2003 October 16
NGC 6888: X-Rays in the Wind
Credit: Y.-H. Chu & R. Gruendl (Univ. Illinois) et al.
X-ray; CXO / NASA, Optical; SDSU / MLO
NGC 6888, also known as the Crescent Nebula, is a cosmic bubble of interstellar gas about 25 light-years across. Created by winds from the bright, massive star seen near the center of this composite image, the shocked filaments of gas glowing at optical wavelengths are represented in green and yellowish hues. X-ray image data from a portion of the nebula viewed by the Chandra Observatory is overlaid in blue. Such isolated stellar wind bubbles are not usually seen to produce energetic x-rays, which require heating gas to a million degrees celsius. Still, NGC 6888 seems to have accomplished this as slow moving winds from the central star's initial transition to a red supergiant were overtaken and rammed by faster winds driven by the intense radiation from the star's exposed inner layers. Burning fuel at a prodigious rate and near the end of its stellar life, NGC 6888's central star should ultimately go out with a bang, creating a supernova explosion in 100,000 years or so. NGC 6888 is about 5,000 light-years close, toward the constellation Cygnus.
NGC 6888: X-Rays in the Wind
Credit: Y.-H. Chu & R. Gruendl (Univ. Illinois) et al.
X-ray; CXO / NASA, Optical; SDSU / MLO
NGC 6888, also known as the Crescent Nebula, is a cosmic bubble of interstellar gas about 25 light-years across. Created by winds from the bright, massive star seen near the center of this composite image, the shocked filaments of gas glowing at optical wavelengths are represented in green and yellowish hues. X-ray image data from a portion of the nebula viewed by the Chandra Observatory is overlaid in blue. Such isolated stellar wind bubbles are not usually seen to produce energetic x-rays, which require heating gas to a million degrees celsius. Still, NGC 6888 seems to have accomplished this as slow moving winds from the central star's initial transition to a red supergiant were overtaken and rammed by faster winds driven by the intense radiation from the star's exposed inner layers. Burning fuel at a prodigious rate and near the end of its stellar life, NGC 6888's central star should ultimately go out with a bang, creating a supernova explosion in 100,000 years or so. NGC 6888 is about 5,000 light-years close, toward the constellation Cygnus.
2003 October 17
Astronomy Quilt of the Week
Credit & Copyright: Judy W. Ross, Point Roberts, WA
Demonstrating her mastery of a traditional astronomical imaging technique quilter and astronomy enthusiast Judy Ross has produced this spectacular composition of "Astronomy Quilt Piece of the Week". Her year-long effort resulted in an arrangement for a six by seven foot quilt consisting of 52 individual pieces (11 inches by 8 inches), one for each week, which she reports were inspired by her steady diet of APOD's daily offerings. Some of the pieces are based on actual pictures, such as the Hubble Space Telescope's view of planet forming AB Aurigae or Bill Keel's image of the nearby Pinwheel Galaxy. Others, with titles like the Blue Carpet Nebula and Duck Contemplates Black Hole, are from her own creative imaginings.
Astronomy Quilt of the Week
Credit & Copyright: Judy W. Ross, Point Roberts, WA
Demonstrating her mastery of a traditional astronomical imaging technique quilter and astronomy enthusiast Judy Ross has produced this spectacular composition of "Astronomy Quilt Piece of the Week". Her year-long effort resulted in an arrangement for a six by seven foot quilt consisting of 52 individual pieces (11 inches by 8 inches), one for each week, which she reports were inspired by her steady diet of APOD's daily offerings. Some of the pieces are based on actual pictures, such as the Hubble Space Telescope's view of planet forming AB Aurigae or Bill Keel's image of the nearby Pinwheel Galaxy. Others, with titles like the Blue Carpet Nebula and Duck Contemplates Black Hole, are from her own creative imaginings.
2003 October 18
The Last Moon Shot
Credit: The Apollo Program, NASA (image scanned by J.L. Pickering)
In 1865 Jules Verne predicted the invention of a space capsule that could carry people. In his science fiction story "From the Earth to the Moon", he outlined his vision of a cannon in Florida so powerful that it could shoot a "Projectile-Vehicle" carrying three adventurers to the Moon. Over 100 years later, NASA, guided by Wernher Von Braun's vision, produced the Saturn V rocket. From a spaceport in Florida, this rocket turned Verne's fiction into fact, launching 9 Apollo Lunar missions and allowing 12 astronauts to walk on the Moon. Pictured is the last moon shot, Apollo 17, awaiting its December 1972 night launch. Spotlights play on the rocket and launch pad at dusk. Humans have not walked on on the lunar surface since.
