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A Cauldron of Stars at the G
…
| Title |
A Cauldron of Stars at the Galaxy's Center |
| Description |
This dazzling infrared image from NASA's Spitzer Space Telescope shows hundreds of thousands of stars crowded into the swirling core of our spiral Milky Way galaxy. In visible-light pictures, this region cannot be seen at all because dust lying between Earth and the galactic center blocks our view. In this false-color picture, old and cool stars are blue, while dust features lit up by blazing hot, massive stars are shown in a reddish hue. Both bright and dark filamentary clouds can be seen, many of which harbor stellar nurseries. The plane of the Milky Way's flat disk is apparent as the main, horizontal band of clouds. The brightest white spot in the middle is the very center of the galaxy, which also marks the site of a supermassive black hole. The region pictured here is immense, with a horizontal span of 890 light-years and a vertical span of 640 light-years. Earth is located 26,000 light-years away, out in one of the Milky Way's spiral arms. Though most of the objects seen in this image are located at the galactic center, the features above and below the galactic plane tend to lie closer to Earth. Scientists are intrigued by the giant lobes of dust extending away from the plane of the galaxy. They believe the lobes may have been formed by winds from massive stars. This image is a mosaic of thousands of short exposures taken by Spitzer's Infrared Array Camera (IRAC), showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8.0 microns (red). The entire region was imaged in less than 16 hours. |
|
A Cauldron of Stars at the G
…
| Title |
A Cauldron of Stars at the Galaxy's Center |
| Description |
This dazzling infrared image from NASA's Spitzer Space Telescope shows hundreds of thousands of stars crowded into the swirling core of our spiral Milky Way galaxy. In visible-light pictures, this region cannot be seen at all because dust lying between Earth and the galactic center blocks our view. In this false-color picture, old and cool stars are blue, while dust features lit up by blazing hot, massive stars are shown in a reddish hue. Both bright and dark filamentary clouds can be seen, many of which harbor stellar nurseries. The plane of the Milky Way's flat disk is apparent as the main, horizontal band of clouds. The brightest white spot in the middle is the very center of the galaxy, which also marks the site of a supermassive black hole. The region pictured here is immense, with a horizontal span of 890 light-years and a vertical span of 640 light-years. Earth is located 26,000 light-years away, out in one of the Milky Way's spiral arms. Though most of the objects seen in this image are located at the galactic center, the features above and below the galactic plane tend to lie closer to Earth. Scientists are intrigued by the giant lobes of dust extending away from the plane of the galaxy. They believe the lobes may have been formed by winds from massive stars. This image is a mosaic of thousands of short exposures taken by Spitzer's Infrared Array Camera (IRAC), showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8.0 microns (red). The entire region was imaged in less than 16 hours. |
|
Luminous Blue Variable: Dest
…
| Title |
Luminous Blue Variable: Destined To Be a Supernova? |
| Description |
A Luminous Blue Variable star (inset) in our galaxy, named HD168625, surrounded by a bipolar nebula that is similar to the one around SN1987A. SN1987A was a supernova that exploded in 1987 in the Large Magellanic Cloud, and was the nearest supernova in about 400 years. The diagram explains the bipolar nebula around HD168625, which has a geometry that makes it a near twin of the famous nebula around SN1987A. Rings near the equator are sometimes seen around stars that shed mass from their surfaces, but the larger rings above the poles are very rare. Tipped toward Earth and illuminated by the star, the rings look like ellipses in images taken with NASA's Spitzer Space Telescope. The image was taken in 2004 by the Infrared Array Camera (IRAC) on NASA's Spitzer Space Telescope at wavelengths between 3.6 and 8 microns. The massive star at the center, which lies within the constellation Sagittarius, is about 7,200 light-years from Earth. |
|
Luminous Blue Variable: Dest
…
| Title |
Luminous Blue Variable: Destined To Be a Supernova? |
| Description |
A Luminous Blue Variable star (inset) in our galaxy, named HD168625, surrounded by a bipolar nebula that is similar to the one around SN1987A. SN1987A was a supernova that exploded in 1987 in the Large Magellanic Cloud, and was the nearest supernova in about 400 years. The diagram explains the bipolar nebula around HD168625, which has a geometry that makes it a near twin of the famous nebula around SN1987A. Rings near the equator are sometimes seen around stars that shed mass from their surfaces, but the larger rings above the poles are very rare. Tipped toward Earth and illuminated by the star, the rings look like ellipses in images taken with NASA's Spitzer Space Telescope. The image was taken in 2004 by the Infrared Array Camera (IRAC) on NASA's Spitzer Space Telescope at wavelengths between 3.6 and 8 microns. The massive star at the center, which lies within the constellation Sagittarius, is about 7,200 light-years from Earth. |
|
Luminous Blue Variable: Dest
…
| Title |
Luminous Blue Variable: Destined To Be a Supernova? |
| Description |
A Luminous Blue Variable star (inset) in our galaxy, named HD168625, surrounded by a bipolar nebula that is similar to the one around SN1987A. SN1987A was a supernova that exploded in 1987 in the Large Magellanic Cloud, and was the nearest supernova in about 400 years. The diagram explains the bipolar nebula around HD168625, which has a geometry that makes it a near twin of the famous nebula around SN1987A. Rings near the equator are sometimes seen around stars that shed mass from their surfaces, but the larger rings above the poles are very rare. Tipped toward Earth and illuminated by the star, the rings look like ellipses in images taken with NASA's Spitzer Space Telescope. The image was taken in 2004 by the Infrared Array Camera (IRAC) on NASA's Spitzer Space Telescope at wavelengths between 3.6 and 8 microns. The massive star at the center, which lies within the constellation Sagittarius, is about 7,200 light-years from Earth. |
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The Milky Way Center Aglow w
…
| Title |
The Milky Way Center Aglow with Dust |
| Description |
Our Milky Way is a dusty place. So dusty, in fact, that we cannot see the center of the galaxy in visible light. But when NASA's Spitzer Space Telescope set its infrared eyes on the galactic center, it captured this spectacular view. Taken with just one of Spitzer's cameras (at a wavelength of 8 microns), the image highlights the region's exceptionally bright and dusty clouds, lit up by young massive stars. Individual stars can also be seen as tiny dots scattered throughout the dust. The top mosaic shows a portion of the galactic center that stretches across a distance of 760 light-years. Thanks to Spitzer's excellent resolution, the dusty features within the galactic center are seen in unprecedented detail. Four examples are shown in the magnified insets at the bottom. The farthest left box shows a pair of star-forming regions resembling owl-like cosmic eyes. To the left of the "eyes," dark lanes of dust can be seen. This object is probably located in a spiral arm between Earth and the galactic center, in contrast to the following examples, which are all located at the galactic center. The next inset to the right includes the extremely luminous "Quintuplet" stars, a set of five massive stars believed to have buried themselves in cocoons of dust. Just below and to the right of the Quintuplet is the "Pistol" nebula, a bubble