суббота, 24 ноября 2018 г.

Meteor Activity Outlook for November 24-30, 2018

Fireball over Clines Corners, New Mexico, Dec. 14th2017 – © AmyM Howard
(Canon EOS 6D, 25s, ISO5000, )

During this period the moon will reach its last quarter phase on Thursday November 29th. At this time the moon will be located 90 degrees west of the sun and will rise near midnight local standard time. This weekend the waning gibbous moon will rise shortly after dusk making it difficult to view meteor activity the remainder of the night. The estimated total 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 9 as seen from mid-northern latitudes and 5 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. Rates are reduced during this period due to bright 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 November 24/25. 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 7pm LST

Radiant Positions at 7:00pm

Local Standard Time

Radiant Positions at 12:00 LST

Radiant Positions at 12:00am

Local Standard Time

Radiant Positions at 5am LST

Radiant Positions at 5:00am

Local Standard Time

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

Details of each source will continue next week when the moon will be in a more favorable position for meteor observations.

RA (RA in Deg.) DEC Km/Sec Local Standard Time North-South
December phi Cassiopeiids (DPC) Dec 06 00:37 (009) +54 17 20:00 <1 -<1 III
Northern Taurids (NTA) Nov 02 04:50 (073) +27 28 00:00 1 – <1 II
Southern Taurids (STA) Oct 29-Nov 03 04:58 (075) +20 27 00:00 <1 -<1 II
November Orionids (NOO) Nov 29 05:49 (087) +16 43 01:00 1 – 1 II
November theta Aurigids (THA) Nov 26 06:18 (095) +35 33 02:00 <1 – <1 IV
sigma Hydrids (HYD) Dec 06 07:40 (115) +05 61 05:00 <1 – <1 II
Orionids (ORI) Oct 22 08:44 (131) +14 67 05:00 <1 – <1 I
Leonids (LEO) Nov 17 10:46 (162) +19 70 07:00 <1 – <1 I

Source link

2018 November 24 Shipwreck at Moonset Image Credit &…

2018 November 24

Shipwreck at Moonset
Image Credit & Copyright: Vikas Chander

Explanation: A crescent Moon is about to sink under the western horizon in this sea and night skyscape. The atmospheric photo was taken on September 11 from the desert shore along the Skeleton Coast of Namibia. So close to moonset, the moonlight is reddened and dimmed by the low, long line-of-sight across the Atlantic. But near the center of the frame Venus still shines brightly, its light reflected in calm ocean waters. The celestial beacon above the brilliant evening star is bright planet Jupiter. Namibia’s Skeleton Coast was so named for the many seal and whale bones that were once strewn along the shoreline. In more recent times it’s better known for shipwrecks.

∞ Source: apod.nasa.gov/apod/ap181124.html

Fluorite | #Geology #GeologyPage #Mineral Locality: Camissinone…

Fluorite | #Geology #GeologyPage #Mineral

Locality: Camissinone Mine, Zogno, Brembana Valley, Bergamo Province, Lombardy, Italy

Size: 11 x 9.5 x 8

Photo Copyright © Saphira Minerals

Geology Page



Tanzanite crystal | #Geology #GeologyPage #Mineral Locality:…

Tanzanite crystal | #Geology #GeologyPage #Mineral

Locality: Merelani Hills (Mererani), Lelatema Mts, Arusha Region, Tanzania

Size: 16mm x 6mm x 6mm

Photo Copyright © Quebul Fine Minerals

Geology Page



Hvítserkur, Iceland | #Geology #GeologyPage #Iceland Dragon…

Hvítserkur, Iceland | #Geology #GeologyPage #Iceland

Dragon drinking from the water !!

Read More & More Photos: http://www.geologypage.com/2017/02/hvitserkur.html

Geology Page



Bronze Age Shield Bosses and Axeheads, Devizes Museum, Wiltshire, 17.11.18.

Bronze Age Shield Bosses and Axeheads, Devizes Museum, Wiltshire, 17.11.18.

