Earth Weather / Space Weather

Extraterrestrial Hurricanes: Other Planets Have Huge Storms, Too

By: Susie77, 9:31 PM GMT on August 29, 2011


by Mike Wall, SPACE.com Senior Writer
Date: 26 August 2011 Time: 03:37 PM ET

By Earth standards, Hurricane Irene is a monster storm. But it's just a
baby compared to the massive cyclones of Jupiter and Saturn.









Our planet is not the only one in the solar system that boasts huge, hurricane-like storms.
The gas giants Jupiter and Saturn, for example, churn out spinning
squalls that can be bigger than the entire Earth. While these storms
aren't fed by warm ocean water the way terrestrial hurricanes are,
they're similar in a lot of ways, scientists say.

"There certainly are storms that have thunder and lightning and rain
that are bigger than terrestrial hurricanes," said atmospheric scientist
Andrew Ingersoll of the California Institute of Technology, a
researcher with NASA's Cassini mission to Saturn. "And more violent —
the winds on those planets are stronger, too." [Photos: Most Powerful Storms of the Solar System]







Hurricane Irene is a large and dangerous storm.
Hurricane
Irene is a large and dangerous storm. In this image, taken by the
Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra
satellite on August 25, 2011, bands of thunderstorms spiral tightly
around a dense center, forming the circular shape of a well-developed
hurricane.
CREDIT: http://www.wnyc.org/blogs/wnyc-news-blog/2011/aug/ 26/latest-irene/
View full size image

Giant planets, giant storms

Hurricane Irene measured about 600 miles (966 kilometers) across as it bore down on the U.S. East Coast today (Aug. 26).

That's big and scary, but it pales next to storms on our solar system's
gas giants. Jupiter's Great Red Spot — which has been raging
continuously for at least 180 years — could fit two entire Earths within
it, Ingersoll said.

And in December, a thunderstorm about 6,200 miles (10,000 km) wide
erupted on Saturn. This one, known as the Great White Spot, is still
going strong, and some of its clouds have wrapped all the way around the
ringed planet. [Top 10 Extreme Planet Facts]

The Great White Spot also generates lots of lightning, just like thunderstorms here on Earth.

"We can see the lightning flashes on the night side, and we can hear
the radio static from the lightning," Ingersoll told SPACE.com. "The
energy in the lightning flashes is a lot stronger than terrestrial
lightning."
Saturn Storm Has Hurricane-Like Features

Cassini
stares deep into the swirling hurricane-like vortex at Saturn's south
pole, where the vertical structure of the clouds is highlighted by
shadows. Such a storm, with a well-developed eye ringed by towering
clouds, is a phenomenon never before seen on another planet.
CREDIT: NASA/JPL/Space Science Institute



Further, last year, astronomers spotted a cyclone at Neptune's south pole
that was thousands of miles wide. The Neptune squall was similar to a
spinning storm discovered a few years earlier at Saturn's south pole,
which even had a well-developed eye, just like an Earth hurricane.

But the Saturn polar vortex
was much bigger than any hurricane found on Earth. Its eye alone
measured about 2,500 miles (4,000 km) in diameter; the eye of a typical
terrestrial hurricane may be just 2 or 3 miles across.

Energy and moisture

Here on Earth, hurricanes gain their power from warm ocean water.

Warm, moist air over tropical or subtropical seas rises, causing a zone
of lower air pressure beneath it. Higher-pressure air zips in to fill
the void. But that air soon warms, becomes moist and rises, too. As this
pattern repeats, a huge, swirling storm is born.

Jupiter and Saturn don't have oceans, so their spinning storms aren't
"hurricanes" in the strict, terrestrial sense. But similar processes
spawn them, according to Ingersoll. [Photos: Jupiter, Largest Planet in the Solar System]

"Heat makes buoyancy; hot air rises," Ingersoll said. "Heat also causes
evaporation of moisture, and when the moisture condenses and forms
rain, that releases the energy. So, energy and moisture."

Most of the energy driving Earth's hurricanes ultimately comes from the
sun. But that may not be the case on Jupiter and Saturn, which orbit
our star from much farther away than Earth does.

"They're so giant that they still have retained some of their heat of
formation," Ingersoll said. "So they have their own internal heat that
can generate these giant storms."

The moisture requirement explains why gigantic, hurricane-like storms don't seem to occur on Venus or Mars, he added.

"The giant planets have moisture down below the clouds," Ingersoll
said. "But Venus doesn't. Venus is dry as a bone, hot and dry. It's not
comparable. And Mars is cold and dry."
Saturn Great White Spot Storm


An
image of Saturn taken in December 2010 by the Cassini spacecraft shows a
storm with a latitudinal and longitudinal extent of 10,000 km and
17,000 km, respectively. The latitudinal extent of the storm’s head is
approximately the distance from London to Cape Town. A "tail" emerging
from its southern edge extends further eastward.
CREDIT: Carolyn Porco and CICLOPS; NASA/JPL-Caltech/SSI
Saturn storm mysteries

Saturn's Great White Spot
tends to erupt every few decades, shattering long periods of calm and
quiescence. Scientists still aren't sure why some storms on the giant
planets should be so big, and so infrequent.

