воскресенье, 13 января 2019 г.

Castlelaw Iron Age Hillfort and Underground Earth House, Scotland, 13.1.19.

Castlelaw Iron Age Hillfort and Underground Earth House, Scotland, 13.1.19.

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Fishermen in Wales find medieval fishing baskets

Fishermen from Black Rock Lave Net Fishery made the discovery on their fishing grounds just off the coast of Portskewett in Monmouthshire.

Fishermen in Wales find medieval fishing baskets
Fishing baskets dating from around the 12th to the 15th century were discovered in the Severn Estuary
[Credit: Black Rock Lave Net Fishery]

The baskets had been buried in the river bank for hundreds of years until a recent storm in the estuary washed away the layers of mud, sand and silt to reveal a glimpse into the history of the area.

It is now the close season for the Black Rock Lave Net Fishery, but the fishermen continue to watch the fishing grounds and often find many things of interest such as these baskets.

This isn’t the first time the group have found artefacts such as these. However, as Martin Morgan, secretary of the fishery, explained, it is unusual to uncover so many baskets grouped together.

Mr Morgan said: “The baskets would have been baited and pegged to the estuary bed at low tide. The catch would have been green eels and lamprey.

Fishermen in Wales find medieval fishing baskets
Fishing baskets dating from around the 12th to the 15th century were discovered in the Severn Estuary
[Credit: Black Rock Lave Net Fishery]

“They are made of willow and hazel in an urn shape with a non-return built into the neck. The overall length is around two feet.”

Previous finds made by the fishermen have been recorded by Cadw and carbon dated by Reading university to be from around the 12th to the 15th century. These baskets were found in the same area and look to be of a similar design.

Mr Morgan explained that members of the fishery were hoping to get their most recent find carbon dated but added: “Once exposed, they are quickly destroyed by the tide so our fishermen record details of them. Time is of the essence.

“People have fished this estuary for thousands of years, and it’s great for our fishermen to uncover and record some history.”

Lave net fishing, as practiced by Mr Morgan and his colleagues at Black Rock, is an ancient fishing method, recorded on the estuary in the 17th century. However, it is thought to have been around for even longer.

The Black Rock Lave Net Fishermen are now the last traditional salmon fishery on the Welsh region of the estuary.

Author: Dan Barnes | Source: South Wales Argus [January 07, 2019]



Ancient Nikouria decree, missing for almost a century, rediscovered on Greek island of...

An ancient stone tablet bearing a historic inscription of the Nikouria decree, dating back to the 3rd century BC, has resurfaced on the island of Amorgos after it had gone missing for roughly a century, the Greek culture ministry announced last week.

Ancient Nikouria decree, missing for almost a century, rediscovered on Greek island of Amorgos
The inscription was found built into the wall of a newly renovated house in the village of Tholaria
[Credit: Greek Minstry of Culture and Sports]

The stele was found by a final-year archaeology student from Amorgos, Stelios Perakis, and German archaeologist N. N. Fischer with the help of local residents.

It was embedded in the outer wall of a recently renovated house  in the village Tholaria, Amorgos that had previously belonged to a shepherd from Nikouria.

According to a ministry announcement, the inscription on the stele contained key information on the history of the Aegean and was first discovered in 1893 in the Panagia Church on the islet of Nikouria, opposite Aigiali on Amorgos.

It had been temporarily transferred to a nearby stable where it remained until 1908 but then disappeared from view and its fate was entirely unknown.

The decree contains a decision of the League (Koinon) of the Islanders’, a political union set up by the Ptolemies, to participate with official representatives in the feast and games organised by Ptolemy II in Alexandria in the memory of his father Ptolemy I, the ministry said.

The specific stele is considered important since it provides evidence concerning the balance of power during the first half of the 3rd century BC and the transition of control from the Macedonians to the Ptolemies.

Dozens of researchers had tried and failed to track down the Nikouria decree over the years.

