5 Facts About Earth’s Radiation Donuts 🍩

Did you know that our planet is surrounded by giant,
donut-shaped clouds of radiation?

image

Here’s what you need to know.

1. The radiation
belts are a side effect of Earth’s magnetic field

image

The Van Allen radiation belts exist because fast-moving charged
particles get trapped inside Earth’s natural magnetic field, forming two
concentric donut-shaped clouds of radiation. Other planets with global magnetic
fields, like
Jupiter
, also have radiation belts.

2. The radiation
belts were one of our first Space Age discoveries

image

Earth’s radiation belts were first
identified in 1958
by Explorer 1, the first U.S. satellite. The
inner belt, composed predominantly of protons, and the outer belt, mostly
electrons, would come to be named the Van Allen Belts, after James Van Allen,
the scientist who led the charge designing the instruments and studying the
radiation data from Explorer 1.

3. The Van Allen
Probes have spent six years exploring the radiation belts

image

In 2012, we launched the twin Van Allen Probes to
study the radiation belts. Over the past six years, these spacecraft have
orbited in and out of the belts, providing brand-new data about how the
radiation belts shift and change in response to solar activity and other
factors.

4. Surprise! Sometimes
there are three radiation belts

image

Shortly after launch, the Van Allen Probes detected a
previously-unknown third
radiation belt
, created by a bout of strong solar activity. All the
extra energy directed towards Earth meant that some particles trapped in our
planet’s magnetic field were swept out into the usually relatively empty region
between the two Van Allen Belts, creating an additional radiation belt.

5. Swan song for the
Van Allen Probes

image

Originally designed for a two-year mission, the Van Allen
Probes have spent more than six years collecting data in the harsh radiation
environment of the Van Allen Belts. In spring 2019, we’re changing their orbit to bring the perigee — the part of the
orbit where the spacecraft are closest to Earth — about 190 miles lower. This
ensures that the spacecraft will eventually burn up in Earth’s atmosphere,
instead of orbiting forever and becoming space junk.

Because the Van Allen Probes have proven to be so hardy,
they’ll continue collecting data throughout the final months of the mission
until they run out of fuel. As they skim through the outer reaches of Earth’s
atmosphere, scientists and engineers will also learn more about how atmospheric
oxygen can degrade satellite measurements — information that can help build
better satellites in the future.

Keep up with the latest on the mission on Twitter, Facebook
or nasa.gov/vanallenprobes.

Medieval archive reveals how nun faked her own death to escape convent

A nun who faked her own death, an archbishop who went into battle with an army of clergymen, and why being a priest was the most dangerous job of the Middle Ages: these are just some of the stories beginning to emerge from fourteenth-century records held in the University of York’s archives.

Medieval archive reveals how nun faked her own death to escape convent
Archbishop’s register reveals how Joan of Leeds crafted a dummy of her body that was buried, while she pursued
‘the way of carnal lust’ [Credit: Nancy Bauer/Shutterstock]

Joan of Leeds was fed up of her life in a medieval nunnery. By 1318, her urge to escape the vows she had pledged to poverty, chastity and obedience had grown so strong that she resorted to faking her own death.

After tricking her fellow sisters into burying a dummy they believed to be her body, Joan fled. But alas, her freedom was short lived as she was soon discovered and ordered to return to the convent by the Archbishop of York.

Archivists from the Borthwick Institute for Archives at the University of York have uncovered Joan’s story as they begin to explore registers recording the business of the archbishops of York between 1304 and 1405.

Secrets

Ink, skilfully scrawled onto parchment by medieval scribes, preserves the secrets of people – from nobles to peasants and bishops to curates — who lived during periods of disease, war, famine, political strife and religious reformation in the King’s City in the North and surrounding province.

Before coming into the University’s care, the 16 heavy volumes had endured a perilous existence and have not been extensively studied. In the Middle Ages they were carried by the Archbishop’s officials on his travels; after the English Civil War they found their way to storage in London, only being restored to the Diocesan Registry in York Minster in the late eighteenth century. Parts of some registers have been published, but often untranslated from the original Latin.

Now, with an injection of just under £1m of funding from the Arts and Humanities Research Council, a research team of medieval historians and archivists from the University and The National Archives (UK) are taking on the painstaking task of translating the volumes and indexing them to make their contents digitally available to all for free.

Rich account

“Archbishops of York in the fourteenth century had incredibly varied roles,” explains Professor Sarah Rees Jones, medieval historian at the University of York and Principal Investigator on the project.

Medieval archive reveals how nun faked her own death to escape convent
The register that details the story of Joan of Leeds [Credit: University of York]

“On the one hand they carried out diplomatic work in Europe and Rome and rubbed shoulders with the VIPs of the Middle Ages. However, they were also on the ground resolving disputes between ordinary people, inspecting priories and monasteries and correcting wayward monks and nuns.