of ejected material from the central, massive Pistol star. The finger-like pillars to the left are part of a structure known as "Sickle." They are similar in size and shape to those in the famous picture of the Eagle Nebula taken by NASA's Hubble Space Telescope. Pillars like these are sculpted out of dense dust clouds by radiation and winds from hot stars. The pillars in the Sickle were likely to have been formed by a cluster of hot stars located to their right but not readily visible here. The third inset highlights a system of long, stringy structures that are seen for the first time near the base of a region known as the "Arched Filaments." These long filaments are about 10 light-years long and less than 1 light-year wide. The bright star-forming regions to the right are some of the brightest in the infrared sky. The final inset to the right shows the center of our galaxy, which is the brightest spot in the entire mosaic. The brightness is a result of dust being heated up by a compact cluster of hot stars. The bright spot also marks the location of a supermassive black hole, around which a rotating ring of gas and dust known as the circumnuclear disk can be seen. This image was taken with Spitzer's Infrared Array Camera (IRAC), using its 8-micron detector. It shows emissions from heated-up molecules in dust clouds called polycyclic aromatic hydrocarbons. |
|
The Milky Way Center Aglow w
…
| Title |
The Milky Way Center Aglow with Dust |
| Description |
Our Milky Way is a dusty place. So dusty, in fact, that we cannot see the center of the galaxy in visible light. But when NASA's Spitzer Space Telescope set its infrared eyes on the galactic center, it captured this spectacular view. Taken with just one of Spitzer's cameras (at a wavelength of 8 microns), the image highlights the region's exceptionally bright and dusty clouds, lit up by young massive stars. Individual stars can also be seen as tiny dots scattered throughout the dust. The top mosaic shows a portion of the galactic center that stretches across a distance of 760 light-years. Thanks to Spitzer's excellent resolution, the dusty features within the galactic center are seen in unprecedented detail. Four examples are shown in the magnified insets at the bottom. The farthest left box shows a pair of star-forming regions resembling owl-like cosmic eyes. To the left of the "eyes," dark lanes of dust can be seen. This object is probably located in a spiral arm between Earth and the galactic center, in contrast to the following examples, which are all located at the galactic center. The next inset to the right includes the extremely luminous "Quintuplet" stars, a set of five massive stars believed to have buried themselves in cocoons of dust. Just below and to the right of the Quintuplet is the "Pistol" nebula, a bubble of ejected material from the central, massive Pistol star. The finger-like pillars to the left are part of a structure known as "Sickle." They are similar in size and shape to those in the famous picture of the Eagle Nebula taken by NASA's Hubble Space Telescope. Pillars like these are sculpted out of dense dust clouds by radiation and winds from hot stars. The pillars in the Sickle were likely to have been formed by a cluster of hot stars located to their right but not readily visible here. The third inset highlights a system of long, stringy structures that are seen for the first time near the base of a region known as the "Arched Filaments." These long filaments are about 10 light-years long and less than 1 light-year wide. The bright star-forming regions to the right are some of the brightest in the infrared sky. The final inset to the right shows the center of our galaxy, which is the brightest spot in the entire mosaic. The brightness is a result of dust being heated up by a compact cluster of hot stars. The bright spot also marks the location of a supermassive black hole, around which a rotating ring of gas and dust known as the circumnuclear disk can be seen. This image was taken with Spitzer's Infrared Array Camera (IRAC), using its 8-micron detector. It shows emissions from heated-up molecules in dust clouds called polycyclic aromatic hydrocarbons. |
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An Asteroid's Sky Trek
| title |
An Asteroid's Sky Trek |
| description |
While analyzing NASA Hubble Space Telescope images of the Sagittarius dwarf irregular galaxy (SagDIG), an international team of astronomers led by Simone Marchi, Yazan Momany, and Luigi Bedin were surprised to see the trail of a faint asteroid that had drifted across the field of view during the exposures. The trail is seen as a series of 13 reddish arcs on the right in this August 2003 Advanced Camera for Surveys image. As the Hubble telescope orbits around the Earth, and the Earth moves around the Sun, a nearby asteroid in our solar system will appear to move with respect to the vastly more distant background stars, due to an effect called parallax. It is somewhat similar to the effect you see from a moving car, in which trees by the side of the road appear to be moving much more rapidly than background objects at much larger distances. If the Hubble exposure were a continuous one, the asteroid trail would appear like a continuous wavy line. However, the exposure with Hubble's camera was actually broken up into more than a dozen separate exposures. After each exposure, the camera's shutter was closed while the image was transferred from the electronic detector into the camera's computer memory, this accounts for the many interruptions in the asteroid's trail. Since the trajectory of the Hubble spacecraft around the Earth is known very accurately, it is possible to triangulate the distance to the asteroid in a manner similar to that used by terrestrial surveyors. It turns out to be a previously unknown asteroid, located 169 million miles from Earth at the time of observation. The distance places the new object, most likely, in the main asteroid belt, lying between the orbits of Mars and Jupiter. Based on the observed brightness of the asteroid, the astronomers estimate that it has a diameter of about 1.5 miles. The brightest stars in the picture (easily distinguished by the spikes radiating from their images, produced by optical effects within the telescope), are foreground stars lying within our own Milky Way galaxy. Their distances from Earth are typically a few thousand light-years. The faint, bluish SagDIG stars lie at about 3.5 million light-years (1.1 Megaparsecs) from us. Lastly, background galaxies (reddish/brown extended objects with spiral arms and halos) are located even further beyond SagDIG at several tens of millions parsecs away. There is thus a vast range of distances among the objects visible in this photo, ranging from about 169 million miles for the asteroid, up to many quadrillions of miles for the faint, small galaxies. The team reported their science findings about the asteroid in the October 2004 issue of New Astronomy. *Image Credit*: NASA, ESA, and Y. Momany (University of Padua) |
|
Quintuplet Cluster
| Title |
Quintuplet Cluster |
| Full Description |
Penetrating 25,000 light-years of obscuring dust and myriad stars, NASA's Hubble Space Telescope has provided the clearest view yet of one of the largest young clusters of stars inside our Milky Way galaxy, located less than 100 light-years from the very center of the Galaxy. Having the equivalent mass greater than 10,000 stars like our sun, the monster cluster is ten times larger than typical young star clusters scattered throughout our Milky Way. It is destined to be ripped apart in just a few million years by gravitational tidal forces in the galaxy's core. But in its brief lifetime it shines more brightly than any other star cluster in the Galaxy. Quintuplet Cluster is 4 million years old. It has stars on the verge of blowing up as supernovae. It is the home of the brightest star seen in the galaxy, called the Pistol star. This image was taken in infrared light by Hubble's NICMOS camera in September 1997. The false colors correspond to infrared wavelengths. The galactic center stars are white, the red stars are enshrouded in dust or behind dust, and the blue stars are foreground stars between us and the Milky Way's center. The cluster is hidden from direct view behind black dust clouds in the constellation Sagittarius. If the cluster could be seen from earth it would appear to the naked eye as a 3rd magnitude star, 1/6th of a full moon's diameter apart. |
