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Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
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1999 July 12

A Delta Rocket Launches
Credit:
KSC, NASA

A Delta rocket is pictured launching NASA's FUSE satellite earlier this month. In use since 1960, Delta rockets have been launched successfully over 250 times. Scientific satellites placed into orbit by a Delta rocket include IUE, COBE, ROSAT, EUVE, WIND, and RXTE. Commercial launches include Iridium. Delta launches have placed Navstar Global Positioning System satellites into orbit. Delta rockets are manufactured for the US Air Force and NASA by Boeing.
1999 July 13

The Flame Nebula in Infrared
Credit:
2MASS Collaboration, U. Mass., IPAC

What lights up the Flame Nebula? Fifteen hundred light years away towards the constellation of Orion lies a nebula which, from its glow and dark dust lanes, appears like a billowing fire. But fire, the rapid acquisition of oxygen, is not what makes this Flame glow. Rather the bright star Alnitak, the easternmost star in the Belt of Orion visible to the nebula's right, shines energetic light into the Flame that knocks electrons away from the great clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. The above false-color picture of the Flame Nebula (NGC 2024) was taken in infrared light, where a young star cluster becomes visible. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula.
1999 July 14

Moon, Planets, and Rocket Trails
Credit and Copyright:
Joe Orman

Are you an early riser? Over the last month or so, the bright planets Jupiter and Saturn have come to adorn eastern skies before sunrise. In fact, astrophotographer Joe Orman anticipated that an early bird's reward for looking east on June 10 would be this pleasing arrangement of Jupiter (top right), a crescent Moon, and Saturn (near center), but he was surprised to also find these eerie, iridescent clouds wafting through the pre-dawn sky over suburban Phoenix, Arizona, USA. The clouds turned out to be rocket engine trails from defense missile tests at the range in White Sands, New Mexico ... about 300 miles away. While the Moon's phase is just past new moon, gone now from the pre-dawn horizon, brilliant Jupiter and Saturn can still be seen high toward the southeast in the constellation Aries.
1999 July 15

Charles P. Conrad, Jr. 1930-1999
Credit:
Courtesy NASA

Known for his sense of humor and infectious grin, Charles P. "Pete" Conrad, as commander of the Apollo 12 mission, was the third person to walk on the moon. Not a tall man, Conrad stepped down onto the lunar surface in November of 1969 and gleefully commented, "Whoopie! Man, that may have been a small one for Neil, but that's a long one for me." Born June 2nd, 1930 in Philadelphia, Pennsylvania, he graduated from Princeton University in 1953 and went on to become a Navy test pilot. Selected as a NASA astronaut in 1962, Conrad is seen here in 1965 during a suiting up activity in preparation for his first space flight - the endurance record setting Gemini 5 mission. His final space flight was to Skylab in 1973. Tragically, Conrad died from injuries in a motorcycle accident on Thursday, July 8.
1999 July 16

Solar Surfin'
Credit:
Steve Albers, Dennis di Cicco (S&T Magazine), Gary Emerson (E. E. Barnard Obs.)
Copyright: Steve Albers

The sun's corona is a tenuous outer atmosphere composed of streams of energetic charged particles, but it is only easily seen from Earth during a total solar eclipse. For example, this 1991 image of totality from atop Mauna Kea, Hawaii forms a fleeting snapshot of the mysterious corona's beautiful, intricate structures and streams. However in space, instruments can use occulting disks to simulate eclipses and more readily monitor the corona beyond the sun's edge. Combined observations from the space-based SOHO UCVS and shuttle-borne Spartan 201 experiments have recently contributed to a major advance in understanding the high-speed component of the wind of particles in the corona. They reveal evidence for magnetic waves within the corona itself that push solar wind particles along, like an ocean wave gives a surfer a ride. Surprisingly, heavier charged particles can surf the magnetic waves faster - oxygen ions were found to achieve speeds of up to 500 miles per second, faster than the lighter hydrogen ions which make up most of the solar wind.
1999 July 17

