away momentum from the hotter side and thereby nudging the asteroid in the opposite direction? OSIRIS-REx will help scientists understand by mapping the rockiness of Bennu’s surface.

“We know surface roughness is going to affect the Yarkovsky effect; we have models” said Chesley. “But the models are speculative. No one has been able to test them.”

After the OSIRIS-REx mission, Chesley said, NASA’s trajectory projections for Bennu will be about 60 times better than they are now.

Related article:

NASA’s Newly Arrived OSIRIS-REx Spacecraft Already Discovers Water on Asteroid

Related links:

Center for Near-Earth Object Studies (CNEOS): https://cneos.jpl.nasa.gov/

OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security Regolith Explorer): http://www.nasa.gov/mission_pages/osiris-rex/index.html

Image (mentioned), Animations (mentioned), Text, Credits: NASA/Dwayne Brown/JoAnna Wendel/Tricia Talbert/JPL/DC Agle/Goddard Space Flight Center, by Lonnie Shekhtman.

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An exoplanet covered with sapphires and rubies discovered by scientists

University of Zurich logo / University of Cambridge logo.

Dec. 31, 2018

Image above: Illustration of one of the exotic planets, rich in sapphires and rubies, observed by Zurich and British researchers. – Thibaut Roger / University of Zurich UZH.

Scientists think they have discovered a new type of exoplanet. A team of researchers from the Universities of Zurich (Switzerland) and Cambridge (United Kingdom) has unearthed an extrasolar planet called HD219134b with a surface covered with sapphires and rubies.

This exoplanet is located in the constellation Cassiopeia, 21 light years from Earth. It is five times heavier than the Earth because it consists of a heart rich in calcium and aluminum.

Planets that shine

The planet HD219134 b has a high temperature because it is very close to its star. According to the first observations of the scientists, this temperature could be at the origin of the chemical reactions which caused the creation of the ruby ​​blocks.

University of Zurich Tweet

“Maybe it shines with a blue and a red like rubies and sapphires, because these precious stones are aluminum oxides, common on this exoplanet”, explains Caroline Dion, astrophysicist at the university from Zurich. According to her, this type of planet could be more common than we think, favoring the creation of a new category of exotic and rocky super-lands.

University of Zurich (UZH): https://www.uzh.ch/en.html

University of Cambridge: https://www.cam.ac.uk/

Images, Text, Credits: ATS / UZH / Orbiter.ch Aerospace / Roland Berga.

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CASC – Long March-2D launches Hongyan-1 and six Yunhai-2 satellites

CASC – China Aerospace Science and Technology Corporation logo.

December 30, 2018

Image above: A Long March 2D rocket lifts off Saturday from the Jiuquan space base in northwestern China’s Inner Mongolia region. Image Credit: China Aerospace Science and Technology Corp. (CASC).

A Chinese Long March 2D booster climbed into orbit from the Jiuquan space base in the northwest of the country Saturday, delivering seven small satellites to space on communications and weather research missions with the help of a new upper stage capable of firing more than 20 times over two days.

With more than 650,000 pounds of thrust, the liquid-fueled Long March 2D rocket took off at 08:00 GMT (3 a.m. EST; 4 p.m. Beijing time) Saturday from Jiuquan, a remote military base in the Gobi Desert. Heading toward the southeast, the Long March 2D’s two main stages fired before giving way to a new upper stage to maneuver the mission’s six payloads into two distinct orbits.

Long March-2D launches Hongyan-1 and six Yunhai-2 satellites

The new upper stage, named Yuanzheng 3, is an evolution of the Yuanzheng 1 upper stage used on launches by other Long March rocket variants to inject Beidou navigation satellites into their intended orbits thousands of miles above Earth.

Yuanzheng 3 upper stage

Three of the six Yunhai 2 satellites were released in an orbit around 320 miles (520 kilometers) above Earth at an inclination of 50 degrees to the equator, and the Yuanzheng 3 boosted the other three into a 680-mile-high (1,095-kilometer) orbit at the same inclination, according to CASC.