| Date |
09/16/1999 |
| NASA Center |
Hubble Space Telescope Center |
|
Giant Twisters in the Lagoon
…
| Title |
Giant Twisters in the Lagoon Nebula |
| Full Description |
This NASA Hubble Space Telescope (HST) image reveals a pair of one-half light-year long interstellar "twisters," eerie funnels and twisted-rope structures in the heart of the Lagoon Nebula (Messier 8) which lies 5,000 light-years away in the direction of the constellation Sagittarius. The central hot star, O Herschel 36 (lower right), is the primary source of the ionizing radiation for the brightest region in the nebula, called the Hourglass. Analogous to the spectacular phenomena of Earth tornadoes, the large difference in temperature between the hot surface and cold interior of the clouds, combined with the pressure of starlight, may produce strong horizontal shear to twist the clouds into their tornado-like appearance. Though the spiral shapes suggest the clouds are "twisting," future observations will be needed, perhaps with Hubble's next generation instruments, with the spectroscopic capabilities of the Space Telescope Imaging Spectrograph (STIS) or the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), to actually measure velocities. These color-coded images are the combination of individual exposures taken in July and September, 1995 with Hubble's Wide Field and Planetary Camera 2 (WFPC2) through three narrow-band filters (red light ionized sulphur atoms, blue light, double ionized oxygen atoms, green light, ionized hydrogen). |
| Date |
09/27/1995 |
| NASA Center |
Hubble Space Telescope Center |
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Giant "Twisters" and Star Wi
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| Title |
Giant "Twisters" and Star Wisps in the Lagoon Nebula |
|
Giant "Twisters" and Star Wi
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| Title |
Giant "Twisters" and Star Wisps in the Lagoon Nebula |
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Hubble Sees Material Ejected
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| Title |
Hubble Sees Material Ejected from Comet Hale-Bopp |
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Hubble Identifies What May B
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| Title |
Hubble Identifies What May Be the Most Luminous Star Known |
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Astronomers Unveil Colorful
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| Title |
Astronomers Unveil Colorful Hubble Photo Gallery |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. A vibrant celestial photo album of some of NASA Hubble Space Telescope's most stunning views of the universe is being unveiled today on the Internet. Called the Hubble Heritage Program, this technicolor gallery is being assembled by a team of astronomers at Hubble's science operations center, the Space Telescope Science Institute in Baltimore, Md. The four images released today are (top row, left to right) spiral galaxy NGC 7742, Saturn, and (bottom row, left to right) the Sagittarius Star Cloud and the Bubble Nebula. Read more: * Release Text [ http://hubblesite.org/newscenter/archive/releases/1998/28/text/ ] |
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Great Balls of Fire! Hubble
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| Title |
Great Balls of Fire! Hubble Sees Bright Knots Ejected From Brilliant Star |
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Hubble Astronomers Feast on
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| Title |
Hubble Astronomers Feast on an Interstellar Hamburger |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. Back to top [ #top ] |
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Hubble Finds Extrasolar Plan
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| Title |
Hubble Finds Extrasolar Planets Far Across Galaxy |
| General Information |
What is a NASA Science Update? Major Hubble discoveries on NASA television ... Astronomers explain their Hubble discoveries at a press conference, called a NASA Science Update (NSU), broadcast on NASA television. The NSU includes a question and answer session with members of the media. NASA's Hubble Space Telescope has discovered 16 extrasolar planet candidates orbiting a variety of distant stars in the central region of our Milky Way galaxy. The planet bonanza was uncovered during a Hubble survey, called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Hubble looked farther than has ever successfully been searched for extrasolar planets. Hubble peered at 180,000 stars in the crowded central bulge of our galaxy 26,000 light-years away or one-quarter the diameter of the Milky Way's spiral disk. The results will appear in the Oct. 5 issue of the journal Nature. Read more: * NASA Press Release [ http://hubblesite.org/newscenter/archive/releases/2006/34/text/ ] |
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Hubble Tracks Asteroid's Sky
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| Title |
Hubble Tracks Asteroid's Sky Trek |
| General Information |
What is Hubble Heritage? A monthly showcase of new and archival Hubble images. Go to the Heritage site. Back to top [ #top ] |
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The Trifid Nebula
| Name of Image |
The Trifid Nebula |
| Date of Image |
1997-09-08 |
| Full Description |
This NASA Hubble Space Telescope (HST) image of the Trifid Nebula reveals a stellar nursery being torn apart by a nearby massive star. Embryonic stars are forming within an ill-fated cloud of dust and gas, which is destined to be eaten away by the glare from the massive neighbor. The cloud is about 8 light years away from the nebula' s central star. This stellar activity is a beautiful example of how the life cycle of stars like our Sun is intimately cornected with their more powerful siblings. Residing in the constellation Sagittarius, the Trifid Nebula is about 9,000 light years from Earth. |
|
Hubble Space Telescope Image
| Name of Image |
Hubble Space Telescope Image |
| Date of Image |
1997-01-01 |
| Full Description |
Astronomers using the Hubble Space Telescope (HST) have identified what may be the most luminous star known, a celestial mammoth that releases up to 10-million times the power of the Sun and is big enough to fill the diameter of Earth's orbit. The star unleashes as much energy in six seconds as our Sun does in one year. The image, taken by a UCLA-led team with the recently installed Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) aboard the HST, also reveals a bright nebula, created by extremely massive stellar eruptions. The UCLA astronomers estimate that the star, called the Pistol Star, (for the pistol shaped nebula surrounding it), is approximately 25,000 light-years from Earth, near the center of our Milky Way galaxy. The Pistol Star is not visible to the eye, but is located in the direction of the constellation Sagittarius, hidden behind the great dust clouds along the Milky Way |
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The Hubble SWEEPS Field
| Title |
The Hubble SWEEPS Field |
| Explanation |
