Monday, January 25, 2016

Fionn MacCumhail, the leader of the Fianna.



Diarmuid and Grainne. ( Jim Fitzpatrick )

Fionn appears in another legend called The Pursuit of Diarmuid and Gráinne . In this story, however, Fionn is not its protagonist, but its antagonist. In this tale, Gráinne, the most beautiful woman in Ireland, and the daughter of Cormac MacAirt, the High King of Ireland, was betrothed to the aging Fionn.

However, the princess fell in love with Diarmuid, one of the Fianna, when she first saw him. During the wedding feast, Gráinne drugged the entire party, with the exception of Diarmuid, and confessed her love for him. Diarmuid, however, was loyal to his leader, and did not reciprocate her love. Gráinne then put a spell on Diarmuid to make him fall in love with her and the pair ran away. When Fionn realized what had happened, he pursued the pair all over Ireland.

In one version of the legend, Diarmuid and Gráinne came across the heath of Ben Bulben, where the pair was confronted by a giant boar, the only creature that could harm Diarmuid. The warrior fought with the beast to protect Gráinne, and though he managed to kill it, was mortally wounded by it as well.

In another version of the legend, Fionn gave up the chase eventually, and allowed the pair to settle down. Years later, Fionn invited Diarmuid to a boar hunt at Ben Bulben, where the warrior was fatally wounded by a boar. The only way that Diarmuid could be saved was for him to drink water from Fionn’s cupped hands. Although the Fianna begged Fionn to save Diarmuid, he refused to do so, and only changed his mind when his son, Oisin, threatened to fight him. By then, however, Diarmuid had died.

Thirteen Towers of Chankillo, Peru





The enigmatic, 2,300-year-old Chankillo ruins, seen from space. The Thirteen Towers — with each tower spaced about five metres apart — are thought to be part of a solar observatory to mark the solstices and equinoxes.

Located in the Peruvian coastal desert at the Casma-Sechin Oasis, stands the incredible monumental complex of Chankillo, also known as Chanquillo, which extends across four square kilometers. The ancient archaeological site consists of a fort located on hilltop and thirteen solar observatory towers, as well as residential and gathering areas. It was occupied for a relatively short period of time – between the mid-fourth century BC and the early first century AD.

Located between two observation platforms, the thirteen astronomical towers span the entire annual rising and setting arcs of the sun, which shift north and south along the horizon gradually over the course of a year. What makes Chankillo so important is the fact that, according to archaeologists, Chankillo may be the earliest known astronomical observatory in the Americas, built some 2,300 years ago. The Incas, also well known astronomers, observed the sun and the stars, but they did so many centuries later.

Research has shown that the astronomical alignments seen at Chankillo were, and still are, incredibly precise. The towers have been known about for a long time but their astronomical value had not been widely realized until Ivan Ghezzi and Clive Ruggles undertook detailed research at the site in 2007.

Archaeologists suggest that the inhabitants of Chankillo would have been able to determine the date with an accuracy of +/- two to three days by observing the sunrise/sunset from the correct observational platform. On the winter solstice, the sun would rise behind the further tower on the left and then over time, would rise behind each of the towers until it reached the furthest tower on the right some six months later on the summer solstice, marking the passage of time. Other ancient sites known for astronomical observatories contain only one point of astronomical alignment which does not provide enough information for an accurate measurement of time over one year.

The towers at Chankillo, which are spaced at intervals between 4.7 and 5.1 meters, vary in shape and size, ranging from 70 to 130 meters in width and up to 6 meters in height.  According to archaeologists, at the time the towers were constructed they were completely flat on top. [To view the thirteen towers of Chankillo on Google Maps, select Google Earth’s ‘Fly To’ option and enter latitude: 9 33 40.27 S and longitude: 78 13 38.53 W.]

The walls of this ancient site were once shiny white, with paintings and figures decorating the monuments. The structures found at Chankillo were built of shaped stone and mortared walls, a combination that reflects the surroundings of this coastal desert and incredibly beautiful environment in Peru. Apart from observing the Sun, the Chankillo observatory would have aided the builders of Chankillo to know the best time to plant and harvest of crops.

The most puzzling aspect of Chankillo is, who built this incredible complex? Archaeologists no almost nothing about these ancient builders who paid tribute to the sun and stars, constructing the first ever solar observatory in the Americas.

Like many other ancient cultures that have worshiped the sun and the Sun God, Chankillo wasn't much different, as the towers were probably built, not only as a calendar and observatory, but also as a place with which to celebrate their mystical connection with the sun.  "If you were just measuring seasons, there would be no need to make such great structures," says Ghezzi . "The idea was to transmit a political and ideological message about a ruler's close relationship with the sun."


