Climatebot
NASA has launched its gamma ray large area telescope (11 June 2008)
If it works as expected, it will be sending us pictures of some very high-energy events.
For NASA's announcement, go to
http://glast.gsfc.nasa.gov/
Several stars have exploded in the earth's cosmic neighborhood over the past billions of years. It will be
interesting to find out more about how these explosions have affected our planet's weather.
Cosmic rays are energetic particles originating from space that impinge on Earth's atmosphere. Almost
90% of all the incoming cosmic ray particles are protons, about 9% are helium nuclei (alpha particles)
and about 1% are electrons (beta minus particles). The term "ray" is a misnomer, as cosmic particles
arrive individually, not in the form of a ray or beam of particles.
The variety of particle energies reflects the wide variety of sources. The origins of these particles range
from energetic processes on the Sun all the way to as yet unknown events in the farthest reaches of the
visible universe. Cosmic rays can have energies of over 1020 eV, far higher than the 1012 to 1013 eV
that man-made particle accelerators can produce. (See Ultra-high-energy cosmic rays for a description
of the detection of a single particle with an energy of about 50 J, the same as a well-hit tennis ball at 42
m/s [about 94 mph].) There has been interest in investigating cosmic rays of even greater energies.
Gamma rays (denoted as γ) are a form of electromagnetic radiation or light emission of frequencies
produced by sub-atomic particle interactions, such as electron-positron annihilation or radioactive
decay. Gamma rays are generally characterized as electromagnetic radiation having the highest
frequency and energy, and also the shortest wavelength (below about 10 picometer), within the
electromagnetic spectrum. Gamma rays consist of high energy photons with energies above about 100
keV. Gamma rays were discovered by Paul Villard, a French chemist and physicist, in 1900, while
studying uranium.
Last Updated: Wednesday, 14 February 2007, 16:50 GMT
The Chilling Stars
The Chilling Stars by science writer Nigel Calder and climate physicist Henrik Svensmark outlines a
controversial new theory on the origins of global warming.
The book sets out to prove that a combination of clouds, the Sun and cosmic rays - sub-atomic particles
from exploding stars - have altered our climate far more than human carbon emissions.
Svensmark's research at the Danish National Space Center suggests cosmic rays play a role in making
clouds in our atmosphere. A reduction in cosmic rays in the last 100 years - due to the activity of our
Sun - has meant fewer clouds and a warmer Earth.
http://news.bbc.co.uk/2/hi/programmes/newsnight/6362407.stm
A lazy Sun launches iceberg armadas
Our ancestors endured shocking variations in climate - Events often matched changes in the Sun's
behaviour - Rare atoms made by cosmic rays signal those changes - When their production increased,
the world was chilled - But are the cosmic rays the agent, or merely a symptom?
A less public-spirited finder might have put the oddity up for sale on eBay, so the archaeologists of Bern
Canton were grateful when Ursula Leuenberger presented them with an archer's quiver made of birch
bark. They were amazed when radiocarbon dating showed the quiver to be 4,700 years old. Frau
Leuenberger had picked it up while walking with her husband in the mountains above Thun. There, the
perennial ice in the Schnidejoch had retreated in the unusually hot summer of 2003, revealing the relic
hidden beneath it.
The hiking couple had unwittingly rediscovered a long forgotten short-cut for travellers and traders
across the barrier of the Swiss Alps. To keep treasure-hunters away, the find remained a secret for two
years while archaeologists scoured the area of the melt-back and analysed the finds. By the end of
2005 they had some 300 items - from the Neolithic Era, the Bronze Age, the Roman period and medieval
times.
The various ages of the items clustered in intervals when the pass of Schnidejoch was open, offering a
quick route to and from the Rhone valley south of the mountains. There were no substantial human
remains to compare with the murdered Ötztal 'ice man', found with a similar quiver high in the Italian
Tyrol in 1991 and dated to 3300 BC. But the emergent history of repeated openings and closures of
Schnidejoch gave a far more interesting picture of climate change.
The Ötztal man is a prize exhibit for those who assert that the climate at the start of the 21st century is
alarmingly warm. The ice that preserved his mummified corpse lay unmelted, 3,250 metres above sea
level, for more than 5,000 years - since the world was in its warmest phase following the most recent ice
age. Then, so the story goes, the manmade global warming of the industrial era outstripped all natural
variations and released the body as a warning to us all.
Quite different is the impression given by the relics found in the pass of Schnidejoch, at an altitude 500
metres lower than the Ötztal man's ice-tomb. They tell of repeated alternations between warm periods
when the pass was useable and cold periods when it was shut by the ice. The discoveries also cleared
up a long-standing mystery about a Roman lodging house found on the slopes above the present-day
town of Thun, where there was a Roman temple and settlement. The head of the cantonal
archaeological service, Peter Suter, explained his satisfaction at the outcome: 'We always asked
ourselves why the lodging house was there. Now we know that it was on the route leading across the
Schnidejoch.'