"For some reason, they store up that energy for a long time, then let
it loose in a violent, huge storm," Ingersoll said. "It didn't have to
work out that way; they could let off a little popcorn now and then. But
they don't do that."

He's hoping that Cassini will help resolve this question — just one of
many that scientists are grappling with as they try to understand the
weather systems on other planets.

"We're working right now on this giant Saturn storm, with that exact question in mind," Ingersoll said.

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Advance Solar Storm Warnings?

By: Susie77, 11:48 AM GMT on August 27, 2011



Sunspot Breakthrough

August 25, 2011: Imagine forecasting a
hurricane in Miami weeks before the storm was even a swirl of clouds off
the coast of Africa—or predicting a tornado in Kansas from the flutter
of a butterfly's wing1 in Texas. These are the kind of forecasts meteorologists can only dream about.

Could the dream come true? A new study by Stanford researchers
suggests that such forecasts may one day be possible—not on Earth, but
on the sun.

"We have learned to detect sunspots before they are visible to the
human eye," says Stathis Ilonidis, a PhD student at Stanford
University. "This could lead to significant advances in space weather
forecasting."

Sunspots are the "butterfly's wings" of solar storms. Visible to
the human eye as dark blemishes on the solar disk, sunspots are the
starting points of explosive flares and coronal mass ejections (CMEs)
that sometimes hit our planet 93 million miles away. Consequences range
from Northern Lights to radio blackouts to power outages.
Sunspot Breakthrough (splash sdo, 558px)
Based on data from the Solar Dynamics Observatory, this movie
shows a sunspot emerging from depth in February 2011. Visualization
credit: Thomas Hartlep and Scott Winegarden, Stanford University. [video] [more]

Astronomers have been studying sunspots for more than 400 years,
and they have pieced together their basic characteristics: Sunspots are
planet-sized islands of magnetism that float in solar plasma. Although
the details are still debated, researchers generally agree that sunspots
are born deep inside the sun via the action of the sun’s inner magnetic
dynamo. From there they bob to the top, carried upward by magnetic
buoyancy; a sunspot emerging at the stellar surface is a bit like a
submarine emerging from the ocean depths.

In the August 19th issue of Science, Ilonidis and
co-workers Junwei Zhao and Alexander Kosovichev announced that they can
see some sunspots while they are still submerged.

Their analysis technique is called "time-distance helioseismology2,"
and it is similar to an approach widely used in earthquake studies.
Just as seismic waves traveling through the body of Earth reveal what is
inside the planet, acoustic waves traveling through the body of the sun
can reveal what is inside the star. Fortunately for helioseismologists,
the sun has acoustic waves in abundance. The body of the sun is
literally roaring with turbulent boiling motions. This sets the stage
for early detection of sunspots.

"We can't actually hear these sounds across the gulf of space,"
explains Ilonidis, "but we can see the vibrations they make on the sun's
surface." Instruments onboard two spacecraft, the venerable Solar and
Heliospheric Observatory (SOHO) and the newer Solar Dynamics Observatory
(SDO) constantly monitor the sun for acoustic activity.
Sunspot Breakthrough (splash soho, 558px)
False-colors in this SOHO movie represent acoustic travel-time
differences heralding a sunspot as it rises toward the sun's surface in
October 2003. Visualization credit: Thomas Hartlep, Stanford University.
[video] [more]

Submerged sunspots have a detectable effect on the sun's inner
acoustics—namely, sound waves travel faster through a sunspot than
through the surrounding plasma. A big sunspot can leapfrog an acoustic
wave by 12 to 16 seconds. "By measuring these time differences, we can
find the hidden sunspot."

Ilonidis says the technique seems to be most sensitive to sunspots
located about 60,000 km beneath the sun’s surface. The team isn't sure
why that is "the magic distance," but it's a good distance because it
gives them as much as two days advance notice that a spot is about to
reach the surface.

"This is the first time anyone has been able to point to a blank
patch of sun and say 'a sunspot is about to appear right there,'" says
Ilonidis's thesis advisor Prof. Phil Scherrer of the Stanford Physics
Department. "It's a big advance."

"There are limits to the technique," cautions Ilonidis. "We can
say that a big sunspot is coming, but we cannot yet predict if a
particular sunspot will produce an Earth-directed flare."

So far they have detected five emerging sunspots—four with SOHO
and one with SDO. Of those five, two went on to produce X-class flares,
the most powerful kind of solar explosion. This encourages the team to
believe their technique can make a positive contribution to space
weather forecasting. Because helioseismology is computationally
intensive, regular monitoring of the whole sun is not yet possible—"we
don’t have enough CPU cycles," says Ilonidis —but he believes it is just
a matter of time before refinements in their algorithm allow routine
detection of hidden sunspots.

The original research reported in this story may be found in Science magazine: "Detection of Emerging Sunspot Regions in the Solar Interior" by Ilonidis, Zhao and Kosovichev, 333 (6045): 993-996.