Thursday, January 14, 2016

Global warming could stave off next ice age for 100,000 years

Global warming is likely to disrupt a natural cycle of ice ages and contribute to delaying the onset of the next big freeze until about 100,000 years from now, scientists have suggested.

In the past million years, the world has had about 10 ice ages before swinging back to warmer conditions like the present.

In the last ice age that ended 12,000 years ago, ice sheets blanketed what is now Canada, northern Europe and Siberia.

In a new explanation for the long-lasting plunges in global temperatures that cause ice ages, scientists pointed to a combination of long-term shifts in the Earth's orbit around the sun, together with levels of carbon dioxide in the atmosphere.

They said the planet seemed naturally on track to escape an ice age for the next 50,000 years, an unusually long period of warmth, according to the study led by the Potsdam Institute for Climate Impact Research and published in the journal Nature.

But rising man-made greenhouse gas emissions since the Industrial Revolution began in the 18th century could mean the balmy period will last for 100,000 years.

The findings suggest human influences "will make the initiation of the next ice age impossible over a time period comparable to the duration of previous glacial cycles".

"Humans have the power to change the climate on geological timescales," lead author Dr Andrey Ganopolski said.

He said the lingering impacts of greenhouse gases in a far distant future did not in any way affect the urgency of cutting emissions now that are blamed for causing downpours, heat waves and rising seas.
"The earlier we stop, the better," Dr Ganopolski said.

Almost 200 governments agreed a deal in Paris last month to shift from fossil fuels to combat climate change.

Last week, another group of scientists said humanity had become a force in shaping the planet's geology and suggested an "Anthropocene epoch" began in the mid-20th century with factors such as nuclear tests and industrialisation.

"Like no other force on the planet, ice ages have shaped the global environment," co-author Professor Hans Joachim Schellnhuber said.

Professor Schellnhuber, director of the Potsdam Institute, suggested a new epoch might instead be called the "Deglacial".

Some past studies have suggested that global warming can delay ice ages, but the current study is more specific.

It indicates the start of past ice ages coincided with low levels of solar energy reaching the Earth in northern summers, like in current times. But an ice age had not begun because of relatively high, apparently natural, levels of carbon dioxide in the atmosphere since before the Industrial Revolution.

Ice age cycles caused by sun plus carbon dioxide
Ice age cycles are caused by regular cycles in the Earth's orbit, amplified by factors such as changes in ice coverage and carbon dioxide, the University of Reading's Professor Richard Allen explained.

"Earth's orbit around the sun is oval in shape but this becomes more circular every 100,000 years and more particularly so every 400,000 year," he said.

Professor Allen said the world was currently in a mild interlude coinciding with a near-circular orbit like one 400,000 years ago when the mild interglacial lasted longer than usual.

"We know that our current warm period will last many tens of thousands of years even without elevated concentrations of greenhouse gases associated with human activity," he said.

But the delay in the timing of an ice age is of less concern than the immediate impact of climate change, Professor Allen said.

"The many tens of thousands of years after which the next ice age may commence is very long compared to the appearance of modern human societies and is not worth worrying about compared to immediate concerns about damaging human-caused climate change expected over the coming decades if no action is takes to mitigate this likelihood," he said.

ABC/Reuters

Gaia and our lack of knowledge...

A very brilliant and talented Doctor once said to me about Global Warming.

"There are so many factors, so many Earth/Nature systems that have not been awakened in this, that prediction of what will happen is too variable."

He was not dissing Global Warming but explaining the uncertainty of what will actually happen, will Gaia react, and how?"

This story reminded me of his prediction.

Giant melting icebergs could be slowing climate change by absorbing carbon: researchers.

 By Bridget Brennan

Scientists have made the surprising discovery that giant melting icebergs could actually be slowing global warming.

 

Satellite images show that as giant icebergs melt, they leave behind trails of nutrients.


The nutrients stimulate growth of marine life, which leads to million of tonnes of carbon being taken from the atmosphere.


It is a process known as 'ocean fertilisation'.


Professor Grant Bigg, an expert in oceanography from the University of Sheffield, was part of the research team that analysed satellite images of about 17 giant icebergs in the Southern Ocean.


"It was a big surprise," he said.


"When you look at the giant icebergs, the influence of these meltwater nutrients is actually four to 10 times as large as we would have expected from looking at the ordinary sized icebergs."