The Last Moon Shot
Credit: The Apollo Program, NASA (image scanned by J.L. Pickering)
In 1865 Jules Verne predicted the invention of a space capsule that could carry people. In his science fiction story "From the Earth to the Moon", he outlined his vision of a cannon in Florida so powerful that it could shoot a "Projectile-Vehicle" carrying three adventurers to the Moon. Over 100 years later, NASA, guided by Wernher Von Braun's vision, produced the Saturn V rocket. From a spaceport in Florida, this rocket turned Verne's fiction into fact, launching 9 Apollo Lunar missions and allowing 12 astronauts to walk on the Moon. Pictured is the last moon shot, Apollo 17, awaiting its December 1972 night launch. Spotlights play on the rocket and launch pad at dusk. Humans have not walked on on the lunar surface since.
2003 October 19
An Unusual Globule in IC 1396
Credit & Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight,
Is there a monster in IC 1396? Known to some as the Elephant's Trunk Nebula, parts of gas and dust clouds of this star formation region may appear to take on foreboding forms, some nearly human. The only real monster here, however, is a bright young star too far from Earth to hurt us. Energetic light from this star is eating away the dust of the dark cometary globule near the top of the above image. Jets and winds of particles emitted from this star are also pushing away ambient gas and dust. Nearly 3,000 light-years distant, the relatively faint IC 1396 complex covers a much larger region on the sky than shown here, with an apparent width of more than 10 full moons.
An Unusual Globule in IC 1396
Credit & Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight,
Is there a monster in IC 1396? Known to some as the Elephant's Trunk Nebula, parts of gas and dust clouds of this star formation region may appear to take on foreboding forms, some nearly human. The only real monster here, however, is a bright young star too far from Earth to hurt us. Energetic light from this star is eating away the dust of the dark cometary globule near the top of the above image. Jets and winds of particles emitted from this star are also pushing away ambient gas and dust. Nearly 3,000 light-years distant, the relatively faint IC 1396 complex covers a much larger region on the sky than shown here, with an apparent width of more than 10 full moons.
2003 October 20
Neptune and Triton from Palomar
Credit & Copyright: D. Banfield, P. D. Nicholson, & B. J. Conrath (Cornell), Palomar Obs., JPL, NASA
How's the weather on Neptune? Tracking major weather patterns on the Solar System's outermost gas giant can help in the understanding of global weather patterns here on Earth. Each summer for the past five years, Neptune has been imaged and major weather patterns studied. The latest picture, taken on September 15, is shown above in false color. Visible in pink near Neptune's lower right is a new storm dubbed Annabelle that is several times larger than her terrestrial sister Isabel, a concurrent storm system that occurred here on Earth. Although Isabel lasted a few weeks, no one knows how long Annabelle will endure. On the upper right is Neptune's largest moon Triton, an unusual moon that sports volcanoes that spew ice.
Neptune and Triton from Palomar
Credit & Copyright: D. Banfield, P. D. Nicholson, & B. J. Conrath (Cornell), Palomar Obs., JPL, NASA
How's the weather on Neptune? Tracking major weather patterns on the Solar System's outermost gas giant can help in the understanding of global weather patterns here on Earth. Each summer for the past five years, Neptune has been imaged and major weather patterns studied. The latest picture, taken on September 15, is shown above in false color. Visible in pink near Neptune's lower right is a new storm dubbed Annabelle that is several times larger than her terrestrial sister Isabel, a concurrent storm system that occurred here on Earth. Although Isabel lasted a few weeks, no one knows how long Annabelle will endure. On the upper right is Neptune's largest moon Triton, an unusual moon that sports volcanoes that spew ice.
2003 October 21
The Belt of Venus over the Valley of the Moon
Credit & Copyright: Christine Churchill
Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink. Called the Belt of Venus, this off-color band between the dark eclipsed sky and the blue sky can be seen in nearly every direction including that opposite the Sun. Straight above, blue sky is normal sunlight reflecting off the atmosphere. In the Belt of Venus, however, the atmosphere reflects light from the setting (or rising) Sun which appears more red. The Belt of Venus can be seen from any location with a clear horizon. Pictured above, the Belt of Venus was photographed above morning fog in the Valley of the Moon, a famous wine-producing region in northern California, USA. The belt is frequently caught by accident in other photographs.