Source link

NASA Highlights Science on Next Resupply Mission to International Space Station

SpaceX – Dragon CRS-16 patch.

Nov. 23, 2018

Image above: The SpaceX Dragon cargo craft is pictured in the grips of the Canadarm2 robotic arm as the International Space Station was orbiting above northern Africa. Scientific investigations on the next SpaceX flight, targeted for Tuesday, Dec. 4. include a test of robotic technology for refueling spacecraft, a project to map the world’s forests, and studies in several areas to benefit future space explorers as well as lives on Earth. Image Credit: NASA.

NASA will host a media teleconference at 1 p.m. EST Wednesday, Nov. 28, to discuss select science investigations launching on the next SpaceX commercial resupply flight to the International Space Station.

SpaceX is targeting Dec. 4 for launch of its Dragon spacecraft on a Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station (CCAFS) in Florida.

Participants in the briefing will be:

– Hsiao Smith, deputy director for technical of the Satellite Servicing Projects Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will discuss the Robotic Refueling Mission-3 to demonstrate the storage and transfer of liquid methane in space for the first time: https://www.nasa.gov/feature/goddard/2018/nasa-to-launch-new-refueling-mission-helping-spacecraft-live-longer-and-journey-farther

– Timothy Etheridge, principal investigator for the Molecular Muscle investigation, and a professor at University of Exeter, Department of Sport and Health Sciences in the United Kingdom,will discuss research to examine the molecular causes of muscle abnormalities during spaceflight in order to establish effective countermeasures: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7576

– Ralph Dubayah, principal investigator for Global Ecosystem Dynamics Investigation (GEDI) at the Joint Global Carbon Cycle Center in College Park, Maryland, will discuss an investigation to test high-quality laser ranging observations of the Earth’s forests and topography required to advance the understanding of important carbon and water cycling processes, biodiversity, and habitat: https://www.nasa.gov/feature/goddard/2018/gedi-to-measure-earths-forests

– Vic Keasler, Director of Research, Development and Engineering at Nalco Champion, an Ecolab company, will discuss an investigation to examine the rate of corrosion on carbon steel materials caused by films made up of microorganisms on Earth and in space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7645

– Jahaun Azadmanesh, a doctoral student at the University of Nebraska Medical Center in Omaha, Nebraska, will discuss the Perfect Crystals investigation which aims to help understand how an antioxidant protein helps protect the human body from oxidizing radiation and oxidants created as a byproduct of metabolism: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7617

Audio of the teleconference will be streamed live online at: https://www.nasa.gov/nasalive

SpaceX’s Dragon spacecraft will carry crew supplies, scientific research and hardware to the orbiting laboratory to support the Expedition 57 and 58 crews for the 16th contracted mission by SpaceX under NASA’s Commercial Resupply Services contract.

For launch countdown coverage, NASA’s launch blog, and more information about the mission, visit: https://www.nasa.gov/spacex

Related links:

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

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

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), Text, Credits: NASA/Sean Potter/Kathryn Hambleton.

Greetings, Orbiter.chArchive link

Himera: One of the greatest archaeological discoveries of recent decades emerges from...

Himera…was conquered by force and the barbarians gave themselves to a long ruthless massacre of all those who remained there (…) Hannibal plundered the sacred places and, snatching away the people who took refuge there, set them on fire and razed the city to the ground, which had been inhabited for 240 years…”

Diodorus Siculus, Bibliotheca historica, 1st century BC.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
Common grave of those fallen in the Battle of Himera in 409 BC and burial of a horse
[Credit: Archaeological Superintendence Palermo]

A necropolis with more than 12,000 almost untouched burials from the Archaic and Classical periods, many of which are rich in grave goods, was discovered between 2008 and 2011, during work on the expansion of the railway line at the site of the ancient Greek city of Himera, the remains of which lie within the borders of the modern Sicilian comune of Termini Imerese.
Many of these burials are associated with an infamous page in the history of the ancient city, located on the strategic border between Hellenic Sicily and the area controlled by the Phoenicians: a vicious battle fought between the Greeks and Carthaginians in 480 BC.

