Stephen Hawking

[Pete]

UNC astrophysicist works with Stephen Hawking

Blake Hoarty | Published 5 hours ago | 17th of September, 2015

Laura Mersini-Houghton, a professor of physics and astronomy, collaborated with Stephen Hawking at a recent conference in
Sweden. Mersini-Houghton has been working in the Department of Physics and Astronomy at UNC since 2004. Her research
is focused around the origins of the universe, dark energy and the quantum physics of the black holes. Mersini-Houghton’s
work has become so well renowned, she has worked with physics extraordinaires like Hawking. “I have known him for
many years,” she said. “He’s an amazing person. Despite his difficulty with his condition, he is the hardest working person
I have ever come across and he still has this child-like curiosity and desire to understand some of the most difficult problems.”

Mersini-Houghton organized a physics conference in Sweden in August, attended by Hawking, Chancellor Carol Folt and
a constellation of other prominent scientists. “We gathered hoping to make progress with a very difficult problem known
as the information loss paradox,” she said. Mersini-Houghton said Einstein’s theory of gravity predicts the creation of
black holes, but a law of quantum theory is at odds with his theory. This problem is called the information loss paradox.
“I specifically collected all the founding fathers of the field, thinking that since these people created the field 40 years ago,
they know all the subtleties around it,” Mersini-Houghton said. “And if we get together (in) one room (for) a week and
do some concentrated thinking, then we are bound to come up not with the final solution, but the direction on how
to solve this problem.”

Beverly Loftin, manager of the physics department, said she isn’t personally acquainted with Mersini-Houghton,
but is well aware of her research. “She is highly publicized. She is very involved in the research community,”
Loftin said. Christopher Clemens, chairman of the physics department, said Mersini-Houghton’s classes tend to be
the most mathematically difficult classes in the department — but the classes are also popular. “They are taken by
a large fraction of the graduate students that are here,” he said. “They are not populated like Introduction to Astronomy,
but you have to consider the size of the audience, and for the size of the audience, yes, they are popular.” Clemens said
Mersini-Houghton excels at expressing complicated topics clearly. “She communicates a very good understanding of
what the questions are and what the resolutions might be,” Clemens said. “She’s a very good presenter, and that is why
she has been on shows with Morgan Freeman and other PBS shows.” “She is a great spokeswoman for the field of cosmology.”

Thanks for reading.


Quoted from The Daily Tar Heel

[Pete]

Pylogenetic 'Tree of life' for 2.3 million species released

Tree of lifeReligion and mythologyBiology



'Tree of life' for 2.3 million species released
September 19, 2015



A first draft of the "tree of life" for the roughly 2.3 million named species of animals, plants, fungi and microbes—
from platypuses to puffballs—has been released.

A collaborative effort among eleven institutions, the tree depicts the relationships among living things as they
diverged from one another over time, tracing back to the beginning of life on Earth more than 3.5 billion years ago.

Tens of thousands of smaller trees have been published over the years for select branches of the tree of life—
some containing upwards of 100,000 species—but this is the first time those results have been combined into
a single tree that encompasses all of life. The end result is a digital resource that available free online for
anyone to use or edit, much like a "Wikipedia" for evolutionary trees.

"This is the first real attempt to connect the dots and put it all together," said principal investigator
Karen Cranston of Duke University. "Think of it as Version 1.0."

The current version of the tree—along with the underlying data and source code—is available to browse and download
at https://tree.opentreeoflife.org.

It is also described in an article appearing Sept. 18 in the Proceedings of the National Academy of Sciences.

Evolutionary trees, branching diagrams that often look like a cross between a candelabra and a subway map,
aren't just for figuring out whether aardvarks are more closely related to moles or manatees, or pinpointing
a slime mold's closest cousins. Understanding how the millions of species on Earth are related to one another
helps scientists discover new drugs, increase crop and livestock yields, and trace the origins and spread of
infectious diseases such as HIV, Ebola and influenza.

Rather than build the tree of life from scratch, the researchers pieced it together by compiling thousands of
smaller chunks that had already been published online and merging them together into a gigantic "supertree"
that encompasses all named species.

The initial draft is based on nearly 500 smaller trees from previously published studies.

