|
|
The Infrared Helix
| Title |
The Infrared Helix |
| Description |
The Helix Nebula, which is composed of gaseous shells and disks puffed out by a dying sunlike star, exhibits complex structure on the smallest visible scales. In this new image from NASA's Spitzer Space Telescope, infrared light at wavelengths of 3.2, 4.5, and 8.0 microns has been colored blue, green, and red (respectively). The color saturation also has been increased to intensify hues. The "cometary knots" show blue-green heads due to excitation of their molecular material from shocks or ultraviolet radiation. The tails of the cometary knots appear redder due to being shielded from the central star's ultraviolet radiation and wind by the heads of the knots. |
|
The Infrared Helix
| Title |
The Infrared Helix |
| Description |
The Helix Nebula, which is composed of gaseous shells and disks puffed out by a dying sunlike star, exhibits complex structure on the smallest visible scales. In this new image from NASA's Spitzer Space Telescope, infrared light at wavelengths of 3.2, 4.5, and 8.0 microns has been colored blue, green, and red (respectively). The color saturation also has been increased to intensify hues. The "cometary knots" show blue-green heads due to excitation of their molecular material from shocks or ultraviolet radiation. The tails of the cometary knots appear redder due to being shielded from the central star's ultraviolet radiation and wind by the heads of the knots. |
|
The Mark of a Dying Star
| Title |
The Mark of a Dying Star |
| Description |
Six hundred and fifty light-years away in the constellation Aquarius, a dead star about the size of Earth, is refusing to fade away peacefully. In death, it is spewing out massive amounts of hot gas and intense ultraviolet radiation, creating a spectacular object called a "planetary nebula." In this false-color image, NASA's Hubble and Spitzer Space Telescopes have teamed up to capture the complex structure of the object, called the Helix nebula, in unprecedented detail. The composite picture is made up of visible data from Hubble and infrared data from Spitzer. The dead star, called a white dwarf, can be seen at the center of the image as a white dot. All of the colorful gaseous material seen in the image was once part of the central star, but was lost in the death throes of the star on its way to becoming a white dwarf. The intense ultraviolet radiation being released by the white dwarf is heating and destabilizing the molecules in its surrounding environment, starting from the inside out. Like an electric stovetop slowly heating up from the center first, the hottest and most unstable gas molecules can be seen at the center of the nebula as wisps of blue. The transition to more stable and cooler molecules is clearly depicted as the color of the gas changes from very hot (blue) to hot (yellow) and warm (red). A striking feature of the Helix, first revealed by ground-based images, is its collection of thousands of filamentary structures, or strands of gas. In this image the filaments can be seen under the transparent blue gas as red lines radiating out from the center. Astronomers believe that the molecules in these filaments are able to stay cooler and more stable because dense clumps of materials are shielding them from ultraviolet radiation. This image is a composite showing ionized H-alpha (green) and O III (blue) gases from the Hubble Space Telescope, and molecular hydrogen (red) from Spitzer observations at 4.5 and 8.0 microns. |
|
The Mark of a Dying Star
| Title |
The Mark of a Dying Star |
| Description |
Six hundred and fifty light-years away in the constellation Aquarius, a dead star about the size of Earth, is refusing to fade away peacefully. In death, it is spewing out massive amounts of hot gas and intense ultraviolet radiation, creating a spectacular object called a "planetary nebula." In this false-color image, NASA's Hubble and Spitzer Space Telescopes have teamed up to capture the complex structure of the object, called the Helix nebula, in unprecedented detail. The composite picture is made up of visible data from Hubble and infrared data from Spitzer. The dead star, called a white dwarf, can be seen at the center of the image as a white dot. All of the colorful gaseous material seen in the image was once part of the central star, but was lost in the death throes of the star on its way to becoming a white dwarf. The intense ultraviolet radiation being released by the white dwarf is heating and destabilizing the molecules in its surrounding environment, starting from the inside out. Like an electric stovetop slowly heating up from the center first, the hottest and most unstable gas molecules can be seen at the center of the nebula as wisps of blue. The transition to more stable and cooler molecules is clearly