The Cyclades Antiquities Ephorate said it will remove and transfer the stele to the Amorgos archaeological collection.

Source: Kathimerini [January 07, 2019]



Two Roman busts found in Israel after heavy rains

Two 1,700-year-old Roman funerary busts were discovered in the northern Israeli city of Beit She’an following heavy rains, the Israel Antiquities Authority (AAI) said Sunday.

Two Roman busts found in Israel after heavy rains
Roman-era statues discovered near burial site in Beit Shean 
[Credit: Eytan Klein/IAA]

Following some rainy days earlier in December, a woman walking through the Beit She’an cemetery saw a small stone head sticking out of the mud and decided to call the AAI, which sent a team that uncovered first one bust and then another next to it.
“These busts were made of local limestone and they show unique facial features, details of clothing and hairstyles,” the deputy head of the AAI’s Theft Prevention Unit, Eitan Klein, said.

Klein said the two busts have an oriental style, with each weighing 30 kilos (66 pounds), and they have been dated to the late Roman Imperial Period (3rd and 4th century AD).

Two Roman busts found in Israel after heavy rains
Israeli archaeologist Eitan Klein of the Israel Antiquities Authority shows off two late Roman busts unearthed near
the ancient city of Beit Shean following a chance find by a woman walker [Credit: Gali Tibbon/AFP]

“It seems that at least one of them depicts a bearded man, but not one resembles another, and that’s the importance of these finds,” the AAI official said.
During the Roman Imperial Period, there was a diverse population in the city of Beit She’an that included Romans, Christians, Jews and Samaritans, Klein said.

The AAI official added that the busts were not considered those of either Jews or Samaritans, because the Jewish religion used to prohibit the reproduction of human images.

“These are very important finds, which tell us a great deal about the inhabitants of the Beit She’an area in antiquity,” AAI Theft Prevention Unit inspector Nir Distelfeld said.

“The discovery of the busts fills in another piece of the puzzle in our understanding of the material culture of the people of this land in the past,” Distelfeld said, urging people to always report such finds to the AAI.

Source: EFE [January 07, 2019]



Medieval sword found in Spanish castle

Archaeologists have discovered a 700-Year-old sword in perfect condition during their second season of work in the medieval castle of Ain in the Spanish region of Castellón.

Medieval sword found in Spanish castle
Credit: Ain City Council

The team of archaeologists said that a discovery of this kind of artefact in such a beautiful state of conservation was “extremely unusual”.
The sword is 94 cm long, has a 13 cm wide guard and a spherical pommel. There are two bronze rivets on the handle and a groove in the centre of the blade.

Medieval sword found in Spanish castle
Credit: Ain City Council

“Due to its typology and archaeological context, the sword likely dates to the 14th century and was probably preserved as a result of the destruction of the castle during the War of the Two Peters (1356-1367)”, according to a statement from the Territorial Service of Culture and Sport of Castellón.
The discovery is part of the second phase of the project to excavate and consolidate the castle of Aín, aimed at “preventing the growing deterioration of this monument, guaranteeing its stability and allowing it to be valued as a cultural resource of the first order”.

Medieval sword found in Spanish castle
Credit: Ain City Council

The castle has Muslim origins and was one of the most important locations during the Moorish rebellion in the area in the 16th century. The most interesting aspects of the site today are a tower and scattered walled enclosures.

Source: EFE [January 07, 2019]



Ancient mosaics discovered in southern Turkey

Ancient mosaics were discovered by construction workers in southern Osmaniye province on Monday.

Ancient mosaics discovered in southern Turkey
Credit: AA

The ancient mosaics, believed to date back to the first century, were discovered during digging in Dere neighbourhood of Kadirli (ancient Flavias or Flaviopolis) district.
“One of the mosaics has a radish on it. It also has a human figure holding grapes and a partridge in his hand. This shows that radishes have been farmed in our region since the first century,” said provincial culture and tourism director Burhan Torun.

