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THE BEST SCIENTIFIC PUBLICATIONS - The deadly threat of a solar superstorm


MY YAHOO - The deadly threat of a solar superstorm




NASA/SDO/AIA, NASA/STEREO, SOHO (ESA & NASA)


A powerful electromagnetic pulse could knock out the power grid and the internet. How serious is the threat? Here's everything you need to know:
What is an electromagnetic pulse?
It's a powerful burst of electromagnetic energy with enormous destructive potential. An EMP can arise from natural phenomena, such as lightning strikes, or from human activity, such as a nuclear explosion. What makes EMPs ominous is their potential to wreak havoc with a world that now is utterly dependent on electrical technology. If strong enough, the storm of electrons and other charged particles from an EMP could disrupt the Earth's magnetic field, disable satellites and the internet, ground all commercial aviation, silence telecommunications, and fry much of the electrical grid — catapulting our society back to the 19th century for months or years. Peter Pry, executive director of the federal EMP Task Force on National and Homeland Security, told Congress this year that a major EMP could cause widespread "starvation, disease, and societal collapse" that could lead to the deaths of tens of millions of people. The Obama administration recently released a multiagency battle plan to study and defend against what many scientists consider the most likely source of EMPs: solar storms, which Bill Murtagh of the White House Office of Science and Technology Policy calls "a real and present danger."
What are solar storms?
Huge eruptions of magnetically charged plasma from the sun's roiling interior, which explode outward into space. Also known as coronal mass ejections, moderate solar storms occur fairly regularly and harmlessly, sometimes causing spectacular auroras that illuminate the sky over the North and South poles. But even typically benign solar storms generate energy that "dwarfs our planet's entire nuclear arsenal," says astronomer Phil Plait. And what of a massive event? "People sometimes ask me if anything in astronomy actually worries me," says Plait. "Something like this is near the top of the list." With good reason: Experts say there is a 12 percent chance that a monster solar storm will strike Earth within the next decade. A National Academy of Sciences study concluded that a storm of that scope could cause $2 trillion of damage in the first year of recovery alone, 20 times the cost of Hurricane Katrina.
Has such a storm ever hit Earth?
Yes, several times. The last one, dubbed the Carrington Event (see box), hit in 1859. A far smaller solar flare in 1989 sent a pulse of radiation that left 6 million people in Quebec without power for up to nine hours. Much more alarming was a solar superstorm that barely missed Earth in July 2012. Astronomers say the sun spewed out a huge magnetic cloud that tracked straight through our planet's orbit. Fortunately for civilization, Earth was elsewhere in its path around the sun at the time, but had the storm roared through nine days earlier, a worst-case scenario would have occurred. Satellites involved in crucial global communications (including GPS) would have been ruined, large electrical transformers would have been destroyed, and ATMs would have stopped functioning. The internet would have been disabled on a massive scale. Most people wouldn't even have been able to flush toilets, which rely on electric pumps. Three years later, "we would still be picking up the pieces," says astronomer Daniel Baker.
What about man-made EMPs?
It's possible that terrorists or rogue states could detonate a nuclear weapon in the atmosphere and generate a paralyzing EMP. In 2001, Congress established an EMP Commission, which recommended a combination of intelligence gathering, disaster-relief planning, and research to brace for an attack. Former CIA director James Woolsey last year told the House Armed Services Committee that "two-thirds of the U.S. population would likely perish" over a period of years. But many analysts doubt that an EMP attack on the U.S. by, say, North Korea is likely, since it would be taken as an act of war and invite a devastating nuclear response. If a country or terrorist group were going to attack the U.S. with nuclear weapons, most analysts think, they would choose to cause more direct and immediate damage by targeting Washington, New York, and other population centers.
What protective measures are possible?
The Obama administration has taken steps to replace some aging satellites that monitor space weather and extra-high-voltage transformers that are vulnerable to solar storms. Its new plan also calls for scientists to establish benchmarks for weather events in space, incorporating something like the Richter scale. "We have to understand how big these storms can be, to know what to protect against," says Murtagh. The strategy also includes assessing the vulnerability of the power grid, increasing international cooperation, and improving solar-flare forecast technology — a crucial step. But Pry, chairman of the EMP commission, says neither the White House nor Congress is taking the threat seriously enough or acting with appropriate urgency. It would cost about $2 billion — the amount of foreign aid we give to Pakistan — to harden the nation's power grid to minimize the damage from either a nuclear EMP or a solar flare, he says. "If we suspended that [aid] for one year and put it toward hardening the electrical grid," Pry says, "we could protect the American people from this threat."
The great solar storm of 1859
On Sept. 1, 1859, British astronomer Richard Carrington noticed a brilliant solar flare over England. In the days that followed, a succession of coronal mass ejections struck Earth head-on. Auroras illuminated night skies from Africa to Hawaii. "The light appeared to cover the whole firmament," one Baltimore newspaper reported. "[It] had an indescribable softness and delicacy." The effects were more than aesthetic. EMPs from the storm caused telegraph systems — the "Victorian internet" — to fail throughout North America and Europe; in some cases, lines sparked and offices caught fire. Otherwise, the damage was minimal; after all, that was long before humanity became utterly reliant on electronics — as it was when history repeated itself 153 years later. "The July 2012 storm was in all respects at least as strong as the Carrington Event," says astronomer Daniel Baker. "The only difference is, it missed."