depicted as the color of the gas changes from very hot (blue) to hot (yellow) and warm (red). A striking feature of the Helix, first revealed by ground-based images, is its collection of thousands of filamentary structures, or strands of gas. In this image the filaments can be seen under the transparent blue gas as red lines radiating out from the center. Astronomers believe that the molecules in these filaments are able to stay cooler and more stable because dense clumps of materials are shielding them from ultraviolet radiation. This image is a composite showing ionized H-alpha (green) and O III (blue) gases from the Hubble Space Telescope, and molecular hydrogen (red) from Spitzer observations at 4.5 and 8.0 microns. |
|
The Infrared Helix (Expanded
…
| Title |
The Infrared Helix (Expanded View) |
| Description |
The Helix Nebula, which is composed of gaseous shells and disks puffed out by a dying sunlike star, exhibits complex structure on the smallest visible scales. In this new image from NASA's Spitzer Space Telescope, infrared light at wavelengths of 3.2, 4.5, and 8.0 microns has been colored blue, green, and red (respectively). The "cometary knots" show blue-green heads due to excitation of their molecular material from shocks or ultraviolet radiation. The tails of the cometary knots appear redder due to being shielded from the central star's ultraviolet radiation and wind by the heads of the knots. |
|
Comets Kick up Dust in Helix
…
| Title |
Comets Kick up Dust in Helix Nebula |
| Description |
This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these colorful beauties were named for their resemblance to gas-giant planets like Jupiter. Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years. In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died. The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded. So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found. This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns, green shows infrared light of 5.8 to 8 microns, and red shows infrared light of 24 microns. |
|
Comets Kick up Dust in Helix
…
| Title |
Comets Kick up Dust in Helix Nebula |
| Description |
This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these colorful beauties were named for their resemblance to gas-giant planets like Jupiter. Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years. In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died. The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded. So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found. This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns, green shows infrared light of 5.8 to 8 microns, and red shows infrared light of 24 microns. |
|
Abell 2597: Chandra Finds Gh
…
| Name |
Abell 2597: Chandra Finds Ghosts Of Eruption In Galaxy Cluster |
| Category |
Groups & Clusters of Galaxies |
| Release Date |
January 08, 2002 |
|
Apollo 13 Splashdown
| Title |
Apollo 13 Splashdown |
| Full Description |
A perilous space flight comes to a smooth ending with the safe splashdown of the Apollo 13 Command Module (CM) in the south Pacific Ocean, only four miles from the prime recovery ship, the U.S.S. Iwo Jima. The Command Module "Odyssey" with Commander, James A. Lovell Jr., Command Module pilot, John L. Swigert Jr. and Lunar Module pilot Fred W. Haise Jr. splashed down at 12:07:44 p.m. (CST), April 17, 1970. The crew men were transported by helicopter from the immediate recovery area to the U.S.S. Iwo Jima. |
| Date |
04/17/1970 |
| NASA Center |
Johnson Space Center |
|
Cometary Knots Around A Dyin
…
| Title |
Cometary Knots Around A Dying Star |
| Full Description |
These gigantic, tadpole-shaped objects are probably the result of a dying star's last gasps. Dubbed "cometary knots" because their glowing heads and gossamer tails resemble comets, the gaseous objects probably were formed during a star's final stages of life. Hubble astronomer C. Robert O'Dell and graduate student Kerry P. Handron of Rice University in Houston, Texas discovered thousands of these knots with the Hubble Space Telescope while exploring the Helix nebula, the closest planetary nebula to Earth at 450 light-years away in the constellation Aquarius. Although ground-based telescopes have revealed such objects, astronomers have never seen so many of them. The most visible knots all lie along the inner edge of the doomed star's ring, trillions of miles away from the star's nucleus. Although these gaseous knots appear small, they're actually huge. Each gaseous head is at least twice the size of our solar system, each tail stretches for 100 billion miles, about 1,000 times the distance between the Earth and the Sun. Astronomers theorize that the doomed star spews hot, lower-density gas from its surface, which collides with cooler, higher-density gas that had been ejected 10,000 years before. The crash fragments the smooth cloud surrounding the star into smaller, denser finger-like droplets, like dripping paint. This image was taken in August, 1994 with Hubble's Wide Field Planetary Camera 2. The red light depicts nitrogen emission ([NII] 6584A), green, hydrogen (H-alpha, 6563A), and blue, oxygen (5007A). |