CASC said the Yunhai 2 satellites will measure atmospheric environmental factors and the space environment, and help in disaster prevention and mitigation. China released no other details about the satellites or their instrumentation.

Yunhai satellite

The Hongyan test satellite will test L-band and Ka-band communications technologies in orbit to pave the way for a planned constellation to provide global communications services. It’s the second low Earth orbit communications satellite launched by China this month, following the Dec. 21 deployment of a pathfinder for the separate Hongyun broadband network.

For more information about China Aerospace Science and Technology Corp (CASC), visit: http://english.spacechina.com/n16421/index.html

Images, Video, Text, Credits: CASC/SciNews/Spaceflight Now/Stephen Clark

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China’s BeiDou Navigation System Starts Global Service

BeiDou Navigation Satellite System patch.

Dec. 30, 2018

China’s BeiDou Navigation Satellite System (BDS) has started to provide global service, according to a press conference of the State Council Information Office.

The positioning accuracy of the system has reached 10 meters globally and five meters in the Asia-Pacific region. Its velocity accuracy is 0.2 meters per second, while its timing accuracy stands at 20 nanoseconds.

BeiDou navigation satellite

By the end of 2018, there were a total of 33 BDS satellites operating in orbit, including 15 BDS-2 satellites and 18 BDS-3 satellites.

China plans to launch another 11 BDS-3 satellites and one BDS-2 satellite in the coming two years to form the complete global network, which will further enhance the global service performance.

China began to construct its navigation system, named after the Chinese term for the Big Dipper constellation, in the 1990s and started serving the Asia-Pacific region in 2012.

This year has seen the most intensive launch of the BDS satellites, with a total of 19 satellites being sent into space, setting a new record in the world navigation system construction.

As an important achievement during the implementation of reform and opening up over the past 40 years, BDS has been widely used in China’s national economy.

More than 14,000 companies and organizations are doing business related to BDS, employing over 500,000 people.

The total number of satellite navigation patent applications in China has reached 54,000, ranking first in the world.

In China, about 6.17 million vehicles, 35,600 postal and express delivery vehicles, as well as 80,000 buses in 36 major cities, use BDS. The system is also used in 3,230 inland river navigation facilities and 2,960 marine navigation facilities.

Related article:

Long March-3B launches BeiDou-3 MEO-17 and BeiDou-3 MEO-18

For more information about China Aerospace Science and Technology Corporation (CASC), visit: http://english.spacechina.com/n16421/index.html

For more information about China National Space Administration (CNSA), visit: http://www.cnsa.gov.cn/

For more information about Beidou navigation system: http://www.beidou.gov.cn/

Images, Text, Credits: CASC/CNSA/BeiDou.

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Chalcophyllite & Parnauite | #Geology #GeologyPage…

Chalcophyllite & Parnauite | #Geology #GeologyPage #Mineral

Locality: Wheal Gorland, St Day, Cornwall, United Kingdom

Size: 5.1 × 6.5 × 3.2 cm

Photo Copyright © Mintreasure /e-rocks. com

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Phosgenite & Cerussite | #Geology #GeologyPage…

Phosgenite & Cerussite | #Geology #GeologyPage #Mineral

Locality: Monteponi Mine, Iglesias, Sardinia, Italy

Size: 2.3 × 3.1 × 2.2 cm

Largest Crystal: 0.30cm

Photo Copyright © Your Systematic Collection di Roberto Bracco /e-rocks. com

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Puerto Princesa Underground River, Philippines | #Geology…

Puerto Princesa Underground River, Philippines | #Geology #GeologyPage #Philippines #River

The Puerto Princesa Subterranean River National Park is a protected area of the Philippines located about 80 kilometres (50 mi) north of the city centre of Puerto Princesa, Palawan. The river is also called Puerto Princesa Underground River.

The national park is located in the Saint Paul Mountain Range on the western coast of the island. It is bordered by St. Paul Bay to the north and the Babuyan River to the east. The City Government of Puerto Princesa has managed the National Park since 1992. The entrance to the subterranean river is a short hike or boat ride from the town Sabang.