MY YAHOO ( THE WEEK) -The enormous astronomical discovery that proved Einstein right, explained





February 18, 2016
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Last week, American physicists made a really, 
really big announcement: the discovery 
of gravitational waves. 
This find — a billion years in the making — 
confirms what Albert Einstein theorized a century 
ago in his general theory of relativity. 
Stephen Hawking said the discovery could
"revolutionize astronomy", and the news media 
trumpeted the discovery as potentially shaping 
our very understanding of the universe we live in.
But what exactly are these gravitational waves, 
and why are they such a big deal? In this podcast, 
we'll explain what gravitational waves are, how 
physicists were able to detect them, and why this 
discovery is so monumental. We'll even hear what gravitational waves sound like. Click on the 
podcast above, 
and join this celebration of science.


MY YAHOO - Gravitational Waves: Did Merging Black Holes Form from Single Star?







Could a single, dying star give birth to not one, but
two black holes? Stranger things have happened in
space.About 1.3 billion years ago, two black holes
merged into one, creating ripples in the fabric of
space-time known as gravitational waves. Those
ripples were recorded by detectors on Earth,
scientists announced on Feb. 11 — the first time 
gravitational waves had ever been directly detected, 
marking a significant achievement for physics and 
astronomy. Scientists have long held different ideas
about how black holes of this size get close enough 
to collide, but another proposal has just entered the ring:
that the black holes were created, shortly before their 
collision, from one, massive star as it was collapsing in
on itself. [No Escape: Dive Into a Black Hole (Infographic)]
This new hypothesis posits that the merger of these two 
black holes would produce light — including, possibly, 
a burst of gamma-rays, the highest-energy form of light.
That possibility is now under investigation by scientists, 
who are following up on the historic gravitational-
wave detection in a variety of ways.
Making two black holes from one star
"It's the cosmic equivalent of a pregnant woman carrying 
twins inside her belly," astrophysicist Avi Loeb, of 
the Harvard-Smithsonian Center for Astrophysics (CfA), said
in a statement, talking about his proposal that two 
black holes can form out of the same dying star.
The internal furnace of a massive star is powered by
the fusion of hydrogen into helium, but even stars run
out of fuel eventually. When a massive star (tens of
times larger than the sun) reaches the end of its
resources, it will explode as a supernova. With no
engine pushing the star's remaining material outward,
that matter will collapse down into a superdense,
leftover nugget. Sometimes, this collapse forms a 
black hole.But Loeb's new paper, which has been accepted
for publication in The Astrophysical Journal Letters,
shows that if the star is spinning extremely rapidly as
it collapses, the infalling material could split into 
a dumbbell configuration, and create two black holes.
It was Albert Einstein who first predicted that space
and time together make up a single cosmic fabric, and
that two black holes spinning around each other and 
merging would not only bend that fabric, but also send 
ripples through it.For decades, scientists have tried 
to detect these ripples directly, but the first team to
succeed was the Laser Interferometer Gravitational
Wave Observatory (LIGO) group, which used big
detectors in Hanford, Washington, and Livingston, 
Louisiana. Both detectors spotted the gravitational-
wave signal in September 2015, and the LIGO team
vetted the find for five months before announcing it
to the world.Loeb told Space.com in an email that 
researchers have investigated the dumbbell process
 in other contexts. That includes star formation, in which
a cloud of dust collapsing down to form a star could
 be spinning fast enough to split into two new stars.
"I had this idea in my head for about a decade," Loeb
said. But he said it was the Feb. 11 announcement of