| Date |
08/01/1994 |
| NASA Center |
Hubble Space Telescope Center |
|
Explosive Evidence
| Title |
Explosive Evidence |
| Full Description |
This view of the damaged Apollo 13 Service Module (SM) was photographed from the Lunar Module/Command Module following SM jettisoning. As seen here, an entire SM panel was blown away by the apparent explosion of oxygen tank number two located in Sector 4 of the SM. Two of the three fuel cells are visible just forward (above) the heavily damaged area. Three fuel cells, two oxygen tanks, and two hydrogen tanks are located in Sector 4. The damaged area is located above the S-Band high gain antenna. Nearest the camera is the Service Propulsion System (SPS) engine and nozzle. The damage to the SM caused the Apollo 13 crewmen to use the Lunar Module (LM) as a "lifeboat." The Lunar Module "Aquarius" was jettisoned just prior to Earth reentry by the Command Module "Odyssey". |
| Date |
04/17/1970 |
| NASA Center |
Johnson Space Center |
|
Hubble Finds Thousands of Ga
…
| Title |
Hubble Finds Thousands of Gaseous Fragments Surrounding a Dying Star |
|
Hubble Finds Thousands of Ga
…
| Title |
Hubble Finds Thousands of Gaseous Fragments Surrounding a Dying Star |
|
Hubble Finds Thousands of Ga
…
| Title |
Hubble Finds Thousands of Gaseous Fragments Surrounding a Dying Star |
|
Hubble Witnesses the Final B
…
| Title |
Hubble Witnesses the Final Blaze of Glory of Sun-Like Stars |
| General Information |
What is a Space Science Update? Major Hubble discoveries on NASA television ... Astronomers explain their Hubble discoveries at a press conference, called a Space Science Update (SSU), broadcast on NASA television. The SSU includes a question and answer session with members of the media. The end of a Sun-like star's life was once thought to be simple: the star gracefully casts off a shell of glowing gas and then settles into a long retirement as a burned-out white dwarf. Now, a dazzling collection of detailed views from the Hubble telescope reveals surprisingly intricate, glowing patterns spun into space by aging stars: pinwheels, lawn sprinkler-style jets, elegant goblet shapes, and even some that look like a rocket engine's exhaust. In this picture of M2-9, twin lobes of material emanate from a central, dying star. Astronomers have dubbed this object the "Twin Jet Nebula" because of the shape of the lobes. If the nebula is sliced across the star, each side appears much like a pair of exhausts from jet engines. Indeed, because of the nebula's shape and the measured velocity of the gas, in excess of 200 miles per second, astronomers believe that the description as a super-super-sonic jet exhaust is quite apt. Read more: * Release Text [ http://hubblesite.org/newscenter/archive/releases/1997/38/text/ ] |
|
Hubble Witnesses the Final B
…
| Title |
Hubble Witnesses the Final Blaze of Glory of Sun-Like Stars |
| General Information |
What is a Space Science Update? Major Hubble discoveries on NASA television ... Astronomers explain their Hubble discoveries at a press conference, called a Space Science Update (SSU), broadcast on NASA television. The SSU includes a question and answer session with members of the media. The end of a Sun-like star's life was once thought to be simple: the star gracefully casts off a shell of glowing gas and then settles into a long retirement as a burned-out white dwarf. Now, a dazzling collection of detailed views from the Hubble telescope reveals surprisingly intricate, glowing patterns spun into space by aging stars: pinwheels, lawn sprinkler-style jets, elegant goblet shapes, and even some that look like a rocket engine's exhaust. In this picture of M2-9, twin lobes of material emanate from a central, dying star. Astronomers have dubbed this object the "Twin Jet Nebula" because of the shape of the lobes. If the nebula is sliced across the star, each side appears much like a pair of exhausts from jet engines. Indeed, because of the nebula's shape and the measured velocity of the gas, in excess of 200 miles per second, astronomers believe that the description as a super-super-sonic jet exhaust is quite apt. Read more: * Release Text [ http://hubblesite.org/newscenter/archive/releases/1997/38/text/ ] |
|
Hubble Makes Precise Measure
…
| Title |
Hubble Makes Precise Measure of Extrasolar World's True Mass |
|
Hubble Makes Precise Measure
…
| Title |
Hubble Makes Precise Measure of Extrasolar World's True Mass |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