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Realgar | #Geology #GeologyPage #Mineral Locality: No 5 Mine,…

Realgar | #Geology #GeologyPage #Mineral

Locality: No 5 Mine, Baia Sprie, Romania

Size: 8.8 × 6.5 × 6 cm

Largest Crystal: 1.50cm

Photo Copyright © Christian Rewitzer /e-rocks. com

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Lepersonnite-(Gd) & Oursinite | #Geology #GeologyPage…

Lepersonnite-(Gd) & Oursinite | #Geology #GeologyPage #Mineral

Locality: Shinkolobwe Mine, Shinkolobwe, Katanga, Democratic Republic of the Congo

Size: 2.2 × 1.6 × 0.8 cm

Photo Copyright © Mintreasure /e-rocks. com

Geology Page



Azurite | #Geology #GeologyPage #Mineral Location: Tsumeb Mine,…

Azurite | #Geology #GeologyPage #Mineral

Location: Tsumeb Mine, Otjikoto, Namibia

Size: 5.0 x 3.0 x 3.0 cm (miniature)

Photo Copyright © Weinrich Minerals

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Best of 2018… Many, many thanks for all the support through the year; looking...

Best of 2018… Many, many thanks for all the support through the year; looking forward to more prehistoric and ancient culture posts in 2019!

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воскресенье, 30 декабря 2018 г.

Raise Your Glass and a Happy New Year to All! Image of the Week…

Raise Your Glass and a Happy New Year to All! Image of the Week – December 31, 2018


Description: Fluorescent image of the sporangium, an enclosure in which spores are formed, of the slime mold Craterium minutum. Honorable Mention, 2011 Olympus BioScapes Digital Imaging Competition®.

Authors: Dalibor Matýsek and 2011 Olympus BioScapes Digital Imaging Competition®

Licensing: Attribution Non-Commercial No Derivatives: This image is licensed under a Creative Commons Attribution, Non-Commercial, No Derivatives License

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Constrained and Restrained Some macrophages [a type of immune…

Constrained and Restrained

Some macrophages [a type of immune cell] circulate in the blood like patrolling soldiers on the lookout for invaders. But others are more akin to stationed sentinels, residing long-term within tissues, inactive but ever-ready. Unlike their circulating counterparts, these tissue-dwelling cells are not easily rallied by inflammatory signals, remaining inactive until the fight (tissue damage) comes to their door. While, this inactivity has benefits, ensuring tissues don’t become unnecessarily inflamed, how it’s controlled was unclear. Now scientists have found that the spatial constraints of the tissue keep the cells in check. This electron microscope image (false coloured) shows a macrophage sequestered in an artificial pore, which reduces the cell’s ability to spread out – an intrinsic part of activation. The discovery not only explains why tissue-resident macrophages remain dormant, but may also inform the design of medical implants, which if given porous surfaces might reduce inflammatory reactions.

Written by Ruth Williams

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2018 December 30 The Galaxy Tree Image Credit & Copyright:…

2018 December 30

The Galaxy Tree
Image Credit & Copyright: César Vega Toledano ; Rollover Annotation: Judy Schmidt

Explanation: First came the trees. In the town of Salamanca, Spain, the photographer noticed how distinctive a grove of oak trees looked after being pruned. Next came the galaxy. The photographer stayed up until 2 am, waiting until the Milky Way Galaxy rose above the level of a majestic looking oak. From this carefully chosen perspective, dust lanes in the galaxy appear to be natural continuations to branches of the tree. Last came the light. A flashlight was used on the far side of the tree to project a silhouette. By coincidence, other trees also appeared as similar silhouettes across the relatively bright horizon. The featured image was captured as a single 30-second frame earlier this month and processed to digitally enhance the Milky Way.

∞ Source: apod.nasa.gov/apod/ap181230.html

Brimham Rocks Photoset 3, Yorkshire, 24.12.18.Amazing Ice Age water and wind shaped rock...