The former prevailed, as evidenced by the discovery of the remains of the Temple of Victory, erected to mark the occasion, but in 409 BC the Carthaginians took revenge by besieging and razing the city.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
View of one of the mass graves of soldiers killed in battle 
[Credit: Archaeological Superintendence Palermo]

Unequivocal evidence of these two epic clashes can be seen in the thousands of skeletons of men and horses, found in mass graves and in individual burials.

There are as many as nine mass graves (seven associated with the battle of 480 BC and two with the battle of 409 BC) containing the bodies of those who fell in battle – arranged in an orderly fashion, one next to the other, in numbers varying from two to more than fifty.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
View of the Himera necropolis [Credit: Archaeological Superintendence Palermo]

According to archaeologists, about thirty burials of horses, probably killed in the battle of 480 BC, were likewise interred in the area of the necropolis, near the mass graves.
The discovery of two bronze greaves of the Iberian type confirm what Herodotus wrote, regarding the presence, in the Carthaginian army commanded by Hamilcar, of mercenaries from various parts of the Western Mediterranean.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
Finds in the Himera necropolis [Credit: Archaeological Superintendence Palermo]

The finds from this the largest Greek necropolis ever discovered in Sicily, which have remained locked in sixteen crates in a warehouse for 10 years, is now finally being transferred to Palermo where they will be displayed in the Real Albergo dei Poveri, a Bourbon-era building.

The issue was raised by a parliamentary question tabled last summer by Luigi Sunseri (Cinquestelle), a regional member of parliament, to whom the Regional Department of Cultural Heritage, chaired by the archaeologist Sebastiano Tusa, replied in detail.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
View of the vast Himera necropolis [Credit: Archaeological Superintendence Palermo]

The arrangement is expected to be temporary in the hope, Sunseri said, that the finds can soon find a worthy museum location in Termini Imerese from whose territory they come. The aim is to make them an important tourist-cultural attraction with all the economic implications that follow. “This”, added the deputy, “is an invaluable heritage that cries out for mercy and requires an adequate location.”

For three years, between 2008 and 2011, a highly talented team of specialists, including archaeologists, anthropologists, restorers and illustrators, led by the Archaeological Superintendence of Palermo, has been engaged in daily excavation activities.

The constant presence of anthropologists, led by Prof. Pier Francesco Fabbri of the University of Salento, has made it possible to collect important information related to the life and culture of the local population, as in the case of the burials of soldiers killed in the battles of Himera in 480 and 409 BC.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
Part of the skeleton and skull of the girl with signs of cranial surgery 
[Credit: Archaeological Superintendence Palermo]

The tombs have mostly re-emerged at a depth of about three metres below ground level, covered by a very compact and homogeneous layer that over the centuries has protected the necropolis. Scholars speculate that possible flooding of the sea or the nearby river may have contributed to this.
During the excavations, various types of graves were found: they range from simple graves dug into the sand, to wooden coffins, stone sarcophagi to cremation burials.

Skeletons of newborns have also been found, placed in terracotta amphorae in the shape of a uterus (enchytrismoi), bearing witness to the high infant mortality rate of the time, the risk of which was particularly high between birth and six months of age.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
One of the burials of horses found in Himera [Credit: Archaeological Superintendence Palermo]

Anthropological studies were carried out to determine the age, sex, height, diseases and nutritional aspects of the deceased, as well as the types of funeral rituals used.

With the Universities of North Colorado, Georgia and Salento, research has been activated on aspects of bioarchaeology, with DNA analysis, useful to investigate human adaptation to the environment and paleonutrition in Himera and in the ancient Mediterranean.