The youngest item found by the archaeologists was part of a shoe dating from the 14th or 15th century
AD. It corresponds with the end of an interval known as the Medieval Warm Period. Thereafter the
Schnidejoch was blocked by the glaciers of the Little Ice Age, the most recent period of intense cold.
Nominally the Little Ice Age ended around 1850, but the gradual retreat of the ice took a century and a
half to clear the pass, until its rediscovery early in the 21st century.
Here is a tale of natural variations in climate having a practical influence on the lives and travels of
Europeans over 5,000 years. The climate was particularly cold in two periods around 800 BC and 1700
AD. Effects of the latter episode, the Little Ice Age, persisted in the Schnidejoch for so long that even
the locals forgot that a useful pass was ever there.
The Medieval Warm Period and the Little Ice Age were an embarrassment for those who, in recent
years, wished to play down the natural variations in climate that occurred before the Industrial
Revolution. A widely publicised but now discredited graph of temperatures, produced in 1998 by Michael
Mann of the University of Massachusetts and his colleagues, tried to iron out the variations. Lampooned
as the hockey stick, Mann's graph showed the world remaining almost uniformly cool through most of the
past 1,000 years until 1800. Then temperatures began to climb towards unprecedented highs in the late
20th century - so making the toe of the hockey stick and the supposed onset of an unprecedented
episode of man-made global warming.
The relics from the Schnidejoch mock this Orwellian effort to make real-life events that were not
politically correct disappear from climate history. They show that warming spells very like that of the past
100 years occurred repeatedly, long before the large-scale use of fossil fuels and the associated
emissions of carbon dioxide gas were a possible factor. Attempts to argue that such events were not
global are contradicted by abundant evidence for the Medieval Warm Period and the Little Ice Age from
East Asia, Australasia, South America and South Africa, as well as from North America and Europe.
Probing the errors that generated the hockey stick can be safely left to the statistical pathologists, while
we explore the character and rhythms of climate change over centuries and millennia.
Sunspots missing in the Little Ice Age
Atomic bullets raining down from exploded stars, the cosmic rays, leave behind them business cards that
record their split-second visits to the Earth's atmosphere. They take the form of unusual atoms created
by nuclear reactions in the upper air. Especially valued by archaeologists as an aid to dating objects is
radiocarbon, or carbon-14, made from nitrogen in the air.
Taken up into carbon dioxide, the gas of life by which plants grow, the carbon-14 finds its way via the
plants and animals into wood, charcoal, bones, leather and other relics. The initial carbon-14 content
corresponds to the amount prevailing in the air at the time of death. Then, over thousands of years, the
atoms gradually decay back into nitrogen. If you see how much carbon-14 is left in an old piece of wood
or fibre or bone, you can tell how many centuries or millennia have elapsed since the plant or animal
was alive.
There's a snag about this gift from the stars, as archaeologists soon discovered. Some of their early
radiocarbon dates seemed nonsensical, even contradictory - for example, a pharaoh of Egypt dated as
being younger than his known successors. Hessel de Vries of Gronigen found the explanation in 1958.
The rate of production of carbon-14 varies. Measurements in well-dated annual rings of growth in
ancient trees sorted out the problem, and the archaeologists had more reliable, though often ambiguous
dates. And physicists could see changes over thousands of years in the performance of the Sun, as the
chief gatekeeper of the cosmic rays. Its magnetic field protects us by repelling many of the cosmic rays
coming from the Galaxy, before they can reach the Earth's vicinity. The variations that confused the
archaeologists followed changes in the Sun's mood. Low production rates of carbon-14 meant that the
Sun was very active, magnetically speaking. When it was lazy, more cosmic rays reached the Earth and
the production of carbon-14 shot up.
The discovery opened the way to modern interpretations of the link between the Sun and the Earth's
everchanging climate, beginning in the 1960s. Roger Bray of New Zealand's Department of Scientific
and Industrial Research traced the variations in the Sun's activity since 527 BC. He was able to connect
increased production of radio carbon by cosmic rays to other symptoms of feeble solar magnetic activity.
A scarcity of dark spots on the face of the Sun, which are made by pools of intense magnetism, was one
such sign. Reports of auroras, which light the northern skies when the Sun is restless, were also scanty
when the cosmic rays were making lots of radiocarbon. And most significantly, Bray linked solar laziness
and high cosmic rays with historically recorded advances of glaciers, pushing their cold snouts down
many valleys. The advances were most numerous in the 17th and 18th centuries, which straddled the
coldest period of the Little Ice Age.