Rising sea levels still a 'major worry'


Giant icebergs are at least 18 kilometres long, and their nutrient-rich plume can reach for up to 1,000 kilometres.


The research team found that the giant icebergs absorbed around 10-40 million tonnes of carbon a year by generating floating environments.


That promotes the growth of algae and other tiny organisms which can extract carbon from the atmosphere.


"We estimated that somewhere between 5 and 10 per cent of all the carbon, which is exported from the surface waters of the Southern Ocean down to the deep ocean, ought to come from these iceberg plumes fertilising the water and the phytoplankton growing and dying as a result."


Professor Bigg said there was likely to be an increase in ocean fertilisation as more ice melted in Antarctica.


But while that might have an impact on greenhouse gas emissions, it will do nothing to slow sea level rise.


"That's one of the major worries," he said.


"The icebergs themselves when they're out in the open ocean probably have this relatively good effect. But the freshwater also will change the ocean currents … and that could have an impact on the way the Southern Ocean works."


Tuesday, January 12, 2016

Milky Way Grew From the Inside Out


This image shows the latest results as colored dots superimposed on an artist’s conception of the Milky Way. Red dots show stars that formed when the Milky Way was young and small, while blue shows stars that formed more recently, when the Milky Way was big and mature. The color scale shows how many billion years have passed since those stars formed.
G. Stinson (MPIA)






ANALYSIS: Usual Suspect: Is Distant Galaxy a Milky Way 'Baby'?

As expected, the analysis shows the galaxy’s central disk formed from the inside out, with red giant stars as old as about 13 billion years clustered toward the center and younger stars about 1 billion years old closer to the disk’s edge, astronomer Melissa Ness, with the Max Planck Institute for Astronomy in Heidelberg, Germany, told reporters at the American Astronomical Society meeting in Kissimmee, Florida.

“What we’re able to do … is understand how our galaxy has formed in detail, looking at the dispersion of ages, the gradient of the ages, how the ages change as a function of both the height from the (disk’s) plane and the radius," Ness said. "It’s understanding the details of this inside-out formation that is now possible."

NEWS: Milky Way's Spiral Arm Shows Off Starry Cluster Bling

Unique to the survey is its age-dating technique, which is based on a star’s size. Ness and colleagues used high-quality Sloan survey spectra, which reveals a star’s chemistry, with optical data collected by NASA’s Kepler space telescope to develop a model that can be used to pinpoint a star’s age.
“This is somewhat revolutionary because ages have previously been considered very hard to get, particularly from stellar spectra. They’re important, but they’re difficult,” Ness said.

The key was a newly discovered relationship between a star’s age and its ratio of carbon-to-nitrogen, concentrations of which can be ferreted out by analyzing a star’s spectra.

NEWS: The Milky Way May Be 50 Percent Bigger Than Thought

Older red giant stars have the highest carbon-to-nitrogen ratios and younger stars the lowest, Ness said.

Working with a sample of 2,000 stars, scientists studied how the ratios change based on a star’s mass. They then incorporated the results into a computer model and used it to calculate masses and ages of all 70,000 red giant stars observed in Sloan’s APOGEE (Apache Point Observatory Galaxy Evolution Experiment) survey.

“We hope there will be many follow-up studies,” Ness told Discovery News. “We’ve only just determined the age catalog ourselves.”

Monday, December 28, 2015

Deep-sea fish found to be warm-blooded


The opah, Lampris guttatus.(NOAA Fisheries, South West Fisheries Science Centre: Ralph Pace.)

Dani Cooper
ABC


Calling someone a cold fish may not hold any more after scientists today revealed a deep-sea fish that is warm-blooded.

While it was previously known that the opah (Lampris guttatus) could heat its eyes and brain, a paper published today in Science shows it can also heat its entire body. This makes the opah the only known fish species to be whole-body endothermic, or warm-blooded.

Dr Nick Wegner, who co-authored the study, says this trait gives the opah distinct advantages as a deep-sea predator.

"It will increase its performance in cold environments - it can swim faster, has faster reaction times and better visual resolution than a lot of its prey," says Wegner, a fisheries research biologist at the National Marine Fisheries Service in California.

The opah Lampris guttatus has a global range that includes the southern waters of Australia and swims at depths between 10 and 450 metres.

It has a disc-like shape with large side or pectoral fins that can extend out by up to 25 centimetres and the fish can grow up to two metres and weigh 30 kilograms.

Wegner says the discovery was an "opportunistic find" after his friend and co-author Owyn Snodgrass sent him a sample of opah gills.