Rockets and Robert Goddard
Credit:
Esther Goddard, Courtesy NASA/Goddard Space Flight Center

Robert H. Goddard, one of the founding fathers of modern rocketry, was born in Worcester Massachusetts in 1882. As a 16 year old, Goddard read H.G. Wells' science fiction classic "War Of The Worlds" and dreamed of space flight. By 1926 he had designed, built, and launched the world's first liquid fuel rocket. During his career he was ridiculed by the press for suggesting that rockets could be flown to the Moon, but he kept up his experiments in rocketry supported in part by the Smithsonian Institution and championed by Charles Lindbergh. Pictured above in 1937 in the desert near Roswell, New Mexico, Goddard examines a nose cone and parachute from one of his test rockets. Widely recognized as a gifted experimenter and engineering genius, his rockets were many years ahead of their time. He died in 1945 holding over 200 patents in rocket technology. A liquid fuel rocket constructed on principles developed by Goddard landed humans on the Moon in 1969.
1999 July 18

Jupiter from Voyager
Credit:
Voyager 1, NASA

This picture of the planet Jupiter was taken by the Voyager 1 spacecraft as it passed the planet in 1979. Jupiter, a gas giant planet with no solid surface, is the largest planet in the Solar System and is made mostly of the hydrogen and helium. Clearly visible in the above photo is the Great Red Spot, a giant, hurricane-like storm system that rotates with the clouds of Jupiter. It is so large three complete Earths could fit inside it. Astronomers have recorded this giant storm on Jupiter for over 300 years.
1999 July 19

NGC 3372: The Great Nebula in Carina
Credit:
K. Weis & W. J. Duschl (ITA, U. Heidelberg)

In one of the brightest parts of the Milky Way lies a nebula where some of the oddest things occur. NGC 3372, known as the Great Nebula in Carina, is home to massive stars and changing nebula. Eta Carina, the most energetic star in the nebula was one of the brightest stars in the sky in the 1830s, but then faded dramatically. The Keyhole Nebula, visible near the center, houses several of the most massive stars known and has also changed its appearance. The Carina Nebula is about 7000 light-years away in the constellation of Carina. The CTIO Curtis-Schmidt Telescope in Chile, South America took the above photograph. Eta Carina might explode in a dramatic supernova within the next thousand years, and has even flared in brightness over just the past two years.
1999 July 20

Moon Rocket
Credit:
NASA

On July 20, 1969, only four days after leaving planet Earth 250,000 miles behind them, Apollo 11 astronauts landed on the moon - the first humans to reach another celestial body. But the Saturn V rocket which took them there actually "began" the journey two months before traveling at a blinding speed of one mile per hour. Seen here in a dramatic aerial view, the giant moon rocket rides on top of a slow moving crawler-transporter vehicle toward Kennedy Space Center's launch complex 39 pad A. The NASA History Office's new Apollo web site celebrates the 30th anniversary of the first moon landing with this and other images, documents, and collections of links commemorating this profound achievement and the people who made it possible.
1999 July 21

Galactic Supernova Remnant IC 443
Credit:
2MASS Collaboration, U. Mass., IPAC

About 8000 years ago, a star in our Galaxy exploded. Ancient humans might have noticed the supernova as a temporary star, but modern humans can see the expanding shell of gas even today. In the above false-color infrared image of supernova remnant IC 443, blue denotes expanding gas where emission is dominated by excited iron atoms. Of particular interest, though, are the wisps of IC 443 colored red, as they are impacting an otherwise normal molecular cloud. Here emission from shock-excited molecular hydrogen is allowing astronomers to study how fast moving supernova gas affects star formation in the cloud. Additionally, astronomers theorize that the impact accelerates some particles to velocities near the speed of light. The horizontal line across the image is not part of the nebula.
1999 July 22