Iridescent Glory of Nearby P
…
| Title |
Iridescent Glory of Nearby Planetary Nebula Showcased on Astronomy Day |
|
A New Twist on an Old Nebula
| Title |
A New Twist on an Old Nebula |
|
A New Twist on an Old Nebula
| Title |
A New Twist on an Old Nebula |
|
A New Twist on an Old Nebula
| Title |
A New Twist on an Old Nebula |
|
A New Twist on an Old Nebula
| Title |
A New Twist on an Old Nebula |
|
A New Twist on an Old Nebula
| Title |
A New Twist on an Old Nebula |
|
A New Twist on an Old Nebula
| Title |
A New Twist on an Old Nebula |
|
Hubble's Advanced Camera for
…
| Title |
Hubble's Advanced Camera for Surveys Resumes Exploring the Universe |
| General Information |
What is a News Nugget? News Nuggets are bulletins from the world of astronomy. After a brief hiatus, the Advanced Camera for Surveys aboard NASA?s Hubble Space Telescope is back in business, probing the far reaches of space in a quest to understand the true nature of the universe?s most dominant constituent: dark energy. This is one of the first images of the universe taken after the ACS camera resumed science operation on July 4th. The camera was offline for nearly two weeks as NASA engineers switched to a backup power supply after the camera?s primary power supply failed. Read more: * The Full Story [ http://hubblesite.org/newscenter/archive/releases/2006/36/full/ ] |
|
Hubble's Advanced Camera for
…
| Title |
Hubble's Advanced Camera for Surveys Resumes Exploring the Universe |
| General Information |
What is a News Nugget? News Nuggets are bulletins from the world of astronomy. After a brief hiatus, the Advanced Camera for Surveys aboard NASA?s Hubble Space Telescope is back in business, probing the far reaches of space in a quest to understand the true nature of the universe?s most dominant constituent: dark energy. This is one of the first images of the universe taken after the ACS camera resumed science operation on July 4th. The camera was offline for nearly two weeks as NASA engineers switched to a backup power supply after the camera?s primary power supply failed. Read more: * The Full Story [ http://hubblesite.org/newscenter/archive/releases/2006/36/full/ ] |
|
Hubble's Advanced Camera for
…
| Title |
Hubble's Advanced Camera for Surveys Resumes Exploring the Universe |
| General Information |
What is a News Nugget? News Nuggets are bulletins from the world of astronomy. After a brief hiatus, the Advanced Camera for Surveys aboard NASA?s Hubble Space Telescope is back in business, probing the far reaches of space in a quest to understand the true nature of the universe?s most dominant constituent: dark energy. This is one of the first images of the universe taken after the ACS camera resumed science operation on July 4th. The camera was offline for nearly two weeks as NASA engineers switched to a backup power supply after the camera?s primary power supply failed. Read more: * The Full Story [ http://hubblesite.org/newscenter/archive/releases/2006/36/full/ ] |
|
Hubble's Advanced Camera for
…
| Title |
Hubble's Advanced Camera for Surveys Resumes Exploring the Universe |
| General Information |
What is a News Nugget? News Nuggets are bulletins from the world of astronomy. After a brief hiatus, the Advanced Camera for Surveys aboard NASA?s Hubble Space Telescope is back in business, probing the far reaches of space in a quest to understand the true nature of the universe?s most dominant constituent: dark energy. This is one of the first images of the universe taken after the ACS camera resumed science operation on July 4th. The camera was offline for nearly two weeks as NASA engineers switched to a backup power supply after the camera?s primary power supply failed. Read more: * The Full Story [ http://hubblesite.org/newscenter/archive/releases/2006/36/full/ ] |
|
Astronaut James Lovell Offic
…
| Name of Image |
Astronaut James Lovell Official Portrait |
| Date of Image |
1966-09-09 |
| Full Description |
This is the official NASA portrait of astronaut James Lovell. Captain Lovell was selected as an Astronaut by NASA in September 1962. He has since served as backup pilot for the Gemini 4 flight and backup Commander for the Gemini 9 flight, as well as backup Commander to Neil Armstrong for the Apollo 11 lunar landing mission. On December 4, 1965, he and Frank Borman were launched into space on the history making Gemini 7 mission. The flight lasted 330 hours and 35 minutes and included the first rendezvous of two manned maneuverable spacecraft. The Gemini 12 mission, commanded by Lovell with Pilot Edwin Aldrin, began on November 11, 1966 for a 4-day, 59-revolution flight that brought the Gemini program to a successful close. Lovell served as Command Module Pilot and Navigator on the epic six-day journey of Apollo 8, the first manned Saturn V liftoff responsible