Saturday, May 30, 2009
NOCTILUCENT CLOUDS
Rick Klawwitter
Brian WhittakerSpace Weather News for May 30, 2009
FIRST NLCs of 2009:
The first noctilucent clouds (NLCs) of 2009 have been sighted over northern Europe.
Last night, May 29th, photographers recorded wispy electric-blue tendrils spreading across the twilight skies of Denmark, Northern Ireland and Scotland.
This follows a similar display over Russia on May 27th.
These sightings signal the beginning of the 2009 NLC season, which is expected to last until late July.
Early-season NLCs are usually feeble, but these were fairly bright and vibrant, suggesting that even better displays are in the offing.
Check today's edition of http://spaceweather.com/
for photos.
Noctilucent clouds are an unsolved puzzle.
They float 83 km above Earth's surface at the edge of space itself.
People first noticed NLCs in the late 19th century.
In those days you had to travel to high northern latitudes to see them.
In recent years, however, the clouds have been sighted in the United States as far south as Oregon, Washington and even Colorado.
Climate change, space dust, and rocket launches have all been cited as possible explanations for the phenomenon.
Interestingly, low solar activity seems to promote the clouds, so the ongoing deep solar minimum could set the stage for a good season in 2009.
The best time to look for NLCs is just after sunset or just before sunrise when the sun is between 6 and 16 degrees below the horizon.
That's when the geometry is just right for sunlight to illuminate the tiny ice crystals that make up the clouds.
Observing tips and sample photos may be found in the 2008 Noctilucent Cloud Gallery:
Thursday, May 28, 2009
Wednesday, May 6, 2009
THE SUN IS ERUPTING
Space Weather News for May 6, 2009
http://spaceweather.com
NASA's STEREO-B spacecraft is monitoring an active region hidden behind the sun's eastern limb.
On May 5th, it produced an impressive coronal mass ejection (CME) and a burst of radio emissions signalling the passage of a shock wave through the sun's outer atmosphere.
Activity has continued apace today, May 6th, with at least two more eruptions. The blast site is not yet visible from Earth, but the sun is turning the region toward us for a better view. Is a new-cycle sunspot in the offing?
Readers with solar telescopes could see it emerge as early as May 7th or 8th.
Visit http://spaceweather.com
for images, movies and updates.
http://spaceweather.com
NASA's STEREO-B spacecraft is monitoring an active region hidden behind the sun's eastern limb.
On May 5th, it produced an impressive coronal mass ejection (CME) and a burst of radio emissions signalling the passage of a shock wave through the sun's outer atmosphere.
Activity has continued apace today, May 6th, with at least two more eruptions. The blast site is not yet visible from Earth, but the sun is turning the region toward us for a better view. Is a new-cycle sunspot in the offing?
Readers with solar telescopes could see it emerge as early as May 7th or 8th.
Visit http://spaceweather.com
for images, movies and updates.
Saturday, April 25, 2009
NEWS FOR APRIL
Space Weather News for April 25, 2009http://spaceweather.comSUNSET CONJUNCTION: When the sun goes down on Sunday, April 26th, step outside and look west. An exquisitely-slender crescent Moon is lining up with Mercury and the Pleiades star cluster for a three-way conjunction in the sunset sky. Click here for the full story and a sky map: http://spaceweather.com/headlines/y2009/24apr_eveningsky.phpUNEXPECTED SOLAR ACTIVITY: The sun produced an unexpected burst of activity on April 23rd when an enormous prominence rose over the northeastern limb and erupted. A coronal mass ejection (CME) billowed away from the blast site, but the billion-ton cloud is not heading toward Earth. Visit http://spaceweather.com for movies of the event.
Tuesday, April 21, 2009
SPACE NEWS
Space Weather News for April 21, 2009
http://spaceweather.com
MORNING METEORS: Earth is entering a stream of debris from Comet Thatcher, the source of the annual Lyrid meteor shower. Forecasters expect the shower to peak on Wednesday, April 22nd, with a display of 10 to 20 meteors per hour over the northern hemisphere.
Occasionally, Earth passes through a dense region of the comet's tail and rates surge five- to ten-fold. In 1982, for instance, observers were surprised by an outburst of 90 Lyrids per hour. Because Thatcher's tail has never been mapped in detail, the outbursts are unpredictable and could happen again at any time. The best time to look, no matter where you live, is during the dark hours before dawn on Wednesday morning April 22nd. Visit http://spaceweather.com for full coverage.
LUNAR OCCULTATION OF VENUS: Even if the Lyrids fizzle, there is still something wonderful to see on Wednesday morning, April 22nd.
The crescent Moon and Venus are going to have a close encounter of jaw-dropping beauty.
Look low and to the east just before sunrise.
Observers in western parts of North America will see a lunar occultation: Venus will disappear behind the Moon's limb just after 5 am PDT and reappear again an hour or so later.
Details may be found in this Science@NASA story: http://science.nasa.gov/headlines/y2009/17apr_lyrids.htm
http://spaceweather.com
MORNING METEORS: Earth is entering a stream of debris from Comet Thatcher, the source of the annual Lyrid meteor shower. Forecasters expect the shower to peak on Wednesday, April 22nd, with a display of 10 to 20 meteors per hour over the northern hemisphere.
Occasionally, Earth passes through a dense region of the comet's tail and rates surge five- to ten-fold. In 1982, for instance, observers were surprised by an outburst of 90 Lyrids per hour. Because Thatcher's tail has never been mapped in detail, the outbursts are unpredictable and could happen again at any time. The best time to look, no matter where you live, is during the dark hours before dawn on Wednesday morning April 22nd. Visit http://spaceweather.com for full coverage.
LUNAR OCCULTATION OF VENUS: Even if the Lyrids fizzle, there is still something wonderful to see on Wednesday morning, April 22nd.
The crescent Moon and Venus are going to have a close encounter of jaw-dropping beauty.
Look low and to the east just before sunrise.
Observers in western parts of North America will see a lunar occultation: Venus will disappear behind the Moon's limb just after 5 am PDT and reappear again an hour or so later.
Details may be found in this Science@NASA story: http://science.nasa.gov/headlines/y2009/17apr_lyrids.htm
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