Ancient mosaics discovered in southern Turkey

Ancient mosaics discovered in southern Turkey
Credit: AA

The construction site has been declared an archaeological site and secured.
“Here we find the mythological characters equivalent to Zeugma. This study will shed light on Kadirli’s history. Also we found the first written document regarding Kadirli on those mosaics,” Torun added.

Ancient mosaics discovered in southern Turkey

Ancient mosaics discovered in southern Turkey
Credit: AA

The Zeugma excavation site is in the southern Turkish city of Gaziantep, the probable site of the Hellenistic city of Antiochia ad Taurum.
Meaning “crossing” or “gateway” in Greek, Zeugma was one of the gateways to Mesopotamia, placed on the Euphrates River, and its history can be traced back to the antiquity period.

Ancient mosaics discovered in southern Turkey
Credit: AA

As a result of Alexander the Great’s policy of mixing Greek people with indigeneous populations, Zeugma had a symbolic value – it was an allegory of cultural amalgamation.

Source: Anadolu Agency [January 08, 2019]



Harappa grave of ancient ‘couple’ reveals secrets

About 4,500 years ago, a man and a woman were buried in a grave together in a sprawling cemetery on the outskirts of a thriving settlement of one of the world’s earliest urban civilisations.

Harappa grave of ancient 'couple' reveals secrets
The couple are believed to have died at the same time [Credit: Vasant Shinde]

In 2016, archaeologists and scientists from India and South Korea found these two “very rare” skeletons in a Harappan (or Indus Valley) city – what is now Rakhigarhi village in the northern Indian state of Haryana. For two years, they researched the “chronology” and possible reasons behind the deaths; and the findings have now been published in a peer-reviewed international journal.

“The man and the woman were facing each other in a very intimate way. We believe they were a couple. And they seemed to have died at the same time. How they died, however, remains a mystery,” archaeologist Vasant Shinde, who led the team, told me.

They were buried in a half-a-metre-deep sand pit. The man was around 35 years old at the time of his death, while the woman was around 25. Both were reasonably tall – he was 5.8ft (1.77m) and she, 5.6ft. They were both possibly “quite healthy” when they died – tests didn’t find any lesions or lines on the bones or any “abnormal thickness” of skull bones, which could hint at injuries or diseases such as brain fever.

Archaeologists say this unique “joint grave” was not an “outcome of any specific funeral customs commonly performed at that time”. They believe that the man and the woman “died almost at the same time and that, therefore, they had been buried together in the same grave”.

Harappa grave of ancient 'couple' reveals secrets
Magnified image of 11A and 11B. They were placed in supine position with arms and legs extended. The 11A’s head faced towards 11B. Asterisk indicate the banded agate bead found near the right clavicle of the 11B. Inset is the magnified image of a bead. Scale bar=2 cm [Credit: Vasant Shinde et al. 2019]

Ancient joint burial sites have always evoked interest. In a Neolithic burial site in an Italian village, archaeologists found a man and a woman in an embrace. In another joint burial reported from Russia, the couple were holding hands and facing each other. Nearly 6,000-year-old skeletons in Greece were found embracing each other, with their legs and arms interlocked.

Everything else they found in the Rakhigarhi grave was unexceptional for its time: a few earthen pots and some semi-precious stone bead jewellery, commonly found in graves from the bronze age Harappan civilisation. “The most striking thing about Harappan burials is how spartan they were. They didn’t have grand burials like, for example, kings in West Asia,” says Tony Joseph, author of Early Indians: The Story of Our Ancestors and Where We Came From.

In Mesopotamia, for example, kings were interred with hoards of precious jewellery and artefacts. Interestingly, jewellery made of carnelian, lapis lazuli and turquoise possibly exported from Harappa were found in graves in Mesopotamia.

In Harappan cities, graves usually contained pots with food and some jewellery – people likely believed in life after death and these materials were meant to be grave offerings. A lot of the pottery, says Mr Joseph, comprised lavishly painted dishes on stands and squat, bulging jars. “There was nothing remotely suggestive of royal funerals, which were common in west Asia,” he adds.