Author: Dr. Tony Phillips | Credit: Science@NASA

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Hidden Suns, Crouching Moons

By: Susie77, 12:46 PM GMT on August 24, 2011



Discovered: Stars as Cool as the Human Body

August 24, 2011: Scientists using data from
NASA's Wide-field Infrared Survey Explorer (WISE) have discovered six "Y
dwarfs"-- star-like bodies with temperatures as cool as the human body.
Room Temperature Stars (concept, 200px)
This artist's conception illustrates what a "Y dwarf" might look
like. Y dwarfs are the coldest star-like bodies known, with
temperatures that can be even cooler than the human body. [more]

Astronomers hunted these dark orbs for more than a decade without
success. When viewed with a visible-light telescope, they are nearly
impossible to see. WISE's infrared vision allowed the telescope to
finally spot the faint glow of a half dozen Y dwarfs relatively close to
our sun, within a distance of about 40 light-years.

"WISE scanned the entire sky for these and other objects, and was
able to spot their feeble light with its highly sensitive infrared
vision," says Jon Morse, Astrophysics Division director at NASA
Headquarters in Washington.

The Y's are the coldest members of the brown dwarf family. Brown
dwarfs are sometimes referred to as "failed" stars. They are too low in
mass to fuse atoms at their cores and thus don't burn with the fires
that keep stars like our sun shining steadily for billions of years.
Instead, these objects cool and fade with time, until what little light
they do emit is at infrared wavelengths. The atmospheres of brown dwarfs
are similar to those of gas giant planets like Jupiter, but they are
easier to observe because they are alone in space, away from the
blinding light of a parent star.

So far, WISE data have revealed 100 new brown dwarfs.  Of these,
six are classified as cool Y's. One of the Y dwarfs, called WISE
1828+2650, is the record holder for the coldest brown dwarf with an
estimated atmospheric temperature cooler than room temperature, or less
than 80 degrees Fahrenheit (25 degrees Celsius).
Room Temperature Stars (coldest, 558px)
WISE 1828+2650, the coldest brown dwarf known so far, is denoted
by a green dot in very center of this infrared image. The chilly
star-like body isn't even as warm as a human body, at less than about 80
degrees Fahrenheit. [more]

"The brown dwarfs we were turning up before this discovery were
more like the temperature of your oven," says Davy Kirkpatrick, a WISE
science team member at the Infrared Processing and Analysis Center at
Caltech. "With the discovery of Y dwarfs, we've moved out of the kitchen
and into the cooler parts of the house."

The Y dwarfs are in our sun's neighborhood, from approximately
nine to 40 light-years away. The Y dwarf approximately nine light-years
away, WISE 1541-2250, may become the seventh closest star system,
bumping Ross 154 back to eighth. By comparison, the star closest to our
solar system, Proxima Centauri, is about four light-years away.
Room Temperature Stars (signup)
"Finding brown dwarfs near our sun is like discovering there's a
hidden house on your block that you didn't know about," says Michael
Cushing, a WISE team member at JPL. "It's thrilling to me to know we've
got neighbors out there yet to be discovered. With WISE, we may even
find a brown dwarf closer to us than our closest known star."

Once the WISE team identified brown dwarf candidates, they turned
to NASA's Spitzer Space Telescope to narrow their list. To definitively
confirm them, the WISE team used some of the most powerful telescopes
and spectrometers on Earth to split apart the objects' light and look
for telltale molecular signatures of water, methane and possibly
ammonia. For the very coldest of the new Y dwarfs, the team used NASA's
Hubble Space Telescope. The Y dwarfs were identified based on a change
in these spectral features compared to other brown dwarfs, indicating
they have a lower atmospheric temperature.

For more information about WISE, visit: http://www.nasa.gov/wise

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Meet Our Dwarf Planets

By: Susie77, 7:27 PM GMT on August 23, 2011

From http://www.space.com/12692-dwarf-planets-solar-sys tem-tour.html/?utm_source=Newsletter&utm_mediu m=Email&utm_campaign=SP_08232011_2


For three-quarters of a century, schoolkids learned that our solar
system has nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, Neptune and Pluto.

But things changed nearly five years ago today. On Aug. 24, 2006, the
International Astronomical Union (IAU) struck Pluto from the list,
demoting it to the newly created category of "dwarf planet."
The move was spurred by the discovery of multiple large bodies orbiting
even farther from the sun than distant Pluto — particularly an object
called Eris, which appeared to be bigger than Pluto.

As a result, the IAU came up with a new definition of "planet": A body
that circles the sun without being some other object's satellite, is
large enough to be rounded by its own gravity (but not so big that it
begins to undergo nuclear fusion, like a star) and has "cleared its
neighborhood" of most other orbiting bodies. [Our Solar System: A Photo Tour of the Planets]

Since Pluto shares orbital space with lots of other objects out in the Kuiper Belt
— the ring of icy bodies beyond Neptune — it didn't make the cut. So
Pluto was newly classified as a dwarf planet, which tend to be smaller
than "true" planets and fall short on the "clearing your neighborhood"
criterion.