To map trees from different sources to the branches and twigs of a single supertree, one of the biggest challenges
was simply accounting for the name changes, alternate names, common misspellings and abbreviations for each species.
The eastern red bat, for example, is often listed under two scientific names, Lasiurus borealis and Nycteris borealis.
Spiny anteaters once shared their scientific name with a group of moray eels.

"Although a massive undertaking in its own right, this draft tree of life represents only a first step," the researchers wrote.

For one, only a tiny fraction of published trees are digitally available.

A survey of more than 7,500 phylogenetic studies published between 2000 and 2012 in more than 100 journals
found that only one out of six studies had deposited their data in a digital, downloadable format that the researchers could use.

The vast majority of evolutionary trees are published as PDFs and other image files that are impossible to enter
into a database or merge with other trees.

"There's a pretty big gap between the sum of what scientists know about how living things are related, and
what's actually available digitally," Cranston said.

As a result, the relationships depicted in some parts of the tree, such as the branches representing the pea and
sunflower families, don't always agree with expert opinion.

Other parts of the tree, particularly insects and microbes, remain elusive.

That's because even the most popular online archive of raw genetic sequences—from which many evolutionary
trees are built—contains DNA data for less than five percent of the tens of millions species estimated to exist on Earth.

"As important as showing what we do know about relationships, this first tree of life is also important in
revealing what we don't know," said co-author Douglas Soltis of the University of Florida.

To help fill in the gaps, the team is also developing software that will enable researchers to log on and update and
revise the tree as new data come in for the millions of species still being named or discovered.

"It's by no means finished," Cranston said. "It's critically important to share data for already-published and
newly-published work if we want to improve the tree."

"Twenty five years ago people said this goal of huge trees was impossible," Soltis said.
"The Open Tree of Life is an important starting point that other investigators can now refine and improve for decades to come."

More information: "Synthesis of Phylogeny and Taxonomy Into a Comprehensive Tree of Life," C. Hinchliff et al.
Proceedings of the National Academy of Sciences Sept. 18, 2015. DOI: 10. 1073/pnas.1423041112.


Read more at: http://phys.org/news/2015-09-tree-li...ecies.html#jCp

Scientists create the first digital 'tree of life'

Researchers from 11 organizations have aggregated tens of thousands of evolutionary trees into a comprehensive map of all known life, open to all and free to use.

By Lonnie Shekhtman, Staff September 20, 2015

Scientists from 11 organizations have digitized a “tree of life,” a genetic map of 2.3 million named species of animals, plants, fungi
and microbes that all branched off over time from a common ancestor.

In a September 18 paper in the Proceedings of the National Academy of Sciences, researchers wrote that
"The Open Tree Taxonomy" is likely the first to aggregate tens of thousands of already published smaller trees into
a comprehensive map of all life. The digital tree is free for anyone to use and update on opentreeoflife.org.

In what looks like a kaleidoscope of rainbow-colored high-rises, the latest digital diagram depicts the evolution
of living things since the beginning of life on Earth more than 3.5 billion years ago.

And because scientists believe that all life on Earth shares a common genetic ancestor, understanding
how millions of species are related helps them improve agricultural methods and better understand viruses, the research team says.

"There's a pretty big gap between the sum of what scientists know about how living things are related,
and what's actually available digitally," lead scientist Karen Cranston, a computational phylogeneticist at
Duke University, said in an announcement of the project.

Only one out of six studies published in about 100 journals in the decade leading up to 2012 have digital
data that others can use, the researchers reported. Most of the 7,500 phylogenetic – or evolutionary branching –
trees are in PDF or image formats that cannot be readily downloaded and merged with other data.

For this reason, the first version of the tree of life is based only on 484 trees that map the genetic evolution of species,
from worm to beetle to human to giraffe.

"This is the first real attempt to connect the dots and put it all together," said Dr. Cranston. "Think of it as version 1.0."

The next step, the research team wrote in its paper, is for biologists to contribute more trees and to revise
existing information, in the same way that people contribute to Wikipedia.

"Twenty five years ago people said this goal of huge trees was impossible," said Douglas Soltis,
a genetics professor at the University of Florida. "The open tree of life is an important starting point that other
investigators can now refine and improve for decades to come."

