Exploring The Universe

Credits: NASA - {Astronomy Picture of the Day}

[livingforstars]

Globular Cluster M3 - July 19th, 1998.

"This huge ball of stars predates our Sun. Long before mankind evolved, before dinosaurs roamed, and even before our Earth existed, ancient globs of stars condensed and orbited a young Milky Way galaxy. Of the 250 or so globular clusters that survive today, M3 is one of the largest and brightest, easily visible in the northern hemisphere with binoculars. M3 contains about half a million stars, most of which are old and red. The existence of young blue stars in M3 once posed a mystery, but these blue stragglers are now thought to form via stellar interactions."

[livingforstars]

Rockets and Robert Goddard - July 18th, 1998.

"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 spaceflight. 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."

[livingforstars]

Hyakutake: Stars Through A Comet's Tail - July 17th, 1998.

"Comets are cosmic icebergs. They follow very elongated orbits which carry them from the frozen, remote outer reaches of the Solar System, to close encounters with the Sun. Heated by sunlight, they slough off layers of material as gas and dust, forming their characteristic awe-inspiring comas (heads) and tails. In the spring of 1996, Comet Hyakutake inspired Arizona photographers Rick Scott and Joe Orman to take this picture, showing faint stars near the constellation Ursa Minor (the Little Dipper) shining through the comet's long, graceful tail. Blown by the solar wind, comet tails generally point away from the Sun."

[livingforstars]

X-Ray Triple Jet - July 16th, 1998.

"Recorded on July 7th, 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 onboard the orbiting Yohkoh observatory. They have a "negative" colour scheme, the darker colours 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 was approaching the active part of its 11 year cycle, similar single jets were seen every week or so. But the appearance of these three widely separated jets at once was considered an unlikely coincidence and was fueling speculations about their origins."

[livingforstars]

Ghost Galaxy NGC 2915 - July 15th, 1998.

"How do you find a nearly invisible galaxy? Pictured above is the blue compact dwarf (BCD) galaxy NGC 2915. In visible light, shown above in yellow, this galaxy appears to be a normal dwarf galaxy, as indicated by the yellow smudge in the image center. Yet when imaged in a very specific colour, shown in blue, a whole spiral galaxy appears. This specific colour is in the radio band and is preferentially emitted by neutral hydrogen atoms. Much about BCD galaxies remains mysterious, such as how the neutral hydrogen obtained its shape, what drives current star formation, and why there is so much dark matter. NGC 2915 is located at the relatively nearby distance of 15 million light-years - just outside our Local Group of Galaxies."

[livingforstars]

At Work on Mars - July 14th, 1998.

"To learn about the history of Mars, just ask the rocks. In 1997, that's exactly what the robot rover Sojourner did. Sojourner can be seen above, analysing a rock nicknamed Moe, trying to discern its past. One significant discovery of the Mars Pathfinder mission was that of conglomerate rocks, indicating the presence of running water in the past. Such water, in turn, indicates that Mars was much more like watery Earth in the distant past. Visible in the foreground of this colour-enhanced mosaic is part of the Sagan Memorial Station, while a hill nicknamed one of the "Twin Peaks" is visible about a kilometer in the distance."

[livingforstars]

GRB 980703: A Reassuring Redshift - July 13th, 1998.

"In the old days, during 1997, astronomers had little idea of the true distance to gamma-ray bursts. Did these enigmatic explosions occur in our outer galaxy, or in the outer Universe? In May, 1997, a first telling distance measure was made - GRB 970508 showed an absorption line with a redshift of about 0.8 - indicating that this gamma-ray burst (GRB) was an enormous distance away. Skeptics, however, are not always convinced by an unrepeated measurement. Since then, though, other tantalising coincidences had occurred: GRB 971214 occurred unusually near a galaxy with the enormous redshift of 3.4, and GRB 980425 occurred unusually near a low-redshift supernova. Skeptics were intrigued. The potentially definitive implications of the above-pictured optical transient might impress even the cautious. GRB 980703's optical transient shows a well-measured redshift from both an absorption line and an emission line: 0.97. The above negative highlights the uncommon transient source with the label "OT", while letters designate common comparison stars."

[livingforstars]

Asteroid Gaspra's Best Face - July 12th, 1998.

"Asteroid 951 Gaspra is a huge rock tumbling in space. Gaspra became one of the best-studied asteroids in 1991 when the spacecraft Galileo flew by. In the above photograph, subtle colour variations have been exaggerated to highlight changes in reflectivity, surface structure and composition. Gaspra is about 20 kilometers long and orbits the Sun in the main asteroid belt between Mars and Jupiter."

[livingforstars]

M64: The Sleeping Beauty Galaxy - July 11th, 1998.

"The Sleeping Beauty galaxy may appear peaceful at first sight, but it is actually tossing and turning. In an unexpected twist, observations showed that the center of this photogenic galaxy is rotating in the opposite direction than the outer regions! Stranger still - there is a middle region where the stars rotate in the opposite direction from the surrounding dust and gas. The fascinating internal motions of M64, also cataloged as NGC 4826, are thought to be the result of a collision between a small galaxy and a large galaxy where the resultant mix has not yet settled down."

[livingforstars]

NGC 1531/2: Interacting Galaxies - July 10th, 1998.

