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Space Science News for March 2, 2000
The Sun appears to be in an unsettled state. Minor short-lived sunspot
groups are appearing at various locations on the Sun's disk and small
flares are erupting in many of the active regions. This morning two
intense solar flares erupted from sunspot group #8882. Impressive coronal
mass ejections followed both flares. Geomagnetic activity could begin in 24
to 48 hours. FULL STORY with updates at http://www.SpaceWeather.com
SPACE WEATHER NEWS from the NASA/Marshall Space Flight Center: Last week an
interplanetary wind storm hit our planet with a gale of energetic particles
from the Sun. During the storm, a strong gust of solar wind triggered
aurora captured by the Ultraviolet Imager on NASA's Polar satellite. FULL
STORY at http://spacescience.com/headlines/y2000/ast02mar_1m.htm
Space Science News for February 24, 2000
A gust of solar wind on February 24 at 1430 UT may have triggered an
intense geomagnetic substorm recorded by NASA's Polar satellite. That
event is subsiding, but the solar wind velocity is still high and variable.
Observers in Alaska, Canada, and the northern tier of US states should be
on the lookout for active aurora tonight. More information and updates
about the ongoing geomagnetic disturbance will be posted at
Space Science News for February 23, 2000
As the sunspot maximum approaches, space weather events are becoming more
frequent. The end of February could mark another good weekend for aurora
watchers, thanks to a large coronal hole straddling the disk of the sun.
High speed solar wind particles reached the Earth today and began to buffet
our planet's magnetosphere. FULL STORY at
Space Science News for February 21, 2000
A Shocking Passage: An interplanetary shock wave of plasma and magnetic
fields passed by Earth on Feb. 20, 2000. The material came from a dramatic
coronal mass ejection that left the Sun on February 17. Geomagnetic
activity is up, but it appears that this event will not cause significant
aurora at middle latitudes. FULL STORY at
Space Science News for February 18, 2000
Here Comes the Sun: A "full halo" coronal mass ejection left the Sun
yesterday, apparently headed directly for Earth. When the leading edge of
the disturbance reaches our planet on Feb. 19 or 20, it could trigger
aurora and other geomagnetic activity. FULL STORY at
Space Science News for February 6, 2000
Small Sunspot, Big Flare: One of the biggest and brightest optical flares
of the current sunspot cycle erupted this weekend. The flare was a whopper,
but the sunspot group it came from wasn't. The full story, which includes
pictures of the flare and a coronal mass ejection, is at:
Space Science News for February 3, 2000
Solar Smoke Rings: The Sun put on a dynamic show this week with a series
of swirling coronal mass ejections that expelled billions of tons of hot
gas into interplanetary space. FULL STORY at
NASA Space Science News for Dec. 13, 1999
The Day the Solar Wind Disappeared -- For two days in May, 1999, the solar
wind that blows constantly from the Sun virtually disappeared -- the most
drastic and longest-lasting decrease ever observed. FULL STORY at
NASA Space Science News for June 23, 1999
SOHO spies the far side of the Sun: An ingenious new technique
for viewing the previously hidden side of the Sun could improve
space weather forecasting. This story includes images and video
of solar hot spots on the far side of the sun and, as an added
bonus, video of a shadow cast by comet Hale-Bopp when it was on the
far side of the sun in 1997. FULL STORY at
NASA Science News for June 2, 1999
Solar flares show their true colors - New research points to a common mechanism
for spectral behavior in solar flares. Using a technique developed for
examining how gamma-ray bursts evolve, NASA scientists are beginning to
understand exactly how a solar flare changes over time. Full story:
NASA Science News for May 31, 1999
"Cool" microflares could be solar
hot spots - One longstanding mystery of the
sun is why its outer atmosphere - the corona - is 200 times hotter than its
surface. Now, a trio of scientists says it's because the corona is heated by
incessant mini-explosions, called microflares. Full story:
NASA Science News for March 9, 1999: Two related stories
Finding the 'smoking gun' before it fires -
Scientists discover a new tool for
predicting solar explosions, improving space weather predictions for storms
that may affect Earth. Story includes realvideo of a coronal mass ejection.