Cosmic Collisions in a Galaxy Cluster
Credit:
P. van Dokkum, M. Franx (U. Groningen/ U. Leiden), ESA, NASA

Hundreds of galaxies appear as faint smudges of light in this Hubble Space Telescope picture of galaxy cluster MS1054-03. Eight billion light-years away, the cluster is among the most distant known clusters of galaxies and is now reported to contain the largest number of colliding galaxies ever found in a cluster. Examples of these truly cosmic collisions are shown in the insets at the right. Disrupted by gravitational effects, the colliding galaxies are thought to merge over a billion years or so to form larger galaxies - a theory of galaxy formation which seems to be borne out by these results. Though galaxy collisions appear to have occurred much more frequently in the distant, early Universe, they are still seen to happen in the nearby, "close-to-present" Universe.
1999 July 23

A Martian Valley
Credit:
Malin Space Science Systems, MGS, JPL, NASA

This tantalizing close-up detail of a network of martian valleys was recorded from orbit this April by Mars Global Surveyor's camera. Water may once have flowed here but now sand dunes stripe the windswept valley floor. The Mars Global Surveyor spacecraft arrived in orbit in September of 1997 and has been exploring the red planet since. Three other spacecraft, Mars Climate Orbiter, Mars Polar Lander, and Nozomi are presently en route.
1999 July 24

Infrared Saturn
Credit:
E. Karkoschka (University of Arizona), HST, NASA

This delightfully detailed false color image of Saturn was earmarked to celebrate the 8th anniversary of the orbiting Hubble Space Telescope. The picture is a combination of three images taken in January 1998 and shows the lovely ringed planet in reflected infrared light. Different colors indicated varying heights and compositions of cloud layers generally thought to consist of ammonia ice crystals. The eye-catching rings cast a shadow on Saturn's upper hemisphere, while the bright stripe seen within the left portion of the shadow is infrared sunlight streaming through the large gap in the rings known as the Cassini Division. Two of Saturn's many moons have also put in an appearance, Tethys just beyond the planet's disk at the upper right, and Dione at the lower left.
1999 July 25

The Cygnus Loop
Credit:
J. Hester (ASU), NASA

The shockwave from a 20,000 year-old supernova in the constellation of Cygnus supernova explosion is still expanding into interstellar space. The collision of this fast moving wall of gas with a stationary cloud has heated it causing it to glow in visible as well as high energy radiation, producing the nebula known as the Cygnus Loop (NGC 6960/95). The nebula is located about 2500 light-years away. The colors used here indicate emission from different kinds of atoms excited by the shock: oxygen-blue, sulfur-red, and hydrogen-green. This picture was taken with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope.
1999 July 26

Noctilucent Clouds
Credit & Copyright:
Pekka Parviainen (NCWG/U. Colorado)

Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above. Under usual circumstances, a pretty sunset might be visible, but unusual noctilucent clouds float so high up they can be seen well after dark. Pictured above, a network of noctilucent clouds casts a colorful but eerie glow visible above the dark. Although noctilucent clouds are thought to be composed of small ice-coated particles, much remains unknown about them.
1999 July 27

Chandra X-ray Telescope
Credit:
NASA

Wrapped in protective blankets and mounted atop an Inertial Upper Stage (IUS) rocket, the Chandra X-ray Telescope is seen in this wide-angle view before launch snuggled into the space shuttle Columbia's payload bay. Columbia's crew released the telescope, named in honor of the late Nobel Laureate Subrahmanyan Chandrasekhar, into orbit on Friday, July 23rd, where it is now undergoing check out and activation of its scientific instruments. To help realize its enormous potential for exploration of the distant Universe at X-ray energies, controllers will perform a series of firings in the coming days which will eventually boost the 10,000 pound telescope into a highly ecentric orbit. In fact, the final working orbit for Chandra will range from a close point of about 6,200 miles out to 87,000 miles or one third of the distance to the Moon. The elongated orbit will carry Chandra's sensitive X-ray detectors beyond interference caused by the Earth's radiation belts allowing Chandra to make about 55 hours of continuous observations per orbit. The shuttle Colombia, commanded by Eileen Collins is scheduled to land this evening at 11:20 pm EDT at Kennedy Space Center.
July 28 1999