for allowing the first humans to leave the gravitational influence of Earth. He completed his fourth mission as Spacecraft Commander of the Apollo 13 flight, April 11-17, 1970, and became the first man to journey twice to the moon. The Apollo 13 mission was cut short due to a failure of the Service Module cryogenic oxygen system. Aborting the lunar course, Lovell and fellow crewmen, John L. Swigert and Fred W. Haise, working closely with Houston ground controllers, converted their lunar module, Aquarius, into an effective lifeboat that got them safely back to Earth. Captain Lovell held the record for time in space with a total of 715 hours and 5 minutes until surpassed by the Skylab flights. On March 1, 1973, Captain Lovell retired from the Navy and the Space Program. |
|
The Helix Nebula from CFHT
| Title |
The Helix Nebula from CFHT |
| Explanation |
One day our Sun may look like this. The Helix Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap960417.html ] is the closest example of a planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space [ http://www.seds.org/messier/planetar.html ] appear from our vantage point as if we are looking down a helix [ http://mathworld.wolfram.com/Helix.html ]. The remnant central stellar core, destined to become a white dwarf star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ], glows in light so energetic [ http://snoopy.gsfc.nasa.gov/~orfeus2/ultraviolet.html ] it causes the previously expelled gas to fluoresce [ http://www.exploratorium.edu/xref/exhibits/fluorescent_tube.html ]. The Helix Nebula [ http://www-personal.umich.edu/~jstys/nebulae/ngc7293.html ], given a technical designation of NGC 7293 [ http://www.seds.org/messier/xtra/ngc/n7293.html ], lies 450 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away towards the constellation [ http://www.emufarm.org/~cmbell/myth/myth.html ] of Aquarius [ http://www.astronomical.org/constellations/aqr.html ] and spans 1.5 light-years. The above image was taken with the Canada-France-Hawaii Telescope [ http://www.cfht.hawaii.edu/ ] (CFHT) located atop a dormant volcano in Hawaii [ http://www.state.hi.us/ ], USA. A close-up of the inner edge [ http://antwrp.gsfc.nasa.gov/apod/ap970720.html ] of the Helix Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap970901.html ] shows unusual gas knots of unknown origin [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998ApJ...503..792B ]. |
|
Dust and the Helix Nebula
| Title |
Dust and the Helix Nebula |
| Explanation |
Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image [ http://www.spitzer.caltech.edu/Media/releases/ ssc2007-03/index.shtml ] shows infrared [ http://coolcosmos.ipac.caltech.edu// ] radiation from the well-studied Helix Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap060112.html ] (NGC 7293) a mere 700 light-years away in the constellation Aquarius [ http://www.seds.org/Maps/Stars_en/Fig/aquarius.html ]. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula [ http://www.noao.edu/jacoby/pn_gallery.html ], representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models [ http://arxiv.org/abs/astro-ph/0702296 ] suggest the glow is produced by a dust debris disk [ http://antwrp.gsfc.nasa.gov/apod/ap041210.html ]. Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could be generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt [ http://www.ifa.hawaii.edu/faculty/jewitt/kb/kb.con.html ] or cometary Oort cloud [ http://www.windows.ucar.edu/tour/ link=/comets/Oort_cloud.html&edu=high ]. Formed in the distant planetary system, the comet-like bodies have otherwise survived even the dramatic late stages of the star's evolution [ http://en.wikipedia.org/wiki/Stellar_evolution ]. |
|
NGC 7293: The Helix Nebula
| Title |
NGC 7293: The Helix Nebula |
| Explanation |
A mere seven hundred light years from Earth, in the constellation Aquarius [ http://hawastsoc.org/deepsky/aqr/index.html ], a sun-like star is dying. Its last few thousand years have produced the Helix Nebula [ http://www.seds.org/messier/xtra/ngc/n7293.html ] (NGC 7293), a well studied and nearby example of a Planetary Nebula [ http://en.wikipedia.org/wiki/Planetary_nebula ], typical of this final phase of stellar evolution. Nearly 11 hours [ http://www.astronomie.be/hambsch/namibia07/ n7293-halrgb_50f3.htm ] of exposure time have gone in to creating this remarkably deep view of the nebula. It shows details of the Helix's brighter inner region [ http://antwrp.gsfc.nasa.gov/apod/ap030510.html ], about 3 light-years across, but also follows fainter outer halo [ http://www.ing.iac.es/~rcorradi/HALOES/ ] features that give the nebula a span of well over six light-years. The white dot at the Helix's center is this Planetary Nebula's hot, central star [ http://hubblesite.org/newscenter/archive/releases/1997/ 38/astrofile/ ]. A simple looking nebula at first glance, the Helix is now understood to have a surprisingly complex geometry [ http://hubblesite.org/newscenter/archive/releases/2004/ 32/image/e/ ]. |