This crowded star field [ http://hubblesite.org/newscenter/newsdesk/archive/ releases/2006/34/ ] towards the center of our Milky Way Galaxy turns out to be a great place to search for planets beyond [ http://www.alienearths.org/online/ starandplanetformation/planetfamilies.php ] our solar system. In fact, repeatedly imaging about 180,000 stars in the field [ http://hubblesite.org/newscenter/newsdesk/archive/ releases/2006/34/fastfacts/ ] over a one week period, the Hubble Space Telescope enabled astronomers to conduct the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Their search looked for brief, periodic dips in brightness caused as a large planet eclipses [ http://antwrp.gsfc.nasa.gov/apod/ap991115.html ] or transits its parent star. Since chances [ http://imgsrc.hubblesite.org/hu/db/2006/34/images/g/ formats/web_print.jpg ] of seeing such an eclipse are slim, it was a definite advantage to examine as many stars as possible. In the end, SWEEPS astronomers found [ http://arxiv.org/abs/astro-ph/0610098 ] 16 candidate stars (green circles identify 11 in this cropped picture) that are likely closely orbited by large Jupiter-sized planets with periods of a few days or less. Large planets orbiting so close to their stars are termed hot Jupiters [ http://www.spitzer.caltech.edu/Media/releases/ ssc2006-18/release.shtml ]. Kepler [ http://www.kepler.arc.nasa.gov/ ], a future NASA mission, is intended to extend the transit technique to search for Earth-sized planets [ http://planetquest.jpl.nasa.gov/index.cfm ]. |
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M55: Globular Star Cluster
| Title |
M55: Globular Star Cluster |
| Explanation |
The fifty-fifth entry [ http://antwrp.gsfc.nasa.gov/apod/ap991023.html ] in Charles Messier's catalog, M55 is [ http://www.seds.org/messier/m/m055.html ] a large and lovely globular cluster [ http://www.seds.org/messier/glob.html ] of around 100,000 stars. Only 20,000 light-years away in the constellation Sagittarius [ http://www.astronomical.org/constellations/ sgr.html ], M55 appears to earth-bound observers to be nearly 2/3 the size of the full moon. Globular star clusters like M55 roam the halo [ http://www.limber.org/globs.html ] of our Milky Way Galaxy as gravitationally bound populations of stars known to be much older than stellar groups found in the galactic disk. Astronomers who make detailed studies [ http://arXiv.org/abs/astro-ph/?9812302 ] of globular cluster stars can accurately measure the cluster ages and distances. Their results ultimately constrain the age of the Universe [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/debate.html ] (... it must be older than the stars in it! ), and provide a fundamental rung on the astronomical distance [ http://casswww.ucsd.edu/public/tutorial/ Distances.html ] ladder. This stunning three-color image [ http://aibn47.astro.uni-bonn.de/~gallery/ articles/imagecolor.html ] made with astronomical (BVI [ http://herbie.ucolick.org/techdocs/filters/ phot_filt_curves.html ]) filters spans about 100 light-years across the globular cluster M55. |
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Constellations and Cloudy Sk
…
| Title |
Constellations and Cloudy Skies |
| Explanation |
Recorded earlier in July, the clouds of planet Earth [ http://earthobservatory.nasa.gov/ ] reflect moonlight and a faint, reddish glow in this serene sea and skyscape. Beyond them lie the cosmic dust and star clouds of the Milky Way [ http://seds.org/messier/more/mw.html ]. The near-midnight view looks south from a beach in northern France and finds the constellation Sagittarius [ http://en.wikipedia.org/wiki/ Sagittarius_%28constellation%29 ], the Archer, peaking above the horizon [ http://www.pixheaven.net/photo_us.php? nom=070705_6674-79constellation ]. Bright planet Jupiter rules [ http://antwrp.gsfc.nasa.gov/apod/ap070525.html ] on the right, wandering among the stars of the constellation Scorpius [ http://hawastsoc.org/deepsky/sco/index.html ]. Of course, the Galactic Center [ http://antwrp.gsfc.nasa.gov/apod/ap011229.html ] itself is hidden behind the Milky Way clouds in Sagittarius. To find them, just put your cursor over the picture and follow the arrow. |
|
Messiers and Mars
| Title |
Messiers and Mars |
| Explanation |
A telescopic tour of the constellation Sagittarius [ http://www.seds.org/Maps/Stars_en/Fig/ sagittarius.html ] offers the many bright clusters and nebulae of dimensioned space [ http://antwrp.gsfc.nasa.gov/apod/ap010418.html ] in a starscape [ http://antwrp.gsfc.nasa.gov/apod/ap000629.html ] surrounding the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap990911.html ]. This gorgeous color deep-sky photograph [ http://members.home.net/fct150/mars_visits_messier.htm ] visits two such lovely sights, cataloged by the 18th century cosmic tourist Charles Messier [ http://www.seds.org/messier/xtra/history/biograph.html ] as M8 and M20. M20 (upper left), the Trifid Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000328.html ], presents a striking contrast in red/blue colors and dark dust lanes. Just below and to the right is the expansive, alluring red glow of M8, the Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap010103.html ]. Both nebulae are a few thousand light-years distant but at the far right, the dominant celestial beacon is a "local" source, the planet Mars [ http://www.seds.org/nineplanets/nineplanets/mars.html ]. Just passing through Sagittarius and strongly overexposed in this picture, the Red Planet [ http://mars.jpl.nasa.gov/ ] is a short 4 light-minutes away. Now near its closest approach [ http://www.skypub.com/sights/moonplanets/0105marsreturn.shtml ] to planet Earth since 1988, Mars rises around sunset and can be seen [ http://members.nbci.com/marsprev/mpenglish.htm ] for most of the night shining [ http://cfa-www.harvard.edu/iauc/07600/07642.html#Item1 ] brightly at about -2.3 magnitude [ http://csep10.phys.utk.edu/astr162/lect/stars/ magnitudes.html ]. Urban imager [ http://members.home.net/mrcolewa/cartoon.htm ] Michael Cole recorded this photograph at 3:00 AM on May 20th in clear skies over Camp Hancock, Oregon, USA. |
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Unusual Flashes Toward Globu
…
| Title |
Unusual Flashes Toward Globular Cluster M22 |
| Explanation |
What is causing the unusual flashes behind globular cluster M22? This teeming ball of stars is the brightest globular cluster [ http://antwrp.gsfc.nasa.gov/apod/globular_clusters.html ] visible from Earth's northern hemisphere. M22 [ http://www.seds.org/messier/m/m022.html ], shown in full in the inset, spans about 50 light-years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] and lies 8,500 light-years away toward the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Sagittarius [ http://www.astronomical.org/constellations/sgr.html ]. M22's center was recently imaged repeatedly [ http://oposite.stsci.edu/pubinfo/PR/2001/20/index.html ] by the high resolution Hubble Space Telescope [ http://www.stsci.edu/hst/ ]. Behind M22 [ http://www.mt.net.au/~southsky/astronomy/m22.html ] are many more stars near the center of our Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap000705.html ]. Unexpectedly, several stars near the Galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap990911.html ] -- well behind M22 [ http://www.noao.edu/image_gallery/html/im0575.html ] -- appeared to nearly double in brightness and return to normal within 20 hours. One hypothesis [ http://www.nature.com/nature/links/010628/010628-5.html ] posed to explain these quick brightness changes is the gravitational lens effect [ http://www.iam.ubc.ca/~newbury/lenses/research.html ] of large planets roaming freely in the cluster. One problem with this is that no such planetary population [ http://exoplanets.org/index.html ] was previously known! Future observations are planned to better understand these mysterious flashes. |
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Around The Arches Cluster
| Title |
Around The Arches Cluster |
| Explanation |