Although hundreds, or perhaps thousands, more solar system bodies may
eventually join the list, the IAU officially recognizes just five dwarf
planets at the moment. Here's a brief tour of all five: Pluto, Eris,
Haumea, Makemake and Ceres.
Pluto: The demoted former planet

Pluto was discovered by American Clyde Tombaugh in 1930, as part of a
search for the mythical "Planet X" that was thought to be perturbing the
orbit of Uranus.

The dwarf planet was initially believed to be at least the size of
Earth, but astronomers now know that it's about 1,455 miles (2,352
kilometers) across — less than 20 percent as big as our planet. And
Pluto is just 0.2 percent as massive as Earth.

Pluto has an extremely elliptical orbit that's not in the same plane as
the eight official planets' orbits. On average, the dwarf planet
cruises around the sun at a distance of 3.65 billion miles (5.87 billion
km), taking 248 years to complete one circuit. [Infographic: Pluto - A Dwarf Planet Oddity]

Because it's so far from the sun, Pluto is one of the coldest places in
the solar system, with surface temperatures hovering around minus 375
degrees Fahrenheit (minus 225 degrees Celsius).

Pluto has four known moons: Charon, Nix, Hydra and a newly discovered tiny satellite currently called P4
(its final name may end up being Cerberus). While Nix, Hydra and P4 are
relatively small, Charon is about half as big as Pluto. Because of
Charon's size, some astronomers regard Pluto and Charon as a double
dwarf planet, or binary system.

While Pluto is tough to study because it's so far away, scientists
think the dwarf planet is about 70 percent rock and 30 percent ice. Its
surface is covered predominantly with nitrogen ice. The dwarf planet has
a thin atmosphere — composed mainly of nitrogen, methane and carbon
monoxide— that extends about 1,860 (3,000 km) into space.

Pluto will start coming into clearer focus in a few years' time. NASA's New Horizons probe
is due to make a close flyby of the dwarf planet in July 2015, marking
the first time a spacecraft has ever visited the frigid, faraway world.

Eris larger Pluto
Artist's
rendering of Eris, announced in July 2005 by Mike Brown of Caltech. It
is more massive than Pluto. The sun is in the background.
CREDIT: NASA/JPL/Caltech
View full size image

Eris: The troublemaker

Caltech astronomer Mike Brown led the team that discovered Eris in
2005. The find spurred the IAU to strip Pluto of its planethood and
create the "dwarf planet" category a year later.

That decision remains controversial to this day, making Eris' name quite fitting:
Eris is the Greek goddess of discord and strife, who stirred up
jealousy and envy among the goddesses, leading to the Trojan War. Eris'
one known moon, Dysnomia, is named after the goddess' daughter, who
served as the spirit of lawlessness.

Eris is virtually the same size as Pluto, but it's about 25 percent
more massive, suggesting that Eris contains considerably more rock (and
less ice) than its Kuiper Belt neighbor. However, the surfaces of the
two dwarf planets appear to be similar, composed primarily of nitrogen
ice.

Like Pluto, Eris has a highly elliptical orbit. But Eris is even more
far-flung, orbiting the sun at an average distance of about 6.3 billion
miles (10.1 billion km). It takes Eris 557 years to complete one lap
around the sun.
Haumea and its 2 Satellites
This is an illustration of Haumea and its two satellites (Hi’iaka and Namaka).
CREDIT: SINC/José Antonio Peñas
View full size image

Haumea: The oddball

Haumea, a Kuiper Belt denizen orbiting slightly beyond Pluto, was
discovered by Brown and his team in late 2004. It's one of the weirdest
objects in the solar system.

Haumea measures about 1,200 miles (1,931 km) across, making it nearly
as wide as Pluto. But Haumea is just one-third as massive as Pluto,
partly because it's not spherical. Rather, Haumea is shaped like a giant
American football.

The dwarf planet also completes one full rotation in less than four
hours, making it one of the fastest-spinning bodies in the solar system.
This super-charged spin is responsible for Haumea's oblong shape, pushing the dwarf planet outward substantially at the equator.

Haumea, named after the Hawaiian goddess of childbirth, has two known
moons, Hi'iaka and Namaka. The moons share their names with two of the
goddess' daughters, who are deities in their own right.

Scientists recently discovered that 75 percent of Haumea's surface is
covered with crystalline water ice, similar to the stuff found in your
freezer. [Video: Dwarf Planet Veiled in Water-Ice]

An energy source is generally required to maintain such organized,
structured ice. Astronomers theorize that energy may come from
radioactive elements inside Haumea, as well as heat generated by the
tidal forces the dwarf planet and its moons exert on each other.

Haumea makes one complete lap around the sun every 283 years.
New Solar System Guide: The Latest Lingo
An artist's illustration of Makemake, a dwarf planet out beyond the orbit of Neptune that also qualifies as a plutoid.
CREDIT: IAU/M. Kornmesser
View full size image

Mysterious Makemake

Brown's team also discovered Makemake, spotting the dwarf planet in 2005.