|
Globular Cluster M2
| Title |
Globular Cluster M2 |
| Explanation |
Beneath the south pole of our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] lies a ball of over 100,000 stars. M2, the second object on Charles Messier [ http://www.seds.org/messier/xtra/history/biograph.html ]'s eighteenth century list of bright diffuse sky objects [ http://www.seds.org/messier/xtra/history/m-cat.html ], is known as a globular cluster [ http://antwrp.gsfc.nasa.gov/apod/globular_clusters.html ], and orbits the center of our Galaxy like nearly 200 other globular clusters [ http://ast.leeds.ac.uk/research/gcs.html ] left over from the early days of our universe. M2 [ http://www.seds.org/messier/m/m002.html ], pictured above [ http://www.noao.edu/image_gallery/html/im0523.html ], spans over 150 light-years, lies about 50,000 light-years [ http://www.howstuffworks.com/question94.htm ] away, and can be seen with binoculars [ http://antwrp.gsfc.nasa.gov/apod/ap010611.html http://www.birdwatching.com/optics/binoculars1.html ] towards the constellation [ http://www.windows.ucar.edu/cgi-bin/tour.cgi?link=/the_universe/Constellations/constnavi.html ] of Aquarius [ http://www.astronomical.org/constellations/aqr.html ]. Determining the distances and ages to globular clusters [ http://www.seds.org/messier/glob.html ] like M2 [ http://www.astr.ua.edu/gifimages/m2r.html ] constrains the scale [ http://antwrp.gsfc.nasa.gov/debate/debate20.html ] and age [ http://www.astro.ucla.edu/~wright/age.html ] of our entire universe. |
|
Asteroid 2002 NY40
| Title |
Asteroid 2002 NY40 |
| Explanation |
Asteroid 2002 NY40 [ http://science.nasa.gov/headlines/y2002/ 30jul_ny40.htm ] will fly by planet Earth early in the morning August 18 Universal Time (late in the evening August 17 Eastern Daylight Time). Approaching to within [ http://neo.jpl.nasa.gov/ ] about 530,000 kilometers or 1.3 times the Earth-Moon distance 2002 NY40 [ http://neo.jpl.nasa.gov/cgi-bin/db?name=2002+NY40 ] will definitely not be close enough to pose any danger of collision. But it will be close enough and just bright enough for experienced skygazers to see this 800 meter wide space rock [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ asteroids.html ] in a small telescope or binoculars as it glides quickly through northern skies [ http://science.nasa.gov/headlines/y2002/images/ny40/ skymap_ut.gif ] past the bright star Vega. It will also be close enough to ping with radar [ http://echo.jpl.nasa.gov/ ], and asteroid hunters using the large Arecibo radio telescope [ http://antwrp.gsfc.nasa.gov/apod/ap981129.html ] in Puerto Rico expect to determine the three dimensional outline of 2002 NY40. Similar investigations of other near Earth [ http://antwrp.gsfc.nasa.gov/apod/ap970120.html ] asteroids have revealed some surprising shapes [ http://antwrp.gsfc.nasa.gov/apod/ap000510.html ]. In this five minute time exposure, recorded at Cerro Tololo [ http://www.ctio.noao.edu/ ] Inter-American Observatory on August 14, 2002 NY40 shows itself as a long smudge as it moves against a background of faint stars in the constellation Aquarius [ http://www.windows.ucar.edu/tour/link=/the_universe/ Constellations/aquarius.html ]. |
|
NGC 7293: The Helix Nebula
| Title |
NGC 7293: The Helix Nebula |
| Explanation |
The Helix nebula (New General Catalog number 7293) is estimated to be a mere 450 light-years from the Sun, in the direction of the constellation Aquarius [ http://bradley.bradley.edu/~dware/aquarius.html ]. At that distance it may well be the closest planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/lib/planetary.html ], offering a dramatic snapshot of a brief final evolutionary stage [ http://fusedweb.pppl.gov/CPEP/Chart_Pages/ 5.Plasmas/Nebula/Planetary.html ] in the life of a solar-type star. In this color image the nebula glows red in the light of nitrogen and hydrogen atoms energized by the ultraviolet radiation [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#uv ] from the central star [ http://antwrp.gsfc.nasa.gov/apod/ap960209.html ]. The main rings themselves, though faint, have an angular size about half that of the full moon and span about 1.5 light-years. Because it is so close, it is a prime subject for study by astronomers [ http://blackhole.aas.org/meetings/aas186/program/abs/S3804.html ]. When the Hubble Space Telescope was focused near the inner edge of the main ring, at about the 12 o'clock position in the above image, it resolved some of the spoke like radial structures visible into intriguing cometary knots [ http://antwrp.gsfc.nasa.gov/apod/ap960416.html ]. |
|
NGC 7293: The Helix Nebula
| Title |