The most compact cluster of stars known in our galaxy, the Arches cluster [ http://oposite.stsci.edu/pubinfo/pr/1999/30/content/ 9930w.jpg ], boasts 100 or so massive, young stars contained within a diameter of one light-year. Seen toward the constellation Sagittarius [ http://chandra.harvard.edu/photo/constellations/ sagittarius.html ], the Arches cluster is [ http://oposite.stsci.edu/pubinfo/pr/1999/30/ pr.html ] about 25,000 light-years from planet Earth and lies within a scant 100 light-years of the supermassive black hole [ http://antwrp.gsfc.nasa.gov/apod/ap001220.html ] believed to lurk in our Milky Way Galaxy's center [ http://antwrp.gsfc.nasa.gov/apod/ap990911.html ]. This combination of [ http://chandra.harvard.edu/photo/cycle1/arches/index.html ] images in radio [ http://imagers.gsfc.nasa.gov/ems/radio.html ], infrared [ http://imagers.gsfc.nasa.gov/ems/infrared.html ], and x-ray [ http://imagers.gsfc.nasa.gov/ems/xrays.html ] light illustrates this star cluster's bizarre galactic neighborhood. Shown in [ http://chandra.harvard.edu/photo/cycle1/arches/more.html ] red, radio emission traces the filamentary arching structures near the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap990128.html ] around the Arches cluster [ http://www.aas.org/publications/baas/v33n2/aas198/ 191.htm ] location. Within the zoomed inset box, infrared image data shows some of the cluster's individual stars as bright point-like sources. The diffuse emission in blue surrounding the cluster stars is a false-color [ http://chandra.harvard.edu/photo/false_color.html ] x-ray image of an enveloping cloud of 60 million degree gas -- the first time [ http://www.physics.nwu.edu/news/reuters.html ] such an energetic star cluster halo has been detected. Astronomers consider [ http://www.physics.nwu.edu/news/starfactory.html ] the tightly packed and relatively nearby Arches cluster, an analog of the furious star forming regions in galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap010606.html ] millions of light-years away. |
|
Moonlight, Mars, and Milky W
…
| Title |
Moonlight, Mars, and Milky Way |
| Explanation |
Aloha [ http://www.mhpcc.edu/~erobello/homepage_ernie/ernie1.html ] and welcome to a breath-taking skyscape. In this celestial scene, a four day old Moon illuminates a dreamlike foreground while bright planet Mars [ http://antwrp.gsfc.nasa.gov/apod/ap010615.html ] (above center) rules and the Milky Way's [ http://www.maths.tcd.ie/~jaymin/chview/chv5.htm ] cosmic clouds of stars and dust seem to stretch from horizon to horizon. The picture was taken on May 27th from what may be the best amateur astronomy observing site on planet Earth [ http://antwrp.gsfc.nasa.gov/apod/ap980725.html ], near the Mauna Kea, Hawai'i Visitor Center [ http://www.ifa.hawaii.edu/info/vis/ ], 9,600 feet above sea level. Remarkable in the volcanic foreground are moonlit clouds and an "ahu hoku" - a star marker or star altar - built up of rocks topped with a white piece of coral gently glowing in the moonlight. Now near its closest approach in 13 years, Mars still lingers [ http://www.skypub.com/sights/moonplanets/ 0105marsreturn.shtml ] between the Milky Way constellations of [ http://antwrp.gsfc.nasa.gov/apod/ap990911.html ] Sagittarius and Scorpius. High above the horizon by midnight, the Red Planet [ http://members.nbci.com/marsprev/mpenglish.htm ] is exceptionally well placed for earthdwellers to [ http://antwrp.gsfc.nasa.gov/apod/ap010331.html ] admire it. Astrophotographer Barney Magrath [ mailto:magraths@kona.net ] comments that this splendid sky view represents one of the joys of photography [ http://antwrp.gsfc.nasa.gov/apod/ap001104.html ] itself. When making the time exposure he did not realize that the ahu hoku would become such a beautiful element in his celestial composition. |
|
The Small Cloud of Magellan
| Title |
The Small Cloud of Magellan |
| Explanation |
Portuguese navigator Ferdinand Magellan [ http://www.mariner.org/educationalad/ageofex/ magellan.php ] and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial wonders easily visible for southern hemisphere skygazers are known as the Clouds of Magellan. These cosmic clouds are now understood to be dwarf irregular galaxies, satellites of our larger spiral [ http://www.atlasoftheuniverse.com/ ] Milky Way Galaxy. The Small Magellanic Cloud [ http://www.seds.org/messier/xtra/ngc/smc.html ] pictured above actually spans 15,000 light-years or so and contains several hundred million stars. About 210,000 light-years distant in the constellation Tucana [ http://www.hawastsoc.org/deepsky/tuc/ ], it is the fourth closest of the Milky Way's known satellite galaxies, after the Canis Major [ http://www.seds.org/messier/more/cma_dw.html ] and Sagittarius Dwarf [ http://www.seds.org/messier/more/sagdeg.html ] galaxies and the Large Magellanic Cloud [ http://www.seds.org/messier/xtra/ngc/lmc.html ]. This gorgeous view [ http://astrosurf.com/sguisard/Pagim/SMC-LHRVB-300mm-V1.html ] also includes two foreground globular star clusters NGC 362 (bottom right) and 47 Tucanae. Spectacular 47 Tuc [ http://antwrp.gsfc.nasa.gov/apod/ap010422.html ]anae is a mere 13,000 light-years away and seen here to the left of the Small Magellanic Cloud [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ multiwavelength_astronomy/multiwavelength_museum/ smc.html ]. |
|
Messiers and Mars
| Title |
Messiers and Mars |
| Explanation |
A telescopic tour of the constellation Sagittarius [ http://www.hawastsoc.org/deepsky/sgr/index.html ] offers the many bright clusters and nebulae of dimensioned space [ http://antwrp.gsfc.nasa.gov/apod/ap010418.html ] in a starscape [ http://antwrp.gsfc.nasa.gov/apod/ap000629.html ] surrounding the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap990911.html ]. This gorgeous color deep-sky photograph [ http://home.earthlink.net/~fct150/mars_visits_messier.htm ] visits two such lovely sights, cataloged by the 18th century cosmic tourist Charles Messier [ http://www.seds.org/messier/xtra/history/biograph.html ] as M8 and M20. M20 (upper left), the Trifid Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap000328.html ], presents a striking contrast in red/blue colors and dark dust lanes. Just below and to the right is the expansive, alluring red glow of M8, the Lagoon Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap010103.html ]. Both nebulae are a few thousand light-years distant but at the far right, the dominant celestial beacon is a "local" source, the planet Mars [ http://www.seds.org/nineplanets/nineplanets/mars.html ]. Just passing through Sagittarius and strongly overexposed in this picture, the Red Planet [ http://mars.jpl.nasa.gov/ ] was a short 4 light-minutes away. Now headed [ http://www.lpl.arizona.edu/~rhill/alpo/mars.html ] for its closest approach [ http://skyandtelescope.com/observing/objects/planets/ article_985_1.asp ] to planet Earth in recorded history, Mars rises in the east southeast by midnight shining brightly at about -1.4 magnitude [ http://csep10.phys.utk.edu/astr162/lect/stars/ magnitudes.html ]. Urban imager [ http://home.earthlink.net/~urbanimager/cartoon.htm ] Michael Cole recorded this photograph at 3:00 AM on May 20th, 2001 in clear skies over Camp Hancock, Oregon, USA. |
|
A Gemini Sky
| Title |
A Gemini Sky |
| Explanation |