The Belt of Venus over the Valley of the Moon
Credit & Copyright: Christine Churchill
Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink. Called the Belt of Venus, this off-color band between the dark eclipsed sky and the blue sky can be seen in nearly every direction including that opposite the Sun. Straight above, blue sky is normal sunlight reflecting off the atmosphere. In the Belt of Venus, however, the atmosphere reflects light from the setting (or rising) Sun which appears more red. The Belt of Venus can be seen from any location with a clear horizon. Pictured above, the Belt of Venus was photographed above morning fog in the Valley of the Moon, a famous wine-producing region in northern California, USA. The belt is frequently caught by accident in other photographs.
2003 October 22
The Heart and Soul Nebulas
Credit & Copyright: Richard Powell, Digitized Sky Survey, Palomar Observatory, STScI
Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible above on the right, has a shape reminiscent of a classical heart symbol. Both nebulas shine brightly in the red light of energized hydrogen. Several young open clusters of stars populate the image and are visible above in blue, including the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focussed on how massive stars form and how they affect their environment.
The Heart and Soul Nebulas
Credit & Copyright: Richard Powell, Digitized Sky Survey, Palomar Observatory, STScI
Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible above on the right, has a shape reminiscent of a classical heart symbol. Both nebulas shine brightly in the red light of energized hydrogen. Several young open clusters of stars populate the image and are visible above in blue, including the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focussed on how massive stars form and how they affect their environment.
2003 October 23
Cygnus Nebulosities
Credit & Copyright: Steve Mandel, Galaxy Images
Looking toward the constellation Cygnus, a stunning and complex region of nebulae strewn along the plane of our Milky Way galaxy is revealed in this unique wide-angle sky view. Recorded with a filter designed to transmit light emitted by hydrogen atoms, the image emphasizes cosmic gas clouds in a 34 by 23 degree field centered on the well known Northern Cross asterism. Bright, hot, supergiant star Deneb (the top of the cross) and popular celestial sights such as the North America and Pelican emission regions, the IC 1318 "butterfly", and the Crescent and Veil nebulae can be identified by placing your cursor over the image. Silhouetted by the glowing interstellar clouds and crowded star fields, the dark Northern Coal Sack is also visible, part of a series of obscuring dust clouds forming the Great Rift in the Milky Way. These Cygnus nebulosities are all located about 2,000 light-years away. Along with the Sun, they lie within the Orion spiral arm of our galaxy.
Cygnus Nebulosities
Credit & Copyright: Steve Mandel, Galaxy Images
Looking toward the constellation Cygnus, a stunning and complex region of nebulae strewn along the plane of our Milky Way galaxy is revealed in this unique wide-angle sky view. Recorded with a filter designed to transmit light emitted by hydrogen atoms, the image emphasizes cosmic gas clouds in a 34 by 23 degree field centered on the well known Northern Cross asterism. Bright, hot, supergiant star Deneb (the top of the cross) and popular celestial sights such as the North America and Pelican emission regions, the IC 1318 "butterfly", and the Crescent and Veil nebulae can be identified by placing your cursor over the image. Silhouetted by the glowing interstellar clouds and crowded star fields, the dark Northern Coal Sack is also visible, part of a series of obscuring dust clouds forming the Great Rift in the Milky Way. These Cygnus nebulosities are all located about 2,000 light-years away. Along with the Sun, they lie within the Orion spiral arm of our galaxy.
2003 October 24
Mars Moons
Credit & Copyright: Johannes Schedler (Panther Observatory)
This year's record close approach of Mars inspired many to enjoy telescopic views of the red planet. But while Mars was so bright it was hard to miss, spotting Mars' two diminutive moons was still a good test for observers with modest sized instruments. Mars' moons were discovered in August of 1877 by Asaph Hall at the US Naval Observatory using the large 26-inch Alvan Clark refractor. Recorded on this August 22nd, innermost moon Phobos and outermost moon Deimos are seen here against the planet's glare in a digital composite image. The picture consists of of a long exposure capturing the faint, city-sized moons and overexposing the planetary disk, combined with a well exposed image of the red planet, revealing dark markings on the surface and the white south polar cap. The images were taken by astronomer Johannes Schedler using an 11-inch Schmidt-Cassegrain telescope at his observatory in southeastern Austria. (Editor's note: For help finding Mars' moons, just put your cursor over the image.)