NGC 7293: The Helix Nebula |
| Explanation |
Will our Sun [ http://www.nineplanets.org/sol.html ] look like this one day? The Helix Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000828.html ] is the closest example of a planetary nebula [ http://antwrp.gsfc.nasa.gov/apod/planetary_nebulae.html ] created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space [ http://www.seds.org/messier/planetar.html ] appear from our vantage point as if we are looking down a helix [ http://mathworld.wolfram.com/Helix.html ]. The remnant central stellar core, destined to become a white dwarf star [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html ], glows in light so energetic [ http://imagers.gsfc.nasa.gov/ems/uv.html ] it causes the previously expelled gas to fluoresce [ http://www.exploratorium.edu/xref/exhibits/fluorescent_tube.html ]. The Helix Nebula [ http://www.seds.org/messier/xtra/ngc/n7293.html ], given a technical designation of NGC 7293 [ http://www.astro.uiuc.edu/~akspeck/evolved-stuff/nebulae/Helix/ ], lies about 650 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away towards the constellation [ http://www.emufarm.org/~cmbell/myth/myth.html ] of Aquarius [ http://www.astronomical.org/constellations/aqr.html ] and spans about 2.5 light-years. The above picture [ http://hubblesite.org/newscenter/archive/2003/11/ ] is a composite [ http://archive.stsci.edu/hst/helix/ ] of newly released images from the ACS [ http://acs.pha.jhu.edu/ ] instrument on the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ] and wide-angle images from the Mosaic Camera on the WIYN [ http://www.noao.edu/wiyn/ ] 0.9-m Telescope [ http://www.noao.edu/dir/09m/description.html ] at Kitt Peak National Observatory [ http://www.noao.edu/kpno/ ]. A close-up [ http://antwrp.gsfc.nasa.gov/apod/ap020512.html ] of the inner edge of the Helix Nebula [ http://hubblesite.org/newscenter/archive/2003/11/fastfacts ] shows complex gas knots of unknown origin [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002ApJ...573L..55H ]. |
|
The Aquarius Dwarf
| Title |
The Aquarius Dwarf |
| Explanation |
Our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] is not alone. It is part of a gathering of about 50 galaxies known as the Local Group [ http://www.seds.org/messier/more/local.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap021021.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ], M33 [ http://antwrp.gsfc.nasa.gov/apod/ap021202.html ], the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010804.html ], the Small Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000430.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap000109.html ], several small irregular galaxies [ http://www.seds.org/messier/irre.html ], and many dwarf elliptical [ http://nedwww.ipac.caltech.edu/level5/Ferguson/frames.html ] and dwarf spheroidal galaxies [ http://www.astro.uu.se/~ns/review.html ]. Pictured above is the Aquarius Dwarf [ http://www.seds.org/~spider/spider/LG/aqr_dw.html ], a faint dwarf irregular galaxy over 3 million light years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away. An earlier [ http://antwrp.gsfc.nasa.gov/apod/ap970329.html ] APOD [ http://antwrp.gsfc.nasa.gov/apod/ap960204.html ] erroneously identified [ http://www.solstation.com/x-objects/sag-deg.htm ] the above image as the Sagittarius Dwarf [ http://www.seds.org/messier/more/sagdeg.html ]. |
|
A Dark and Stormy Night
| Title |
A Dark and Stormy Night |
| Explanation |
It was a dark and stormy night [ http://antwrp.gsfc.nasa.gov/apod/ap030424.html ]. But on August 29th the red planet Mars, near its closest approach [ http://hubblesite.org/newscenter/archive/2003/22/astrofile ] to Earth in almost 60,000 years, shone brightly in the sky against a background of stars in the constellation Aquarius [ http://allthesky.com/constellations/aquarius/ constell.html ]. In the foreground of this scary view [ http://www.allthesky.de/various/marsflash.html ], huge thunder clouds are lit by lightning strokes [ http://thunder.msfc.nasa.gov/primer/ ] from within. Mars [ http://mars.jpl.nasa.gov/ ], of course, has nothing to do with storms on Earth, though both have the power to excite the imagination [ http://antwrp.gsfc.nasa.gov/apod/ap010331.html ] and wonder of Earthdwellers [ http://www.fourmilab.ch/etexts/www/warworlds/warw.html ]. And who knows [ http://www.cccoe.k12.ca.us/bats/welcome.html ] what luminous [ http://www.spaceweather.com/ ] sights you might see if you go out tonight? Have a safe and Happy Halloween [ http://kids.msfc.nasa.gov/events/ Halloween.asp ]! |
|
Peculiar Arp 295
| Title |
Peculiar Arp 295 |
| Explanation |