Where will Gemini take us tonight? It is dusk and Gemini North [ http://antwrp.gsfc.nasa.gov/apod/ap990629.html ], one of the largest telescopes [ http://www.seds.org/billa/bigeyes.html ] on planet Earth [ http://antwrp.gsfc.nasa.gov/apod/ap010204.html ], prepares to peer into the distant universe. Gemini's flexible 8.1-mirror [ http://www.gemini.edu/media/factssheet.html ] has taken already effectively taken humanity to distant stars [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003MNRAS.343..880G ], nebulas [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001AAS...198.1905K ], galaxies [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003AJ....125.3046D ], and quasars [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003AJ....125.1053H ], telling us about the geometry, composition, and evolution of our universe. The above picture is actually a composite of over 40 images taken while the Gemini dome rotated, later adding an image of the star field taken from the same location. The Gemini dome [ http://www.gemini.edu/media/factsheets/enclosurefacts.html ] is not transparent -- it only appears so because it rotated during the exposures of this image. The constellations of Scorpius [ http://www.astronomical.org/constellations/sco.html ] and Sagittarius [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Sagittarius.html ] can be seen above the dome, as well as the sweeping band [ http://antwrp.gsfc.nasa.gov/apod/ap990224.html ] of our Milky Way Galaxy [ http://www.seds.org/messier/more/mw.html ], including the direction toward the Galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap011229.html ]. Gemini North's twin, Gemini South [ http://www.gemini.edu/media/GSDedication/ ], resides in Cerro Pach n, Chile [ http://www.cia.gov/cia/publications/factbook/geos/ci.html ]. This night, 2003 August 19, Gemini North [ http://www.gemini.edu/media/GNDedication/ ] took us only into the outer Solar System [ http://www.nineplanets.org/overview.html ], observing [ http://www.gemini.edu/sciops/schedules/schedIndex.html ] Pluto [ http://www.nineplanets.org/pluto.html ] in an effort to better determine the composition of its thin atmosphere. |
|
Infrared Trifid
| Title |
Infrared Trifid |
| Explanation |
The Trifid nebula [ http://seds.lpl.arizona.edu/messier/m/m020.html ] (M20) is a bright star forming region in Sagittarius [ http://antwrp.gsfc.nasa.gov/apod/ap960723.html ], 5000 light years from Earth. In visible light [ http://antwrp.gsfc.nasa.gov/apod/ap951221.html ], the interstellar gas cloud is crossed by dark, obscuring dust lanes [ http://antwrp.gsfc.nasa.gov/apod/ap970824.html ] which roughly divide the glowing emission nebula into three major parts. But the Trifid nebula's well known appearance is dramatically reversed in this infrared view [ http://www.estec.esa.nl/spdwww/iso/html/iso18085.htm ]. At longer infrared wavelengths [ http://heasarc.gsfc.nasa.gov/docs/learning_center/ introduction/emspectrum.html ] the dust lanes are brighter, radiating more energy than the gas. This image was recorded by the liquid helium cooled Infrared Space Observatory [ http://isowww.estec.esa.nl/ISO/ISO.html ] (ISO). |
|
M55: Globular Star Cluster
| Title |
M55: Globular Star Cluster |
| Explanation |
The fifty-fifth entry [ http://antwrp.gsfc.nasa.gov/apod/ap040424.html ] in Charles Messier's catalog, M55 is [ http://www.seds.org/messier/m/m055.html ] a large and lovely globular cluster [ http://www.seds.org/messier/glob.html ] of around 100,000 stars. Only 20,000 light-years away in the constellation Sagittarius [ http://www.hawastsoc.org/deepsky/sgr/index.html ], M55 appears to earth-bound observers to be nearly 2/3 the size of the full moon. Globular star clusters like M55 roam the halo [ http://www.belmontnc.4dw.net/globulars.htm ] of our Milky Way Galaxy as gravitationally bound populations of stars known to be much older than stellar groups found in the galactic disk. Astronomers who make detailed studies [ http://arXiv.org/abs/astro-ph/?9812302 ] of globular cluster stars can accurately measure the cluster ages and distances. Their results ultimately constrain the age of the Universe [ http://antwrp.gsfc.nasa.gov/diamond_jubilee/debate.html ] (... it must be older than the stars in it! ), and provide a fundamental rung on the astronomical distance [ http://cassfos02.ucsd.edu/public/tutorial/ Distances.html ] ladder. This stunning three-color image [ http://www.allthesky.com/articles/ imagecolor.html ] made with astronomical (BVI [ http://herbie.ucolick.org/techdocs/filters/ phot_filt_curves.html ]) filters spans about 100 light-years across the globular cluster M55. |
|
The Sagittarius Dwarf Tidal
…
| Title |
The Sagittarius Dwarf Tidal Stream |
| Explanation |
Is our Milky Way Galaxy out to lunch? Recent wide field images and analyses [ http://www.astro.virginia.edu/~mfs4n/sgr/ ] now indicate that our home galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] is actually still in the process of devouring one of its closer satellite neighbors [ http://www.astro.uu.se/~ns/mwsat.html ]. This unfortunate neighbor [ http://antwrp.gsfc.nasa.gov/apod/ap991003.html ], the Sagittarius Dwarf [ http://www.seds.org/messier/more/sagdeg.html ] galaxy, is now seen to be part of a larger Sagittarius Tidal Stream [ http://arxiv.org/abs/astro-ph/0308009 ], a loose filament of stars, gas, and possibly dark matter that entangles the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap020719.html ]. An artist's depiction of the stream is shown above. Speculation [ http://xxx.lanl.gov/abs/astro-ph/0309567 ] also holds that the Sagittarius Dwarf [ http://www.astro.wesleyan.edu/~kvj/sgr.html ] was once pulled through the Milky Way disk [ http://antwrp.gsfc.nasa.gov/apod/ap990224.html ] very close to our Sun's current location [ http://www.ecology.com/earth-at-a-glance/earth-at-a-glance-feature/ ]. An important resulting realization is that galaxies [ http://antwrp.gsfc.nasa.gov/apod/spiral_galaxies.html ] contain a jumble of clumps and filaments [ http://arXiv.org/abs/astro-ph/0309162 ] of both dim [ http://antwrp.gsfc.nasa.gov/apod/ap030727.html ] and dark matter [ http://csep10.phys.utk.edu/guidry/violence/darkmatter.html ]. |
|
The Small Cloud of Magellan
| Title |
The Small Cloud of Magellan |
| Explanation |
Portuguese navigator Ferdinand Magellan [ http://www.mariner.org/educationalad/ageofex/ magellan.php ] and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial wonders easily visible for southern hemisphere skygazers are known as the Clouds of Magellan. These cosmic clouds are now understood to be dwarf irregular galaxies, satellites of our larger spiral [ http://www.anzwers.org/free/universe/ sattelit.html ] Milky Way Galaxy. The Small Magellanic Cloud pictured above actually spans 15,000 light-years or so and contains several hundred million stars. About 210,000 light-years distant in the constellation Tucana [ http://www.hawastsoc.org/deepsky/tuc/ ], it is the fourth closest of the Milky Way's known satellite galaxies, after the Canis Major [ http://www.seds.org/messier/more/cma_dw.html ] and Sagittarius Dwarf [ http://www.seds.org/messier/more/sagdeg.html ] galaxies and the Large Magellanic Cloud [ http://www.seds.org/messier/xtra/ngc/lmc.html ]. This gorgeous view [ http://www.robgendlerastropics.com/SMC.html ] also includes two foreground globular star clusters NGC 362 (top left) and 47 Tucanae. Spectacular 47 Tuc [ http://antwrp.gsfc.nasa.gov/apod/ap010422.html ]anae is a mere 13,000 light-years away and seen here to the right of the Small Magellanic Cloud [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ multiwavelength_astronomy/multiwavelength_museum/ smc.html ]. |
|
Two Moons and the Pleiades f
…
PIA06340
Sol (our sun)
Panoramic Camera
| Title |
Two Moons and the Pleiades from Mars |
| Original Caption Released with Image |