Mars Moons
Credit & Copyright: Johannes Schedler (Panther Observatory)
This year's record close approach of Mars inspired many to enjoy telescopic views of the red planet. But while Mars was so bright it was hard to miss, spotting Mars' two diminutive moons was still a good test for observers with modest sized instruments. Mars' moons were discovered in August of 1877 by Asaph Hall at the US Naval Observatory using the large 26-inch Alvan Clark refractor. Recorded on this August 22nd, innermost moon Phobos and outermost moon Deimos are seen here against the planet's glare in a digital composite image. The picture consists of of a long exposure capturing the faint, city-sized moons and overexposing the planetary disk, combined with a well exposed image of the red planet, revealing dark markings on the surface and the white south polar cap. The images were taken by astronomer Johannes Schedler using an 11-inch Schmidt-Cassegrain telescope at his observatory in southeastern Austria. (Editor's note: For help finding Mars' moons, just put your cursor over the image.)
2003 October 25
Islands in the Photosphere
Credit & Copyright: Gunther Groenez
Awash in a sea of plasma and anchored in magnetic fields, sunspots are planet-sized, dark islands in the solar photosphere, the bright surface of the Sun. Before the enlightened(!) age of cameras, solar observers created detailed drawings of sunspots as they changed and progressed across the visible solar disk. But contemporary observers also regularly use this time-honored method of monitoring sunspots. In this sketch from March 6th 2001, astronomer Gunther Groenez has faithfully recorded the intriguing shapes and shades of major visible sunspot groups and labeled them according to their NOAA active region number. Solar north is up and east to the right. Groenez' technical equipment includes H and 2H pencil leads for the sunspot umbra (dark) and penumbra (light) areas respectively. Want to draw sunspots too? Now's your chance as two large sunspot groups are presently making their way across the solar disk. Activity associated with these large sunspots may trigger aurora in the coming days.
Islands in the Photosphere
Credit & Copyright: Gunther Groenez
Awash in a sea of plasma and anchored in magnetic fields, sunspots are planet-sized, dark islands in the solar photosphere, the bright surface of the Sun. Before the enlightened(!) age of cameras, solar observers created detailed drawings of sunspots as they changed and progressed across the visible solar disk. But contemporary observers also regularly use this time-honored method of monitoring sunspots. In this sketch from March 6th 2001, astronomer Gunther Groenez has faithfully recorded the intriguing shapes and shades of major visible sunspot groups and labeled them according to their NOAA active region number. Solar north is up and east to the right. Groenez' technical equipment includes H and 2H pencil leads for the sunspot umbra (dark) and penumbra (light) areas respectively. Want to draw sunspots too? Now's your chance as two large sunspot groups are presently making their way across the solar disk. Activity associated with these large sunspots may trigger aurora in the coming days.
2003 October 26
M16: Stars from Eagle's EGGs
Credit: J. Hester, P. Scowen (ASU), HST, NASA
Newborn stars are forming in the Eagle Nebula. This image, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away.
M16: Stars from Eagle's EGGs
Credit: J. Hester, P. Scowen (ASU), HST, NASA
Newborn stars are forming in the Eagle Nebula. This image, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away.
2003 October 27
Large Sunspot Groups 10484 and 10486
Credit & Copyright: Juan Carlos Casado
Two unusually large sunspot groups are now crossing the face of the Sun. Each group, roughly the size of Jupiter, is unusual not only for its size but because it is appearing over three years after solar maximum, the peak of solar surface activity. Sunspot group 10484 appears near the image center, while sunspot group 10486 is just coming over the left limb of the Sun. The active region associated with Sunspot 484 (the shorter nickname) has already jettisoned a large coronal mass ejection (CME) of particles out into the Solar System. When striking Earth, radiation of this sort has the power to interrupt normal satellite operations while simultaneously providing beautiful auroras. Rotating with the Sun, sunspots 484 and 486 will take about 30 days to make one complete circle, slowly evolving in size and shape during this time. After using extreme care never to look directly at the Sun, the above image was created by holding a digital camera up to a small telescope.