Also interesting is the evidence of cranial surgery performed on a 19-21 year old girl, who lived between the sixth and fifth centuries BC, and who had a circular drill hole (132 mm in diametre) on the right hemi-frontal bone of the skull. An operation that evidently had no therapeutic effects but which nonetheless testifies to the existence in Himera of a school of advanced medicine.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
Skull of a horse buried in Himera with bronze bit [Credit: Archaeological Superintendence Palermo]

The high concentration of males is in fact what links most of the mass graves, to the two great battles of 480 and 409 BC, rather than attributing the high mortality rate to epidemics or other tragic natural events that would inevitably have involved women and children.

They are in fact individuals aged between 15 and 57 years, with traces of deep wounds caused by cutting or throwing weapons, some of which – such as arrows, spear heads, swords, daggers – were still found embedded in the skeletons because they were not removed before burial. The study of these types of finds has made it possible to reconstruct the dynamics of duels between soldiers and the battle techniques of the time.

The burials of thirty horses are traced back by experts to the clash of 480 BC. A detailed study has been made of these remains and which will significantly illuminate both archaeological and zoological aspects.

Himera: One of the greatest archaeological discoveries of recent decades emerges from oblivion
Lekythoi found in the Himera necropolis [Credit: Archaeological Superintendence Palermo]

Signs that the mass slaughter of 409 BC also involved a large part of the civilian population have also been found, especially in the eastern part of the necropolis, in front of the city walls, especially in the upper layers: here hundreds of skeletons were placed chaotically, with men and women of all ages and bones sometimes no longer anatomically connected. These are probably disorderly burials made in a hurry by the survivors of the great massacre.
At the site of the discovery, great care was taken to analyse the finds, to carry out photographic documentation, cleaning, consolidation, assembly of the fragments, integration of missing parts, final protection with microcrystalline wax, labelling and storage.

Two restoration laboratories have been set up – one for the restoration of large ceramic vessels, the other for the restoration of small items, such as funerary objects – which have enabled more than 6,000 restorations to be carried out.

In short, an enormous amount of work and a vast wealth of knowledge on a Greek city and its funeral practices, made even more poignant by the state of neglect in which everything had been left to stagnate, until the recent turning point.

Source: Fame Di Sud [November 21, 2018]



Early Bronze Age cave burials found in southern Turkey

A mass grave in southern Turkey dating back thousands of years could give new insight into the people of that era, according to Turkish researchers.

Early Bronze Age cave burials found in southern Turkey
Credit: AA

The cave full of prehistoric skeletons was discovered around a year ago in a cave called Kadıini by a group of extreme athletes. They took photos and told anthropologists at the nearby Süleyman Demirel University.

Anthropologist Nalan Damla Yılmaz Usta, who carries out the excavations, said that the skeletons were found in a depth of 400-800 metres and dated back 5,000-7,000 years ago.

“The skeletons hold important data that could shed light on biological and morphological features of the peoples in the Chalcolithic and Early Bronze Ages. We will reveal the cultural history of Alanya (Greek as Korakesion from the Luwian Korakassa) thanks to this study,” she said.

Another important thing for the findings was that this is the first time such a mass grave was found in a cave in Anatolia, Usta said, adding that the Akdeniz University Cave Study Group (AKÜMAK) and Anatolian Speleology (ASPEG) members found the skeletons by chance during their activity in the cave.

“A few members of the group got in touch with us. Then we went to the area and initiated studies. Headed by Alanya Museum director Seher Türkmen, we carried out rescue excavations in the Kadıini Cave. We removed more than 100 skeletons in five days. After the documentation, illustration and photographing works, we removed the skeletons from the Kadıini cave. We did not only find skeletons here but some archaeological findings. Studies on the skeletons continue at the university’s anthropology department,” Usta said.

Early Bronze Age cave burials found in southern Turkey
Credit: AA

She said the findings were in a depth of 400-800 metres in the branches of the cave, adding, “Over the years, there have been many movements such as floods and collapses in the cave and some bones have been buried among each other. However, some examples remained as they were buried, and some were combined with the karstic sediment accumulated over time. Now when we look at the examples, there is a layer on the skulls. This layer is karstic formation and completely stuck to the bone. Some of these were removed by small scraping in a laboratory. But the majority is still on the bones. There are also skeletons not covered by this formation.”