Astronomers aren't sure of Makemake's exact size, but the dwarf planet
is thought to be about three-quarters as big as Pluto. It's therefore
likely the third-largest dwarf planet, after Eris and Pluto.

Makemake orbits the sun from slightly farther away than Pluto, at an
average distance of 4.26 billion miles (6.85 billion km), and completes
an orbit every 310 years or so. 

Makemake is the second-brightest Kuiper Belt object (after Pluto) and
can be seen with a high-end amateur telescope, according to the IAU.
Like Haumea, Makemake is named
after a Polynesian deity — in this case, the creator of humanity and
god of fertility in the pantheon of the Rapanui, the native people of
Easter Island.

Like Pluto and Eris, Makemake appears to be a reddish color in the
visible-light spectrum. Scientists think its surface is covered by a
layer of frozen methane, and the distant world has no known moons.
Hubble photo Ceres
This
Hubble Space Telescope image shows Ceres, the most massive object in
the asteroid belt, a region between Mars and Jupiter. Hubble images are
helping astronomers plan for the Dawn spacecraft's visit to Ceres in
2015.
CREDIT: NASA, ESA, J. Parker (Southwest Research Institute), L. McFadden (University of Maryland)
View full size image

Ceres: King of the asteroid belt

Ceres is the only dwarf planet not found in the freezing cold, faraway
Kuiper Belt. Rather, it orbits in the main asteroid belt between Mars
and Jupiter, completing one lap around the sun every 4.6 years.

Ceres is by far the largest object in the asteroid belt, containing
about one-third of the belt's mass. However, at 590 miles (950 km)
across, it is the smallest known dwarf planet. It is named after the
Roman goddess of the harvest and motherly love.

Because it's so much closer to Earth than the other dwarf planets,
Ceres was discovered far earlier. Italian astronomer Giuseppe Piazzi
spotted it first, on Jan. 1, 1801. For the next half-century, many
astronomers regarded Ceres as a true planet.

That changed when it became apparent that Ceres was just one of many bodies hurtling through space in the asteroid belt. [The Seven Strangest Asteroids]

These days, most astronomers regard Ceres as a protoplanet, saying it
likely would have continued growing into a full-fledged rocky planet
like Earth or Mars if Jupiter hadn't shaken up the asteroid belt long
ago.

Ceres is thought to be a complex, differentiated body harboring quite a
bit of water. Scientists think it has a rocky core surrounded by a
water-ice mantle, and its rocky surface may also sport some water ice.
Some researchers believe an ocean of liquid water may slosh about
beneath Ceres' surface.

Scientists and the world will get a much better look at Ceres less than four years from now. In February 2015, NASA's Dawn spacecraft
— which is currently orbiting Vesta, the asteroid belt's second-largest
resident — will arrive at Ceres to undertake a detailed study of the
dwarf planet.

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Storm Engulfs Earth, Caught on Video

By: Susie77, 9:33 PM GMT on August 18, 2011



Spacecraft Sees Solar Storm Engulf Earth

August 18, 2011: For the first time, a
spacecraft far from Earth has turned and watched a solar storm engulf
our planet. The movie, released today during a NASA press conference,
has galvanized solar physicists, who say it could lead to important
advances in space weather forecasting.

“The movie sent chills down my spine,” says Craig DeForest of the
Southwest Research Institute in Boulder, Colorado.  "It shows a CME
swelling into an enormous wall of plasma and then washing over the tiny
blue speck of Earth where we live.  I felt very small.”
CME Engulfs Earth (splash, 558px)
A wide-angle movie recorded by NASA's STEREO-A spacecraft shows a
solar storm traveling all the way from the sun to Earth and engulfing
our planet. A 17 MB Quicktime zoom adds perspective to the main 40 MB Quicktime movie.

CMEs are billion-ton clouds of solar plasma launched by the same
explosions that spark solar flares.   When they sweep past our planet,
they can cause auroras, radiation storms, and in extreme cases power
outages.  Tracking these clouds and predicting their arrival is an
important part of space weather forecasting.

“We have seen CMEs before, but never quite like this,” says  Lika
Guhathakurta, program scientist for the STEREO mission at NASA
headquarters.  “STEREO-A has given us a new view of solar storms.”

STEREO-A is one of two spacecraft launched in 2006 to observe
solar activity from widely-spaced locations. At the time of the storm,
STEREO-A was more than 65 million miles from Earth, giving it the “big
picture” view other spacecraft in Earth orbit have been missing.

When CMEs first leave the sun, they are bright and easy to see.
Visibility is quickly reduced, however, as the clouds expand into the
void.  By the time a typical CME crosses the orbit of Venus, it is a
billion times fainter than the surface of the full Moon, and more than a
thousand times fainter than the Milky Way.  CMEs that reach Earth are
almost as gossamer as vacuum itself and correspondingly transparent.
CME Engulfs Earth (signup)
“Pulling these faint clouds out of the confusion of starlight and
interplanetary dust has been an enormous challenge,” says DeForest.