Large Sunspot Groups 10484 and 10486
Credit & Copyright: Juan Carlos Casado
Two unusually large sunspot groups are now crossing the face of the Sun. Each group, roughly the size of Jupiter, is unusual not only for its size but because it is appearing over three years after solar maximum, the peak of solar surface activity. Sunspot group 10484 appears near the image center, while sunspot group 10486 is just coming over the left limb of the Sun. The active region associated with Sunspot 484 (the shorter nickname) has already jettisoned a large coronal mass ejection (CME) of particles out into the Solar System. When striking Earth, radiation of this sort has the power to interrupt normal satellite operations while simultaneously providing beautiful auroras. Rotating with the Sun, sunspots 484 and 486 will take about 30 days to make one complete circle, slowly evolving in size and shape during this time. After using extreme care never to look directly at the Sun, the above image was created by holding a digital camera up to a small telescope.
2003 October 28
The SDSS 3D Universe Map
Credit & Copyright: Sloan Digital Sky Survey Team, NASA, NSF, DOE
The latest map of the cosmos again indicates that dark matter and dark energy dominate our universe. The Sloan Digital Sky Survey (SDSS) is on its way to measuring the distances to over one million galaxies. Galaxies first identified on 2D images, like the one shown above on the right, have their distances measured to create the 3D map. The SDSS currently reports 3D information for over 200,000 galaxies, now rivaling the 3D galaxy-count of the Two-Degree Field sky map. The latest SDSS map, shown above on the left, could only show the galaxy distribution it does if the universe was composed and evolved a certain way. After trying to match many candidate universes to it, the Cinderella universe that best fits the above map has 5% atoms, 25% dark matter, and 70% dark energy. Such a universe was previously postulated because its rapid recent expansion can explain why distant supernovas are so dim, and its early evolution can explain the spot distribution on the very distant cosmic microwave background.
The SDSS 3D Universe Map
Credit & Copyright: Sloan Digital Sky Survey Team, NASA, NSF, DOE
The latest map of the cosmos again indicates that dark matter and dark energy dominate our universe. The Sloan Digital Sky Survey (SDSS) is on its way to measuring the distances to over one million galaxies. Galaxies first identified on 2D images, like the one shown above on the right, have their distances measured to create the 3D map. The SDSS currently reports 3D information for over 200,000 galaxies, now rivaling the 3D galaxy-count of the Two-Degree Field sky map. The latest SDSS map, shown above on the left, could only show the galaxy distribution it does if the universe was composed and evolved a certain way. After trying to match many candidate universes to it, the Cinderella universe that best fits the above map has 5% atoms, 25% dark matter, and 70% dark energy. Such a universe was previously postulated because its rapid recent expansion can explain why distant supernovas are so dim, and its early evolution can explain the spot distribution on the very distant cosmic microwave background.
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2003 October 29
A Powerful Solar Flare
Credit: SOHO Consortium, LASCO, ESA, NASA
Yesterday, our Sun produced one of the most powerful solar flares in recorded history. Seen across the electromagnetic spectrum, the Sun briefly became over 100 times brighter in X-rays than normal. Over the next few days, as energetic particles emitted from these regions strike the Earth, satellite communications might be affected and auroras might develop. The flare and resulting CME, emitted from giant sunspot group 10486, was captured above as it happened by the by the LASCO instrument aboard the Sun-orbiting SOHO satellite. The disk of the Sun is covered to accentuate surrounding areas. The time-lapse movie shows the tremendous explosion in frames separated in real time by about 30 minutes each. The frames appear progressively noisier as protons from the flare begin to strike the detector. The SOHO satellite has been put in a temporary safe mode to avoid damage from the solar particle storm.
A Powerful Solar Flare
Credit: SOHO Consortium, LASCO, ESA, NASA
Yesterday, our Sun produced one of the most powerful solar flares in recorded history. Seen across the electromagnetic spectrum, the Sun briefly became over 100 times brighter in X-rays than normal. Over the next few days, as energetic particles emitted from these regions strike the Earth, satellite communications might be affected and auroras might develop. The flare and resulting CME, emitted from giant sunspot group 10486, was captured above as it happened by the by the LASCO instrument aboard the Sun-orbiting SOHO satellite. The disk of the Sun is covered to accentuate surrounding areas. The time-lapse movie shows the tremendous explosion in frames separated in real time by about 30 minutes each. The frames appear progressively noisier as protons from the flare begin to strike the detector. The SOHO satellite has been put in a temporary safe mode to avoid damage from the solar particle storm.