Usta said there were no remains from the Chalcolithic and Early Bronze Ages in the history of Alanya.

“Therefore the findings are very important. In the 1950s, studies by Professor Kılıç Kökten unearthed human traces belonging to the Upper Palaeolithic Period. But their number is limited. Now, these skeletons are important in providing information that the cave was used very frequently by people. At the same time, the skeleton series which dates back to the Early Bronze Age in Anatolia is not very common. The skeletons are in very good condition, because the iron ions in the cave were processed into the bone and had hardened the structure of the bone. The skeletons have survived to this day and are really important in terms of shedding light on this period of Anatolia. They provide important data that can shed light on the biological, morphological and cultural characteristics of people in the Chalcolithic and Old Bronze Ages,” she added.

Usta said studies continued at the university and the results would be published when finished. She said they were seeking answers to the question on why those skeletons were inside the cave. “This community used the deepest part of the cave as the area where they buried their dead, because we have also encountered gifts from the dead among them. There are traces that some skeletons were burned. It has meaning in terms of burial customs. Perhaps the patients were treated with such a procedure,” she added.

Early Bronze Age cave burials found in southern Turkey
Credit: IHA

Usta said they tried to reveal the demographical features of the individuals.

“What was the age at death and average life expectancy of the individuals? How was the rate of infant and child mortality? What were the diseases that left their mark on their bones? Were there any infections or traumas? What was the epigenesis like? What were these people eating? How was oral and dental health? Who was close to this community in Anatolia and in the world? We are trying to determine the diseases of the bones and teeth. We will be able to find answers to these questions. I think we can provide some clues about their faith systems in general. In short, we will try to understand the lives of Kadıini people. We can say that Kadıini was a community that was both engaged in agriculture and engaged in livestock,” Usta said.

Source: Hurriyet Daily News [November 22, 2018]



First human remains found in El Salvador’s Joya de Ceren

The Directorate General of Cultural and Natural Heritage of El Salvador’s Ministry of Culture reported on November 22, 2018, that the investigation will be expanded in Complex 1 of Joya de Cerén after the discovery of a skeleton, human footprints and cultivation furrows in the excavations carried out as part of the project Construction of Protection Works and Improvement of the archaeological park.

First human remains found in El Salvador's Joya de Ceren
Credit: Ministerio de Cultura El Salvador

The discoveries “have led us to take the decision to extend the excavations in the southern zone of Complex 1, where we will make a larger trench by joining three of the exploratory pits,” explained archaeologist Michelle Toledo, who directs the research at the site.

First human remains found in El Salvador's Joya de Ceren
Credit: Ministerio de Cultura El Salvador

Toledo added that the expansion will serve to “achieve a better interpretation of the Complex 1 and make the decision of where to put the columns that will support the new roof.” The excavation works will last until the end of November or the beginning of December.

First human remains found in El Salvador's Joya de Ceren
Credit: Ministerio de Cultura El Salvador

Regarding the skeleton, the archaeologist commented: “A few days ago a pit was identified that contained organic and skeletal remains; the cleaning was carried out and it was determined that it was a burial of a person who probably inhabited the village, but who did not die because of the eruption. There are long bones and we believe that this burial is from the Late Classic period (600-900 AD), because inside the pit there is fine white tephra, known as “Tierra Blanca Joven” (young white earth), a product of the eruption of the Ilopango volcano in 535 A.D.); if so, this individual would be from a burial possibly from the moment when the people of Joya de Cerén lived here.”

First human remains found in El Salvador's Joya de Ceren
Credit: Ministerio de Cultura El Salvador

This is the first time in more than forty years of research that human remains have been discovered in Joya de Cerén. Unfortunately, the skeleton – discovered next to an obsidian knife – is in a poor state of conservation. “Maybe this burial was beneath some structure that was removed by a tractor,” when workers from the now defunct Instituto Regulador de Abastecimientos (IRA), who were building silos, discovered the site in 1976, said Toledo of the Archaeology Directorate.