Taking advantage of extra solar energy collected during the day, NASA's Mars Exploration Rover Spirit recently settled in for an evening of stargazing, photographing the two moons of Mars as they crossed the night sky. In this view, the Pleiades, a star cluster also known as the "Seven Sisters," is visible in the lower left corner. The bright star Aldebaran and some of the stars in the constellation Taurus are visible on the right. Spirit acquired this image the evening of martian day, or sol, 590 (Aug. 30, 2005). The image on the right provides an enhanced-contrast view with annotation. Within the enhanced halo of light is an insert of an unsaturated view of Phobos taken a few images later in the same sequence. "It is incredibly cool to be running an observatory on another planet," said planetary scientist Jim Bell of Cornell University, Ithaca, N.Y., lead scientist for the panoramic cameras on Spirit and Opportunity. In the annotated animation (figure 2), both martian moons, Deimos on the left and Phobos on the right, travel across the night sky in front of the constellation Sagittarius. Part of Sagittarius resembles an upside-down teapot. In this view, Phobos moves toward the handle and Deimos moves toward the lid. Phobos is the brighter object on the right, Deimos is on the left. Each of the stars in Sagittarius is labeled with its formal name. The inset shows an enlarged, enhanced view of Phobos, shaped rather like a potato with a hole near one end. The hole is the large impact creater Stickney, visible on the moon's upper right limb. On Mars, Phobos would be easily visible to the naked eye at night, but would be only about one-third as large as the full Moon appears from Earth. Astronauts staring at Phobos from the surface of Mars would notice its oblong, potato-like shape and that it moves quickly against the background stars. Phobos takes only 7 hours, 39 minutes to complete one orbit of Mars. That is so fast, relative to the 24-hour-and-39-minute sol on Mars (the length of time it takes for Mars to complete one rotation), that Phobos rises in the west and sets in the east. Earth's moon, by comparison, rises in the east and sets in the west. The smaller martian moon, Deimos, takes 30 hours, 12 minutes to complete one orbit of Mars. That orbital period is longer than a martian sol, and so Deimos rises, like most solar system moons, in the east and sets in the west. Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this composite with the panoramic camera, using the camera's broadband filter, which was designed specifically for acquiring images under low-light conditions. |
|
Two Moons and the Pleiades f
…
PIA06340
Sol (our sun)
Panoramic Camera
| Title |
Two Moons and the Pleiades from Mars |
| Original Caption Released with Image |
Taking advantage of extra solar energy collected during the day, NASA's Mars Exploration Rover Spirit recently settled in for an evening of stargazing, photographing the two moons of Mars as they crossed the night sky. In this view, the Pleiades, a star cluster also known as the "Seven Sisters," is visible in the lower left corner. The bright star Aldebaran and some of the stars in the constellation Taurus are visible on the right. Spirit acquired this image the evening of martian day, or sol, 590 (Aug. 30, 2005). The image on the right provides an enhanced-contrast view with annotation. Within the enhanced halo of light is an insert of an unsaturated view of Phobos taken a few images later in the same sequence. "It is incredibly cool to be running an observatory on another planet," said planetary scientist Jim Bell of Cornell University, Ithaca, N.Y., lead scientist for the panoramic cameras on Spirit and Opportunity. In the annotated animation (figure 2), both martian moons, Deimos on the left and Phobos on the right, travel across the night sky in front of the constellation Sagittarius. Part of Sagittarius resembles an upside-down teapot. In this view, Phobos moves toward the handle and Deimos moves toward the lid. Phobos is the brighter object on the right, Deimos is on the left. Each of the stars in Sagittarius is labeled with its formal name. The inset shows an enlarged, enhanced view of Phobos, shaped rather like a potato with a hole near one end. The hole is the large impact creater Stickney, visible on the moon's upper right limb. On Mars, Phobos would be easily visible to the naked eye at night, but would be only about one-third as large as the full Moon appears from Earth. Astronauts staring at Phobos from the surface of Mars would notice its oblong, potato-like shape and that it moves quickly against the background stars. Phobos takes only 7 hours, 39 minutes to complete one orbit of Mars. That is so fast, relative to the 24-hour-and-39-minute sol on Mars (the length of time it takes for Mars to complete one rotation), that Phobos rises in the west and sets in the east. Earth's moon, by comparison, rises in the east and sets in the west. The smaller martian moon, Deimos, takes 30 hours, 12 minutes to complete one orbit of Mars. That orbital period is longer than a martian sol, and so Deimos rises, like most solar system moons, in the east and sets in the west. Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this composite with the panoramic camera, using the camera's broadband filter, which was designed specifically for acquiring images under low-light conditions. |
|
Two Moons and the Pleiades f
…
PIA06340
Sol (our sun)
Panoramic Camera
| Title |
Two Moons and the Pleiades from Mars |
| Original Caption Released with Image |
Taking advantage of extra solar energy collected during the day, NASA's Mars Exploration Rover Spirit recently settled in for an evening of stargazing, photographing the two moons of Mars as they crossed the night sky. In this view, the Pleiades, a star cluster also known as the "Seven Sisters," is visible in the lower left corner. The bright star Aldebaran and some of the stars in the constellation Taurus are visible on the right. Spirit acquired this image the evening of martian day, or sol, 590 (Aug. 30, 2005). The image on the right provides an enhanced-contrast view with annotation. Within the enhanced halo of light is an insert of an unsaturated view of Phobos taken a few images later in the same sequence. "It is incredibly cool to be running an observatory on another planet," said planetary scientist Jim Bell of Cornell University, Ithaca, N.Y., lead scientist for the panoramic cameras on Spirit and Opportunity. In the annotated animation (figure 2), both martian moons, Deimos on the left and Phobos on the right, travel across the night sky in front of the constellation Sagittarius. Part of Sagittarius resembles an upside-down teapot. In this view, Phobos moves toward the handle and Deimos moves toward the lid. Phobos is the brighter object on the right, Deimos is on the left. Each of the stars in Sagittarius is labeled with its formal name. The inset shows an enlarged, enhanced view of Phobos, shaped rather like a potato with a hole near one end. The hole is the large impact creater Stickney, visible on the moon's upper right limb. On Mars, Phobos would be easily visible to the naked eye at night, but would be only about one-third as large as the full Moon appears from Earth. Astronauts staring at Phobos from the surface of Mars would notice its oblong, potato-like shape and that it moves quickly against the background stars. Phobos takes only 7 hours, 39 minutes to complete one orbit of Mars. That is so fast, relative to the 24-hour-and-39-minute sol on Mars (the length of time it takes for Mars to complete one rotation), that Phobos rises in the west and sets in the east. Earth's moon, by comparison, rises in the east and sets in the west. The smaller martian moon, Deimos, takes 30 hours, 12 minutes to complete one orbit of Mars. That orbital period is longer than a martian sol, and so Deimos rises, like most solar system moons, in the east and sets in the west. Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this composite with the panoramic camera, using the camera's broadband filter, which was designed specifically for acquiring images under low-light conditions. |
|
Luminous Blue Variable: Dest
…
PIA09119
Infrared Array Camera (IRAC)
| Title |
Luminous Blue Variable: Destined To Be a Supernova? |
| Original Caption Released with Image |