Asia at Night
Credit & Copyright:
DMSP Digital Archive, NGDC, NOAA

This is what Asia looks like at night! Can you find your favorite Asian city? Although not all of Asia is shown, city lights might make this task possible. The above picture is actually a composite of over 200 images made by satellites orbiting the Earth. Scans were made by the USAF Defense Meteorological Satellite Program (DMSP) Operational Linescan System. The DMSP satellites continue to help in the understanding and prediction of weather phenomena as well as provide key information about population patterns, city light levels, and even rural forest fires.
1999 July 29

Hydrogen Blob N88A in the Small Magellanic Cloud
Credit:
M. Heydari-Malayeri (Paris Observatory) et al., WFPC2, HST, ESA, NASA

The bright blob of hydrogen gas cataloged as N88A is seen at the right. It measures a mere 3 light years across. Emerging from the cool, dusty interstellar medium in a nearby irregular galaxy known as the Small Magellanic Cloud, N88A hides hot young stars at its core. The false-color Hubble Space Telescope image was recorded in the characteristic "H-alpha" light emitted by hydrogen atoms as they are ionized by the young star's energetic ultraviolet light and then recombine. Other regions of ionized hydrogen (H II regions) which surround new born stars can be over a thousand light-years across but astronomers now recognize that these small ionized hydrogen blobs contain some of the most massive stars known.
1999 July 30

The Sea of Tranquillity: 5 Seconds To Impact
Credit:
NASA

On February 20th, 1965, the Ranger 8 spacecraft crashed into the Moon. Rapidly transmitting a series of pictures to ground controllers, its camera recorded this one at an altitude of about 11 kilometers, 5 seconds before impacting the lunar surface. Two kilometers across, with 4 meter sized objects visible, the picture is of an area in the Sea of Tranquillity north of the Apollo 11 landing site. The Ranger spacecraft represented the first attempts by the US to obtain high resolution photos of the Moon, flying a crash course toward selected areas and sending back pictures until the moment of impact. Tomorrow, another spacecraft will be intentionally crashed into the Moon. Its very successful mission in lunar orbit complete, the Lunar Prospector is scheduled to crash into a crater near the Moon's south pole in an effort to confirm the presence of water-ice by studying the impact's debris cloud.
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1999 July 31

X-Ray Triple Jet
Credit:
ISAS, Yohkoh Project, SXT Group

Recorded on July 7, 1998, this animation using X-ray images of the Sun shows an amazing event - three nearly simultaneous jets connected with solar active regions. The two frames were taken several hours apart by the Soft X-ray Telescope on board the orbiting Yohkoh observatory. They have a "negative" color scheme, the darker colors representing more intense X-rays from the corona and active regions on the solar surface. The pictures clearly show two curving jets of X-ray hot plasma appearing above the solar equator and one below. A sharp vertical stripe near the jet above center is a digital blemish while the overall shift of the image is due to solar rotation. As the Sun is now approaching the active part of its 11 year cycle, numerous single jets have been seen. But the appearance of these three widely separated jets at once is considered an unlikely coincidence and has fueled current speculations about their origins.
1999 August 1

Walking in Space
Credit:
James McDivitt, Gemini 4, NASA

Pictured above is the first american astronaut to walk in space: Edward White. White is seen floating outside the Gemini 4 capsule in 1965. The term spacewalk is deceiving since astronauts do not actually walk - they float - usually without their feet touching anything solid. White was connected to the spaceship only by a thick tether. He carried a Hand-Held Self-Maneuvering Unit which expelled gas allowing him to move around. A maneuvering device is necessary in the free-fall of space since there is nothing (besides the spacecraft) to push off of to guide movements.