2003 October 30
Aurora in Colorado Skies
Credit & Copyright: Jimmy Westlake (Colorado Mountain College)
Vivid auroral displays were triggered by a cloud of high energy particles and magnetic fields from the Sun that collided with planet Earth's magnetosphere yesterday, October 29, at about 06:30 Universal Time. The collision was anticipated, following an intense solar flare and coronal mass ejection detected on October 28, and many anxious skywatchers were rewarded with an enjoyable light show. While aurorae don't normally haunt skies in the southern United States, they were reported from locations in Missouri, Texas, New Mexico, and California in the early morning hours. Near Yampa, Colorado astronomer Jimmy Westlake also spent early yesterday morning enjoying the stormy space weather. He was impressed by this colorful apparition of the northern lights -- produced by oxygen and nitrogen atoms excited by collisions with energetic particles from the magnetosphere and returning to lower energy states, at altitudes of 100 kilometers or more. Brighter stars shine through the extreme high-altitude glow which shows much lower clouds and the distant horizon in silhouette.
Aurora in Colorado Skies
Credit & Copyright: Jimmy Westlake (Colorado Mountain College)
Vivid auroral displays were triggered by a cloud of high energy particles and magnetic fields from the Sun that collided with planet Earth's magnetosphere yesterday, October 29, at about 06:30 Universal Time. The collision was anticipated, following an intense solar flare and coronal mass ejection detected on October 28, and many anxious skywatchers were rewarded with an enjoyable light show. While aurorae don't normally haunt skies in the southern United States, they were reported from locations in Missouri, Texas, New Mexico, and California in the early morning hours. Near Yampa, Colorado astronomer Jimmy Westlake also spent early yesterday morning enjoying the stormy space weather. He was impressed by this colorful apparition of the northern lights -- produced by oxygen and nitrogen atoms excited by collisions with energetic particles from the magnetosphere and returning to lower energy states, at altitudes of 100 kilometers or more. Brighter stars shine through the extreme high-altitude glow which shows much lower clouds and the distant horizon in silhouette.
2003 October 31
A Dark and Stormy Night
Credit & Copyright: T. Credner & S. Kohle, AlltheSky.com
It was a dark and stormy night. But on August 29th the red planet Mars, near its closest approach to Earth in almost 60,000 years, shone brightly in the sky against a background of stars in the constellation Aquarius. In the foreground of this scary view, huge thunder clouds are lit by lightning strokes from within. Mars, of course, has nothing to do with storms on Earth, though both have the power to excite the imagination and wonder of Earthdwellers. And who knows what luminous sights you might see if you go out tonight? Have a safe and Happy Halloween!
A Dark and Stormy Night
Credit & Copyright: T. Credner & S. Kohle, AlltheSky.com
It was a dark and stormy night. But on August 29th the red planet Mars, near its closest approach to Earth in almost 60,000 years, shone brightly in the sky against a background of stars in the constellation Aquarius. In the foreground of this scary view, huge thunder clouds are lit by lightning strokes from within. Mars, of course, has nothing to do with storms on Earth, though both have the power to excite the imagination and wonder of Earthdwellers. And who knows what luminous sights you might see if you go out tonight? Have a safe and Happy Halloween!
2003 November 1
Halo of the Cat's Eye
Credit: R. Corradi (Isaac Newton Group), D. Goncalves (Inst. Astrofisica de Canarias)
The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula. Made with data from the Nordic Optical Telescope in the Canary Islands, the composite picture shows emission from nitrogen atoms as red and oxygen atoms as green and blue shades. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. Only much more recently however, have some planetaries been found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years.
Halo of the Cat's Eye
Credit: R. Corradi (Isaac Newton Group), D. Goncalves (Inst. Astrofisica de Canarias)
The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula. Made with data from the Nordic Optical Telescope in the Canary Islands, the composite picture shows emission from nitrogen atoms as red and oxygen atoms as green and blue shades. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. Only much more recently however, have some planetaries been found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years.