Brimham Rocks Photoset 3, Yorkshire, 24.12.18.

Amazing Ice Age water and wind shaped rock formations.

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Meteor Activity Outlook for December 29, 2018-January 4, 2019

During this period the moon will reach its last quarter phase on Saturday December 29th. At this time the half-illuminated moon will rise near midnight local standard time and will remain above the horizon the remainder of the night. Under these conditions successful meteor sessions can be held as long as you face away from the moon. Hourly meteor rates for evening observers this week is near 3 as seen from mid-northern latitudes (45N) and 2 as seen from tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 14 as seen from mid-northern latitudes and 9 from the southern tropics. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Morning rates are reduced during this period due to moonlight. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.

The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning December 29/30. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies near the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.

Radiant Positions at 7:00pm Local Standard Time

Radiant Positions at 12:00am Local Standard Time

Radiant Positions at 5:00am Local Standard Time

These sources of meteoric activity are expected to be active this week.

Now that the activity from particles produced by comet 2P/Encke have ceased encountering the Earth, the Taurid showers for 2018 are over and we resume reporting activity from the Anthelion (ANT) radiant. This is not a true radiant but rather activity caused by the Earth’s motion through space. As the Earth revolves around the sun it encounters particles orbiting in a pro-grade motion that are approaching their perihelion point. They all appear to be radiating from an area near the opposition point of the sun, hence the name Anthelion. These were once recorded as separate showers throughout the year but it is now suggested to bin them into their category separate from true showers and sporadics. There are several lists that have the Chi Orionids currently active, but we include them with the Anthelions as the celestial positions overlap. This radiant is a very large oval some thirty degrees wide by fifteen degrees high. Activity from this radiant can appear from more than one constellation. The position listed here is for the center of the radiant which is currently located at 07:24 (111) +22. This position lies in eastern Gemini, close to the spot occupied by the 4th magnitude star known as Wasat (delta Geminorum). Since the radiant is so large, Anthelion activity may also appear from western Cancer as well as Gemini. This radiant is best placed near 01:00 local standard time (LST) when it lies on the meridian and is highest in the sky. Rates at this time should be near 2 per hour as seen from the northern hemisphere and 1 per hour as seen from south of the equator. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The alpha Hydrids (AHY) were discovered by Dr. Peter Brown and are mentioned in his article “A meteoroid stream survey using the Canadian Meteor Orbit Radar”. This shower is active from December 17 through January 17 with maximum activity occurring on January 3rd. The radiant is currently located at 08:14 (123) -08. This position lies in southwestern Hydra, 15 degrees west of the 2nd magnitude star known as Alphard (alpha Hydrae). These meteors are best seen near 0200 LST when the radiant lies highest above the horizon. At 43 km/sec. the alpha Hydrids produce meteors of medium velocity. Expected rates this week are near  1 per hour no matter your location.

The C Velids (CVE) is a continuation of the Puppid/Velid activity this time of year. Unlike the two week activity during the first half of December, the C Velids are only active on 6 nights centered on December 29th. This segment of the Puppid/Velids is not as strong as the previous one and rates are low, even at maximum activity. At maximum, the radiant is located at 09:20 (140) -54. This area of the sky lies in southern Vela, 2 degrees north of the 2nd magnitude star known as Markeb (kappa Velorum). These meteors are best seen near 0300 LST when the radiant lies highest above the horizon. At 39 km/sec. the C Velids produce meteors of medium velocity. Like all sources of the Puppid/Velid complex, these meteors are not well seen from the northern hemisphere. They are best seen from the deep southern hemisphere where the sources are found high in the sky during the southern summer mornings. Activity from this complex is weak in January with barely discernible radiants in Carina and Crux. Activity increases in February with several radiants spread across Centaurus. This complex weakens again in March with the last traces appearing in the Lupus/Norma region of the sky.