the black hole collision that inspired him to put the 
hypothesis down on paper — that, and the possible 
detection of a bright burst of light from the same
region of the sky.A flash of light in the sky
Living up to their name, black holes don't radiate any
kind of light. However, many black holes can be 
"seen" because they are surrounded by material 
that is accelerated and heated by the black hole's gravity,
causing the matter to emit light.But two black holes
with masses a few tens of times that of the sun are
 not expected to be surrounded by material as they 
circle around one another and eventually collide.
Loeb's hypothesis offers a possible case in which the
two black holes could release a gamma-ray burst.
Gamma rays are the highest-energy form of light, and 
gamma-ray bursts are caused by very energetic events. 
The bursts can occur when a single star collapses 
into a black hole, Loeb said."In order to produce a 
gamma-ray burst, one needs to feed a black hole at
 an enormous
rate of somewhere between the mass of a planet and
the mass of the sun every second," Loeb told Space.com.
As a star begins to collapse into a black hole, the "infall
of matter … can lead to the production of a jet that drills
a hole through the envelope of a star and produces a 
gamma-ray flash for an observer that happens to lie in
its direction."Assuming the dying star could split into
two black holes, it follows that such a star might also 
produce a gamma-ray burst. Thankfully, a gamma-ray
 telescope was looking at the sky at the same time that
LIGO detected the black hole collision.Scientists with 
NASA's Fermi Gamma-ray Space Telescope announced
that the space-based observatory may have seen a
flash of gamma-ray light "in the same region of the sky"
as the LIGO detection, only 0.4 seconds after LIGO
detected its signal. Fermi scientists are still working
to confirm whether the signal was real, or if it was a
false alarm in the detector. [Record-Breaking Gamma-
ray Burst Capturedby Fermi (Video)]
"I think that the Fermi/GBM detection is unlikely to be
real (there are a variety of objections floating around
the community)," Edo Berger, a professor of astronomy
at Harvard University, told Space.com in an email.
"This does not mean that Avi's paper is wrong (since it
is just a theoretical model)," Berger added. "But right
now there are no specific tests of the proposed model. 
Whether the process he's suggesting actually happens
in nature remains to be seen with future observations. 
Luckily, LIGO and Virgo will find many more of these
binary black hole mergers when they turn on for the
next science run."Virgo is a facility in Italy that will 
soon join the LIGO detectors in the search for 
gravitational waves.And even if the Fermi detection 
was real, there's still a question of whether or not the
 gamma-ray burst
came from the black hole merger. LIGO can currently
only narrow down the location of the merger to an area
on the sky measuring 600 square degrees. (The full 
moon covers 0.2 square degrees of the sky).
"I am rather doubtful that the Fermi report is indeed 
associated with the [gravitational wave] source; it is
of relatively small statistical significance, and the sky
patch associated with the [gravitational wave] source
is huge," Vicky Kalogera, a black hole scientist at 
Northwestern University in Illinois and a member of
the LIGO team, told Space.com in an email.
Kalogera also wondered why only gamma-rays would
be detected if the black hole merger created light, she
said. Other instruments searching in different
wavelengths did not see a signal at the same time
as the gravitational wave detection.
There is still the possibility that the Fermi signal was
real, and that it did indeed come from the black hole 
collision. But even if this particular black hole event
wasn't an example of Loeb's dumbbell hypothesis, he
said there could be other events that LIGO detects in
the future that involve twin black holes, born from
the same stellar mother.

Follow Calla Cofield @callacofield. Follow us
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Original article on Space.com.