A spectacular bridge of stars and gas [ http://www.cv.nrao.edu/~jhibbard/MergeSeq/mergeseq.html ] stretches for nearly 250,000 light-years and joins this famous peculiar [ http://nedwww.ipac.caltech.edu/level5/Arp/frames.html ] pair of galaxies cataloged as Arp 295 [ http://www.cv.nrao.edu/~jhibbard/a295/a295.html ]. The cosmic bridge between the galaxies [ http://starchild.gsfc.nasa.gov/docs/StarChild/ universe_level2/galaxies.html ] and the long tail extending below and right of picture center are strong evidence that these two immense star systems have passed close to each other [ http://antwrp.gsfc.nasa.gov/apod/ap020506.html ] in the past, allowing violent tides induced by mutual gravity to create the eye-catching plumes [ http://antwrp.gsfc.nasa.gov/apod/ap020502.html ] of stellar material. While such interactions [ http://gladstone.uoregon.edu/~cturner/p401/collisions.html ] are drawn out over billions of years, repeated close passages [ http://www.npaci.edu/online/v4.9/galaxies2.html ] should ultimately result in the merger of this pair of galaxies into a larger single galaxy of stars. Although this scenario [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=1972ApJ...178..623T&db_key=AST&high=3c862d41db22593 ] does look peculiar, galactic mergers are thought to be common, with Arp 295 representing an early stage of this inevitable process. The Arp 295 pair are the largest of a loose grouping of galaxies about 270 million light-years distant toward the constellation Aquarius. This deep color image [ http://www.ghg.net/akelly/ ] of the region was recorded in September using the USNO 1 meter telescope [ http://www.nofs.navy.mil/about_NOFS/telescopes/rc.html ] near Flagstaff, Arizona. |
|
Infrared Helix
| Title |
Infrared Helix |
| Explanation |
Five hundred light years from Earth, in the constellation Aquarius [ http://bradley.bradley.edu/~dware/aquarius.html ], a sun-like star is dying. Its last few thousand years have produced the Helix [ http://antwrp.gsfc.nasa.gov/apod/ap960417.html ], a well studied [ http://antwrp.gsfc.nasa.gov/apod/ap960422.html ] and nearby example of a Planetary Nebula [ http://fusedweb.pppl.gov/CPEP/Chart_Pages/5.Plasmas/Nebula/ Planetary.html ] - typical of this final phase of stellar evolution [ http://antwrp.gsfc.nasa.gov/apod/ap960117.html ]. The emission in this Infrared Space Observatory [ http://isowww.estec.esa.nl/ISO/ISO.html ] image of the Helix nebula comes mostly from the expanding shells of molecular hydrogen gas. Dust, normally expected in such nebulae, should also radiate strongly at infrared wavelengths but mysteriously seems to be absent here [ http://isowww.estec.esa.nl/activities/info/2597/iso18083.html ]. The culprit may may well be the Helix's central star, a contracting white dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap961203.html ]. This small but extremely hot star radiates most of its energy at short Ultraviolet wavelengths [ http://heasarc.gsfc.nasa.gov/docs/learning_center/introduction/ emspectrum.html ] and is invisible in this infrared mage. Astronomers suspect that over time, this intense Ultraviolet radiation may have destroyed the dust [ http://antwrp.gsfc.nasa.gov/apod/ap961119.html ]. The Sun is expected to go through its own [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/interv.html ] Planetary Nebula phase ... in another 5 billion years. |
|
A Planet For Gliese 876
| Title |
A Planet For Gliese 876 |
| Explanation |
Centered in this unremarkable, 1/4 degree wide patch of sky [ http://skyview.gsfc.nasa.gov ] in the constellation Aquarius [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Aquarius.html ] is the star Gliese 876. Gliese 876 [ http://ledas-www.star.le.ac.uk/arnie/ dbhlp_WOOLLEY.html#L3Sequence_Number ] is smaller than the Sun, only about 1/3 as massive, and too faint to be seen without a telescope. But it is known to be one of the nearest stars [ http://ledas-www.star.le.ac.uk/arnie/dbhlp_WOOLLEY.html#L1Overview ], only 15 light-years distant. Astronomers have just announced findings that imply Gliese 876 [ http://cannon.sfsu.edu/~gmarcy/planetsearch/gl876/gl876.html ] has a planet at least 1.6 times as massive as Jupiter - making this now one of the closest suspected planetary [ http://antwrp.gsfc.nasa.gov/apod/ap961019.html ] systems. Like many recent discoveries [ http://cannon.sfsu.edu/~williams/planetsearch/planetsearch.html ], this planet's detection [ http://whyfiles.news.wisc.edu/017planet/search_techniques.html ] is not based on direct imaging [ http://antwrp.gsfc.nasa.gov/apod/ap980529.html ] but on spectroscopic measurements of the periodic change in motion or "Doppler wobble" [ http://cannon.sfsu.edu/~gmarcy/planetsearch/tech/techpg.html ]produced in the parent star as the planet orbits. The Doppler wobble of Gliese 876 indicates [ http://cannon.sfsu.edu/~gmarcy/planetsearch/gl876/gl876.html ] that its planet orbits once every 61 days at an average distance of about 1/5 the radius of the Earth's orbit. |
|
|