The January Leonids  (JLE) were also discovered by Dr. Peter Brown and are mentioned in the same source as the Alpha Hydrids. This shower is active from December 30 through January 7 with maximum activity occurring on January 3rd. The radiant is currently located at 09:39 (144) +26. This position lies in northwestern Leo, 2 degrees northwest of the 4th magnitude star known as Rasalas (mu Leonis). These meteors are best seen near 0300 LST when the radiant lies highest above the horizon. At 59 km/sec. the January Leonids produce meteors of swift velocity. Expected rates this week are less than 1 per hour no matter your location.

The December Leonis Minorids (DLM) are a shower of long duration active from December 6th through January 18th. Maximum occurs near December 21st when rates may reach 3 an hour. The radiant is currently located at 11:13 (168) +26. This position lies in eastern Leo, 5 degrees north of the 4th magnitude star known as Zosma (delta Leonis). These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. At 63 km/sec. the December Leonis Minorids produce mostly swift meteors.

The Coma Berenicids (COM) are best seen from December 24 through January 3. Maximum activity occurs on December 31st. The current radiant position lies at 12:18 (184) +12. This position lies on the Virgo/Coma Berenices border, 7 degrees southeast of the 2nd magnitude star known as Denebola (Beta Leonis). Current hourly rates should be near 2 shower member per hour no matter your location. These meteors are best seen near 0500 LST when the radiant lies highest above the horizon. At 69 km/sec. The Coma Berenicids would produce mostly swift meteors.

The December Sigma Virginids (DSV) was discovered by John Greaves using the data of SonotaCo. IMO video cameras confirmed that this source is active during the month of December. Peak rates occur near December 14th. The current radiant location is at 14:21 (215) -00 which places it in eastern Virgo, 4 degrees southeast of the 4th magnitude star known as tau Virginis. Current hourly rates should be less than 1 shower member no matter you location. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 68 km/sec. the December Sigma Virginids would produce mostly swift meteors.

The Quadrantids (QUA) are active from December 22nd through January 17th. Maximum occurs on January 4 when rates may reach 100 an hour from dark sky locations over Europe and western Asia. The radiant is currently located at 15:12 (228) +51. This position lies in northern Bootes in a blank area of sky located 10 degrees north of Beta Bootis. These meteors are best seen during the last hour before dawn when the radiant lies highest above the horizon in a dark sky. At 41 km/sec. the Quadrantids produce  meteors of moderate velocity. These meteors are visible from the southern tropics but not seen from the deep southern hemisphere.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 8 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 6 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.

The list below offers the information from above in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.

RA (RA in Deg.) DEC Km/Sec Local Standard Time North-South
Anthelion (ANT) 07:24 (111) +22 30 01:00 2 – 1 II
alpha Hydrids (AHY) Jan 03 08:14 (123) -08 43 02:00 1 – 1 IV
c Velids (CVE) Dec 29 09:20 (140) -54 39 03:00 <1 – <1 IV
January Leonids (JLE) Jan 03 09:39 (144) +26 59 03:00 <1 – <1 IV
December Leonis Minorids (DLM) Dec 21 11:13 (168) +26 63 04:00 1 – <1 II
Coma Berenicids (COM) Dec 31 12:18 (184) +12 70 05:00 2 – 1 II
December sigma Virginids (DSV) Dec 13 14:21 (215) -00 66 07:00 <1 – <1 IV
Quadrantids (QUA) Jan 04 15:12 (228) +51 41 08:00 <1 – <1 I

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Grimspound Bronze Age Hut Circle and Enclosure, Dartmoor, 29.12.18.

Grimspound Bronze Age Hut Circle and Enclosure, Dartmoor, 29.12.18.

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jason-1971: Ancient tree at Avebury


Ancient tree at Avebury

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суббота, 29 декабря 2018 г.

Brimham Rocks Photoset 2, Yorkshire, 24.12.18.Amazing Ice Age water and wind shaped rock...

Brimham Rocks Photoset 2, Yorkshire, 24.12.18.

Amazing Ice Age water and wind shaped rock formations.

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