Harappa grave of ancient 'couple' reveals secrets
Archaeologists have excavated 62 graves in Rakhigarhi
[Credit: Deccan College]

Archaeologists believe the “mystery couple” lived in a settlement spread over more than 1,200 acres, housing tens of thousands of people. Of the 2,000-odd Harappan sites discovered in India and Pakistan so far, the settlement in Rakhigarhi is the largest, overtaking the more well-known city of Mohenjo Daro in Pakistan. (The ancient civilisation was first discovered at Mohenjo Daro in the 1920s.)

To be sure, this is not the first time archaeologists have discovered a couple in a Harappan grave.

In the 1950s, the skeletal remains of a man and a woman, heaped on top of each other, were found in a sand pit in Lothal in what is now Gujarat. The skull of the woman bore injury marks. Some excavators made a controversial claim that the grieving woman had killed herself after her husband’s death – a claim that could never be proved.

At Rakhigarhi, archaeologists have discovered 70 graves in the cemetery, barely a kilometre away from the settlement, and excavated 40 of them. But this single grave of the “mystery couple” has turned to be most fascinating of all.

Author: Soutik Biswas | Source: BBC News Website [January 09, 2019]



Immortality Kill Switch This is a deadly glioblastoma brain…

Immortality Kill Switch

This is a deadly glioblastoma brain tumour, seen down a microscope and stained to reveal living (purple) and dying (red) cancer cells. Scientists have long been struggling to understand what makes these cancers so difficult to treat and the search has now led to a gene called TERT, which is the most commonly altered gene in glioblastoma. TERT is an important component of telomerase – the molecular ‘immortality machine’ that maintains DNA so cancer cells can keep dividing. Unfortunately, TERT is also needed by healthy cells so it’s hard to target with anti-cancer drugs. But researchers have now found that TERT is activated by another molecule, GABP-beta1L, which isn’t needed by healthy cells but is essential for making cancer cells immortal. Getting rid of GABP-beta1L dramatically slows down the growth of glioblastoma cells in the lab – an approach that could be developed into a potentially powerful treatment in the future.

Written by Kat Arney

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2019 January 13 Tycho’s Supernova Remnant in X-ray Image…

2019 January 13

Tycho’s Supernova Remnant in X-ray
Image Credit: NASA / CXC / F.J. Lu (Chinese Academy of Sciences) et al.

Explanation: What star created this huge puffball? What’s pictured is the hot expanding nebula of Tycho’s supernova remnant, the result of a stellar explosion first recorded over 400 years ago by the famous astronomer Tycho Brahe. The featured image is a composite of three X-ray colors taken by the orbiting Chandra X-ray Observatory. The expanding gas cloud is extremely hot, while slightly different expansion speeds have given the cloud a puffy appearance. Although the star that created SN 1572, is likely completely gone, a star dubbed Tycho G, too dim to be discerned here, is thought to be a companion. Finding progenitor remnants of Tycho’s supernova is particularly important because the supernova is of Type Ia, an important rung in the distance ladder that calibrates the scale of the visible universe. The peak brightness of Type Ia supernovas is thought to be well understood, making them quite valuable in exploring the relationship between faintness and farness in the distant universe.

∞ Source: apod.nasa.gov/apod/ap190113.html

… a Full Heart … Image of the Week – January 14,…

… a Full Heart … Image of the Week – January 14, 2019

CIL:39011 – http://cellimagelibrary.org/images/39011

Description: Confocal image of a sea squirt heart. The sea squirt heart is a tube made of a single layer of muscle cells. The contractile elements are the long striations stained red and the nuclei are also red. The green spots indicate gap junctions between the cells, which facilitate the conduction of electrical impulses through the heart, thus coordinating its contraction.

