Earth Weather / Space Weather

The Moon Gets Broadband Wireless Connection

By: Susie77, 1:08 AM GMT on May 31, 2014

The Moon Gets Broadband Wireless Connection

May 30, 2014 | by Janet Fang









Photo credit:

Design drawing of the optical module on the satellite showing the telescope and gimbal (pivoted support) / NASA



 

Working from moon? Forget dial-up speeds. A team of MIT and NASA researchers
is demonstrating a laser-based data communication technology that
provides space workers (or maybe even dwellers) with the connectivity we
have on Earth. That means large data transfers and high-definition
video streaming from and on the lunar surface.  

Last fall, the on-orbit performance of their moon-to-Earth uplink
shattered previous transmission speed records. Now they’ve got the
underlying physics sorted out, and they think the technology could even
extend into deep-space missions to Mars. 

The Lunar Laser Communication Demonstration (LLCD)
transmitted over 384,633 kilometers between here and the moon at a
download rate of 622 megabits per second. They also sent data from Earth
to the moon at 19.44 megabits per second. That’s 4,800 times faster
than the best radio frequency uplink ever used.

“Communicating at high data rates from Earth to the moon with laser
beams is challenging because of the 400,000-kilometer distance spreading
out the light beam,” Mark Stevens of MIT Lincoln Laboratory says in a news release.
“It’s doubly difficult going through the atmosphere, because turbulence
can bend light -- causing rapid fading or dropouts of the signal at the
receiver.”

To avoid a fading signal over such a distance, they employed several
techniques to help overcome a wide range of atmospheric conditions, in
both darkness and light, and through clouds in our atmosphere. 

A ground terminal (pictured below) at White Sands, New Mexico, uses
four telescopes to send the uplink signal to the moon. Each telescope is
about 15 centimeters in diameter and fed by a laser transmitter that
sends information coded as pulses of infrared light. The four separate
transmitters combined results in 40 watts of power. 




Each telescope transmits light through a different column of air
experiencing different bending effects from the atmosphere. This
increases the chance that at least one of the laser beams will interact
with the receiver mounted on a satellite that’s orbiting the moon. 

The receiver (top photo) collects the light using a narrow telescope.
The light is focused into an optical fiber (like the ones used in our
fiber optic networks), and the signal is amplified 30,000 times. The
pulses of light are converted into electrical pulses, and these,
finally, are converted into data bit patterns that carry the transmitted
message. 

Of the 40-watt signals sent by the transmitters, less than a
billionth of a watt is received at the satellite. “But that’s still
about 10 times the signal necessary to achieve error-free
communication,” Stevens says.

The work will be presented at the Conference on Lasers and Electro-Optics (CLEO) next month. 

[Via The Optical Society]
Read more at http://www.iflscience.com/space/moon-gets-broadban d-wireless-connection#ABhbczBZJ2gPXHP0.99

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TONIGHT'S METEOR SHOWER

By: Susie77, 5:47 PM GMT on May 23, 2014


ANTICIPATION BUILDS FOR TONIGHT'S METEOR SHOWER: This
weekend, Earth will pass through a stream of debris from Comet
209P/LINEAR. If forecasters are correct, the encounter could produce an outburst of bright meteors
numbering more than 200 per hour.  Most models agree that peak rates
should occur between the hours of 0600 UT and 0800 UT (2 a.m. and 4 a.m.
EDT) on Saturday morning, May 24th, a time frame that favors
observers in North America.  It is worth noting, however, that Earth
has never encountered this stream of debris before, so forecasters
cannot be certain of their predictions.  The display could be a
complete dud, a fantastic "meteor storm," or anything in
between. Whatever happens, NASA plans to chat about it.

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Jupiter's Big Red Spot is Shrinking

By: Susie77, 12:30 PM GMT on May 19, 2014


Jupiter’s Great Red Spot is smaller than ever before seen
Jupiter’s trademark Great Red Spot — a swirling anticyclonic storm feature larger than Earth — has shrunken to the smallest size ever measured.






Image credit : NASA, ESA, and A. Simon (Goddard Space Flight Center)
Image credit : NASA, ESA, and A. Simon (Goddard Space Flight Center)

Astronomers have followed the downsizing of planet Jupiter’s Great Red Spot since the 1930s.