Indeed, it took almost three years for his team to learn how to do
it. Footage of the storm released today was recorded back in December
2008, and they have been working on it ever since.  Now that the
technique has been perfected, it can be applied on a regular basis
without such a long delay.

Alysha Reinard of NOAA’s Space Weather Prediction Center explains the benefits for space weather forecasting:

“Until quite recently, spacecraft could see CMEs only when they
were still quite close to the sun. By calculating a CME's speed during
this brief period, we were able to estimate when it would reach Earth.
After the first few hours, however, the CME would leave this field of
view and after that we were 'in the dark' about its progress.”

“The ability to track a cloud continuously from the Sun to Earth
is a big improvement,” she continues.  “In the past, our very best
predictions of CME arrival times had uncertainties of plus or minus 4
hours,” she continues.  “The kind of movies we’ve seen today could
significantly reduce the error bars.”
CME Engulfs Earth (zoom, 200px)
This 17 MB Quicktime zoom adds perspective to the main 40 MB Quicktime movie of the CME engulfing Earth.

The movies pinpoint not only the arrival time of the CME, but also
its mass.  From the brightness of the cloud, researchers can calculate
the gas density with impressive precision.  Their results for the Dec.
2008 event agreed with actual in situ measurements at the few
percent level.  When this technique is applied to future storms,
forecasters will be able to estimate its impact with greater confidence.

At the press conference, DeForest pointed out some of the movie’s
highlights:   When the CME first left the sun, it was cavernous, with
walls of magnetism encircling a cloud of low-density gas.   As the CME
crossed the Sun-Earth divide, however, its shape changed.  The CME
“snow-plowed” through the solar wind, scooping up material to form a
towering wall of plasma. By the time the CME reached Earth, its forward
wall was sagging inward under the weight of accumulated gas.  

The kind of magnetic transformations revealed by the movie deeply
impressed Guhathakurta:  “I have always thought that in heliophysics
understanding the magnetic field is equivalent to the ‘dark energy’
problem of astrophysics.  Often, we cannot see the magnetic field, yet
it orchestrates almost everything.   These images from STEREO give us a
real sense of what the underlying magnetic field is doing.”

All of the speakers at today’s press event stressed that the
images go beyond the understanding of a single event.  The inner physics
of CMEs have been laid bare for the first time—a development that will
profoundly shape theoretical models and computer-generated forecasts of
CMEs for many years to come.

“This is what the STEREO mission was launched to do,” concludes
Guhathakurta, “and it is terrific to see it live up to that promise."



Author: Dr. Tony Phillips | Credit: Science@NASA

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Perseids

By: Susie77, 11:28 AM GMT on August 12, 2011

Space Weather News for Aug. 12, 2011

http://spaceweather.com



METEOR SHOWER: The Perseid meteor shower is underway. International
observers are now reporting more than 20 meteors per hour as Earth
passes through a stream of debris from Comet Swift-Tuttle. Forecasters
expect the shower to peak on the night of Aug. 12-13.  The best time to
look is during the hours before dawn on Saturday morning, August 13th,
when the glaring Moon is relatively low and meteor rates are highest.
 Visit http://spaceweather.com for full coverage.



WATCH OUT FOR THE SPACE STATION, TOO:  Consider it a cosmic coincidence.
  During the peak of the Perseid meteor shower, the International Space
Station will fly over many US towns and cities.  The behemoth
spacecraft is easy to see if you know when to look.  Check
SpaceWeather.com's Simple Satellite Tracker for flyby times: http://spaceweather.com/flybys/

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2011 Perseid meteor shower / ISS Viewing

By: Susie77, 11:18 AM GMT on August 10, 2011



Spaceships, Meteors, and Moonlight



August 9, 2011:
Bright moonlight streams through your window. A nugget of space debris
disintegrates in a sparkling fireball. A huge spaceship glides silently
overhead.

By itself, any one of these events might be enough to get you out
of bed. This weekend, all three are going to happen at the same time.

On August 12th and 13th, as the Moon waxes full, the International
Space Station will glide over US towns and cities during the peak of
the annual Perseid meteor shower.
Perseids 2011 (splash, 558px)
Above: Click on the image to view a ScienceCast video about the Perseid meteor shower. The video includes a sky map.

The meteor shower is already underway. Earth is passing through a
broad stream of debris from Comet Swift-Tuttle, and specks of comet dust
are hitting the top of Earth's atmosphere at 140,000 mph. These
disintegrating meteors stream out of the constellation Perseus--hence
the name "Perseids." According to the International Meteor Organization,
worldwide observers now are counting more than a dozen Perseids per
hour with more to come on August 12-13 when Earth passes near the heart
of the debris stream.

Experts note that moonlight and meteor showers don't mix. Indeed,
the great number of faint Perseids that observers would normally count
in a dark year will be invisible in 2011 with the Moon glaring overhead.
On the bright side--no pun intended--any Perseid that does manage to
pierce the glare is likely to be a fireball. These are caused by
relatively big pieces of debris disintegrating in flashes too bright to
be subdued. It's not unusual to see at least a few Perseid
shadow-casters on peak night.
Perseids 2011 (signup)
Perseid meteors can appear any time Perseus is above the
horizon--i.e., between about 10 pm and sunrise. The best time to look is
during the hours before dawn especially on Saturday morning, August
13th. The full Moon will be relatively low, and the meteor rate should
be peaking at that time.

