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Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 June 20 Solstice Celebration Credit: SOHO - EIT Consortium, ESA, NASA Explanation: Season's greetings! Today or tomorrow, depending on your time zone, the Sun reaches its northernmost point in planet Earth's sky marking a season change and the first solstice of the year 2004. In celebration, consider this delightfully detailed, brightly colored image of the active Sun. From the EIT instrument onboard the space-based SOHO observatory, the...

Titan and Dione, two of the moons orbiting Saturn, apparently aren't exactly what researchers had previously believed. Photographs taken during a flyby of the Cassini space probe this week may clarify and even overturn long-held assumptions about the surfaces of these satellites, according to researchers at the American Geophysical Union conference taking place in San Francisco this week. Click to view Bright streaks on the surface of Dione, a heavily cratered moon with little atmosphere, have long been believed to be ice, noted Carolyn Porco, imaging team leader for the Cassini project from the Space Science Institute in Boulder....

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 July 1 NGC 7331: A Galaxy So Inclined Credit: M. Regan (STScI) et al., JPL, Caltech, NASA Explanation: If our own Milky Way galaxy were 50 million light-years away with its disk inclined slightly to our line of sight, it would look a lot like large spiral galaxy NGC 7331. In fact, seen here in a false-color infrared image from the Spitzer Space Telescope, NGC 7331 is...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 August 9 The Dark River to Antares Credit & Copyright: Loke Kun Tan (StarryScapes) Explanation: Connecting the Pipe Nebula to the bright star Antares is a flowing dark cloud nicknamed the Dark River. The murkiness of the Dark River is caused by absorption of background starlight by dust, although the nebula contains mostly hydrogen and molecular gas. Antares, the brightest star in the frame, is embedded in...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 July 24 A String Of Pearls Credit H. Weaver (JHU), T. Smith (STScI), NASA Explanation: Comet Shoemaker-Levy 9, named after its co-discoverers, was often referred to as the "string of pearls" comet. It is famous for its suggestive appearance as well as its collision with the planet Jupiter! The comet's original single nucleus was torn to pieces by Jupiter's strong gravity during a close encounter with the...

Lakes on Saturn’s moon Titan don’t do the wave very well. Radar images from NASA’s Cassini spacecraft show glassy smooth surfaces, even on bodies like Ligeia Mare, a large sea roughly 400 kilometers (250 miles) wide. There are patterns on the shoreline of the southern hemisphere's Ontario Lacus that might be from waves, but the features aren’t definitive. Winds haven’t been too high on Titan since Cassini first arrived in Saturn's system in 2004, so the lack of waves is odd but understandable. The ESA’s Huygens probe sent back amazing surface images, including snapshots of delta-looking features, when it made...

LOS ANGELES - The international Cassini spacecraft has spotted what appears to be an ice volcano on Saturn's planet-size moon, a finding that may help explain the source of Titan's thick atmosphere. Infrared images snapped by the orbiting Cassini reveal a 20-mile-wide dome that appears to be a cryovolcano, a volcanic-like vent that spews forth ice instead of lava. Scientists theorize the volcano at one time spat out icy plumes that released methane into Titan's atmosphere. The findings appear in Thursday's issue of the journal Nature. Titan is the only moon in the solar system that has a significant atmosphere...

SPOKANE, Wash. - David Atkinson spent 18 years designing an experiment for the unmanned space mission to Saturn. Now some pieces of it are lost in space. Someone forgot to turn on the instrument Atkinson needed to measure the winds on Saturn's largest moon. "The story is actually fairly gruesome," the University of Idaho scientist said in an e-mail from Germany, the headquarters of the European Space Agency. "It was human error — the command to turn the instrument on was forgotten." The mission to study Saturn and its moons was launched in 1997 from Cape Canaveral, Fla., a...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 August 30 Announcing Comet C/2003 K4 (LINEAR) Credit & Copyright: Mike Holloway Explanation: A comet discovered last year has brightened unexpectedly and now may become visible to the unaided eye within the next month. Designated Comet C/2003 K4 (LINEAR), the comet was discovered in 2003 May by project LINEAR. Many reports already place the comet as brighter than magnitude 7, meaning that it can now be seen...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 April 3 A Mystery In Gamma Rays Credit: N. Gehrels, D. Macomb, D. Bertsch, D. Thompson, R. Hartman (GSFC), EGRET, NASA Explanation: Gamma rays are the most energetic form of light, packing a million or more times the energy of visible light photons. If you could see gamma rays, the familiar skyscape of steady stars would be replaced by some of the most bizarre objects known to...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 October 28 Tantalizing Titan Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: Normally hidden by a thick, hazy atmosphere, tantalizing features on Titan's surface appear in this false-color view. The image was recorded as the Cassini spacecraft approached its first close flyby of Saturn's smog-shrouded moon on October 26. Here, red and green colors represent specific infrared wavelengths absorbed by Titan's atmospheric methane while bright and...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 February 28 POX 186: Not So Long Ago Credit: Michael Corbin (CSC/STScI), William Vacca (MPE), NASA Explanation: Not so long ago and not so far, far away, a galaxy was born. Seen in this Hubble Space Telescope image, the island universe of stars, gas, and dust cataloged as POX 186 is a mere 68 million light-years distant toward an uncrowded region in the constellation Virgo. POX 186...