2003 November 2
A Giant Starspot on HD 12545
Credit & Copyright: K. Strassmeier (U. Wien), Coude Feed Telescope, AURA, NOAO, NSF
What could cause a star to have such a large spot? Our Sun itself frequently has sunspots, relatively cool dark magnetic depressions that move across its surface. HD 12545, however, exhibits the largest starspots yet observed. Doppler imaging - the use of slight changes in color caused by the rotation of the star - was used to create this false-color image. The vertical bar on the right gives a temperature scale in kelvins. This giant, binary, RS CVn star, also known as XX Trianguli, is visible with binoculars in the constellation of Triangulum. The starspot is thought to be caused by large magnetic fields that inhibit hot matter from flowing to the surface.
A Giant Starspot on HD 12545
Credit & Copyright: K. Strassmeier (U. Wien), Coude Feed Telescope, AURA, NOAO, NSF
What could cause a star to have such a large spot? Our Sun itself frequently has sunspots, relatively cool dark magnetic depressions that move across its surface. HD 12545, however, exhibits the largest starspots yet observed. Doppler imaging - the use of slight changes in color caused by the rotation of the star - was used to create this false-color image. The vertical bar on the right gives a temperature scale in kelvins. This giant, binary, RS CVn star, also known as XX Trianguli, is visible with binoculars in the constellation of Triangulum. The starspot is thought to be caused by large magnetic fields that inhibit hot matter from flowing to the surface.
2003 November 3
Spiral Galaxy NGC 3982 Before Supernova
Credit: Stephen Smartt (U. Cambridge), HST, ESA, NASA
What do stars look like just before they explode? To find out, astronomers are taking detailed images of nearby galaxies now, before any supernova is visible. Hopefully, a star in one of the hundreds of high resolution galaxy images will explode in the coming years. If so, archival images like that taken above by the Hubble Space Telescope can be inspected to find what the star looked like originally. This information is likely important for better understanding of how and why supernovas occur, as well as why some supernovas appear brighter than others. Pictured above, beautiful spiral galaxy NGC 3982 displays numerous spiral arms filled with bright stars, blue star clusters, and dark dust lanes. NGC 3982, which spans about 30,000 light years, lies about 60 million light years from Earth and can be seen with a small telescope toward the constellation of Ursa Major.
Spiral Galaxy NGC 3982 Before Supernova
Credit: Stephen Smartt (U. Cambridge), HST, ESA, NASA
What do stars look like just before they explode? To find out, astronomers are taking detailed images of nearby galaxies now, before any supernova is visible. Hopefully, a star in one of the hundreds of high resolution galaxy images will explode in the coming years. If so, archival images like that taken above by the Hubble Space Telescope can be inspected to find what the star looked like originally. This information is likely important for better understanding of how and why supernovas occur, as well as why some supernovas appear brighter than others. Pictured above, beautiful spiral galaxy NGC 3982 displays numerous spiral arms filled with bright stars, blue star clusters, and dark dust lanes. NGC 3982, which spans about 30,000 light years, lies about 60 million light years from Earth and can be seen with a small telescope toward the constellation of Ursa Major.
2003 November 4
Aurora Over Edmonton
Credit & Copyright: Lance Taylor (Edmonton RASC)
Northern and southern locales saw many a beautiful aurora over the last week, as particles from several large solar flares impacted the Earth. Many reported unusually red auroras, although colors across the spectrum were also seen. Power grids and orbiting satellites braced for the onslaught, but little lasting damage was reported. Pictured above, the Clover Bar Power Plant was photographed from the banks of the North Saskatchewan River in Edmonton, Alberta, Canada. A small pond in the foreground reflects predominantly green aurora light far in the distance. Two days ago, again unexpectedly, another large solar flare occurred from sunspot group 10486, the site of other recent major flares. This unusually active solar region is now rotating to the far side of the Sun.
Aurora Over Edmonton
Credit & Copyright: Lance Taylor (Edmonton RASC)
Northern and southern locales saw many a beautiful aurora over the last week, as particles from several large solar flares impacted the Earth. Many reported unusually red auroras, although colors across the spectrum were also seen. Power grids and orbiting satellites braced for the onslaught, but little lasting damage was reported. Pictured above, the Clover Bar Power Plant was photographed from the banks of the North Saskatchewan River in Edmonton, Alberta, Canada. A small pond in the foreground reflects predominantly green aurora light far in the distance. Two days ago, again unexpectedly, another large solar flare occurred from sunspot group 10486, the site of other recent major flares. This unusually active solar region is now rotating to the far side of the Sun.