“Recent Hubble Space Telescope observations confirm that the Great
Red Spot (GRS) is now approximately 10,250 miles across, the smallest
diameter we’ve ever measured,” said Amy Simon of NASA’s Goddard Space
Flight Center in Greenbelt, Md. Historic observations as far back as the
late 1800s gauged the GRS to be as big as 25,500 miles on its long
axis. The NASA Voyager 1 and Voyager 2 flybys of Jupiter in 1979
measured the GRS to be 14,500 miles across.

Starting in 2012, amateur observations revealed a noticeable increase
in the spot’s shrinkage rate. The GRS’s “waistline” is getting smaller
by 580 miles per year. The shape of the GRS has changed from an oval to a
circle. The cause behind the shrinking has yet to be explained.

“In our new observations it is apparent that very small eddies are
feeding into the storm,” said Simon. “We hypothesized that these may be
responsible for the accelerated change by altering the internal dynamics
and energy of the Great Red Spot.”

Simon’s team plans to study the motions of the small eddies and also
the internal dynamics of the GRS to determine if these eddies can feed
or sap momentum entering the upwelling vortex.

In the comparison images one Hubble photo was taken in 1995 when the
long axis of the GRS was estimated to be 13,020 miles across. In a 2009
photo, the GRS was measured at 11,130 miles across.

The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. NASA’s Goddard Space Flight
Center in Greenbelt, Md., manages the telescope. The Space Telescope
Science Institute (STScI) in Baltimore conducts Hubble science
operations. STScI is operated for NASA by the Association of
Universities for Research in Astronomy, Inc., in Washington, DC.

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Comet LINEAR Meteor Shower May 24/25

By: Susie77, 1:45 PM GMT on May 13, 2014



New Meteor Shower from Comet Could Dazzle Stargazers Next Week


By Nola Taylor Redd, Space.com Contributor   |   May 12, 2014 06:50am ET


A new meteor shower spawned by a comet is due to light up the sky next
week, with some forecasters predicting up to 200 "shooting stars" per
hour — a potentially spectacular opening act for the meteor display.
Comet 209P/LINEAR


If it performs as expected, the never-before-seen Camelopardalid meteor shower
is due to peak overnight on May 23 and 24 as the Earth passes through a
debris stream left by the Comet 209P/LINEAR nearly 200 years ago. The
new meteor display could rival the brilliance of the annual Perseid
meteor shower that graces the night sky each August.

The prospect of a brand-new meteor shower has scientists understandably excited.





"There could be a new meteor shower, and I want to see it with my own
eyes,"  said NASA meteor expert Bill Cooke, head of the Meteoroid
Environment Office at the Marshall Space Flight Center in Huntsville,
Ala., in a statement. [New Meteor Shower from Comet 209P/LINEAR (Gallery)]











  200-year-old comet leftovers

Meteor showers occur when the Earth passes through clouds of dust and
gas left behind from comets as the planet orbits the sun. This gas and
dust falls into Earth's atmosphere, where it burns up on its downward
journey creating a meteor display. The amount of debris in space
determines how much of a show the shower will present to observers.

In February 2004, the Lincoln Near-Earth Asteroid Research (LINEAR) team discovered Comet 209P/LINEAR. The relatively dim comet crosses Earth's orbit once every five years in its journey around the sun.

Two years ago, in 2012 meteor experts Esko Lyytinen of Finland and
Peter Jenniskens at NASA Ames Research Center determined that Earth
would pass through debris from the comet this year. Material shed from
the comet in the 1800s would encounter Earth on May 24, 2014.
This sky map from a NASA video shows the location of the new


This sky map from a NASA video shows the location
of the new "Camelopardid" meteor shower spawned by the Comet
209P/LINEAR, which will make its first appearance in Earth's night sky
overnight on May 23 and 24, 2014. The meteor shower will appear to
radiate out from a point near the constellation Camelopardalis.
Credit: NASA/JPL-CaltechView full size image


How many "shooting stars"?


While experts agree that an encounter is imminent, no one is certain how much material lies waiting in space to create the new meteor shower. It depends on how active the faint comet was when it crossed Earth's path.

"We have no idea of what the comet was doing in the 1800s," Cooke said.
"There could be a great meteor shower — or a complete dud."

The best time to watch is between 6 and 8 Universal Time on May 24,
which translates to between 2 a.m. and 4 a.m. Eastern Daylight Time,
when modelers say Earth is most likely to encounter the debris. North
Americans will receive the best show because the peak occurs at night in
that region, when the apparent source of the streams of gas will lie
high in the sky.