"This dramatic image of an interacting pair of galaxies was made using the 1.5 meter telescope at the Cerro Tololo Inter-American Observatory near La Serena, Chile. NGC 1531 is the background galaxy with a bright core, just above the center, and NGC 1532 is the foreground spiral galaxy laced with dust lanes. The pair is about 70 million light-years away in the southern constellation Eridanus. These galaxies lie close enough together so that each feels the influence of the other's gravity. The gravitational tug-of-war has triggered star formation in the foreground spiral as evidenced by the young, bright blue star clusters along the edge of the front spiral arm. Though the spiral galaxy in this pair is viewed nearly edge-on, astronomers believe the system is similar to the face-on spiral and companion known as M51, the Whirlpool Galaxy."

[livingforstars]

Hale-Bopp: The Crowd Pleaser Comet - July 9th, 1998.

"In 1997, the bright Comet Hale-Bopp may have become the most viewed comet in history - visible even to casual sky-watchers in light polluted cities around the globe. In this picture, taken by photographer Joe Orman on the evening of May 8th, 1997, Hale-Bopp easily competes with near twilight skies and a shining, over-exposed, crescent Moon above Mobile, Arizona, USA. Where did Hale-Bopp go? Still being visible to telescopic observers in the southern hemisphere, the comet was outbound, presently about 537 million miles from the Sun. (Jupiter orbits at about 480 million miles.) The long lead time provided by the early discovery of Comet Hale-Bopp allowed extensive observing campaigns, producing a bonanza of information about this primordial chunk of our Solar System."

[livingforstars]

Mysterious Pluto and Charon - July 8th, 1998.

"Pluto used to be the only planet in our Solar System unphotographed by a passing spacecraft. Distant Pluto and its moon Charon therefore remained somewhat mysterious. In addition to direct imaging by the Hubble Space Telescope, careful tracking of brightness changes that occur as each object eclipses the other allowed astronomers to build up the above black and white surface maps. These maps depict the face of Pluto (left) that always faces Charon, and the face of Charon that always faces away from Pluto. The rectangular pixels are an artifact of the mapping software. The Pluto-Kuiper Express mission was tentatively planned for launch in 2003 and would encounter Pluto around the year 2012."

[livingforstars]

M8: The Lagoon Nebula - July 7th, 1998.

"The bright Lagoon Nebula is home to a diverse array of astronomical objects. Particularly interesting sources include a bright open cluster of stars and several energetic star-forming regions. The general red glow is caused by luminous hydrogen gas, while the dark filaments are caused by absorption by dense lanes of dust. The Lagoon Nebula, also known as M8 and NGC 6523, lies about 5000 light-years away. It can be located with binoculars in the constellation of Sagittarius, spanning a region over three times the diameter of a full Moon."

[livingforstars]

Sizzling Io - July 6th, 1998.

"What's cooking on Io? This active moon of Jupiter is marked with volcanoes spewing lava that is hotter than any lava on Earth. Above is a high resolution colour-enhanced image composed of the most active surface in our Solar System. Features as small as three kilometers are visible. Sulfur compounds cause many of Io's unusual colours, while darker regions are likely composed of silicate rock."

[livingforstars]

Apollo 15's Home on the Moon - July 5th, 1998.

"Could you ever call this place home? The lunar module shown above, named "Falcon," served as home for Apollo 15 astronauts David Scott and James Irwin during their stay on the Moon in July and August of 1971. Meanwhile, astronaut Alfred Worden circled in the command module overhead. Harsh sunlight on the grey lunar surface lends the image an eerie quality, while the Lunar Apennine Mountains frame the background. Mount Hadley Delta is visible on the right. Visible in the foreground are tracks from the first Lunar Roving Vehicle, an electric car which enabled the astronauts to explore extended areas on the lunar surface. Apollo 15 confirmed that most lunar surface features were created by impacts. Rocks returned by the Apollo 15 crew included green glasses whose formation mechanism was unclear."

[livingforstars]

The Firework Nebula - July 4th, 1998.

"Imaged by the WIYN Telescope, the Firework Nebula is the result of a type of stellar explosion called a nova. In a nova, a nuclear detonation on the surface of a compact white dwarf star blasts away material that has been dumped on its surface by a companion star. Also known as GK Persei, or Nova Persei, this nova became one of the brightest stars in the night sky during the year of 1901. As it faded, astronomers could see an expanding shell of gas that eventually became this spectacular nebula. While not exactly predictable, GK Per undergoes minor outbursts every three or four years."

[livingforstars]

Mir Above - July 3rd, 1998.

"Photographed from the approaching Space Shuttle Endeavour, the Mir space station floats above the clouds of planet Earth. Mir's modular construction, bristling with solar panels and antennas, lends it a slightly whimsical, insect-like appearance. Astronaut Andrew Thomas was dropped off at Mir by Endeavour in January, 1998, and picked up by the Space Shuttle Discovery during STS-91, the ninth and last Mir docking mission. Thomas' four and a half month stay culminates the shuttle-Mir program in which seven U.S. astronauts spent a total of 977 days with Russian crews onboard Mir. The experience gained would be applied toward the construction of the International Space Station scheduled to begin with launches in November and December of 1998."