He recognised the presence of blood vessels that "weren't supposed to be there" and describes the unique configuration he noted as a "counter-current heat exchange".

Wegner says the fish initially produces heat through the flapping of its large pectoral fins, which warms up the body core.

As the warm blood leaves the core and travels toward the surface of the gills, it transfers its heat to the cold blood that is travelling back from the gills where it has absorbed oxygen from the water.
Wegner likens the system to a car radiator and says the exchange stops the heat from nearing the gill surface where it would be cooled by the water flow through the gills.

Further fatty tissue surrounds the gills, heart and muscle tissue where the opah generates much of its internal heat, insulating them from the frigid water.

The researchers found the opah was able to maintain body warmth of about 5 degrees Celsius higher than the surrounding water temperature.

"The fish aren't warming up to the same degree as animals and birds," says Wegner. "If the opah was swimming in waters at 10 degrees Celsius than its body temperature would be about 15 degrees Celsius."

To record the body temperature of the fish the research team measured temperatures of fish that had been caught and also attached temperature tags to wild fish that could measure both the water temperature and body core temperature.

Interesting find
Museum of Victoria senior curator of Ichthyology Dr Martin Gomon says it is an interesting find and suggests it is likely the southern moonfish which is another species of Lampris would have the same feature.

Like the opah, Gomon says, the southern moonfish is known to be very active despite living in cold, deep waters.

"They are very, very similar externally so my guess is they would be very similar internally as well."

"Opah belongs to a group of fishes that are oceanic so they have had a longer evolutionary history to develop this system," Gomon says.

He says there are a number of different marine groups that have "gone down this evolutionary path" including some species of tuna and the Lamnidae family of sharks which includes the Great White.

But Gomon says these fish are only regionally endothermic - they can only warm parts of their bodies, such as muscles to enhance swimming performance, and the trait is temporary.

"The opah has a system where more of the body is kept warm and a high body temperature makes its entire physiological system more efficient," he says.

"It is a more efficient predator and has the ability to go into deeper water."

Wegner says he thinks the Lampris may be unique, but adds "if you asked me a few years ago if there was a fish that could warm its entire body I would have said no".

"The discovery just shows how little we know," he says.

Wednesday, November 11, 2015

Black holes: We explode six myths to prevent you from getting sucked in

Artist's concept of a supermassive black hole, billions of times the mass of our sun, surrounded by an accretion disk where matter flows into the black hole.

By Stuart Gary

Black holes are the stuff of science and sci-fi and the line between fact and fiction can often be blurred. So, here are some common black hole myths that you'll never be sucked into again.

Are black holes portals to other worlds or monsters gobbling up everything in sight? How much of what we see in movies is science fiction and how much is science fact?

"Most people know that a black hole is a very small volume of space with a lot of stuff in it, so that its gravity is so strong nothing can escape from it, not even if it's travelling at the speed of light," said Dr Amanda Bauer, astronomer at the Australian Astronomical Observatory.

But there's a lot more to know about black holes than that.

Myth 1: Our Sun will become a black hole when it dies

No, our Sun isn't massive enough to become a black hole. Instead in about 6 billion years' time, the Sun will expand to become a red giant star with a diameter stretching maybe as far as Earth's orbit.
The Sun will then puff off its outer gaseous envelope, leaving behind its white hot stellar core, and become a white dwarf.

If the Sun was a far more massive star then it would have a more violent death, exploding as a supernova and leaving behind a super-dense object called a neutron star.

"When a star maybe 10 times more massive than the Sun goes supernova, its core collapses beyond the neutron star phase to form an even denser object called a stellar mass black hole," Dr Bauer said.

Myth 2: Black holes aren't real because you can't see them

Black holes can't be seen because light can't escape from them, but that doesn't mean they can't be detected using other means. Astronomers can see the effects of black holes on the space around them.
"While we can't actually see them directly, mathematically we have known about black holes since Albert Einstein's time, since the early 1900s," Dr Bauer said.

With modern telescopes we can see how black holes affect the stars orbiting around them.
"We have something at the centre of our Milky Way galaxy called SgrA* that doesn't produce any light, and we can watch individual stars going around it, not in nice circular orbits, but in highly elliptical, elongated paths," Dr Bauer said.

We can watch maybe a dozen of these stars orbiting around SgrA*, Dr Bauer says, and use very basic physics equations to calculate the mass of any of these stars and the thing they're orbiting around in order to account for the motion of that star.

"And you find that there is something there that's over four million times the mass of our Sun but in a tiny area that produces absolutely no light. There's nothing else we think that it could be other than a black hole."