“That’s why these Registers provide such a rich account of people from all walks of fourteenth-century life during a fascinating and extremely turbulent period.”

Priest army

Over the course of their research, the team is hoping to find out more about some of history’s most extraordinary archbishops — characters such as William Melton, who led an army of priests and citizens into battle to defend the City of York against the Scots in 1319.

“In the Middles Ages, York was an extremely important northern city on the frontline of the Scottish wars of independence,” says Professor Rees Jones. “But unfortunately the fight didn’t go well for Melton and his army of clergy. Their lack of military training resulted in a reported 4,000 men dying on the battlefield and a further 1,000 are believed to have drowned in the River Swale trying to escape.”

Not all archbishops of York documented by the registers were such loyal subjects to their kings. Archbishop Richard le Scrope was executed in 1405 for his participation in the Northern Rising against Henry IV — an act immortalised in the eponymous Shakespeare play. “The records may well provide more information on this episode and offer some fresh insights into Scrope’s motivations for getting involved,” Professor Rees Jones adds.

Black Death

The registers also chronicle the Black Death which swept through Europe from 1347 to 1351 and wiped out 60% of the British population. “The equivalent would be if 40 million people died in Britain today within the space of around four years” says Professor Rees Jones. “There were empty monasteries and entire villages were decimated.”

Medieval archive reveals how nun faked her own death to escape convent
Gary Brannan, Archivist, and Professor Sarah Rees Jones examine one of the registers
[Credit: University of York]

“Being a priest was one of the most dangerous jobs in Europe during that time as they visited the sick and administered last rites at death beds.”

New light

However, the Black Death did bring about important change in the church. “Because so many priests had died there weren’t enough people trained in Latin, so delivering sermons in English had to be adopted as the new status quo,” Professor Rees Jones adds.

“The registers may shed new light on what it was like to live through this period and will perhaps give us a sense of how the Church reasserted its authority after such catastrophic events.”

The project, called ‘The Northern Way’ will run for 33 months in partnership with The National Archives (UK) and with the support of the Chapter of York Minster. The team will also generate a programme of lectures, publications and joint research with local history groups and postgraduate students.

Northern identity

Once indexed, the material from the registers will be linked via the York’s Archishops’ Registers Revealed platform to ecclesiastical records at The National Archives, the British Library and York Minster to provide a complete picture of the role of the northern archbishops in national affairs.

“These chronicles will give us a window into the lives of important figures and ordinary people,” Professor Rees Jones says. “Their revelations may change our perception of northern identity and parts of history as we know it.”

Source: University of York [February 12, 2019]

TANN

Archive

Underwater remains of Prague’s first bridge explored

For a few days in mid-January, tourists on Prague’s Charles Bridge got to experience a highly unusual sight. Just a few dozen metres to the north, a team of scientists and divers were carrying out archaeological research on the remains of the Charles Bridge’s predecessor. The early medieval Judith Bridge was named after the wife of its builder, King Vladislav II.

Underwater remains of Prague's first bridge explored
Credit: Andrea Kiss

Barbora Machová, the coordinator of the team that has been examining its remnants, said: “The foundations of the Judith Bridge comprise an oak frame and sandstone blocks. That means it was one of the first stone bridges on the territory of today’s Czech Republic – previously all the bridges were wooden. The Judith Bridge was destroyed by flooding in the first half of the 14th century, when it was replaced by the Charles Bridge.”
Ms. Machová, an expert in the highly specialised field of underwater archaeological research, says her project is the continuation of the first noteworthy modern examination of the Judith Bridge’s remnants, which took place a few decades back.

Underwater remains of Prague's first bridge explored
Credit: Czech Television

Ms. Machová added: “This research has actually been going on since the end of the last century – since the 1980s or the 1990s, I believe – when the first geo-radar measurements were taken. Periodically teams of divers return. In around 2014 there was renewed interest in the Judith Bridge after a period of relative disinterest. But otherwise it has been receiving attention for a very long time.”
Barbora Machová says a key finding in January’s research was that the best-preserved underwater pillar is not deteriorating. “At present, there are 13 pillars of the Judith Bridge. Some of the pillars and arches have been preserved on both banks of the Vltava. What we’re interested in is the pillars that are in the water. The 11th pillar is completely preserved. We knew about it from the earlier research. However, it had only been photographed, and this year we were able to carry out geo-radar measurements for the first time. We discovered that it hadn’t been damaged by the ever-increasing level of traffic on the river.”

Underwater remains of Prague's first bridge explored
Charles Bridge construction model with Judith Bridge on the right
[Credit: Štěpánka Budková]

The heavy boat traffic on the Vltava for most of the year is the main reason explorations are carried out in the winter months. Indeed the intensity of river transport is a key reason for the research, which is also closely documenting the state of the underwater parts of Charles Bridge in a bid to ensure their preservation.

Authors: Magdalena Hrozínková, Ian Willoughby | Source: Radio Praha [February 12, 2019]

TANN

Archive