Building the computer code and compiling the data took three years, and involved collaborators from
Chicago's Field Museum of Natural History, the Web development firm Interrobang,
the University of Michigan, the University of Florida, Duke University, and George Washington University.

"Many participants on the project contributed hundreds of hours tracking down and cleaning up thousands of
trees from the literature, then selecting 484 of them that were used to generate the draft tree of life,"
said Cody Hinchliff, a scientist from the University of Idaho, in the announcement.

The team had to develop its own software and data algorithms to make it possible to combine such large numbers of trees.

“The goal of reconstructing the tree of life is one of the most daunting challenges in biology,” the research team wrote in its paper.

There are about 1.8 million named species, most of which we don’t know anything about, because
scientists haven’t yet collected enough data. Just 22 percent of known species have been genetically mapped.

Researchers draft the first comprehensive tree of life

by Jon Fingas

It's very poetic to talk about a tree of life, where every species can trace its roots, but actually illustrating this
tree is no mean feat when Earth has been home to at least 2.3 million known species. However, scientists have
finally given it a shot. They've published the first draft of a comprehensive tree of life that shows every major
evolutionary branch, ranging from the very first organisms to complex beings like humans. This isn't a complete tree,
of course (it's doubtful that we'll ever know all the species that ever existed), but it beats the patchwork from before.

The best part is that this tree isn't buried inside an academic paper or otherwise hidden to the public.
Its creators have posted the tree of life online (it's down as I write this, likely due to high traffic),
including both the pure data and the source code for tying it all together. If you need to trace the history of
a species any time soon, this may be your go-to resource.

[Pete]

Missed Supermoon/Bloodmoon ? > Here is the video

Here is a short You Tube video of the

Super Moon => Blood Moon

which occurred on Sunday, September 27, 2015 in case you missed it.



Note that this is unrelated / related to OP.

An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day for one year. But the trick to imaging an analemma of the Moon is to understand that on average the Moon returns to the same position in the sky about 51 minutes later each day. So, if you photograph the Moon 51 minutes later on successive days, over one lunation or lunar month it will trace out an analemma-like curve as the actual position of the Moon wanders compared to the average -- due to the Moon's tilted and elliptical orbit. For this excellent demonstration of the lunar analemma, astronomer Rich Richins chose the lunar month containing this year's northern hemisphere summer solstice. The southernmost Full Moon rises at the lower right above the Organ Mountains in southern New Mexico, USA, with the New Moon phase at the upper left. The multiple exposure image required some digital manipulation, particularly to include thin crescent phases in daytime skies.

[Pete]

Welcome to the dark side: Comet's hidden face emerges

Welcome to the dark side: Comet's hidden face emerges

By Sarah Lewin
Published October 06, 2015

Space dot com

For a long five and a half years, Comet 67P/Churyumov–Gerasimenko's southern side has been shrouded by darkness. Now, it's coming into the light, and new microwave images, taken before the big reveal, suggest that the comet's "dark side" may have a very unusual composition.



The European Space Agency's Rosetta probe has been orbiting and investigating Comet 67P since August 2014 with the help of its Philae comet lander. The probe pulled together the most detailed portrait ever of a comet, but had one particular blind spot: the comet's southern side, which is dark for over 5.5 years before a brief, searing-hot year in the light during the comet's closest approach to the sun. Until that time, only Rosetta's microwave instrument, MIRO, could make any sense of the blackness.

"We observed the 'dark side' of the comet with MIRO on many occasions after Rosetta's arrival at 67P/C-G, and these unique data are telling us something very intriguing about the material just below its surface," Mathieu Choukroun, lead author of the new study and researcher at NASA's Jet Propulsion Laboratory in California, said in a statement.

The group investigated data from that region from August to October 2014, and found evidence suggesting a large amount of ice had built up. MIRO's measurements indicated that material very near the surface is transparent, probably consisting of water ice or carbon-dioxide ice. This is very different from the dusty surface elsewhere on the comet.

Potentially, the researchers said in the statement, the water and gases were released when the comet's south pole last saw sunlight, while the comet was closest to the sun. That material then condensed and coated the surface when the area plunged back into darkness. But there's no way to know exactly how that occurred until that region's shape is understood better, the researchers said.

"We plan to revisit the MIRO data using an updated version of the shape model, to verify these early results and refine the interpretation of the measurements," Choukroun said.