Washington: A US-European space probe that will start orbiting Saturn this month has already shown "spectacular" images of the planet's crater-pocked Phoebe moon, scientists said on Monday. The Cassini-Huygens probe, which was launched on October 15, 1997, is to start orbiting Saturn on June 30. It passed within 2068 kilometres of Phoebe on Friday, the National Aeronautics and Space Administration said. Cassini-Huygens is a $US3 billion ($A4.31 billion) joint mission between NASA and the European Space Agency (ESA). "What spectacular images. So sharp and clear and showing a great many geological features, large and small," said Carolyn Porco, Cassini Imaging...

A giant ridge girdles Saturn's satellite Iapetus - making the moon look like a walnut shell - reveal the latest images from the Cassini-Huygens mission. Scientists are at a loss to explain the feature, which is unique in the solar system. The Cassini spacecraft flew past Iapetus on New Year's Day, approaching to within 123,400 kilometres of the moon's surface. Its camera captured the most detailed images of Iapetus yet, revealing wisps of dark material and two-tone craters. But the ridge is the greatest surprise to scientists. It extends for at least 1300 km, following the equator exactly. In...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 April 18 Stellar Spectral Types: OBAFGKM Credit & Copyright: KPNO 0.9-m Telescope, AURA, NOAO, NSF Explanation: Astronomers divide stars into different spectral types. First started in the 1800s, the spectral type was originally meant to classify the strength of hydrogen absorption lines. A few types that best describe the temperature of the star remain in use today. The seven main spectral types OBAFGKM are shown above with...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 April 5 A Berry Bowl of Martian Spherules Credit: Mars Exploration Rover Mission, JPL, NASA Explanation: How were these unusual Martian spherules created? Thousands of unusual gray spherules, made of iron and rock but dubbed blueberries, were found embedded in and surrounding rocks near the landing site of the robot Opportunity rover on Mars. To help investigate their origin, Opportunity found a surface dubbed the Berry Bowl...

Physicists of the University of Granada and the University of Valencia (Spain) have developed a proceeding to analyse specific data sent by the Huygens probe from Titan, the largest moon of Saturn, proving "in an unequivocal way" that there is natural electric activity in its atmosphere. The scientific community thinks that there is a higher probability that organic molecules precursors to life could form in those planets or satellites which have an atmosphere with electric storms. Researcher Juan Antonio Morente, from the Department of Applied Physics of the University of Granada, has informed the SINC that Titan is considered to...

CHARLESTON, W.Va. -- West Virginia's Robert C. Byrd Green Bank Telescope was the first to trace the faint radio signal of the European Space Agency's Huygens landing craft as it descended through the dense atmosphere of Saturn's largest moon and approached its never-seen, ice-strewn surface. The signal early Friday let scientists know the probe was "alive." "As the time approached when we expected to detect its signal, our group was very tense," said Sami Asmar, a radio scientist with the Jet Propulsion Laboratory in Pasadena, Calif., which designed and built the Cassini orbiter that took Huygens on its seven-year journey...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 August 5 Emission Nebula IC 1396 Credit & Copyright: Richard Crisp Explanation: Sprawling across hundreds of light-years, emission nebula IC 1396 mixes glowing cosmic gas and dark dust clouds. Stars are forming in this area, only about 3,000 light-years from Earth. This particularly colorful view of the region is a composite of digital images recorded through narrow band filters. The filters actually block out most of the...

IMAGES OF TITAN: Icy pebbles litter the satellite's surface (top); the rounding of the pebbles is evidence of erosion, possibly caused by liquid flow. During its descent, the Huygens probe saw an icy ridge about 100 meters high and a network of riverlike channels (bottom). On January 14 a saucer-shaped spacecraft weighing 320 kilograms made the "splat" heard round the solar system. The successful landing of the Huygens probe on Titan, Saturn's large and mysterious satellite, delighted planetary scientists, who thrilled at the probe's images of icy ridges and dark, riverlike channels. In the following weeks, though, the euphoria turned...