Author: David Becker

Licensing: Attribution-NonCommercial-NoDerivs 2.0 UK: England & Wales (CC BY-NC-ND 2.0 UK)

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Thousands of Stars Observed Turning into Crystals for the First Time

Crystalized White Dwarf

Credit: University of Warwick/Mark Garlick)

Austin, Texas — The first direct evidence of crystallized white dwarf stars has been discovered by an international team of researchers that includes an astronomer at The University of Texas at Austin. Predicted half a century ago, the direct evidence of these stars will be published tomorrow in the journal Nature.

Observations have revealed that these stars have a core of solid carbon and oxygen due to a phase transition during their lifecycle, similar to water turning into ice. This phase transition slows their cooling in multiple ways, making them potentially billions of years older than previously thought.

The discovery, led by Pier-Emmanuel Tremblay of the U.K.’s University of Warwick, is largely based on observations taken with the European Space Agency’s Gaia satellite.

Almost all stars end up as white dwarfs, and some of them are among the oldest stars in the universe. They are useful to astronomers because their predictable cooling rate allows them to be used as cosmic clocks to estimate the ages of groups of stars. They are the leftover cores of red giant stars, after these huge stars have died and shed their outer layers. They are then constantly cooling as they release their stored-up heat over billions of years.

The Gaia satellite has enabled the selection of a sample of white dwarfs with precise luminosities and colors that is significantly larger and more complete than any previous survey. For the study, the team selected 15,000 white dwarfs within about 300 light-years of Earth.

White dwarfs get fainter and redder as they cool, which leads to a predictable distribution of white dwarfs in a plot of brightness versus color. The astronomers identified a pile-up in this plot, an excess in the number of stars at specific colors and luminosities. When compared with evolutionary models of white dwarfs, the pile-up strongly coincides with the phase in their development in which latent heat is predicted to be released in large amounts, resulting in a slowdown of their cooling process. It is estimated that in some cases these stars have slowed their aging by as much as 2 billion years.

Bart Dunlap, a postdoctoral fellow with UT Austin’s Wootton Center for Astrophysical Plasma Properties, working with JJ Hermes, made the discovery independently of the Warwick team and later joined forces with Tremblay. Hermes, a former UT graduate student, is now an assistant professor at Boston University.

“More than 50 years ago, Hugh Van Horn, an astronomer at the University of Rochester, predicted that we should see a crystallization sequence because of a slowdown in cooling when white dwarfs crystallize, but at the time, the data weren’t good enough to check this prediction,” Dunlap said. “Gaia finally made it possible to see what he predicted, and it really pops out in the data.”

Just as liquid water releases extra energy when it changes into ice — this energy is known as latent heat — the dense plasmas in the interiors of white dwarfs were predicted to release enough energy to noticeably slow their trek toward cool, faint stellar embers.

“All white dwarfs will crystallize at some point in their evolution, although more massive white dwarfs go through the process sooner,” said Tremblay, who led the study. “This means that billions of white dwarfs in our galaxy have already completed the process and are essentially metallic crystal spheres in the sky.”

This includes our own sun, which will become a crystal white dwarf in about 10 billion years.

Crystallization is the process of a material becoming a solid state in which its atoms form an ordered structure. Under the extreme pressures in white dwarf cores, atoms are packed so densely that their electrons become unbound, leaving a conducting electron gas governed by quantum physics, and positively charged nuclei in a fluid form. When the core cools to about 10 million degrees, the dense carbon oxygen plasma is cool enough that the fluid begins to solidify, forming a crystalline core at its heart.

“These results are really telling us a lot about the amount of pent-up energy these stars can release while cooling off,” Dunlap said.

The astronomers say they should have access to even better data from Gaia by 2021.

Media Contact:

Rebecca Johnson, 
Communications Mgr.
UT Austin McDonald Observatory

Science Contacts:

Dr. Bart Dunlap
Postdoctoral Fellow
UT Austin Wootton Center for Astrophysical Plasma Properties & McDonald Observatory

Dr. JJ Hermes
Assistant Professor of Astronomy
Boston University

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How to Watch the Only Total Lunar Eclipse of 2019, Plus a Supermoon

NASA logo.