Click on the image for full resolution Poster Version of Diagram A luminous blue variable star (inset) in our galaxy, named HD168625, surrounded by a bipolar nebula that is similar to the one around SN1987A. SN1987A was a supernova that exploded in 1987 in the Large Magellanic Cloud, and was the nearest supernova in about 400 years. The diagram explains the bipolar nebula around HD168625, which has a geometry that makes it a near twin of the famous nebula around SN1987A. Rings near the equator are sometimes seen around stars that shed mass from their surfaces, but the larger rings above the poles are very rare. Tipped toward Earth and illuminated by the star, the rings look like ellipses in images taken with NASA's Spitzer Space Telescope. The image was taken in 2004 by the infrared array camera on Spitzer at wavelengths between 3.6 and 8 microns. The massive star at the center, which lies within the constellation Sagittarius, is about 7,200 light-years from Earth. |
|
Luminous Blue Variable: Dest
…
PIA09119
Infrared Array Camera (IRAC)
| Title |
Luminous Blue Variable: Destined To Be a Supernova? |
| Original Caption Released with Image |
Click on the image for full resolution Poster Version of Diagram A luminous blue variable star (inset) in our galaxy, named HD168625, surrounded by a bipolar nebula that is similar to the one around SN1987A. SN1987A was a supernova that exploded in 1987 in the Large Magellanic Cloud, and was the nearest supernova in about 400 years. The diagram explains the bipolar nebula around HD168625, which has a geometry that makes it a near twin of the famous nebula around SN1987A. Rings near the equator are sometimes seen around stars that shed mass from their surfaces, but the larger rings above the poles are very rare. Tipped toward Earth and illuminated by the star, the rings look like ellipses in images taken with NASA's Spitzer Space Telescope. The image was taken in 2004 by the infrared array camera on Spitzer at wavelengths between 3.6 and 8 microns. The massive star at the center, which lies within the constellation Sagittarius, is about 7,200 light-years from Earth. |
|
Luminous Blue Variable: Dest
…
PIA09119
Infrared Array Camera (IRAC)
| Title |
Luminous Blue Variable: Destined To Be a Supernova? |
| Original Caption Released with Image |
Click on the image for full resolution Poster Version of Diagram A luminous blue variable star (inset) in our galaxy, named HD168625, surrounded by a bipolar nebula that is similar to the one around SN1987A. SN1987A was a supernova that exploded in 1987 in the Large Magellanic Cloud, and was the nearest supernova in about 400 years. The diagram explains the bipolar nebula around HD168625, which has a geometry that makes it a near twin of the famous nebula around SN1987A. Rings near the equator are sometimes seen around stars that shed mass from their surfaces, but the larger rings above the poles are very rare. Tipped toward Earth and illuminated by the star, the rings look like ellipses in images taken with NASA's Spitzer Space Telescope. The image was taken in 2004 by the infrared array camera on Spitzer at wavelengths between 3.6 and 8 microns. The massive star at the center, which lies within the constellation Sagittarius, is about 7,200 light-years from Earth. |
|
Hubble Sees Material Ejected
…
PIA01291
Sol (our sun)
Wide Field Planetary Camera
…
| Title |
Hubble Sees Material Ejected From Comet Hale-Bopp |
| Original Caption Released with Image |
These NASA Hubble Space Telescope pictures of comet Hale-Bopp show a remarkable "pinwheel" pattern and a blob of free-flying debris near the nucleus. The bright clump of light along the spiral (above the nucleus, which is near the center of the frame) may be a piece of the comet's icy crust that was ejected into space by a combination of ice evaporation and the comet's rotation, and which then disintegrated into a bright cloud of particles. Although the "blob" is about 3.5 times fainter than the brightest portion at the nucleus, the lump appears brighter because it covers a larger area. The debris follows a spiral pattern outward because the solid nucleus is rotating like a lawn sprinkler, completing a single rotation about once per week. Ground-based observations conducted over the past two months have documented at least two separate episodes of jet and pinwheel formation and fading. By coincidence, the first Hubble images of Hale-Bopp, taken on September 26, 1995, immediately followed one of these outbursts and allow researchers to examine it at unprecedented detail. For the first time they see a clear separation between the nucleus and some of the debris being shed. By putting together information from the Hubble images and those taken during the recent outburst using the 82 cm telescope of the Teide Observatory (Tenerife, Canary Islands, Spain), astronomers find that the debris is moving away from the nucleus at a speed (projected on the sky) of about 68 miles per hour (109 kilometers per hour). The Hubble observations will be used to determine if Hale-Bopp is really a giant comet or rather a more moderate-sized object whose current activity is driven by outgassing from a very volatile ice which will "burn out" over the next year. Comet Hale-Bopp was discovered on July 23, 1995 by amateur astronomers Alan Hale and Thomas Bopp. Though this comet is still well outside the orbit of Jupiter (almost 600 million miles, or one billion kilometers from Earth) it looks surprisingly bright, fueling predictions that it could become the brightest comet of the century in early 1997. The full-field picture on the left, taken with the Wide Field Planetary Camera 2 (in WF mode), shows the comet against a stellar backdrop in the constellation Sagittarius. The stars are streaked due to a combination of Hubble's orbital motion and its tracking of the nucleus, which is now falling toward the Sun at 33,800 miles per hour (54,000 km/hr). In the close-up picture on the right, the stars have been subtracted through image processing. Each picture element is nearly 300 miles (480 km) across at the comet's distance. In this false color scale the faintest regions are black, the brightest regions are white, and intermediate intensities are represented by different levels of red. Even more detailed Hubble images will be taken with the Planetary Camera in late October to follow the further evolution of the spiral, look for more outbursts, place limits on the size of, the nucleus, and use spectroscopy to study the enigmatic comet's chemical composition. The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science. This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/ |
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Stardust Returns to Earth (A
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PIA03181
| Title |
Stardust Returns to Earth (Artist's Concept) |
| Original Caption Released with Image |
This artist's rendering depicts Stardust returning to Earth. Stardust is the first U.S. space mission dedicated solely to the exploration of a comet, and the first robotic mission designed to return extraterrestrial material from outside the orbit of the Moon. The Stardust spacecraft will bring back samples of interstellar dust, including recently discovered dust streaming into our Solar System from the direction of Sagittarius. |
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Sample Return Capsule Parach
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PIA03184
| Title |
Sample Return Capsule Parachuting Down To Earth (Artist's Concept) |
| Original Caption Released with Image |
Artist's rendering of the Stardust capsule returning to Earth. The Stardust spacecraft will bring back samples of interstellar dust, including recently discovered dust streaming into our Solar System from the direction of Sagittarius. |
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Sample Return Capsule Landin
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PIA03185
| Title |
Sample Return Capsule Landing (Artist's Concept) |
| Original Caption Released with Image |
Artist's rendering of the Stardust capsule's return to Earth. The Stardust spacecraft will bring back samples of interstellar dust, including recently discovered dust streaming into our Solar System from the direction of Sagittarius. |
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