"We expect these meteors to radiate from a point in Camelopardalis,
also known as 'the giraffe,' a faint constellation near the North Star,"
Cooke said. "It will be up all night long for anyone who wishes to
watch throughout the night."

Although the forecast calls for a two-hour encounter, avid watchers may
wish to extend their viewing time to allow for potential surprises from
the new meteor shower. Outbursts could occur in the hours before or
after the event.

If the anticipated meteor shower
fizzles out, observers will still be able to observe the tight
conjunction of the crescent moon and Venus, which will rise together
just ahead of the sun.

"That's a nice way to start the day, meteors or not," Cooke said.

Editor's Note: If you capture an amazing photo of the
new meteor shower, or any other night sky view, that you'd like to share
for a possible story or image gallery, please contact managing editor
Tariq Malik at spacephotos@space.com.

This story was updated at 12:45 pm ET to correct the name of Comet 209P/LINEAR.

Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

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Yikes!!

By: Susie77, 8:32 PM GMT on May 02, 2014



Carrington-class CME Narrowly Misses Earth


May 2, 2014:
Last month (April 8-11), scientists, government officials, emergency
planners and others converged on Boulder, Colorado, for NOAA's Space
Weather Workshop—an annual gathering to discuss the perils and
probabilities of solar storms. 

The current solar cycle is weaker than usual, so you might expect a
correspondingly low-key meeting.  On the contrary, the halls and
meeting rooms were abuzz with excitement about an intense solar storm
that narrowly missed Earth.

"If it had hit, we would still be picking up the pieces," says
Daniel Baker of the University of Colorado, who presented a talk
entitled The Major Solar Eruptive Event in July 2012: Defining Extreme Space Weather Scenarios.  
splash

A new ScienceCast video recounts the near-miss of a solar superstorm in July 2012.  Play it
The close shave happened almost two years ago. On July 23, 2012, a
plasma cloud or "CME" rocketed away from the sun as fast as 3000 km/s,
more than four times faster than a typical eruption. The storm tore
through Earth orbit, but fortunately Earth wasn't there. Instead it hit
the STEREO-A spacecraft. Researchers have been analyzing the data ever
since, and they have concluded that the storm was one of the strongest
in recorded history. "It might have been stronger than the Carrington
Event itself," says Baker.

The Carrington Event of Sept. 1859 was a series of powerful CMEs
that hit Earth head-on, sparking Northern Lights as far south as Tahiti.
Intense geomagnetic storms caused global telegraph lines to spark,
setting fire to some telegraph offices and disabling the 'Victorian
Internet." A similar storm today could have a catastrophic effect on
modern power grids and telecommunication networks. According to a study
by the National Academy of Sciences, the total economic impact could
exceed $2 trillion or 20 times greater than the costs of a Hurricane
Katrina. Multi-ton transformers fried by such a storm could take years
to repair and impact national security.

A recent paper in Nature Communications authored by UC
Berkeley space physicist Janet G. Luhmann and former postdoc Ying D. Liu
describes what gave the July 2012 storm Carrington-like potency. For
one thing, the CME was actually two CMEs separated by only 10
to 15 minutes. This double storm cloud traveled through a region of
space that had been cleared out by another CME only four days earlier.
As a result, the CMEs were not decelerated as much as usual by their
transit through the interplanetary medium.
image

A report by the National Academy of Sciences details the consequences of extreme solar storms. More
Had the eruption occurred just one week earlier, the blast site
would have been facing Earth, rather than off to the side, so it was a
relatively narrow escape.

When the Carrington Event enveloped Earth in the 19th
century, technologies of the day were hardly sensitive to
electromagnetic disturbances.  Modern society, on the other hand, is
deeply dependent on sun-sensitive technologies such as GPS, satellite
communications and the internet.

"The effect of such a storm on our modern technologies would be tremendous," says Luhmann.

During informal discussions at the workshop, Nat Gopalswamy of the
Goddard Space Flight Center noted that "without NASA's STEREO probes,
we might never have known the severity of the 2012 superstorm.  This
shows the value of having 'space weather buoys' located all around the
sun."

It also highlights the potency of the sun even during so-called
"quiet times." Many observers have noted that the current solar cycle is
weak, perhaps the weakest in 100 years. Clearly, even a weak solar
cycle can produce a very strong storm.

Says Baker, "We need to be prepared."

Credits:Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA

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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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