January 12, 2019

Image above: The supermoon lunar eclipse captured as it moved over NASA’s Glenn Research Center on September 27, 2015. Image Credits: NASA/Rami Daud.

In the News

Looking up at the Moon can create a sense of awe at any time, but those who do so on the evening of January 20 will be treated to the only total lunar eclipse of 2019. Visible for its entirety in North and South America, this eclipse is being referred to by some as a super blood moon – “super” because the Moon will be closest to Earth in its orbit during the full moon (more on supermoons here) and “blood” because the total lunar eclipse will turn the Moon a reddish hue (more on that below). This is a great opportunity for students to observe the Moon – and for teachers to make connections to in-class science content.

How It Works

Eclipses can occur when the Sun, the Moon and Earth align. Lunar eclipses can happen only during a full moon, when the Moon and the Sun are on opposite sides of Earth. At that point, the Moon can move into the shadow cast by Earth, resulting in a lunar eclipse. However, most of the time, the Moon’s slightly tilted orbit brings it above or below Earth’s shadow.

Understanding Lunar Eclipses

The time period when the Moon, Earth and the Sun are lined up and on the same plane – allowing for the Moon to pass through Earth’s shadow – is called an eclipse season. Eclipse seasons last about 34 days and occur just shy of every six months. When a full moon occurs during an eclipse season, the Moon travels through Earth’s shadow, creating a lunar eclipse.

Image above: When a full moon occurs during an eclipse season, the Moon travels through Earth’s shadow, creating a lunar eclipse. Image Credits: NASA/JPL-Caltech.

Unlike solar eclipses, which require special glasses to view and can be seen only for a few short minutes in a very limited area, a total lunar eclipse can be seen for about an hour by anyone on the nighttime side of Earth – as long as skies are clear.

The Moon passes through two distinct parts of Earth’s shadow during a lunar eclipse. The outer part of the cone-shaped shadow is called the penumbra. The penumbra is less dark than the inner part of the shadow because it’s penetrated by some sunlight. (You have probably noticed that some shadows on the ground are darker than others, depending on how much outside light enters the shadow; the same is true for the outer part of Earth’s shadow.) The inner part of the shadow, known as the umbra, is much darker because Earth blocks additional sunlight from entering the umbra.

At 0:36 GMT (6:36 p.m. PST 9:36 p.m. EST) on January 20, the edge of the Moon will begin entering the penumbra. The Moon will dim very slightly for the next 57 minutes as it moves deeper into the penumbra. Because this part of Earth’s shadow is not fully dark, you may notice only some dim shading (if anything at all) on the Moon near the end of this part of the eclipse.

Image above: During a total lunar eclipse, the Moon first enters into the penumbra, or the outer part of Earth’s shadow, where the shadow is still penetrated by some sunlight. Image Credit: NASA.

At 1:33 GMT (7:33 p.m. PST 10:33 p.m. EST), the edge of the Moon will begin entering the umbra. As the Moon moves into the darker shadow, significant darkening of the Moon will be noticeable. Some say that during this part of the eclipse, the Moon looks as if it has had a bite taken out of it. That “bite” gets bigger and bigger as the Moon moves deeper into the shadow.

Image above: As the Moon starts to enter into the umbra, the inner and darker part of Earth’s shadow, it appears as if a bite has been taken out of the Moon. This “bite” will grow until the Moon has entered fully into the umbra. Image Credit: NASA.

At 2:41 GMT (8:41 p.m. PST 11:41 p.m. EST), the Moon will be completely inside the umbra, marking the beginning of the total lunar eclipse. The moment of greatest eclipse, when the Moon is halfway through the umbra, occurs at 3:12 GMT (9:12 p.m. PST 12:12 a.m. EST).