S Marks the spot - NASA headquarter's press
release announcing a new tool for
predicting coronal mass ejections. Full story:
NASA Science News for March 2:
Future telescope could shatter solar high-resolution barrier - Scientists look
ahead at a new telescope which could lead to observations of violent magnetic
fields on the sun with resolution 10 times better than the best solar
instrument today. Full Story:
NASA Space Science News for Feb. 16, 1999
Space weather camera set for launch in
2000: A unique
camera that will take some of the first pictures of Earth's
invisible magnetic shield is being prepared for flight.
The mission, called IMAGE, will explore a region of space where
the aurora is energized. FULL STORY at
NASA Science News for Jan 21:
Up, Up, and away to the Magnetosphere - A space weather rocket blasted
off from a launch pad in Norway early this morning. During the
successful 20 minute flight, its instruments gathered valuable data on
the "auroral fountain," where the solar wind directly interacts with
Earth's atmosphere. Full story:
NASA Space Science News -- Jan 19, 1999
CAPER Update: A NASA rocket is poised to blast off from
Norway to explore a region of Earth's atmosphere directly exposed
to the solar wind. FULL STORY at
Scientists hope to meet the Jan. 25 launch deadline
Jan. 19, 1999: A NASA rocket is poised to blast off from Norway
to study space weather high above the Arctic circle. CAPER, the Cleft
Accelerated Plasma Experimental Rocket, will carry one of the most complex
instrument packages ever launched into the region where the Earth's
atmosphere is directly exposed to space. The mission has been in development
for more than three years. Now scientists are waiting expectantly to send
CAPER aloft before the launch window closes on Jan. 25.
Geomagnetic activity and viewing conditions at Longyearbyen tracking station
were favorable yesterday, but high winds at Andoya Rocket Range again kept
CAPER on the ground. Earthly weather has held CAPER on the ground in Norway
since it was readied a week ago.
Scientists plan Arctic CAPER to study space weather
"The weather [at the tracking station at Longyearbyen] has become challenging with high winds and fresh snow producing snow drifts that slowly snake across the valley like mute ghosts condemned to wander eternally," Dr. Paul Kintner of Cornell University, CAPER's principal investigator, wrote on Saturday.
"Both of our 4-wheel drive vehicles were stuck in the snow during our trip
to the station. One still remains stuck as the [launch] window closes....
Visibility is zero within a few meters of the ground and during the drive
out to the Nordlysstajonen occasionally the road could only be seen by
opening the car door and looking down."
Although CAPER has been ready since Jan. 11, launch has been postponed each
evening because the right science conditions were not available, or because
of weather. The CAPER team is anxious to start the countdown and then launch
over an aurora arc. Data from instruments on the ground and on the Polar
satellite are used to determine when conditions are right. When CAPER
finally takes off it will soar to an apex of about 1,400 km (828 mi) in its
"We're studying a region that is believed to provide the majority of the mass
that makes up the magnetosphere," said Victoria Coffey, a scientist at NASA's
Marshall Space Flight Center. Coffey is the experiment scientist for two CAPER
instruments, TECHS (the Thermal Electron Capped Hemisphere Spectrometer) and
TICHS (the Thermal Ion Capped Hemisphere Spectrometer).
An initial study was made by SCIFER - the Sounding of the Cleft Ion Fountain
Energization Region - on Jan. 25, 1995. It showed that plasmas (electrified
gases) are accelerated to energies of a few hundred electron volts in a few
well-defined regions of the cleft or cusp.
However, the Earth is exposed to space at the north and south
magnetic poles where the magnetic field lines are open to space because of
their dipole (two-pole) shape.
A keogram depicts auroral conditions over the Longyearbyen tracking
station north of Andoya. Keograms take strip images of the aurora, as seen
by all-sky cameras, and stack them side-by-side to depict changes over time.
Keogram is derived from keoitt, old Eskimo for aurora.
"It's the only place where solar wind particles can directly enter Earth's
ionosphere," Coffey explained.