Before dawn is also the time of the ISS. All week long and into
the weekend, the International Space Station will be making a series of
early-morning flybys over the United States. The massive spacecraft
glides silently among the stars, shining so brightly that moonlight and
even city lights have little affect on its visibility. You simply cannot
miss it if you know when to look. Check NASA's ISS Tracker
for local flyby times. Several major cities are favored with flybys on
August 12th and 13th including Chicago, Dallas, Denver, Los Angeles, New
York and others.

Set your alarm and enjoy the show.

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Major Solar Storm in Progress!

By: Susie77, 2:05 AM GMT on August 06, 2011

From:  spaceweather.com

GEOMAGNETIC
STORM IN PROGRESS:
A major geomagnetic
storm is in
progress
following the impact of a CME on August
5th around 1800 UT. Sky watchers at all latitudes
should be alert for auroras after nightfall. Tip:
the best hours for aurora sightings are usually
around local midnight. Aurora
alerts:
text,
voice.

Reports of Northern Lights are coming in from many
European countries including Germany,
Denmark,
Scotland
and the
Netherlands
.
Analysts at the Goddard Space Weather Lab say that
the CME impact may have strongly compressed Earth's
magnetic field, directly exposing satellites in
geosynchronous orbit to solar wind plasma. Stay
tuned for updates on this aspect of the storm.
The arriving CME left the sun on August 4th, propelled
by an M9.3-category
eruption in the magnetic canopy of sunspot 1261.
Click on the image to view a movie of the expanding
cloud recorded by the Solar and Heliospheric Observatory:


Note: The many speckles in this movie
are caused by energetic solar protons hitting the
camera.
July
2011 Aurora Gallery


[previous Julys: 2010,
2009,
2008,
2007, 2006,
2005,
2004,
2003]
NIGHT-TIME
SOLAR RADIO BURST:
The M9-class
solar flare of August 4th produced a burst of shortwave
static so powerful that receivers on Earth picked
it up after sunset. "A RadioJove
observer in Florida recorded the burst when the
sun was 38 degrees below the horizon," reports
amateur radio astronomer Thomas Ashcraft. Ashcraft's
own radio telescope in New Mexico recorded the event
1 hour and 54 minutes after sunset:

"To my knowledge, receptions like this are
very rare," says Ashcraft.
Indeed they are. This event brings to mind the
iconic night-time solar radio burst of March 8,
1958. Five radio telescopes at the University of
Florida picked up emissions from the sun while observing
the planet Jupiter in tthe middle of the night.
On the other side of the world, radio astronomers
in daylit Australia confirmed that a powerful solar
radio burst had taken place at that exact time.
The event is described in a 1959
Nature paper
by pioneering radio astronomers
Alex Smith and Tom Carr. They considered the possibility
that solar radio waves might have been reflected
by the Moon or carried to the night side of Earth
by ionospheric ducting. In tthe end, they could
not conclusively explain what happened and to this
day night-time solar radio bursts remain a puzzle.

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Incoming!

By: Susie77, 11:05 AM GMT on August 04, 2011

Space Weather News for August 4, 2011

http://spaceweather.com



SOLAR ACTIVITY: For the third day in a row, sunspot 1261 has unleashed a
significant M-class solar flare.  The latest blast at 0357 UT on August
4th registered M9.3 on the Richter Scale of Flares, almost crossing the
threshold into X-territory (X-flares are the most powerful kind). Also,
at least two coronal mass ejections are en route to Earth, and they
could provoke mild to moderate geomagnetic storms when they arrive on
August 4th through 6th.  High-latitude sky watchers should be alert for
auroras.  Check http://spaceweather.com for details and updates.



DON'T MISS THE STORM: Would you like a call when geomagnetic storms are in progress? Space weather alerts are available from http://spaceweathertext.com (text) and http://spaceweatherphone.com (voice).

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2011 Perseid meteor shower

By: Susie77, 1:25 AM GMT on August 02, 2011



How to minimize moon and optimize 2011 Perseid meteor shower

From:
http://earthsky.org/astronomy-essentials/h ow-to-minimize-moon-and-optimize-2011-perseid-mete or-shower

In 2011, the legendary Perseid meteor shower – the northern
hemisphere’s best summertime meteor shower – is expected to peak between
midnight and dawn on Saturday, August 13. That night, however, the
full moon will be shining brightly in the sky from dusk until dawn,
obliterating all but the brightest Perseid meteors. Here’s how to
minimize the moon and optimize the 2011 Perseid meteors.