Luckily, there isn't long to wait: Data collected from May 2015 to early 2016 will reveal the full dark side at last. Once all Rosetta's instruments have been focused on that part of the comet, the whole story should be clearer.

Matt Taylor, Rosetta's project scientist, said in the statement that the probe has flown over the southern region several times since the area's summer began, especially around the time the comet was closest to the sun, Aug. 13 — which is when the comet shows the most activity.

"First, we observed these dark regions with MIRO, the only instrument able to do so at the time, and we tried to interpret these unique data," Taylor said. "Now, as these regions became warmer and brighter around perihelion, we can observe them with other instruments, too."

"We hope that by combining data from all these instruments, we will be able to confirm whether or not the [comet's] south pole had a different composition and whether or not it is changing seasonally," added Mark Hofstadter, MIRO's principal investigator.

The new research was recently accepted for publication in the journal Astronomy and Astrophysics.

Why 'Rosetta'?Rosetta Stone

[Pete]

Stephen Hawking returns to former college

Stephen Hawking returns to former college, as Cambridge launches fundraising appeal

By Cambridge News University of Cambridge

University of Oxford

[Pete]

[Pete]

The hunt for Albert Einstein's missing waves

By Rebecca Morelle Science Correspondent, BBC News

In the Italian countryside, not far from Pisa, a vast experiment is about to be switched on. If it's a success, one of Albert Einstein's greatest predictions will have been directly observed for the first time. If it fails, laws of physics might have to be reconsidered. The experiment is called Advanced Virgo, and it will be hunting for the most elusive of astrophysical phenomena. "Maybe we have the opportunity for the first time to detect gravitational waves on the Earth," explains Dr Franco Frasconi, from the University Pisa, who is part of Virgo's international team. "This would be a clear demonstration that what [Einstein] said 100 years ago is absolutely correct."



On 25 November 1915, Albert Einstein presented the final version of his field equations to the Prussian Academy of Sciences. They underpinned his Theory of General Relativity - a pillar of modern physics that has transformed our understanding of space, time and gravity.

From it, we have been able to understand so much - from the expansion of the Universe, to the motion of the planets and the existence of black holes.
But he also proposed the presence of gravitational waves, essentially ripples of energy that distort the fabric of space-time.
Think of them as a bit like the waves that radiate out when you throw a stone into a pond. Any object with mass should generate them when it's on the move. Even us. But the greater the mass, and more dramatic the motion, the larger the waves.

And Einstein predicted that the Universe was awash with them.

• The waves are an inevitable consequence of the Theory of General Relativity
• Their existence has been inferred by science but not yet directly detected
• They are ripples in the fabric of space and time produced by violent events
• Accelerating masses will produce waves that propagate at the speed of light
• Detectable sources ought to include merging black holes and exploding stars
• Virgo bounces laser beams down tunnels; the waves should disturb the light
• Detecting the waves opens up the Universe to completely new investigations

But while astronomers have indirect evidence for their existence, getting a glimpse of these cosmic curiosities has not yet been possible.
Physicist Dr Toby Wiseman, from Imperial College London, UK, explained: "I'm not surprised we haven't directly seen gravity waves yet.
"Gravity is actually the most feeble of the forces and even dramatic astrophysical sources only emit weak gravity waves."
Now, in Italy, scientists hope to find them. But it won't be easy. The first incarnation of the Virgo experiment ran from 2007 - and didn't see anything. Neither did its US-counterpart, the Laser Interferometer Gravitational-Wave Observatory (Ligo). But both machines - called interferometers - are now undergoing expensive upgrades, and the teams hope major improvements in sensitivity could hold the key to success.



Dr Frasconi explained: "The technology available to detect gravitational waves is available just today. "During the last 10 years, we have developed very sophisticated technology to construct this kind of interferometer." The scientists are attempting to spot the tiny distortions created when gravitational waves pass through the Earth. They are hoping to see those emanating from violent cosmic events, such as exploding stars or colliding black holes.