Myth 3: Black holes will suck up all the matter in the universe like a giant vacuum cleaner

Fortunately, this isn't likely to be true.

This is because you have to be very close to a black hole to feel the strength of its gravity, and gravity gets weaker the further away you get, Dr Bauer said.

"If the Sun could magically turn into a black hole (which as we already pointed out it can't), then all its stuff would get shoved down into a tiny little volume maybe a couple of kilometres across.

"Think about what would happen to Earth, the Sun would still have the same mass if it were a black hole instead of a star. Earth also still has the same mass and still be the same 150 million kilometres away from it, and gravitationally speaking the only things that matter are your mass and how far away you are."

This means gravitationally nothing changes, Earth has no idea that the Sun has suddenly changed into a black hole and so it just continues its orbit. And the same thing happens on the larger scale of the galaxy.

Mind you, things would be a lot darker on Earth.

"Remember at the centre of our galaxy we have SgrA*, we have this supermassive black hole that's there and our Sun just orbits around it with the rest of the galaxy," Dr Bauer said.

"The Sun doesn't care what's there creating that mass. There are also hundreds of billions of stars between us and that black hole, so gravitationally we don't care what it is. You have to be very close to the black hole to get sucked in."

Myth 4: Entering a black hole takes you through a wormhole to another place and time

Mathematically, this is possible. But there are several problems with this possibility, including spaghettification.

"You could potentially have a wormhole that ties you to another place in the universe and maybe you'll pop out of a white hole on the other side," Dr Bauer said.

But these are very delicate solutions. If anything happens to the black hole, if you disturb it by something falling into it, or if the black hole's spinning, then this solution falls apart.
"Mathematically it's possible but it's not very likely," Dr Bauer said.

And it's unlikely that we'll be able to ever find out.

"We are never going to be able to measure this scientifically because if we send something into a black hole we could not get a signal out to tell us what's happening," Dr Bauer said.

"The signal will travel at the speed of light, and that's not fast enough to escape the gravity of a black hole."

Also, any object falling into a black hole would experience huge amounts of gravitational force as it fell closer to the event horizon, the point beyond which light can no longer escape a black hole's gravity.

For example, a clock falling into a black hole would feel a far stronger gravitational pull on the side nearest the black hole than the part further away from the black hole, so the clock would slowly start to elongate and be pulled apart.

"We have a word for this. We call it spaghettification, as you get stripped down to your individual atoms as you get pulled into the black hole," Dr Bauer said.

If somehow the clock magically survived spaghettification and you were able to see it ticking, you would see the ticking appear to slow down as it fell towards the event horizon. This is because time slows down as you get closer to a massive body, like a black hole.

"But from the clock's perspective time is still ticking at the same rate it actually doesn't seem like anything happened," Dr Bauer said.

Myth 5: Supermassive black holes form when a massive star dies

There are supermassive black holes in the centres of most galaxies — but the way they form is more uncertain.

"One possibility is that the very first generation of stars which were made out of almost pure hydrogen and helium from the Big Bang 13.8 billion years ago were bigger than today's stars, maybe hundreds of times the mass of our Sun," Dr Bauer said.

These stars were so hot and huge that they burned through their nuclear fuel supplies in just a few million years before going supernova and forming primordial black holes.

Formed in regions where lots of gas was collecting and forming the first galaxies, these primordial black holes probably sank to the centre and grew over time, eventually forming supermassive black holes, Dr Bauer said.

"Another possibility is nearby black holes merged to create progressively bigger black holes, so you get this merging of black holes, which over time form supermassive black holes.

"The big challenge is that we haven't seen any intermediate-sized black holes, we haven't seen anything between stellar mass and supermassive black holes, so we're not sure yet whether this is the formation process, but it's a good theory."

Myth 6: The universe will be consumed by black holes

Feel free to breathe a sigh of relief because this is not likely to happen.


"The universe does go through various transitions in its future but this is over trillions of trillions of years in the future," Dr Bauer said.

"Eventually stars won't be able to form any more, but black holes are very long-lived and will continue to absorb material becoming more massive, but they don't last forever."

Black holes slowly evaporate through a process called Hawking radiation, but this will take trillions of years.

"So in this scenario of the fate of the universe, all the stars will slowly burn out, no new stars will form, and you'll be left with a black hole epoch, dominated by these supermassive black holes which will slowly evaporate," Dr Bauer said.

"In the end what we're left with is a big, huge, vast space with lots of tiny little elementary particles floating around but nothing really to bump into, and with no more stars it's very cold and dark."