The 2010 Perseid shower over the Very Large Telescope in Chile. Click here for more about this image. ESO/S. Guisard
Click here to expand image above
There’s no way around it. We have to work around the moon in 2011
because the full moon and the Perseids’ expected peak will both fall on
Saturday, August 13, 2011. But EarthSky can provide some helpful hints
on how best to enjoy summertime meteors this year.
1) Start watching for Perseid meteors now, and continue watching until after the shower’s peak on August 13.
What, you say? Watch now for a shower that peaks nearly two weeks
from now? Yes. The Perseids actually begin in mid-July, and they
gradually build to a peak. If you’re in a dark location, you can see
plenty of Perseids in the week or two before the peak.
2) Watch in the wee hours before dawn on August 9 and 10
On the peak night of August 12/13, there won’t be any moon-free time
for viewing. However, on August 9 and 10, the moon will set a few to
several hours before sunrise, providing an hour or two of dark sky for
watching the Perseid meteors. Meteors fly at a lower rate several days
before the peak date, perhaps at 15 to 20 Perseids per hour, but a dark
sky makes all the difference in the world for watching summertime’s
classic shower.
The moon’s setting time in your sky
3) Sprawl out in a moon shadow The best viewing on
any date is from about 2 a.m. until dawn. As seen from mid-northern
latitudes, the moon will be shining low in the south to southwest sky on
the peak nights. That means the moon will be casting looooong shadows.
Find a moon shadow somewhere that still provides a wide expanse of sky. A
plateau area with high-standing mountains to the south and southwest
would work just fine. If you can’t do that, find a hedgerow of trees
bordering a great big hay field somewhere (though obtain permission, if
it’s private land). Or simply sit in the shadow of a barn. Ensconced
within a moon shadow and far from the glow of city lights, the night all
of a sudden darkens while the meteors brighten.
Best view of Perseid meteors could be before dawn August 10
If blessed with clear skies on or near the predicted peak date, a
moon shadow may be your ticket to this year’s production. This annual
meteor shower is beloved by many for its rich and reliable display of
meteors. It does not disappoint – unless of course there are clouds (or
a full moon) at the time of the Perseids peak.
EarthSky’s meteor shower guide for 2011
From Deborah … When I was young, I spent many a predawn hour
reclining on a lawn chair under a bright moon or no moon at all,
watching for meteors. I saw a bunch of Perseids even on moonlit nights,
but they tended to be fleeting little meteors rushing along against the
moon-washed sky. Over time, I began to feel more and more strongly
that those moonlit meteor experiences couldn’t compare with
meteor-watching in dark moonless skies. But, in recent years,
I’ve changed my mind about this. It began with my daughter – now 31,
and herself a veteran meteor-watcher. She would bubble with excitement
about seeing meteors in all sorts of locations – moon or no moon – city
lights or no city lights. Since the advent of social media, we now hear
from hundreds of people who glimpse meteors in the light of the moon
and feel elevated because of it. So even though there’s a moonlit sky
on the night of the Perseids peak in 2011, you can still glimpse a
meteor or two, or more – and you can still enjoy them very much.
From Bruce … If you want to see the Perseid shower in a
totally moonless sky, 2011 is not your year. The Perseids are an
especially rich and dependable meteor shower. In the northern
hemisphere, they are often the best meteor shower of the year. They
shoot across the sky – often leaving persistent trains – and
occasionally lighting up the sky with bright fireballs. The shower
typically produces 50 or more meteors per hour on the mornings of their
peak – and this year it’ll be fun to know how many meteors people can
manage to see from a moon shadow on the morning of the peak, August 13.
Between now and then, the moon will be waxing in the evening sky, and –
before the moon waxes too large – you might see some Perseids in the
the evening hours. Although the Perseids are best after midnight – and
don’t tend to produce a high number of meteors in the evening – evening
is the best time to catch an earthgrazer, which is a
slow-moving and long-lasting meteor that travels horizontally across the
sky. If you see one, you’ll have a new appreciation for evening meteor
watching.
If you’re serious about trying to see a large number of Perseids, you
should avoid city lights. A wide open area – a field or a lonely
country road – can work well. If you’re watching between midnight and
dawn, the meteors will appear in all parts of the sky. Watch with
friend or friends, and try facing in different directions so that if
someone sees a meteor, that person can call out “meteor” to the rest.
Perseid RadiantThe constellation Perseus, the radiant for the annual Perseid meteor shower
The Perseid meteors are named for the constellation Perseus the Hero.
If you trace the paths of the meteors backwards, they seem to radiate
from this constellation.
Meteors are also called shooting stars, but they have nothing to do with actual stars.
Instead, they start out as bits of dust left behind in space by a
comet. The Perseid meteor shower peaks annually at this time of year,
as our planet Earth passes through the orbital path of Comet Swift-Tuttle.
Even though this comet is now moving in the outer solar system, the
stream of rubble trailing Swift-Tuttle extends for hundreds of millions
of kilometers in space. For several weeks from late July to mid-August,
debris left behind by this comet slams into Earth’s atmosphere. The
fragments vaporize as they fall through our atmosphere, and the result
is the Perseid meteor shower.

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About Susie77

Sometimes I complain about the earthly weather, but mostly I like to post about astronomy and space events. Hope you enjoy the articles.

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