The Virgo detector is formed of two identical 3km-tunnels, in a giant L-shape formation. A laser beam is generated, then split into two - with one half being fired along one tunnel, and the other half surging through the second tunnel. Mirrors at either end send the lasers travelling back and forth many times, before they are recombined. This might seem elaborate, but it takes advantage of a handy property of lasers - the fact that they are intense beams of light, and light is a wave. Imagine if two waves in the ocean crashed into each other, while one was at a peak, and one was at a trough - the waves would cancel each other out. The same is true inside the experiment. And if the waves have travelled exactly the same distance along the two tunnels, then they cancel each other out, producing no signal.

However, if a gravitational wave has travelled through the tunnel, it will very subtly distort its surroundings, changing the length of the tunnels by a minute amount - just a fraction of the width of an atom. And the way the waves move through space and time means that one tunnel would be stretched and one squeezed, which would result in one laser travelling a slightly longer distance while the other would have a shorter journey. As a result, the split beams will re-combine in a different way: the waves of light will interfere with each other, rather than cancelling out - and scientists will detect a signal.
Great efforts have been made to insulate the experiments from the general rumbles that pervade the Earth, from traffic noise to earthquakes.
"You are trying to a build a machine to avoid potential noise," says Dr Frasconi. "This machine is anchored directly on the ground floor - and the ground floor typically vibrates. The most important challenge is to isolate the mirrors. "For Virgo, this is the most important challenge. From the beginning we have spent a lot of time to develop the multistage pendulum to isolate the mirrors from seismic noise."



But even then, a signal in Italy will not be enough. If a gravitational wave is spotted there, the upgraded Advanced Ligo in America, which has the same set-up as Virgo, but is made up of two detectors with 4km-long arms, should also see the signal. So potentially should another, smaller experiment in Germany. Advanced Ligo is now up and running, and scientists hope Virgo will be ready to be switched on by the end of the year. The collaborating teams are so confident of success that they're forecasting that 1 January 2017 will be the day the breakthrough is made. This prediction may be a little tongue in cheek, but Dr Frasconi, who has been working in this field for two decades, is confident that the end of the search is near.
"Right now, it is extremely important to detect for the first time on Earth gravitational waves. Otherwise we do not have the right information, the right knowledge of the rest of the Universe."

• A laser is fed into the machine and its light is split along two paths
• The separate beams bounce back and forth between damped mirrors
• Eventually, the two light paths are recombined and sent to a detector
• Gravitational waves passing through the lab should disturb the set-up
• Theory holds they should very subtly stretch and squeeze its space
• This ought to show itself as a change in the lengths of the light arms
• The photodetector hopes to capture this signal in the recombined beam

If the waves do not show up now it will mean that the experiments may need to be redesigned. And in the most extreme case, perhaps physicists might have to rethink the way that the Universe works. But a direct glimpse will open a new window on the cosmos - one that wouldn't have been possible without Einstein. Dr Wiseman, from Imperial College London, explains: "Seeing gravity waves would be fantastic confirmation of our understanding of general relativity. "We have good reason to think they exist, but we can't be sure we have understood general relativity correctly until we see these ripples in space and time directly. "Observing them would allow us new ways to test general relativity, but also give us an entirely new tool for observing some of the most fascinating objects in our Universe."

Developing general relativity

[jon00]

World renowned physicist Stephen Hawking has died at the age of 76

World renowned physicist Stephen Hawking has died at the age of 76.

He died peacefully at his home in Cambridge in the early hours of Wednesday, his family said.

The Briton was known for his work with black holes and relativity, and wrote several popular science books including A Brief History of Time.

At the age of 22 Prof Hawking was given only a few years to live after being diagnosed with a rare form of motor neurone disease.

The illness left him in a wheelchair and largely unable to speak except through a voice synthesiser.

In a statement his children, Lucy, Robert and Tim, said: "We are deeply saddened that our beloved father passed away today.

"He was a great scientist and an extraordinary man whose work and legacy will live on for many years."

They praised his "courage and persistence" and said his "brilliance and humour" inspired people across the world.

"He once said, 'It would not be much of a universe if it wasn't home to the people you love.' We will miss him forever."

A book of condolence is due to be opened at Conville and Caius College in Cambridge, where Prof Hawking was a fellow.

Prof Hawking was the first to set out a theory of cosmology as a union of relativity and quantum mechanics.

He also discovered that black holes leak energy and fade to nothing - a phenomenon that would later become known as Hawking radiation.

[Pete]

Rest in Peace Stephen Hawking