If it works as expected, it will be sending us pictures of some very high-energy events.
For NASA's announcement, go to
http://glast.gsfc.nasa.gov/
Several stars have exploded in the earth's cosmic neighborhood over the past billions of years. It will be
interesting to find out more about how these explosions have affected our planet's weather.
Cosmic rays are energetic particles originating from space that impinge on Earth's atmosphere. Almost
90% of all the incoming cosmic ray particles are protons, about 9% are helium nuclei (alpha particles)
and about 1% are electrons (beta minus particles). The term "ray" is a misnomer, as cosmic particles
arrive individually, not in the form of a ray or beam of particles.
The variety of particle energies reflects the wide variety of sources. The origins of these particles range
from energetic processes on the Sun all the way to as yet unknown events in the farthest reaches of the
visible universe. Cosmic rays can have energies of over 1020 eV, far higher than the 1012 to 1013 eV
that man-made particle accelerators can produce. (See Ultra-high-energy cosmic rays for a description
of the detection of a single particle with an energy of about 50 J, the same as a well-hit tennis ball at 42
m/s [about 94 mph].) There has been interest in investigating cosmic rays of even greater energies.
Gamma rays (denoted as γ) are a form of electromagnetic radiation or light emission of frequencies
produced by sub-atomic particle interactions, such as electron-positron annihilation or radioactive
decay. Gamma rays are generally characterized as electromagnetic radiation having the highest
frequency and energy, and also the shortest wavelength (below about 10 picometer), within the
electromagnetic spectrum. Gamma rays consist of high energy photons with energies above about 100
keV. Gamma rays were discovered by Paul Villard, a French chemist and physicist, in 1900, while
studying uranium.
Last Updated: Wednesday, 14 February 2007, 16:50 GMT
The Chilling Stars
The Chilling Stars by science writer Nigel Calder and climate physicist Henrik Svensmark outlines a
controversial new theory on the origins of global warming.
The book sets out to prove that a combination of clouds, the Sun and cosmic rays - sub-atomic particles
from exploding stars - have altered our climate far more than human carbon emissions.
Svensmark's research at the Danish National Space Center suggests cosmic rays play a role in making
clouds in our atmosphere. A reduction in cosmic rays in the last 100 years - due to the activity of our
Sun - has meant fewer clouds and a warmer Earth.
http://news.bbc.co.uk/2/hi/programmes/newsnight/6362407.stm
A lazy Sun launches iceberg armadas
Our ancestors endured shocking variations in climate - Events often matched changes in the Sun's
behaviour - Rare atoms made by cosmic rays signal those changes - When their production increased,
the world was chilled - But are the cosmic rays the agent, or merely a symptom?
A less public-spirited finder might have put the oddity up for sale on eBay, so the archaeologists of Bern
Canton were grateful when Ursula Leuenberger presented them with an archer's quiver made of birch
bark. They were amazed when radiocarbon dating showed the quiver to be 4,700 years old. Frau
Leuenberger had picked it up while walking with her husband in the mountains above Thun. There, the
perennial ice in the Schnidejoch had retreated in the unusually hot summer of 2003, revealing the relic
hidden beneath it.
The hiking couple had unwittingly rediscovered a long forgotten short-cut for travellers and traders
across the barrier of the Swiss Alps. To keep treasure-hunters away, the find remained a secret for two
years while archaeologists scoured the area of the melt-back and analysed the finds. By the end of
2005 they had some 300 items - from the Neolithic Era, the Bronze Age, the Roman period and medieval
times.
The various ages of the items clustered in intervals when the pass of Schnidejoch was open, offering a
quick route to and from the Rhone valley south of the mountains. There were no substantial human
remains to compare with the murdered Ötztal 'ice man', found with a similar quiver high in the Italian
Tyrol in 1991 and dated to 3300 BC. But the emergent history of repeated openings and closures of
Schnidejoch gave a far more interesting picture of climate change.
The Ötztal man is a prize exhibit for those who assert that the climate at the start of the 21st century is
alarmingly warm. The ice that preserved his mummified corpse lay unmelted, 3,250 metres above sea
level, for more than 5,000 years - since the world was in its warmest phase following the most recent ice
age. Then, so the story goes, the manmade global warming of the industrial era outstripped all natural
variations and released the body as a warning to us all.
Quite different is the impression given by the relics found in the pass of Schnidejoch, at an altitude 500
metres lower than the Ötztal man's ice-tomb. They tell of repeated alternations between warm periods
when the pass was useable and cold periods when it was shut by the ice. The discoveries also cleared
up a long-standing mystery about a Roman lodging house found on the slopes above the present-day
town of Thun, where there was a Roman temple and settlement. The head of the cantonal
archaeological service, Peter Suter, explained his satisfaction at the outcome: 'We always asked
ourselves why the lodging house was there. Now we know that it was on the route leading across the
Schnidejoch.'