First human remains found in El Salvador's Joya de Ceren
Credit: Ministerio de Cultura El Salvador

The project being carried out at the site seeks to protect the structures and contemplates the construction of three metal roofs for Complexes 1, 2 and 3, stabilization of ash slopes, renovation of the museum, as well as updating the signage and the interpretive trail, which will be in Spanish, French and English.

First human remains found in El Salvador's Joya de Ceren
Credit: Ministerio de Cultura El Salvador

Joya de Cerén was buried in the ashes of the Loma Caldera volcano around 650 AD. The ashes preserved the site and this has allowed us to appreciate the way of life of the Mayan village: rituals, agriculture, commerce, space management, citizen organization, food habits, etc.

Source: Ministerio de Cultura El Salvador [November 23, 2018]



NASA’s Lucy in the Sky with … Asteroids?

NASA – LUCY Mission patch.

Nov. 23, 2018

A little over 4 billion years ago, the planets in our solar system coexisted with vast numbers of small rocky or icy objects orbiting the Sun. These were the last remnants of the planetesimals – the primitive building blocks that formed the planets. Most of these leftover objects were then lost, as shifts in the orbits of the giant planets scattered them to the distant outer reaches of the solar system or beyond. But some were captured in two less-distant regions, near points where the gravitational influence of Jupiter and the Sun balance, and have remained trapped there, mostly untouched, for billions of years.

Not quite 4 million years ago, an ancient ancestor of modern humans roamed the land in what later would become the country of Ethiopia. Thirty-four years ago, Donald Johanson discovered the fossilized skeleton of this creature, later named Lucy, after the Beatles’ 1967 hit “Lucy in the Sky with Diamonds.”

Image above: Conceptual image of the Lucy mission to the Trojan asteroids. Image Credits: NASA/SwRI.

Three years from now, a spacecraft named Lucy, inspired by the famous fossil, will begin its exploration that could help determine the early history of the Solar System.

NASA’s Lucy mission will fly by six of those trapped planetesimals – the Jupiter Trojan asteroids – giving humanity its first glimpse of these ancient objects. By studying these fossils of planet formation, the Lucy mission could reveal as much about the development of the solar system as the Lucy fossil did about human evolution. And on the way to the Trojans, Lucy will visit an asteroid that the team has named Donaldjohanson, after the anthropologist that discovered the fossilized skeleton of our ancestor.

“The Trojans hold vital clues to the origin of the Solar System because they are leftover remnants from, and so were witnesses to, the process that built the planets,” said Principal Investigator Harold Levison of the Southwest Research Institute in Boulder, Colorado.

Animation above: The time-lapsed animation above shows the movements of the inner planets, Jupiter and both swarms of Trojans (green) during the time period of the Lucy mission. The L4 Trojans lead Jupiter in its orbit and the L5 Trojans follow. By tradition, the L4 Trojans are named for Greek characters in accounts of the Trojan War. The L5 bodies are named for characters on the Trojan side of the conflict. Animation Credits: Astronomical Institute of CAS/Petr Scheirich (used with permission).

The Trojans orbit the Sun in synchrony with Jupiter, following almost the same path, but leading the giant planet by about one-sixth of the way around the orbit, or trailing by the same amount. This keeps them near one of two gravitationally stable “Lagrange” points, L4 and L5, positioned at the apex of an equilateral triangle with Jupiter and the Sun, where they are protected from being perturbed onto different orbits or out of the solar system entirely. The areas around Jupiter’s L4 and L5 points each contain a swarm of objects billions of years old that hold information about the history of our solar system.

Image above: SwRI scientist studied the binary asteroid Patroclus-Menoetius, shown in this artist’s conception, to determine that a shake-up of the giant planets likely happened early in the solar system’s history, within the first 100 million years. Image Credits: Image Courtesy of W.M. Keck Observatory/Lynette Cook.