Author: Dave Dooling
Curator: Linda Porter
NASA Official: Gregory S. Wilson
January 7: Rocket will study space weather effects - Scientists plan a CAPER to
study the solar wind high above the arctic circle, in Norway. They hope to
find out how atoms from Earth's upper atmosphere have escaped to become part of
Earth's "auroral fountain." Full story:
Data Systems Branch
NASA/Marshall Space Flight Center
Huntsville AL 35812
Headquarters, Washington, DC December 8, 1998
Goddard Space Flight Center, Greenbelt, MD
SOLAR WIND SQUEEZES SOME OF EARTH'S ATMOSPHERE INTO SPACE
Researchers using NASA's Polar spacecraft have found the first direct evidence that bursts of energy from the Sun can cause oxygen and other gases to gush from Earth's upper atmosphere into space.
Scientists first saw this effect September 24-25, 1998, when a storm from the Sun smacked into the Earth. Using particle detectors on Polar, they found that the flow of "polar wind" out of Earth's upper atmosphere increased substantially when the storm hit. In effect, pressure from the solar ejection squeezed gas out of the ionosphere.
Scientists have known since the early 1980s that Earth's upper atmosphere leaks oxygen, helium, and hydrogen ions (atoms that have gained or lost an electron) into space from regions near the poles. But it was not until the Polar spacecraft flew through this fountain of ionized gas in September 1998 that scientists confirmed that the flow of ions was caused by solar activity.
"We now have the first direct, quantifiable evidence that disturbances in the solar wind produce changes in the flow of ions out of the ionosphere," said Dr. Thomas E. Moore of NASA's Goddard Space Flight Center, Greenbelt, MD, principal investigator for Polar's Thermal Ion Dynamics Experiment (TIDE). "This solar wind energy essentially 'cooks' the upper atmosphere off of the Earth." Moore's observations were presented on December 8 in San Francisco, CA, during the fall meeting of the American Geophysical Union.
On September 22, 1998, the Sun ejected a mass of hot, ionized gas (known as plasma) toward Earth. This magnetic cloud of plasma (called a coronal mass ejection) increased the density and pressure of the solar wind and produced a shock wave similar to a sonic boom. When that shock wave arrived at
Earth late on September 24, it rammed into and compressed Earth's magnetic shell in space (the magnetosphere).
This shock to the magnetosphere excited the plasma trapped in Earth's ionosphere to a point where some ions gained enough energy to escape Earth's gravity and flow downwind of Earth.
The amount of oxygen and other gases lost from the ionosphere amounted to a few hundred tons, roughly equivalent to the mass of oxygen inside the Louisiana Superdome.
"This is the supply of plasma that makes things interesting in space," said Moore. "Much of the gas ejected from the ionosphere is caught in Earth's wake. It then flows back toward the Earth while being heated and accelerated by the same processes that create auroral particles and the radiation belts."
The ionosphere is a series of invisible layers of ions and electrons that are suspended in Earth's upper atmosphere at about 50 to 650 miles (80 to 1,000 kilometers) in altitude.
These particles are produced when the Sun's ultraviolet light ionizes the atoms and molecules in the upper atmosphere. The ionosphere makes long-distance radio communication possible by
reflecting radio waves back to Earth. It also is home to the aurora and the electrical currents that heat the upper atmosphere during magnetic storms.
"Our research shows that Earth's own ionosphere is a major contributor to the growth of space storms," said Barbara Giles, a co-investigator on the TIDE team and researcher at
Goddard. "These new observations will help us understand the conditions that enable space storms to form, thereby moving one step closer to the forecasting of the most damaging storms."
Prior to the launch of Polar, such observations of ions flowing out of the ionosphere were nearly impossible. But the TIDE instrument was specifically designed to neutralize the electrical charge that naturally builds up on the surface of spacecraft due to sunlight (about 40 to 50 volts). By squirting a small plume of Xenon ions and electrons, TIDE offsets the charge on the spacecraft and allows detectors to
observe cold plasmas like the oxygen ions seen during the September event.
- end -
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