The youngest item found by the archaeologists was part of a shoe dating from the 14th or 15th century
AD. It corresponds with the end of an interval known as the Medieval Warm Period. Thereafter the
Schnidejoch was blocked by the glaciers of the Little Ice Age, the most recent period of intense cold.
Nominally the Little Ice Age ended around 1850, but the gradual retreat of the ice took a century and a
half to clear the pass, until its rediscovery early in the 21st century.
Here is a tale of natural variations in climate having a practical influence on the lives and travels of
Europeans over 5,000 years. The climate was particularly cold in two periods around 800 BC and 1700
AD. Effects of the latter episode, the Little Ice Age, persisted in the Schnidejoch for so long that even
the locals forgot that a useful pass was ever there.
The Medieval Warm Period and the Little Ice Age were an embarrassment for those who, in recent
years, wished to play down the natural variations in climate that occurred before the Industrial
Revolution. A widely publicised but now discredited graph of temperatures, produced in 1998 by Michael
Mann of the University of Massachusetts and his colleagues, tried to iron out the variations. Lampooned
as the hockey stick, Mann's graph showed the world remaining almost uniformly cool through most of the
past 1,000 years until 1800. Then temperatures began to climb towards unprecedented highs in the late
20th century - so making the toe of the hockey stick and the supposed onset of an unprecedented
episode of man-made global warming.
The relics from the Schnidejoch mock this Orwellian effort to make real-life events that were not
politically correct disappear from climate history. They show that warming spells very like that of the past
100 years occurred repeatedly, long before the large-scale use of fossil fuels and the associated
emissions of carbon dioxide gas were a possible factor. Attempts to argue that such events were not
global are contradicted by abundant evidence for the Medieval Warm Period and the Little Ice Age from
East Asia, Australasia, South America and South Africa, as well as from North America and Europe.
Probing the errors that generated the hockey stick can be safely left to the statistical pathologists, while
we explore the character and rhythms of climate change over centuries and millennia.
Sunspots missing in the Little Ice Age
Atomic bullets raining down from exploded stars, the cosmic rays, leave behind them business cards that
record their split-second visits to the Earth's atmosphere. They take the form of unusual atoms created
by nuclear reactions in the upper air. Especially valued by archaeologists as an aid to dating objects is
radiocarbon, or carbon-14, made from nitrogen in the air.
Taken up into carbon dioxide, the gas of life by which plants grow, the carbon-14 finds its way via the
plants and animals into wood, charcoal, bones, leather and other relics. The initial carbon-14 content
corresponds to the amount prevailing in the air at the time of death. Then, over thousands of years, the
atoms gradually decay back into nitrogen. If you see how much carbon-14 is left in an old piece of wood
or fibre or bone, you can tell how many centuries or millennia have elapsed since the plant or animal
was alive.
There's a snag about this gift from the stars, as archaeologists soon discovered. Some of their early
radiocarbon dates seemed nonsensical, even contradictory - for example, a pharaoh of Egypt dated as
being younger than his known successors. Hessel de Vries of Gronigen found the explanation in 1958.
The rate of production of carbon-14 varies. Measurements in well-dated annual rings of growth in
ancient trees sorted out the problem, and the archaeologists had more reliable, though often ambiguous
dates. And physicists could see changes over thousands of years in the performance of the Sun, as the
chief gatekeeper of the cosmic rays. Its magnetic field protects us by repelling many of the cosmic rays
coming from the Galaxy, before they can reach the Earth's vicinity. The variations that confused the
archaeologists followed changes in the Sun's mood. Low production rates of carbon-14 meant that the
Sun was very active, magnetically speaking. When it was lazy, more cosmic rays reached the Earth and
the production of carbon-14 shot up.
The discovery opened the way to modern interpretations of the link between the Sun and the Earth's
everchanging climate, beginning in the 1960s. Roger Bray of New Zealand's Department of Scientific
and Industrial Research traced the variations in the Sun's activity since 527 BC. He was able to connect
increased production of radio carbon by cosmic rays to other symptoms of feeble solar magnetic activity.
A scarcity of dark spots on the face of the Sun, which are made by pools of intense magnetism, was one
such sign. Reports of auroras, which light the northern skies when the Sun is restless, were also scanty
when the cosmic rays were making lots of radiocarbon. And most significantly, Bray linked solar laziness
and high cosmic rays with historically recorded advances of glaciers, pushing their cold snouts down
many valleys. The advances were most numerous in the 17th and 18th centuries, which straddled the
coldest period of the Little Ice Age.
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