Earth-based observations have enabled astronomers to classify the Trojan asteroids by subtle variations in color and likely composition. “We see variation in the properties we can measure from the Earth and we would like to know the physical basis behind this variation,” Lucy Project Scientist Keith Noll said. “A mission to a single object would not have allowed that kind of comparison – by sampling a diverse set of objects, Lucy will provide a better basis for understanding what we are seeing in the broader population.” By visiting six Trojans spanning all of the major types, two of which make up a binary system (two objects that orbit each other), Lucy will gain a wealth of information about the objects that made up the solar system’s original planetesimal disk. Noll works at NASA’s Goddard Space Flight Center in Greenbelt, Maryland which is a key partner in the Lucy mission.

One characteristic the Trojans have in common is that they are dark. “They only reflect four or five percent of the light that hits them,” said Noll. “That’s really dark. Black pavement on the road is far more reflective.”

What darkens the Trojans is a mystery that could have surprising implications for our Earth. “Dark objects may have organic (carbon-containing) compounds on their surfaces,” said Senior Scientist Amy Simon. “If many of the Trojans we survey show evidence of organics, it will imply that the building blocks for life were common throughout the early solar system.” Simon works at NASA Goddard where she serves as a deputy principal investigator for one of the Lucy spacecraft’s instruments.

Some of the same processes that trapped the Trojans in their present orbits sent other leftover planetesimals farther from the Sun, and we now find them in the Kuiper Belt, the icy region beyond Neptune that is home to Pluto and other dwarf planets. (NASA’s New Horizons spacecraft explored Pluto following a 9-year journey, and will fly past another Kuiper Belt Object on New Year’s Day 2019.)

Image above: An artist’s concept of the Lucy Mission. Image Credit: SwRI.

Data collection will be vital to Lucy’s success. The mission will carry four instruments in its payload: L’Ralph, consisting of MVIC (Multi-spectral Visible Imaging Camera), a multi-color imager, and LEISA (Linear Etalon Imaging Spectral Array), a spectrograph that will provide information on surface composition; L’LORRI (Long Range Reconnaissance Imager), a high-resolution camera; and L’TES (Thermal Emission Spectrometer), which will measure the surface temperatures of the Trojans. And in addition to the scientific instruments, Lucy’s communications (radio) and target acquisition system (TTCam) will contribute to the science mission. L’Ralph will analyze the Trojans’ surfaces to look for the presence of different silicates, ices and organics on these asteroids. L’LORRI will take high-definition pictures of the Trojans supplemented by TTCam at closest approach. L’TES will investigate the physical state of the Trojans’ surfaces, and the radio data will be used jointly with the imaging data to determine their masses and densities.

Lucy is scheduled to launch in October 2021, flying by more targets in different orbits around the Sun than any other mission in history. Answers to key questions about the solar system’s distant past will be now within reach, thanks to the Lucy mission.

The Lucy mission is led by Dr. Harold Levison and his team at the Southwest Research Institute and is managed by NASA’s Goddard Space Flight Center. The instruments on Lucy are developed by Goddard, Arizona State University, and the Johns Hopkins University Applied Physics Laboratory. The spacecraft will be developed and constructed by Lockheed Martin. Following its construction, Lucy will undergo further testing, and in three years be launched on a mission that will forever change our knowledge of the solar system.

For more information about the Lucy mission, visit: http://www.nasa.gov/lucy

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Karl Hille/Goddard Space Flight Center, by Tamsyn Brann.

Greetings, Orbiter.chArchive link

HiPOD (23 November 2018): Dust Devil Tracks in the Diacria…

HiPOD (23 November 2018): Dust Devil Tracks in the Diacria Region 

   – Our eye might deceive us, but that bright spot in the enhanced color image looks suspiciously like a dust devil in action. Hmmm…. (Alt: 350 km. Black and white is less than 5 km; enhanced color is less than 1 km.)

NASA/JPL/University of Arizona


https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...