Image above: The total lunar eclipse starts once the moon is completely inside the umbra. And the moment of greatest eclipse happens with the Moon is halfway through the umbra as shown in this graphic. Image Credit: NASA.

As the Moon moves completely into the umbra, something interesting happens: The Moon begins to turn reddish-orange. The reason for this phenomenon? Earth’s atmosphere. As sunlight passes through it, the small molecules that make up our atmosphere scatter blue light, which is why the sky appears blue. This leaves behind mostly red light that bends, or refracts, into Earth’s shadow. We can see the red light during an eclipse as it falls onto the Moon in Earth’s shadow. This same effect is what gives sunrises and sunsets a reddish-orange color.

Image above: As the Moon moves completely into the umbra, it turns a reddish-orange color. Image Credit: NASA.

A variety of factors affect the appearance of the Moon during a total lunar eclipse. Clouds, dust, ash, photochemical droplets and organic material in the atmosphere can change how much light is refracted into the umbra. Additionally, the January 2019 lunar eclipse takes place when the full moon is at or near the closest point in its orbit to Earth – a time popularly known as a supermoon. This means the Moon is deeper inside the umbra shadow and therefore may appear darker. The potential for variation provides a great opportunity for students to observe and classify the lunar eclipse based on its brightness. Details can be found in the “Teach It” section below.

At 3:43 GMT (9:43 p.m. PST 12:43 a.m. EST), the edge of the Moon will begin exiting the umbra and moving into the opposite side of the penumbra. This marks the end of the total lunar eclipse.

At 4:50 GMT (10:50 p.m. PST 1:50 a.m. EST), the Moon will be completely outside the umbra. It will continue moving out of the penumbra until the eclipse ends at 5:48 GMT (11:48 p.m 2:48 a.m. EST).

What if it’s cloudy where you live? Winter eclipses always bring with them the risk of poor viewing conditions. If your view of the Moon is obscured by the weather, explore options for watching the eclipse online, such as the Time and Date live stream: https://www.timeanddate.com/live/

Lunar eclipses have long played an important role in understanding Earth and its motions in space.

Total Lunar Eclipse. Animation Credits: NASA/JPL

In ancient Greece, Aristotle noted that the shadows on the Moon during lunar eclipses were round, regardless of where an observer saw them. He realized that only if Earth were a spheroid would its shadows be round – a revelation that he and others had many centuries before the first ships sailed around the world.

Earth wobbles on its axis like a spinning top that’s about to fall over, a phenomenon called precession. Earth completes one wobble, or precession cycle, over the course of 26,000 years. Greek astronomer Hipparchus made this discovery by comparing the position of stars relative to the Sun during a lunar eclipse to those recorded hundreds of years earlier. A lunar eclipse allowed him to see the stars and know exactly where the Sun was for comparison – directly opposite the Moon. If Earth didn’t wobble, the stars would appear to be in the same place they were hundreds of years earlier. When Hipparchus saw that the stars’ positions had indeed moved, he knew that Earth must wobble on its axis!

Lunar eclipses are also used for modern-day science investigations. Astronomers have used ancient eclipse records and compared them with computer simulations. These comparisons helped scientists determine the rate at which Earth’s rotation is slowing.

More on supermoons here: https://www.jpl.nasa.gov/edu/news/2017/11/15/whats-a-supermoon-and-just-how-super-is-it/

Images (mentioned), Animation (mentioned), Video, Text, Credits: NASA/Goddard/JPL/Lyle Tavernier.

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Moel Goedog Stone Row (Stones 1 to 5), Harlech, North Wales, 4.1.19.The prehistoric...

Moel Goedog Stone Row (Stones 1 to 5), Harlech, North Wales, 4.1.19.

The prehistoric complex of Moel Goedog is an extensive one; at least eight standing stones mark a route between cairns, trackways, settlements and hillforts. Many of the stones are broken or fragmentary but the scale of the ritual route is visible at the site.

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